William Paul Segars

Journal Article Med Phys · April 2025 BACKGROUND: This Special Report summarizes the 2022, AAPM grand challenge on Truth-based CT image reconstruction. PURPOSE: To provide an objective framework for evaluating CT reconstruction methods using virtual imaging resources consisting of a library of ... Full text Link to item Cite

Virtual imaging trials in medicine: A brief takeaway of the lessons from the first international summit.

Journal Article Medical physics · March 2025 BackgroundThe rapid advancement of medical technologies presents significant challenges for researchers and practitioners. While traditional clinical trials remain the gold standard, they are often limited by high costs, lengthy durations, and eth ... Full text Open Access Cite

The potential of photon-counting CT for the improved precision of lung nodule radiomics.

Journal Article Phys Med Biol · January 27, 2025 Objective.Lung nodule appearance may provide prognostic information, as the presence of spiculation increases the suspicion of a nodule being cancerous. Spiculations can be quantified using morphological radiomics features extracted from CT images. Radiomi ... Full text Link to item Cite

Photon-Counting CT Effects on Sensitivity for Liver Lesion Detection: A Reader Study Using Virtual Imaging.

Journal Article Radiology · January 2025 Background Detection of hepatic metastases at CT is a daily task in radiology departments that influences medical and surgical treatment strategies for oncology patients. Purpose To compare simulated photon-counting CT (PCCT) with energy-integrating detect ... Full text Link to item Cite

Virtual Lung Screening Trial (VLST): An In Silico Replica of the National Lung Screening Trial for Lung Cancer Detection.

Journal Article ArXiv · October 28, 2024 IMPORTANCE: Clinical imaging trials are crucial for evaluation of medical innovations, but the process is inefficient, expensive, and ethically-constrained. Virtual imaging trial (VIT) approach addresses these limitations by emulating the components of a c ... Link to item Cite

Modeling the effect of patient size on cerebral perfusion during veno-arterial extracorporeal membrane oxygenation.

Journal Article Perfusion · October 2024 INTRODUCTION: A well-known complication of veno-arterial extracorporeal membrane oxygenation (VA ECMO) is differential hypoxia, in which poorly-oxygenated blood ejected from the left ventricle mixes with and displaces well-oxygenated blood from the circuit ... Full text Link to item Cite

Simulating cardiac fluid dynamics in the human heart.

Journal Article PNAS Nexus · October 2024 Cardiac fluid dynamics fundamentally involves interactions between complex blood flows and the structural deformations of the muscular heart walls and the thin valve leaflets. There has been longstanding scientific, engineering, and medical interest in cre ... Full text Link to item Cite

Estimation of threshold thickness of residual normal tissue in lung dysfunction detectable by dynamic chest radiography: A virtual imaging trial.

Journal Article Med Phys · September 2024 BACKGROUND: Dynamic chest radiography (DCR) is a recently developed functional x-ray imaging technique that detects pulmonary ventilation impairment as a decrease in changes in lung density during respiration. However, the diagnostic performance of DCR is ... Full text Link to item Cite

Photon-counting computed tomography versus energy-integrating computed tomography for detection of small liver lesions: comparison using a virtual framework imaging.

Journal Article J Med Imaging (Bellingham) · September 2024 PURPOSE: Photon-counting computed tomography (PCCT) has the potential to provide superior image quality to energy-integrating CT (EICT). We objectively compare PCCT to EICT for liver lesion detection. APPROACH: Fifty anthropomorphic, computational phantoms ... Full text Link to item Cite

CardSegNet: An adaptive hybrid CNN-vision transformer model for heart region segmentation in cardiac MRI.

Journal Article Comput Med Imaging Graph · July 2024 Cardiovascular MRI (CMRI) is a non-invasive imaging technique adopted for assessing the blood circulatory system's structure and function. Precise image segmentation is required to measure cardiac parameters and diagnose abnormalities through CMRI data. Be ... Full text Link to item Cite

A systematic assessment and optimization of photon-counting CT for lung density quantifications.

Journal Article Med Phys · April 2024 BACKGROUND: Photon-counting computed tomography (PCCT) has recently emerged into clinical use; however, its optimum imaging protocols and added benefits remains unknown in terms of providing more accurate lung density quantification compared to energy-inte ... Full text Open Access Link to item Cite

Development of physiologically-informed computational coronary artery plaques for use in virtual imaging trials.

Journal Article Med Phys · March 2024 BACKGROUND: As a leading cause of death, worldwide, cardiovascular disease is of great clinical importance. Among cardiovascular diseases, coronary artery disease (CAD) is a key contributor, and it is the attributed cause of death for 10% of all deaths ann ... Full text Link to item Cite

Quantitative accuracy of lung function measurement using parametric response mapping: A virtual imaging study.

Conference Proc SPIE Int Soc Opt Eng · February 2024 Parametric response mapping (PRM) is a voxel-based quantitative CT imaging biomarker that measures the severity of chronic obstructive pulmonary disease (COPD) by analyzing both inspiratory and expiratory CT scans. Although PRM-derived measurements have be ... Full text Link to item Cite

Development and Application of a Virtual Imaging Trial Framework for Longitudinal Quantification of Emphysema in CT.

Journal Article Proc SPIE Int Soc Opt Eng · February 2024 Pulmonary emphysema is a progressive lung disease that requires accurate evaluation for optimal management. This task, possible using quantitative CT, is particularly challenging as scanner and patient attributes change over time, negatively impacting the ... Full text Link to item Cite

Virtual NLST: Towards Replicating National Lung Screening Trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Virtual Imaging Trials, known as VITs, provide a computational substitute for clinical trials. These traditional trials tend to be sluggish, costly, and frequently deficient in definitive evidence, all the while subjecting participants to ionizing radiatio ... Full text Cite

Synthesizing heterogeneous lung lesions for virtual imaging trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Virtual imaging trials of malignancies require realistic models of lesions. The purpose of this study was to create hybrid lesion models and associated tool incorporating morphological and textural realism. The developed tool creates a lesion morphology ba ... Full text Cite

Deep learning-based algorithm to segment pediatric and adult lungs from dynamic chest radiography images using virtual patient datasets

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Dynamic chest radiography (DCR) enables the evaluation of lung function based on changes in lung density, lung area, and diaphragm level due to respiration. The need for lung segmentation techniques for sequential chest images is growing. Thus, this study ... Full text Cite

A generic model of semiconductor-based photon-counting detectors for spectral CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Photon-counting CT (PCCT) is an emerging x-ray spectral imaging technology. There are several PCCT prototypes available for clinical and experimental applications. Despite many published results, objective quantitative evaluation of PCCT systems remains ch ... Full text Cite

A CT system-free Approach for Brain CT Perfusion Assessment: Temporal Perfusion Index Estimation

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 Real-time brain perfusion would be highly beneficial to fully leverage interventional procedures such as endovascular thrombectomy in treating ischemic stroke. However, the existing standard of care is constrained due to the absence of intra-operative real ... Full text Cite

Random Walk Small Intestine Models for Virtual Patient Populations

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2024 We develop the XCAT series of phantoms for medical imaging research. The phantoms model different individuals over various ages, heights, and weights, but a current drawback is they do not include small intestine variability. Each phantom has a small intes ... Full text Cite

Surface-based anthropomorphic bone structures for use in high-resolution simulated medical imaging.

Journal Article Phys Med Biol · December 28, 2023 Objective.Virtual imaging trials enable efficient assessment and optimization of medical image devices and techniques via simulation rather than physical studies. These studies require realistic, detailed ground-truth models or phantoms of the relevant ana ... Full text Link to item Cite

Coronary stenosis quantification in cardiac computed tomography angiography: multi-factorial optimization of image quality and radiation dose.

Journal Article J Med Imaging (Bellingham) · November 2023 BACKGROUND: The accuracy and variability of quantification in computed tomography angiography (CTA) are affected by the interplay of imaging parameters and patient attributes. The assessment of these combined effects has been an open engineering challenge. ... Full text Link to item Cite

Emphysema Quantifications With CT Scan: Assessing the Effects of Acquisition Protocols and Imaging Parameters Using Virtual Imaging Trials.

Journal Article Chest · May 2023 BACKGROUND: CT scan has notable potential to quantify the severity and progression of emphysema in patients. Such quantification should ideally reflect the true attributes and pathologic conditions of subjects, not scanner parameters. To achieve such an ob ... Full text Link to item Cite

A systematic assessment of photon-counting CT for bone mineral density and microarchitecture quantifications.

Journal Article Proc SPIE Int Soc Opt Eng · February 2023 Photon-counting CT (PCCT) is an emerging imaging technology with potential improvements in quantification and rendition of micro-structures due to its smaller detector sizes. The aim of this study was to assess the performance of a new PCCT scanner (NAEOTO ... Link to item Cite

Development and Application of a Virtual Imaging Trial framework for Airway Quantifications via CT.

Journal Article Proc SPIE Int Soc Opt Eng · February 2023 Chronic obstructive pulmonary disease (COPD) is one of the top three causes of death worldwide, characterized by emphysema and bronchitis. Airway measurements reflect the severity of bronchitis and other airway-related diseases. Airway structures can be ob ... Full text Link to item Cite

Phase-contrast virtual chest radiography.

Journal Article Proc Natl Acad Sci U S A · January 3, 2023 Respiratory X-ray imaging enhanced by phase contrast has shown improved airway visualization in animal models. Limitations in current X-ray technology have nevertheless hindered clinical translation, leaving the potential clinical impact an open question. ... Full text Link to item Cite

Bone suppression technique for multidirectional dynamic chest radiography: A virtual imaging trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2023 Prediction of pleural invasion in lung cancer is crucial in planning appropriate operating procedures and can be assessed using dynamic chest radiography (DCR). However, this assessment is negatively affected by rib shadows in conventional images. The purp ... Full text Cite

Automatic quality control in computed tomography volumes segmentation using a small set of XCAT as reference images

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2023 Deep learning methods have performed superiorly to segment organs of interest from Computed Tomography images than traditional methods. However, the trained models do not generalize well at the inference phase, and manual validation and correction are not ... Full text Cite

Development of scalable lymphatic system in the 4D XCAT phantom: Application to quantitative evaluation of lymphoma PET segmentations.

Journal Article Med Phys · November 2022 BACKGROUND: Digital anthropomorphic phantoms, such as the 4D extended cardiac-torso (XCAT) phantom, are actively used to develop, optimize, and evaluate a variety of imaging applications, allowing for realistic patient modeling and knowledge of ground trut ... Full text Link to item Cite

S-values for radium-223 and absorbed doses estimates for 223RACL2 using three computational phantoms.

Journal Article Appl Radiat Isot · November 2022 Radium-223 dichloride (223RaCl2), approved by FDA (Food and Drug Administration) in 2013 and in Brazil by ANVISA (Agência Nacional de Vigilância Sanitária) in 2016, offers a new therapeutic option for bone metastases from castration-resistant prostate canc ... Full text Link to item Cite

TransMorph: Transformer for unsupervised medical image registration.

Journal Article Med Image Anal · November 2022 In the last decade, convolutional neural networks (ConvNets) have been a major focus of research in medical image analysis. However, the performances of ConvNets may be limited by a lack of explicit consideration of the long-range spatial relationships in ... Full text Link to item Cite

XCIST-an open access x-ray/CT simulation toolkit.

Journal Article Phys Med Biol · September 28, 2022 Objective. X-ray-based imaging modalities including mammography and computed tomography (CT) are widely used in cancer screening, diagnosis, staging, treatment planning, and therapy response monitoring. Over the past few decades, improvements to these moda ... Full text Link to item Cite

Dose coefficients for organ dosimetry in tomosynthesis imaging of adults and pediatrics across diverse protocols.

Journal Article Med Phys · August 2022 PURPOSE: The gold-standard method for estimation of patient-specific organ doses in digital tomosynthesis (DT) requires protocol-specific Monte Carlo (MC) simulations of radiation transport in anatomically accurate computational phantoms. Although accurate ... Full text Open Access Link to item Cite

Model-based pulse pileup and charge sharing compensation for photon counting detectors: A simulation study.

Journal Article Med Phys · August 2022 PURPOSE: We aim at developing a model-based algorithm that compensates for the effect of both pulse pileup (PP) and charge sharing (CS) and evaluates the performance using computer simulations. METHODS: The proposed PCP algorithm for PP and CS compensation ... Full text Link to item Cite

Quantitative analysis of changes in lung density by dynamic chest radiography in association with CT values: a virtual imaging study and initial clinical corroboration.

Journal Article Radiol Phys Technol · March 2022 Dynamic chest radiography (DCR) identifies pulmonary impairments as decreased changes in radiographic lung density during respiration (Δpixel values), but not as scaled/standardized computed tomography (CT) values. Quantitative analysis correlated with CT ... Full text Link to item Cite

A GPU-accelerated framework for individualized estimation of organ doses in digital tomosynthesis.

Journal Article Med Phys · February 2022 PURPOSE: Estimation of organ doses in digital tomosynthesis (DT) is challenging due to the lack of existing tools that accurately and flexibly model protocol- and view-specific collimations and motion trajectories of the source and detector for a variety o ... Full text Link to item Cite

Corrections to "iPhantom: A Framework for Automated Creation of Individualized Computational Phantoms and its Application to CT Organ Dosimetry".

Journal Article IEEE J Biomed Health Inform · January 2022 In [1], the dose estimation accuracy using the alternative baseline method under modulated tube current was not correctly calculated due to an unintentional simulation error. ... Full text Link to item Cite

Development and Clinical Applications of a Virtual Imaging Framework for Optimizing Photon-counting CT.

Journal Article Proc SPIE Int Soc Opt Eng · 2022 The purpose of this study was to develop a virtual imaging framework that simulates a new photon-counting CT (PCCT) system (NAEOTOM Alpha, Siemens). The PCCT simulator was built upon the DukeSim platform, which generates projection images of computational ... Full text Link to item Cite

Photon-counting CT versus conventional CT for COPD quantifications: intra-scanner optimization and inter-scanner assessments using virtual imaging trials.

Journal Article Proc SPIE Int Soc Opt Eng · 2022 Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease and a major cause of death and disability worldwide. Quantitative CT is a powerful tool to better understand the heterogeneity and severity of this disease. Quantitative CT ... Full text Link to item Cite

Quality or quantity: toward a unified approach for multi-organ segmentation in body CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Organ segmentation of medical images is a key step in virtual imaging trials. However, organ segmentation datasets are limited in in terms of quality (because labels cover only a few organs) and quantity (since case numbers are limited). In this study, we ... Full text Cite

Simulation of the combined effects of charge sharing and pulse pileup in photon-counting CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Photon-counting CT (PCCT) is an emerging CT technology that uses photon-counting detectors (PCDs) to offer better spatial resolution, higher contrast, lower noise, and material-specific imaging as compared to conventional energy-integrating CT. To study th ... Full text Cite

Cardiac CT reconstruction for vendor-neutral virtual imaging trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Cardiac CT imaging is invaluable in a variety of applications including non-invasive assessment of coronary artery calcifications, the ruling out of acute coronary artery syndrome, and the planning of valve replacement procedures. Newer applications includ ... Full text Cite

Optimization of imaging conditions in pediatric dynamic chest radiography: a virtual imaging trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Ventilatory impairment is detected as decreased changes in lung density during respiration in dynamic chest radiography (DCR). The purpose of this study was to determine optimum imaging conditions in pediatric DCR through a virtual imaging trial (VIT). An ... Full text Cite

Virtual versus reality: external validation of COVID-19 classifiers using XCAT phantoms for chest radiography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Many published studies use deep learning models to predict COVID-19 from chest x-ray (CXR) images, often reporting high performances. However, the models do not generalize well on independent external testing. Common limitations include the lack of medical ... Full text Cite

Virtual vs. reality: External validation of COVID-19 classifiers using XCAT phantoms for chest computed tomography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 Research studies of artificial intelligence models in medical imaging have been hampered by poor generalization. This problem has been especially concerning over the last year with numerous applications of deep learning for COVID-19 diagnosis. Virtual imag ... Full text Cite

Optimization of imaging parameters of an investigational photon-counting CT prototype for lung lesion radiomics

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2022 The aim of this study was to evaluate and optimize the imaging parameters of a new dual-source photon-counting CT (PCCT) scanner (NAEOTOM Alpha, Siemens Healthineers) for lung lesion radiomics using virtual imaging trials. Virtual patients (XCAT phantoms) ... Full text Cite

Development of a Population of Digital Anthropomorphic Phantoms with Simulated Acquisitions for use in Deep Learning Improvement of DMSA Quantification and Estimation of Attenuation Maps from Emission Reconstructions in DMSA Pediatric SPECT Imaging

Conference 2022 IEEE NSS/MIC RTSD - IEEE Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference · January 1, 2022 PEDIATRICS have increased tissue radio-sensitivity and longer potential lifespan when compared to adults. Therefore, their risk of developing health problems such as cancer per unit administered activity (AA) is significantly higher than adults [1] , empha ... Full text Cite

Deep learning classification of COVID-19 in chest radiographs: performance and influence of supplemental training.

Journal Article J Med Imaging (Bellingham) · November 2021 Purpose: Accurate classification of COVID-19 in chest radiographs is invaluable to hard-hit pandemic hot spots. Transfer learning techniques for images using well-known convolutional neural networks show promise in addressing this problem. These methods ca ... Full text Open Access Link to item Cite

Correction to: Comparison of 12 surrogates to characterize CT radiation risk across a clinical population.

Journal Article Eur Radiol · October 2021 Full text Link to item Cite

A scanner-specific framework for simulating CT images with tube current modulation.

Journal Article Phys Med Biol · September 13, 2021 Although tube current modulation (TCM) is routinely implemented in modern computed tomography (CT) scans, no existing CT simulator is capable of generating realistic images with TCM. The goal of this study was to develop such a framework to (1) facilitate ... Full text Link to item Cite

Comparison of 12 surrogates to characterize CT radiation risk across a clinical population.

Journal Article Eur Radiol · September 2021 OBJECTIVES: Quantifying radiation burden is essential for justification, optimization, and personalization of CT procedures and can be characterized by a variety of risk surrogates inducing different radiological risk reflections. This study compared how t ... Full text Open Access Link to item Cite

iPhantom: A Framework for Automated Creation of Individualized Computational Phantoms and Its Application to CT Organ Dosimetry.

Journal Article IEEE J Biomed Health Inform · August 2021 OBJECTIVE: This study aims to develop and validate a novel framework, iPhantom, for automated creation of patient-specific phantoms or "digital-twins (DT)" using patient medical images. The framework is applied to assess radiation dose to radiosensitive or ... Full text Link to item Cite

Generation of annotated multimodal ground truth datasets for abdominal medical image registration.

Journal Article International journal of computer assisted radiology and surgery · August 2021 PurposeSparsity of annotated data is a major limitation in medical image processing tasks such as registration. Registered multimodal image data are essential for the diagnosis of medical conditions and the success of interventional medical proced ... Full text Cite

A dynamic simulation framework for CT perfusion in stroke assessment built from first principles.

Journal Article Med Phys · July 2021 PURPOSE: Physicians utilize cerebral perfusion maps (e.g., cerebral blood flow, cerebral blood volume, transit time) to prescribe the plan of care for stroke patients. Variability in scanning techniques and post-processing software can result in difference ... Full text Link to item Cite

Novel Methodology for Measuring Regional Myocardial Efficiency.

Journal Article IEEE Trans Med Imaging · June 2021 Our approach differs from the usual global measure of cardiac efficiency by using PET/MRI to measure efficiency of small pieces of cardiac tissue whose limiting size is equal to the spatial resolution of the PET scanner. We initiated a dynamic cardiac PET ... Full text Link to item Cite

A generative adversarial network (GAN)-based technique for synthesizing realistic respiratory motion in the extended cardiac-torso (XCAT) phantoms.

Journal Article Phys Med Biol · May 31, 2021 Objective. Synthesize realistic and controllable respiratory motions in the extended cardiac-torso (XCAT) phantoms by developing a generative adversarial network (GAN)-based deep learning technique.Methods. A motion generation model was developed using bic ... Full text Link to item Cite

Assessment of pleural invasion and adhesion of lung tumors with dynamic chest radiography: A virtual clinical imaging study.

Journal Article Med Phys · April 2021 PURPOSE: Accurate preoperative assessment of tumor invasion/adhesion is crucial for planning appropriate operative procedures. Recent advances in digital radiography allow a motion analysis of lung tumors with dynamic chest radiography (DCR) with total exp ... Full text Link to item Cite

A GPU-accelerated framework for rapid estimation of scanner-specific scatter in CT for virtual imaging trials.

Journal Article Phys Med Biol · March 23, 2021 Virtual imaging trials (VITs), defined as the process of conducting clinical imaging trials using computer simulations, offer a time- and cost-effective alternative to traditional imaging trials for CT. The clinical potential of VITs hinges on the realism ... Full text Link to item Cite

Patient-Informed Organ Dose Estimation in Clinical CT: Implementation and Effective Dose Assessment in 1048 Clinical Patients.

Journal Article AJR Am J Roentgenol · March 2021 OBJECTIVE. The purpose of this study is to comprehensively implement a patient-informed organ dose monitoring framework for clinical CT and compare the effective dose (ED) according to the patient-informed organ dose with ED according to the dose-length pr ... Full text Open Access Link to item Cite

Virtual Imaging Trials for Coronavirus Disease (COVID-19).

Journal Article AJR Am J Roentgenol · February 2021 OBJECTIVE. The virtual imaging trial is a unique framework that can greatly facilitate the assessment and optimization of imaging methods by emulating the imaging experiment using representative computational models of patients and validated imaging simula ... Full text Link to item Cite

Task-dependent estimability index to assess the quality of cardiac computed tomography angiography for quantifying coronary stenosis.

Journal Article J Med Imaging (Bellingham) · January 2021 Purpose: Quantifying stenosis in cardiac computed tomography angiography (CTA) images remains a difficult task, as image noise and cardiac motion can degrade image quality and distort underlying anatomic information. The purpose of this study was to develo ... Full text Link to item Cite

A framework to simulate ct images with tube current modulation

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Tube current modulation (TCM) is routinely implemented in clinical CT imaging. By modifying the x-ray tube current as a function of patient attenuation, image quality can be made more consistent and radiation dose can be better managed. Optimal TCM setting ... Full text Cite

An analysis of radiomics features in lung lesions in covid-19

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Radiomic features extracted from CT imaging can be used to quantitively assess COVID-19. The objective of this work was to extract and analyze radiomics features in RT-PRC confirmed COVID-19 cases to identify relevant characteristics for COVID-19 diagnosis ... Full text Cite

A probabilistic conditional adversarial neural network to reduce imaging variation in radiography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Medical images can vary due to differences in imaging equipment and conditions. This variability negatively can impact the consistency and accuracy of diagnostic processes. Hence, it is critical to decrease the variability in image acquisition to achieve c ... Full text Cite

Copd quantifications via ct imaging: Ascertaining the effects of acquisition protocol using virtual imaging trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 COPD is the fourth leading cause of death in the United States. The structural and functional attributes of this disease can be assessed in vivo using computed tomography (CT). The value of quantitative CT has been demonstrated towards characterization and ... Full text Cite

Estimation of lung volume changes from frontal and lateral views of dynamic chest radiography using a convolutional neural network model: A computational phantom study

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 TWe aimed to estimate respiratory changes in lung volumes (i"lung volume) using frontal and lateral dynamic chest radiography (DCR) by employing a convolutional neural network (CNN) learning approach trained and tested using the four-dimensional (4D) exten ... Full text Cite

Optimization of CT angiography using physiologically-informed computational plaques, dynamic XCAT phantoms, and physics-based CT simulation

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Cardiovascular disease is a leading cause of death worldwide. Among all cardiovascular diseases, coronary artery disease (CAD) is a major contributor to mortality, accounting for approximately 10% of deaths per annum. Imaging techniques such as computed to ... Full text Cite

Multi-factorial optimization of imaging parameters for quantifying coronary stenosis in cardiac ct

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 The accuracy and variability of quantifications in Computed Tomography Angiography (CTA) are affected by imaging parameters and patient attributes. While patient attributes cannot usually be altered for a scan, imaging parameters can be optimized to improv ... Full text Cite

Correlation of respiratory changes in lung density on dynamic chest radiographs with changes in the ct value: A computational phantom study

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 Pulmonary impairments are observed as decreased changes in lung density during respiration on dynamic chest radiographs (DCR). To facilitate pulmonary function evaluation based on DCR, the present study was conducted to correlate respiratory changes in pix ... Full text Cite

IPhantom: An automated framework in generating personalized computational phantoms for organ-based radiation dosimetry

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2021 We propose an automated framework to generate 3D detailed person-specific computational phantoms directly from patient medical images. We investigate the feasibility of this framework in terms of accurately generating patient-specific phantoms and the clin ... Full text Cite

Justification of radiological procedures in COVID-19 pandemic based on radiation risk only

Conference · December 2, 2020 Purpose. Radiologic procedures are recommended based on benefit-to-risk justification. In X-ray imaging, while the benefit is often immediate for the patient, the associated radiation burden risk is a longer-term effect. Such a temporal gap can bias the ju ... Open Access Cite

Virtual Imaging Trials for Novel Coronavirus Disease (COVID-19)

Conference · December 2, 2020 PURPOSE Virtual imaging trial is a unique framework that can greatly facilitate the assessment and optimization of imaging, by emulating the experiments using representative models of patients and scanners. This study aimed to impalement and demonstrate a ... Cite

Three-dimensional regions-of-interest-based intra-operative four-dimensional soft tissue perfusion imaging using a standard x-ray system with no gantry rotation: A simulation study for a proof of concept.

Journal Article Med Phys · December 2020 PURPOSE: Many interventional procedures aim at changing soft tissue perfusion or blood flow. One problem at present is that soft tissue perfusion and its changes cannot be assessed in an interventional suite because cone-beam computed tomography is too slo ... Full text Link to item Cite

Impact of Using Uniform Attenuation Coefficients for Heterogeneously Dense Breasts in a Dedicated Breast PET/X-ray Scanner.

Journal Article IEEE Trans Radiat Plasma Med Sci · September 2020 We investigated PET image quantification when using a uniform attenuation coefficient (μ) for attenuation correction (AC) of anthropomorphic density phantoms derived from high-resolution breast CT scans. A breast PET system was modeled with perfect data co ... Full text Link to item Cite

Virtual clinical trials in medical imaging: a review.

Journal Article J Med Imaging (Bellingham) · July 2020 The accelerating complexity and variety of medical imaging devices and methods have outpaced the ability to evaluate and optimize their design and clinical use. This is a significant and increasing challenge for both scientific investigations and clinical ... Full text Link to item Cite

Virtual clinical trial for quantifying the effects of beam collimation and pitch on image quality in computed tomography.

Journal Article J Med Imaging (Bellingham) · July 2020 Purpose: To utilize a virtual clinical trial (VCT) construct to investigate the effects of beam collimation and pitch on image quality (IQ) in computed tomography (CT) under different respiratory and cardiac motion rates. Approach: A computational human mo ... Full text Link to item Cite

Clinical Decision Making in CT: Risk Assessment Comparison Across 12 Risk Metrics in Patient Populations

Conference Journal of Medical Physics · June 30, 2020 Purpose The Medical Physics 3.0 initiative aims to enhance direct physicist involvement in clinical decision making to improve patient care. In this involvement, it is crucial to achieve effective and patient-specific radiation risk assessment. CT risk cha ... Full text Open Access Cite

THE 2020 AAPM ANNUAL MEETING PROGRAM.

Conference Med Phys · June 2020 Full text Open Access Link to item Cite

Development of realistic multi-contrast textured XCAT (MT-XCAT) phantoms using a dual-discriminator conditional-generative adversarial network (D-CGAN).

Journal Article Phys Med Biol · March 19, 2020 Develop a machine learning-based method to generate multi-contrast anatomical textures in the 4D extended cardiac-torso (XCAT) phantom for more realistic imaging simulations. As a pilot study, we synthesize CT and CBCT textures in the chest region. For tra ... Full text Link to item Cite

Optimization of energy thresholds in photon-counting CT via a virtual clinical trial

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2020 In photon-counting CT, detector energy thresholds directly affect image quality attributes such as contrast and noise. The purpose of this study was to identify optimum energy thresholds using a comprehensive virtual clinical trial platform. The virtual tr ... Full text Cite

Virtual imaging trials: An emerging experimental paradigm in imaging research and practice

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2020 As medical imaging technologies continue to accelerate in complexity, application, and multiplicity of design choices and use features, they should ideally be evaluated and optimized through human clinical trials. However, such trials are often impossible ... Full text Cite

Prediction of pleural invasion of lung cancer with dynamic chest radiography: A simulation study

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2020 We aimed to investigate the feasibility of predicting pleural invasion or adhesion of lung cancers with dynamic chest radiography (DCR), using a four-dimensional (4D) extended cardiac-torso (XCAT) computational phantom. An XCAT phantom of an adult man (50t ... Full text Cite

NOVEL METHODOLGY FOR MEASURING REGIONAL MYOCARDIAL EFFICIENCY

Conference JOURNAL OF NUCLEAR MEDICINE · 2020 Cite

A real-time Monte Carlo tool for individualized dose estimations in clinical CT.

Journal Article Phys Med Biol · November 4, 2019 The increasing awareness of the adverse effects associated with radiation exposure in computed tomography (CT) has necessesitated the quantification of dose delivered to patients for better risk assessment in the clinic. The current methods for dose quanti ... Full text Link to item Cite

Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique.

Journal Article Med Phys · November 2019 PURPOSE: The purpose of this study was to simulate and validate organ doses from different computed tomography (CT) localizer radiograph geometries using Monte Carlo methods for a population of patients. METHODS: A Monte Carlo method was developed to estim ... Full text Open Access Link to item Cite

Organ doses from CT localizer radiographs: Development, validation, and application of a Monte Carlo estimation technique

Journal Article MEDICAL PHYSICS · November 1, 2019 Full text Open Access Link to item Cite

Development of a scanner-specific simulation framework for photon-counting computed tomography.

Journal Article Biomed Phys Eng Express · August 2019 The aim of this study was to develop and validate a simulation platform that generates photon-counting CT images of voxelized phantoms with detailed modeling of manufacturer-specific components including the geometry and physics of the x-ray source, source ... Full text Link to item Cite

DukeSim: A Realistic, Rapid, and Scanner-Specific Simulation Framework in Computed Tomography.

Journal Article IEEE Trans Med Imaging · June 2019 The purpose of this study was to develop a CT simulation platform that is: 1) compatible with voxel-based computational phantoms; 2) capable of modeling the geometry and physics of commercial CT scanners; and 3) computationally efficient. Such a simulation ... Full text Link to item Cite

Multiresolution spatiotemporal mechanical model of the heart as a prior to constrain the solution for 4D models of the heart.

Journal Article Proc SPIE Int Soc Opt Eng · June 2019 In several nuclear cardiac imaging applications (SPECT and PET), images are formed by reconstructing tomographic data using an iterative reconstruction algorithm with corrections for physical factors involved in the imaging detection process and with corre ... Full text Link to item Cite

Fetal XCMR: a numerical phantom for fetal cardiovascular magnetic resonance imaging.

Journal Article J Cardiovasc Magn Reson · May 23, 2019 BACKGROUND: Validating new techniques for fetal cardiovascular magnetic resonance (CMR) is challenging due to random fetal movement that precludes repeat measurements. Consequently, fetal CMR development has been largely performed using physical phantoms o ... Full text Link to item Cite

IN VIVO MEASURE OF CARDIAC EFFICIENCY USING HYBRID PET/MRI TECHNOLOGY

Conference JOURNAL OF NUCLEAR MEDICINE · May 1, 2019 Link to item Cite

Incorporation of the Living Heart Model into the 4D XCAT Phantom for Cardiac Imaging Research.

Journal Article IEEE Trans Radiat Plasma Med Sci · January 2019 The 4D extended cardiac-torso (XCAT) phantom has provided a valuable tool to study the effects of anatomy and motion on medical images, especially cardiac motion. One limitation of the XCAT was that it did not have a physiological basis which to realistica ... Full text Link to item Cite

Modeling "Textured" Bones in Virtual Human Phantoms.

Journal Article IEEE Trans Radiat Plasma Med Sci · January 2019 The purpose of this study was to develop detailed and realistic models of the cortical and trabecular bones in the spine, ribs, and sternum and incorporate them into the library of virtual human phantoms (XCAT). Cortical bone was modeled by 3D morphologica ... Full text Link to item Cite

Trade-off between spatial details and motion artifact in multi-detector CT: A virtual clinical trial with 4D textured human models

Conference Medical Imaging 2019: Physics of Medical Imaging · 2019 Cite

A comprehensive GPU-based framework for scatter estimation in single source, dual source, and photon-counting CT

Conference Medical Imaging 2019: Physics of Medical Imaging · 2019 Cite

A framework for realistic virtual clinical trials in photon counting computed tomography

Conference Medical Imaging 2019: Physics of Medical Imaging · 2019 Cite

Multi-organ segmentation in clinical-computed tomography for patient-specific image quality and dose metrology

Conference Medical Imaging 2019: Physics of Medical Imaging · 2019 Cite

Anatomically- and computationally-informed hepatic contrast perfusion simulations for use in virtual clinical trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 This study modeled a framework for virtual human liver phantoms, focusing primarily on the intricate vascular networks that comprise the liver. Large vasculature was segmented from clinical liver perfusion images to ascertain a general starting point for t ... Full text Cite

Deep learning of 3D computed tomography (CT) images for organ segmentation using 2D multi-channel SegNet model

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 Purpose To accurately segment organs from 3D CT image volumes using a 2D, multi-channel SegNet model consisting of a deep Convolutional Neural Network (CNN) encoder-decoder architecture. Method We trained a SegNet model on the extended cardiac-Torso (XCAT) ... Full text Cite

Utilizing deformable image registration to create new living human heart models for imaging simulation

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 The Living Heart Model (LHM) was developed as part of the Living Heart Project by Dassault Systemes to provide a numerical finite element (FE) model of the human heart that accurately reproduces the normal cardiac physiology. We previously incorporated the ... Full text Cite

Dynamic chest radiography for pulmonary function diagnosis: A validation study using 4D extended cardiac-torso (XCAT) phantom

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 This study was performed to investigate the detection performance of trapped air in dynamic chest radiography using 4D extended cardiac-torso (XCAT) phantom with a user-defined ground truth. An XCAT phantom of an adult male (50th percentile in height and w ... Full text Cite

Cardiac CT estimability index: An ideal estimator in the presence of noise and motion

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 Estimating parameters of clinical significance, like coronary stenosis, accurately and precisely from cardiac CT images remains a difficult task as image noise and cardiac motion can degrade image quality and distort underlying anatomic information. The pu ... Full text Cite

Characterization of Radiation Risk across a Clinical CT Patient Population: Comparison across 12 Risks Metrics

Conference · November 27, 2018 PURPOSE Ascertaining radiological procedure radiation burden is essential for justification, optimization, and personalization of the procedure. While the exact radiation risk for an individual exam is unknowable, various risk-related figures have been use ... Cite

Effective Dose for Computed Tomography in Large, Clinical Populations

Conference · November 27, 2018 PURPOSE Effective dose can efficiently integrate multiple organ dose values into a singular scalar value of radiation dose. The effective dose can also be calculated using dose length product (DLP) to effective dose conversion coefficients. The purpose of ... Cite

Application of the 4-D XCAT Phantoms in Biomedical Imaging and Beyond.

Journal Article IEEE Trans Med Imaging · March 2018 The four-dimensional (4-D) eXtended CArdiac-Torso (XCAT) series of phantoms was developed to provide accurate computerized models of the human anatomy and physiology. The XCAT series encompasses a vast population of phantoms of varying ages from newborn to ... Full text Link to item Cite

Modeling Lung Architecture in the XCAT Series of Phantoms: Physiologically Based Airways, Arteries and Veins.

Journal Article IEEE Trans Med Imaging · March 2018 The purpose of this paper was to extend the extended cardiac-torso (XCAT) series of computational phantoms to include a detailed lung architecture including airways and pulmonary vasculature. Eleven XCAT phantoms of varying anatomy were used in this paper. ... Full text Link to item Cite

Quantification of uncertainty in the assessment of coronary plaque in CCTA through a dynamic cardiac phantom and 3D-printed plaque model.

Journal Article J Med Imaging (Bellingham) · January 2018 The purpose of this study was to develop a dynamic physical cardiac phantom with a realistic coronary plaque to investigate stenosis measurement accuracy under clinically relevant heart-rates. The coronary plaque model (5 mm diameter, 50% stenosis, and 32 ... Full text Link to item Cite

From patient-informed to patient-specific organ dose estimation in clinical computed tomography

Conference Medical Imaging 2018: Physics of Medical Imaging · 2018 Cite

Virtual clinical trial in action: Textured XCAT phantoms and scanner-specific CT simulator to characterize noise across CT reconstruction algorithms

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 Although non-linear CT systems offer improved image quality over conventional linear systems, they disrupt certain assumptions of the dependency of noise and resolution on radiation dose that are true of linear systems. As such, simplistic phantoms do not ... Full text Cite

A rapid GPU-based Monte-Carlo simulation tool for individualized dose estimations in CT

Conference Medical Imaging 2018: Physics of Medical Imaging · 2018 Cite

Development of a fast, voxel-based, and scanner-specific CT simulator for image-quality-based virtual clinical trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 This study aimed to develop a simulation framework to synthesize accurate and scanner-specific Computed Tomography (CT) images of voxel-based computational phantoms. Two phantoms were used in the simulations, a geometry-based Mercury phantom and a "texture ... Full text Cite

Evaluation of statistical breast phantoms with higher resolution

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 In previous work, we generated computational breast phantoms by using a principal component analysis (PCA) or "Eigenbreast" technique. For this study, we sought to address resolution limitations in the previous synthesized breast phantoms by analyzing new ... Full text Cite

Variability of stenosis characterization: Impact of coronary vessel motion in cardiac CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 Despite much advancement, quantitative optimization of cardiac CT has remained an elusive challenge. The purpose of this study was to quantify the stenosis measurement variability introduced by the relative motion of coronary vessels in cardiac CT. Even wi ... Full text Cite

Development of a Computerized 4-D MRI Phantom for Liver Motion Study.

Journal Article Technol Cancer Res Treat · December 2017 PURPOSE: To develop a 4-dimensional computerized magnetic resonance imaging phantom with image textures extracted from real patient scans for liver motion studies. METHODS: The proposed phantom was developed based on the current version of 4-dimensional ex ... Full text Link to item Cite

Radiation risk index for pediatric CT: a patient-derived metric.

Journal Article Pediatr Radiol · December 2017 BACKGROUND: There is a benefit in characterizing radiation-induced cancer risk in pediatric chest and abdominopelvic CT: a singular metric that represents the whole-body radiation burden while also accounting for age, gender and organ sensitivity. OBJECTIV ... Full text Link to item Cite

Synthetic breast phantoms from patient based eigenbreasts.

Journal Article Med Phys · December 2017 PURPOSE: The limited number of 3D patient-based breast phantoms available could be augmented by synthetic breast phantoms in order to facilitate virtual clinical trials (VCTs) using model observers for breast imaging optimization and evaluation. METHODS: T ... Full text Link to item Cite

Breast dose reduction with organ-based, wide-angle tube current modulated CT.

Journal Article J Med Imaging (Bellingham) · July 2017 This study aimed to estimate the organ dose reduction potential for organ-dose-based tube current modulated (ODM) thoracic computed tomography (CT) with a wide dose reduction arc. Twenty-one computational anthropomorphic phantoms (XCAT) were used to create ... Full text Link to item Cite

Organ dose variability and trends in tomosynthesis and radiography.

Journal Article J Med Imaging (Bellingham) · July 2017 The purpose of this study was to investigate relationships between patient attributes and organ dose for a population of computational phantoms for 20 tomosynthesis and radiography protocols. Organ dose was estimated from 54 adult computational phantoms (a ... Full text Link to item Cite

Enhancing ejection fraction measurement through 4D respiratory motion compensation in cardiac PET imaging.

Journal Article Phys Med Biol · June 7, 2017 ECG gated cardiac PET imaging measures functional parameters such as left ventricle (LV) ejection fraction (EF), providing diagnostic and prognostic information for management of patients with coronary artery disease (CAD). Respiratory motion degrades spat ... Full text Link to item Cite

The Effect of Contrast Material on Radiation Dose at CT: Part I. Incorporation of Contrast Material Dynamics in Anthropomorphic Phantoms.

Journal Article Radiology · June 2017 Purpose To develop a method to incorporate the propagation of contrast material into computational anthropomorphic phantoms for estimation of organ dose at computed tomography (CT). Materials and Methods A patient-specific physiologically based pharmacokin ... Full text Link to item Cite

The Effect of Contrast Material on Radiation Dose at CT: Part II. A Systematic Evaluation across 58 Patient Models.

Journal Article Radiology · June 2017 Purpose To estimate the radiation dose as a result of contrast medium administration in a typical abdominal computed tomographic (CT) examination across a library of contrast material-enhanced computational patient models. Materials and Methods In part II ... Full text Link to item Cite

Realistic phantoms to characterize dosimetry in pediatric CT.

Journal Article Pediatr Radiol · May 2017 BACKGROUND: The estimation of organ doses and effective doses for children receiving CT examinations is of high interest. Newer, more realistic anthropomorphic body models can provide information on individual organ doses and improved estimates of effectiv ... Full text Link to item Cite

Analysis of uncertainties in Monte Carlo simulated organ and effective dose in chest CT: scanner- and scan-related factors.

Journal Article Phys Med Biol · April 21, 2017 In Monte Carlo simulation of CT dose, many input parameters are required (e.g. bowtie filter properties and scan start/end location). Our goal was to examine the uncertainties in patient dose when input parameters were inaccurate. Using a validated Monte C ... Full text Link to item Cite

CT breast dose reduction with the use of breast positioning and organ-based tube current modulation.

Journal Article Med Phys · February 2017 PURPOSE: This study aimed to investigate the breast dose reduction potential of a breast-positioning (BP) technique for thoracic CT examinations with organ-based tube current modulation (OTCM). METHODS: This study included 13 female anthropomorphic computa ... Full text Link to item Cite

Correction of hysteretic respiratory motion in SPECT myocardial perfusion imaging: Simulation and patient studies.

Journal Article Med Phys · February 2017 PURPOSE: Amplitude-based respiratory gating is known to capture the extent of respiratory motion (RM) accurately but results in residual motion in the presence of respiratory hysteresis. In our previous study, we proposed and developed a novel approach to ... Full text Link to item Cite

Automated, patient-specific estimation of regional imparted energy and dose from tube current modulated computed tomography exams across 13 protocols.

Journal Article J Med Imaging (Bellingham) · January 2017 Currently, computed tomography (CT) dosimetry relies on surrogates for dose, such as CT dose index and size-specific dose estimates, rather than dose per se. Organ dose is considered as the gold standard for radiation dosimetry. However, organ dose estimat ... Full text Link to item Cite

An atlas-based organ dose estimator for tomosynthesis and radiography

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2017 The purpose of this study was to provide patient-specific organ dose estimation based on an atlas of human models for twenty tomosynthesis and radiography protocols. The study utilized a library of 54 adult computational phantoms (age: 18-78 years, weight ... Full text Cite

Estimation of breast dose reduction potential for organ-based tube current modulated CT with wide dose reduction arc

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2017 This study aimed to estimate the organ dose reduction potential for organ-dose-based tube current modulated (ODM) thoracic CT with wide dose reduction arc. Twenty-one computational anthropomorphic phantoms (XCAT, age range: 27- 75 years, weight range: 52.0 ... Full text Cite

Airways, vasculature, and interstitial tissue: Anatomically informed computational modeling of human lungs for virtual clinical trials

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2017 This study aimed to model virtual human lung phantoms including both non-parenchymal and parenchymal structures. Initial branches of the non-parenchymal structures (airways, arteries, and veins) were segmented from anatomical data in each lobe separately. ... Full text Cite

Detectability of artificial lesions in anthropomorphic virtual breast phantoms of variable glandular fraction

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2017 This work seeks to utilize a cohort of computational, patient-based breast phantoms and anthropomorphic lesions inserted therein to determine trends in breast lesion detectability as a function of several clinically relevant variables. One of the measures ... Full text Cite

Improved virtual cardiac phantom with variable diastolic filling rates and coronary artery velocities

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2017 To facilitate studies of measurement uncertainty in computed tomography angiography (CTA), we investigated the cardiac motion profile and resulting coronary artery motion utilizing innovative dynamic virtual and physical phantoms. The four-chamber cardiac ... Full text Cite

Impact of breast structure on lesion detection in breast tomosynthesis, a simulation study.

Journal Article J Med Imaging (Bellingham) · July 2016 This study aims to characterize the effect of background tissue density and heterogeneity on the detection of irregular masses in breast tomosynthesis, while demonstrating the capability of the sophisticated tools that can be used in the design, implementa ... Full text Link to item Cite

Convolution-based estimation of organ dose in tube current modulated CT.

Journal Article Phys Med Biol · May 21, 2016 Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pedi ... Full text Link to item Cite

Finite-element modeling of compression and gravity on a population of breast phantoms for multimodality imaging simulation.

Journal Article Med Phys · May 2016 PURPOSE: The authors are developing a series of computational breast phantoms based on breast CT data for imaging research. In this work, the authors develop a program that will allow a user to alter the phantoms to simulate the effect of gravity and compr ... Full text Link to item Cite

Biomechanics Simulations Using Cubic Hermite Meshes with Extraordinary Nodes for Isogeometric Cardiac Modeling.

Journal Article Comput Aided Geom Des · March 2016 Cubic Hermite hexahedral finite element meshes have some well-known advantages over linear tetrahedral finite element meshes in biomechanical and anatomic modeling using isogeometric analysis. These include faster convergence rates as well as the ability t ... Full text Link to item Cite

LROC Investigation of Three Strategies for Reducing the Impact of Respiratory Motion on the Detection of Solitary Pulmonary Nodules in SPECT.

Journal Article IEEE Trans Nucl Sci · February 2016 The objective of this investigation was to determine the effectiveness of three motion reducing strategies in diminishing the degrading impact of respiratory motion on the detection of small solitary pulmonary nodules (SPN) in single photon emission comput ... Full text Link to item Cite

Modeling the respiratory motion of solitary pulmonary nodules and determining the impact of respiratory motion on their detection in SPECT imaging.

Journal Article IEEE Trans Nucl Sci · February 2016 The objectives of this investigation were to model the respiratory motion of solitary pulmonary nodules (SPN) and then use this model to determine the impact of respiratory motion on the localization and detection of small SPN in SPECT imaging for four rec ... Full text Link to item Cite

Population of 224 realistic human subject-based computational breast phantoms.

Journal Article Med Phys · January 2016 PURPOSE: To create a database of highly realistic and anatomically variable 3D virtual breast phantoms based on dedicated breast computed tomography (bCT) data. METHODS: A tissue classification and segmentation algorithm was used to create realistic and de ... Full text Link to item Cite

Eigenbreasts for statistical breast phantoms

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 To facilitate rigorous virtual clinical trials using model observers for breast imaging optimization and evaluation, we demonstrated a method of defining statistical models, based on 177 sets of breast CT patient data, in order to generate tens of thousand ... Full text Cite

Organ dose conversion coefficients for tube current modulated CT protocols for an adult population

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 In computed tomography (CT), patient-specific organ dose can be estimated using pre-calculated organ dose conversion coefficients (organ dose normalized by CTDIvol, h factor) database, taking into account patient size and scan coverage. The conversion coef ... Full text Cite

An automated technique for estimating patient-specific regional imparted energy and dose in TCM CT exams

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 Currently computed tomography (CT) dosimetry relies on CT dose index (CTDI) and size specific dose estimates (SSDE). Organ dose is a better metric of radiation burden. However, organ dose estimation requires precise knowledge of organ locations. Regional i ... Full text Cite

Estimation of breast dose saving potential using a breast positioning technique for organ-based tube current modulated CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 In thoracic CT, organ-based tube current modulation (OTCM) reduces breast dose by lowering the tube current in the 120° anterior dose reduction zone of patients. However, in practice the breasts usually expand to an angle larger than the dose reduction zon ... Full text Cite

Synthesized interstitial lung texture for use in anthropomorphic computational phantoms

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 A realistic model of the anatomical texture from the pulmonary interstitium was developed with the goal of extending the capability of anthropomorphic computational phantoms (e.g., XCAT, Duke University), allowing for more accurate image quality assessment ... Full text Cite

Development of a realistic, dynamic digital brain phantom for CT perfusion validation

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 Physicians rely on CT Perfusion (CTP) images and quantitative image data, including cerebral blood flow, cerebral blood volume, and bolus arrival delay, to diagnose and treat stroke patients. However, the quantification of these metrics may vary depending ... Full text Cite

Adult abdomen-pelvis CT: Does equilibrium dose-pitch product better account for the kVp dependence of organ dose than conventional CTDI?

Journal Article Med Phys · November 2015 PURPOSE: In CT imaging, a desirable quality assurance dose quantity should account for the dose variability across scan parameters and scanner models. Recently, AAPM Task Group 111 proposed to use equilibrium dose-pitch product (Dˆeq), in place of CT dose ... Full text Link to item Cite

Two Realistic Beagle Models for Dose Assessment.

Journal Article Health Phys · September 2015 Previously, the authors developed a series of eight realistic digital mouse and rat whole body phantoms based on NURBS technology to facilitate internal and external dose calculations in various species of rodents. In this paper, two body phantoms of adult ... Full text Link to item Cite

The development of a population of 4D pediatric XCAT phantoms for imaging research and optimization.

Journal Article Med Phys · August 2015 PURPOSE: We previously developed a set of highly detailed 4D reference pediatric extended cardiac-torso (XCAT) phantoms at ages of newborn, 1, 5, 10, and 15 yr with organ and tissue masses matched to ICRP Publication 89 values. In this work, we extended th ... Full text Link to item Cite

Effect of Non-Alignment/Alignment of Attenuation Map Without/With Emission Motion Correction in Cardiac SPECT/CT.

Journal Article IEEE Trans Nucl Sci · August 2015 PURPOSE: We investigate the differences without/with respiratory motion correction in apparent imaging agent localization induced in reconstructed emission images when the attenuation maps used for attenuation correction (from CT) are misaligned with the p ... Full text Link to item Cite

Realistic wave-optics simulation of X-ray phase-contrast imaging at a human scale.

Journal Article Sci Rep · July 14, 2015 X-ray phase-contrast imaging (XPCI) can dramatically improve soft tissue contrast in X-ray medical imaging. Despite worldwide efforts to develop novel XPCI systems, a numerical framework to rigorously predict the performance of a clinical XPCI system at a ... Full text Link to item Cite

Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data.

Journal Article Med Phys · July 2015 PURPOSE: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-di ... Full text Link to item Cite

The direct incorporation of perfusion defect information to define ischemia and infarction in a finite element model of the left ventricle.

Journal Article J Biomech Eng · May 2015 This paper describes the process in which complex lesion geometries (specified by computer generated perfusion defects) are incorporated in the description of nonlinear finite element (FE) mechanical models used for specifying the motion of the left ventri ... Full text Link to item Cite

Prospective estimation of organ dose in CT under tube current modulation.

Journal Article Med Phys · April 2015 PURPOSE: Computed tomography (CT) has been widely used worldwide as a tool for medical diagnosis and imaging. However, despite its significant clinical benefits, CT radiation dose at the population level has become a subject of public attention and concern ... Full text Link to item Cite

The impact of breast structure on lesion detection in breast tomosynthesis

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2015 Virtual clinical trials (VCT) can be carefully designed to inform, orient, or potentially replace clinical trials. The focus of this study was to demonstrate the capability of the sophisticated tools that can be used in the design, implementation, and perf ... Full text Cite

Determination of contrast media administration to achieve a targeted contrast enhancement in CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2015 Contrast enhancement is a key component of CT imaging and offer opportunities for optimization. The design and optimization of new techniques however requires orchestration with the scan parameters and further a methodology to relate contrast enhancement a ... Full text Cite

Convolution-based estimation of organ dose in tube current modulated CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2015 Among the various metrics that quantify radiation dose in computed tomography (CT), organ dose is one of the most representative quantities reflecting patient-specific radiation burden.1 Accurate estimation of organ dose requires one to effectively model t ... Full text Cite

Analysis of uncertainties in Monte Carlo simulated organ dose for chest CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2015 In Monte Carlo simulation of organ dose for a chest CT scan, many input parameters are required (e.g., half-value layer of the x-ray energy spectrum, effective beam width, and anatomical coverage of the scan). The input parameter values are provided by the ... Full text Cite

Anatomy-based transmission factors for technique optimization in portable chest x-ray

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2015 Portable x-ray examinations often account for a large percentage of all radiographic examinations. Currently, portable examinations do not employ automatic exposure control (AEC). To aid in the design of a size-specific technique chart, acrylic slabs of va ... Full text Cite

Performance comparison of breast imaging modalities using a 4AFC human observer study

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2015 This work compares the visibility of spheres and simulated masses in 2D-mammography and tomosynthesis systems using human observer studies. Performing comparison studies between breast imaging systems poses a number of practical challenges within a clinica ... Full text Cite

Organ localization: toward prospective patient-specific organ dosimetry in computed tomography.

Journal Article Med Phys · December 2014 PURPOSE: With increased focus on radiation dose from medical imaging, prospective radiation dose estimates are becoming increasingly desired. Using available populations of adult and pediatric patient phantoms, radiation dose calculations can be catalogued ... Full text Link to item Cite

Effect of respiratory motion on lung counting efficiency using a 4D NURBS-based cardio-torso (NCAT) phantom.

Journal Article Health Phys · December 2014 The Human Monitoring Laboratory (Canada) has looked at parameters (lung volume, lung deposition pattern, etc.) that can affect the counting efficiency of its lung counting system. The calibration of the system is performed using the Lawrence Livermore Nati ... Full text Link to item Cite

Determining organ dose: the holy grail.

Journal Article Pediatr Radiol · October 2014 Among the various metrics to quantify CT radiation dose, organ dose is generally regarded as one of the best to reflect patient radiation burden. Organ dose is dependent on two main factors, namely patient anatomy and irradiation field. An accurate estimat ... Full text Link to item Cite

Radiation dosimetry in digital breast tomosynthesis: report of AAPM Tomosynthesis Subcommittee Task Group 223.

Journal Article Med Phys · September 2014 The radiation dose involved in any medical imaging modality that uses ionizing radiation needs to be well understood by the medical physics and clinical community. This is especially true of screening modalities. Digital breast tomosynthesis (DBT) has rece ... Full text Link to item Cite

The impact on CT dose of the variability in tube current modulation technology: a theoretical investigation.

Journal Article Phys Med Biol · August 21, 2014 Body CT scans are routinely performed using tube-current-modulation (TCM) technology. There is notable variability across CT manufacturers in terms of how TCM technology is implemented. Some manufacturers aim to provide uniform image noise across body regi ... Full text Link to item Cite

MRXCAT: Realistic numerical phantoms for cardiovascular magnetic resonance.

Journal Article J Cardiovasc Magn Reson · August 20, 2014 BACKGROUND: Computer simulations are important for validating novel image acquisition and reconstruction strategies. In cardiovascular magnetic resonance (CMR), numerical simulations need to combine anatomical information and the effects of cardiac and/or ... Full text Link to item Cite

Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging.

Journal Article Phys Med Biol · July 21, 2014 The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often the performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly use ... Full text Link to item Cite

Development and application of a suite of 4-D virtual breast phantoms for optimization and evaluation of breast imaging systems.

Journal Article IEEE Trans Med Imaging · July 2014 Mammography is currently the most widely utilized tool for detection and diagnosis of breast cancer. However, in women with dense breast tissue, tissue overlap may obscure lesions. Digital breast tomosynthesis can reduce tissue overlap. Furthermore, imagin ... Full text Link to item Cite

Patient-based estimation of organ dose for a population of 58 adult patients across 13 protocol categories.

Journal Article Med Phys · July 2014 PURPOSE: This study aimed to provide a comprehensive patient-specific organ dose estimation across a multiplicity of computed tomography (CT) examination protocols. METHODS: A validated Monte Carlo program was employed to model a common CT system (LightSpe ... Full text Link to item Cite

Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver.

Journal Article Med Phys · June 2014 PURPOSE: Understanding the radiation dose to a patient is essential when considering the use of an ionizing diagnostic imaging test for clinical diagnosis and screening. Using Monte Carlo simulations, the authors estimated the three-dimensional organ-dose ... Full text Link to item Cite

A set of 4D pediatric XCAT reference phantoms for multimodality research.

Journal Article Med Phys · March 2014 PURPOSE: The authors previously developed an adult population of 4D extended cardiac-torso (XCAT) phantoms for multimodality imaging research. In this work, the authors develop a reference set of 4D pediatric XCAT phantoms consisting of male and female ana ... Full text Link to item Cite

Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus.

Journal Article Med Phys · February 2014 PURPOSE: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for ... Full text Link to item Cite

Pediatric chest and abdominopelvic CT: organ dose estimation based on 42 patient models.

Journal Article Radiology · February 2014 PURPOSE: To estimate organ dose from pediatric chest and abdominopelvic computed tomography (CT) examinations and evaluate the dependency of organ dose coefficients on patient size and CT scanner models. MATERIALS AND METHODS: The institutional review boar ... Full text Link to item Cite

Population of 100 realistic, patient-based computerized breast phantoms for multi-modality imaging research

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2014 Breast imaging is an important area of research with many new Techniques being investigated To further reduce The morbidity and mortality of breast cancer Through early detection. Computerized phantoms can provide an essential Tool To quantitatively compar ... Full text Cite

Dose reduction in CT with correlated-polarity noise reduction: Context-dependent spatial resolution and noise properties demonstrating two-fold dose reduction with minimal artifacts

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2014 Correlated-polarity noise reduction (CPNR) is a novel noise reduction technique that uses a statistical approach to reducing noise while maintaining excellent spatial resolution and a traditional noise appearance. It was demonstrated in application to CT i ... Full text Cite

A second generation of physical anthropomorphic 3D breast phantoms based on human subject data

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2014 Previous fabrication of anthropomorphic breast phantoms has demonstrated Their viability as a model for 2D (mammography) and 3D (tomosynthesis) breast imaging systems. Further development of These models will be essential for The evaluation of breast x-ray ... Full text Cite

The development of a population of 4D pediatric XCAT phantoms for CT imaging research and optimization

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2014 With The increased use of CT examinations, The associated radiation dose has become a large concern, especially for pediatrics. Much research has focused on reducing radiation dose Through new scanning and reconstruction methods. Computational phantoms pro ... Full text Cite

Prospective optimization of CT under Tube current modulation: I. organ dose

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2014 In an environment in which computed Tomography (CT) has become an indispensable diagnostic Tool employed with great frequency, dose concerns at The population level have become a subject of public attention. In That regard, optimizing radiation dose has be ... Full text Cite

Image-based estimation of passive myocardial properties using finite element modeling

Chapter · January 1, 2014 Patient-specific cardiac finite element (FE) models, which are used to estimate the stress state of the heart, are highly dependent upon the assumed material properties defined in the models. A method is developed for determining cardiac material propertie ... Full text Cite

Dose coefficients in pediatric and adult abdominopelvic CT based on 100 patient models.

Journal Article Phys Med Biol · December 21, 2013 Recent studies have shown the feasibility of estimating patient dose from a CT exam using CTDI(vol)-normalized-organ dose (denoted as h), DLP-normalized-effective dose (denoted as k), and DLP-normalized-risk index (denoted as q). However, previous studies ... Full text Link to item Cite

A technique for estimating 4D-CBCT using prior knowledge and limited-angle projections.

Journal Article Medical physics · December 2013 PurposeTo develop a technique to estimate onboard 4D-CBCT using prior information and limited-angle projections for potential 4D target verification of lung radiotherapy.MethodsEach phase of onboard 4D-CBCT is considered as a deformation ... Full text Cite

Evaluation of the effect of respiratory and anatomical variables on a Fourier technique for markerless, self-sorted 4D-CBCT.

Journal Article Phys Med Biol · October 21, 2013 A novel technique based on Fourier transform theory has been developed that directly extracts respiratory information from projections without the use of external surrogates. While the feasibility has been demonstrated with three patients, a more extensive ... Full text Link to item Cite

A three-dimensional finite element model of human atrial anatomy: new methods for cubic Hermite meshes with extraordinary vertices.

Journal Article Med Image Anal · July 2013 Featured Publication High-order cubic Hermite finite elements have been valuable in modeling cardiac geometry, fiber orientations, biomechanics, and electrophysiology, but their use in solving three-dimensional problems has been limited to ventricular models with simple topolo ... Full text Link to item Cite

Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters.

Journal Article Phys Med Biol · June 7, 2013 In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceutic ... Full text Link to item Cite

Organ dose in chest CT: Effect of modulation scheme on estimation accuracy

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 3, 2013 The purpose of this study was to evaluate how different implementations of the tube current modulation (TCM) technology affect organ dose conversion factors in chest CT and how organ dose can be accurately estimated for various modulation schemes. Computat ... Full text Cite

Comparative dosimetry of radiography, tomosynthesis, and CT for chest imaging across 59 adult patients

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 3, 2013 There are three main x-ray based modalities for imaging the thorax: radiography, tomosynthesis, and CT. CT provides perhaps the highest level of feature resolution but at notably higher radiation dose. To implement the ALARA (as low as reasonable achievabl ... Full text Cite

Simulation of anatomical texture in voxelized XCAT phantoms

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 3, 2013 While great advances are made toward making highly realistic, surface models of the human anatomy, very little has been done to fill these bounded surfaces with models of anatomical texture. We propose a method whereby realistic anatomically-based computed ... Full text Cite

Generation of a suite of 3D computer-generated breast phantoms from a limited set of human subject data.

Journal Article Med Phys · April 2013 Featured Publication PURPOSE: The authors previously reported on a three-dimensional computer-generated breast phantom, based on empirical human image data, including a realistic finite-element based compression model that was capable of simulating multimodality imaging data. ... Full text Link to item Cite

Population of anatomically variable 4D XCAT adult phantoms for imaging research and optimization.

Journal Article Med Phys · April 2013 Featured Publication PURPOSE: The authors previously developed the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. The XCAT consisted of highly detailed whole-body models for the standard male and female adult, including the cardiac and respiratory ... Full text Link to item Cite

Workflow for creating a simulation ready virtual population for finite element modeling

Journal Article ASME 2013 Conference on Frontiers in Medical Devices: Applications of Computer Modeling and Simulation, FMD 2013 · January 1, 2013 A proof of concept workflow is demonstrated to easily translate 3D medical image data into finite element (FE) simulation ready phantom models. First, novel methods are used to drastically reduce manual segmentation time for a virtual population. Next, usi ... Full text Cite

Anthropomorphic Phantoms: Early Developments and Current Advances

Chapter · 2013 Cite

Patient-specific model of NaF PET to facilitate multicenter clinical trial PET imaging protocols and analysis: preliminary results of a CT-based simulation

Conference JOURNAL OF NUCLEAR MEDICINE · 2013 Cite

Dose reduction in CT with correlated-polarity noise reduction: Comparable image quality at half the dose with projection space processing

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · 2013 Correlated-polarity noise reduction (CPNR) is a novel noise reduction technique that uses a statistical approach to reduce noise while maintaining excellent resolution and a "normal" noise appearance. It is applicable to any type of medical imaging, and we ... Full text Cite

Development of matched virtual and physical breast phantoms based on patient data

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · 2013 Physical phantoms are essential for the development, optimization, and clinical evaluation of x-ray systems. These phantoms are used for various tests such as quality assurance testing, system characterization, reconstruction evaluation, and dosimetry. The ... Full text Cite

Multi-modal rigid and non-rigid registration for attenuation correction in cardiac SPECT/CT using emission scatter to CT conversion

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2012 Patient body or respiratory motion between emission imaging and CT can cause misalignment of position of heart in the emission and attenuation maps, causing significant artifacts in emission reconstruction upon attenuation correction. In this work, we inve ... Full text Cite

Effects of protocol and obesity on dose conversion factors in adult body CT.

Journal Article Med Phys · November 2012 Featured Publication PURPOSE: In computed tomography (CT), organ dose, effective dose, and risk index can be estimated from volume-weighted CT dose index (CTDI(vol)) or dose-length product (DLP) using conversion coefficients. Studies have investigated how these coefficients va ... Full text Link to item Cite

RADAR reference adult, pediatric, and pregnant female phantom series for internal and external dosimetry.

Journal Article J Nucl Med · November 2012 UNLABELLED: A new generation of reference computational phantoms, based on image-based models tied to the reference masses defined by the International Commission on Radiological Protection (ICRP) for dose calculations, is presented. METHODS: Anatomic mode ... Full text Link to item Cite

Adaptation and applications of a realistic digital phantom based on patient lung tumor trajectories.

Journal Article Phys Med Biol · June 7, 2012 Digital phantoms continue to play a significant role in modeling and characterizing medical imaging. The currently available XCAT phantom incorporates both the flexibility of mathematical phantoms and the realistic nature of voxelized phantoms. This phanto ... Full text Link to item Cite

SU-E-J-145: Implementing 4D XCAT Phantom for 4D Radiotherapy Research.

Journal Article Med Phys · June 2012 PURPOSE: To characterize and implement the 4D Integrated Extended Cardiac Torso (XCAT) digital phantom for 4D radiotherapy (RT) application. METHODS: A computer program was developed to facilitate the characterization and implementation of the 4D XCAT phan ... Full text Link to item Cite

MO-A-213AB-04: Verification of 4D Dose Delivery Using 4D Digital Human Phantom.

Journal Article Med Phys · June 2012 PURPOSE: At present, techniques of 4D dose verification in radiation therapy for lung cancers associated with respiratory motion are very limited, due to either lack of patient anatomy or breathing information. The aim of this study is to develop a 4D dose ... Full text Link to item Cite

SU-D-218-02: 4D-MRI Based on Body Area (BA) Surrogate and Sagittal Image Acquisition.

Journal Article Med Phys · June 2012 PURPOSE: 4D-MRI based on body area (BA) surrogate using axial image acquisition has been demonstrated. Since respiratory motion mostly occurs in the superior-inferior (SI) direction, it is expected that sagittal acquisition may provide more robust and accu ... Full text Link to item Cite

Organ doses, effective doses, and risk indices in adult CT: comparison of four types of reference phantoms across different examination protocols.

Journal Article Med Phys · June 2012 Featured Publication PURPOSE: Radiation exposure from computed tomography (CT) to the public has increased the concern among radiation protection professionals. Being able to accurately assess the radiation dose patients receive during CT procedures is a crucial step in the ma ... Full text Link to item Cite

Interactive generation of digital anthropomorphic phantoms from XCAT shape priors

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 14, 2012 In SPECT imaging, patient respiratory and body motion can cause artifacts that degrade image quality. Developing and evaluating motion correction algorithms are facilitated by simulation studies where a numerical phantom and its motion are precisely known, ... Full text Cite

Development of a dynamic 4D anthropomorphic breast phantom for contrast-based breast imaging

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 4, 2012 Mammography is currently the most widely accepted tool for detection and diagnosis of breast cancer. However, the sensitivity of mammography is reduced in women with dense breast tissue due to tissue overlap, which may obscure lesions. Digital breast tomos ... Full text Cite

Series of 4D adult XCAT phantoms for imaging research and dosimetry

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 4, 2012 Computerized phantoms are finding an increasingly important role in medical imaging research. With the ability to simulate various imaging conditions, they offer a practical means with which to quantitatively evaluate and improve imaging devices and techni ... Full text Cite

Patient- and cohort-specific dose and risk estimation for abdominopelvic CT: A study based on 100 patients

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 4, 2012 The purpose of this work was twofold: (a) to estimate patient- and cohort-specific radiation dose and cancer risk index for abdominopelvic computer tomography (CT) scans; (b) to evaluate the effects of patient anatomical characteristics (size, age, and gen ... Full text Cite

Realistic reference adult and paediatric phantom series for internal and external dosimetry.

Journal Article Radiat Prot Dosimetry · March 2012 A new generation of realistic, image-based anthropomorphic phantoms has been developed based on the reference masses and organ definitions given in the International Commission on Radiological Protection Publication 89. Specific absorbed fractions for inte ... Full text Link to item Cite

TU‐C‐213CD‐06: Patient Lung Tumor Trajectory Based Modified‐XCAT and Its Applications

Conference Medical Physics · January 1, 2012 Purpose: To modify the digital XCAT phantom to include patient‐specific 3D lung tumor trajectories and demonstrate potential applications. Methods: An algorithm is developed to program the existing XCAT phantom to move according to recorded patient 3D lung ... Full text Cite

Anthropomorphic Phantoms: Early Developments and Current Advances

Chapter · January 1, 2012 Monte Carlo modeling of the transmission and attenuation of internal radiation sources has led to a better understanding of the image formation process in diagnostic radiology. Since much higher statistics are necessary to model imaging simulations (compar ... Full text Cite

Establishing a framework to implement 4D XCAT phantom for 4D radiotherapy research.

Journal Article J Cancer Res Ther · 2012 AIMS: To establish a framework to implement the 4D integrated extended cardiac torso (XCAT) digital phantom for 4D radiotherapy (RT) research. MATERIALS AND METHODS: A computer program was developed to facilitate the characterization and implementation of ... Full text Link to item Cite

Four-dimensional magnetic resonance imaging (4D-MRI) using image-based respiratory surrogate: a feasibility study.

Journal Article Med Phys · December 2011 PURPOSE: Four-dimensional computed tomography (4D-CT) has been widely used in radiation therapy to assess patient-specific breathing motion for determining individual safety margins. However, it has two major drawbacks: low soft-tissue contrast and an exce ... Full text Link to item Cite

Incorporation of perfusion information into a finite element model of the left ventricle

Journal Article ASME 2011 Summer Bioengineering Conference, SBC 2011 · December 1, 2011 Full text Cite

An analysis of the mechanical parameters used for finite element compression of a high-resolution 3D breast phantom.

Journal Article Med Phys · October 2011 Featured Publication PURPOSE: The authors previously introduced a methodology to generate a realistic three-dimensional (3D), high-resolution, computer-simulated breast phantom based on empirical data. One of the key components of such a phantom is that it provides a means to ... Full text Link to item Cite

Development of a 4D Digital Phantom for Tracer Kinetic Modeling and Analysis of Dynamic Perfusion PET and SPECT Simulation Studies.

Journal Article IEEE Nucl Sci Symp Conf Rec (1997) · October 2011 The goal is to develop a 4D digital perfusion cardiac-torso (PCAT) phantom, a tracer kinetic extension of the XCAT phantom, by modeling the time activity curves (TACs) of individual organ regions in the phantom for dynamic perfusion PET and SPECT simulatio ... Full text Link to item Cite

Development of a model of the coronary arterial tree for the 4D XCAT phantom.

Journal Article Phys Med Biol · September 7, 2011 A detailed three-dimensional (3D) model of the coronary artery tree with cardiac motion has great potential for applications in a wide variety of medical imaging research areas. In this work, we first developed a computer-generated 3D model of the coronary ... Full text Link to item Cite

Generating patient-specific dosimetry phantoms with whole-body diffeomorphic image registration

Journal Article 2011 IEEE 37th Annual Northeast Bioengineering Conference, NEBEC 2011 · June 16, 2011 This work describes a protocol for creating a population of pediatric, patient specific, computational dosimetry phantoms. Pediatric CT data are mapped to a detailed adult template using multi channel (MC) - large deformation diffeomorphic metric mapping ( ... Full text Cite

Patient-specific radiation dose and cancer risk for pediatric chest CT.

Journal Article Radiology · June 2011 PURPOSE: To estimate patient-specific radiation dose and cancer risk for pediatric chest computed tomography (CT) and to evaluate factors affecting dose and risk, including patient size, patient age, and scanning parameters. MATERIALS AND METHODS: The inst ... Full text Link to item Cite

Quantitative study of cardiac motion estimation and abnormality classification in emission computed tomography.

Journal Article Med Eng Phys · June 2011 Quantitative description of cardiac motion is desirable to assist in detecting myocardial abnormalities from gated myocardial perfusion (GMP) emission computed tomography (ECT) images. While "optical flow" type of cardiac motion estimation (ME) techniques ... Full text Link to item Cite

Creation of 3D digital anthropomorphic phantoms which model actual patient non-rigid body motion as determined from MRI and position tracking studies of volunteers

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 16, 2011 Patient motion can cause artifacts, which can lead to difficulty in interpretation. The purpose of this study is to create 3D digital anthropomorphic phantoms which model the location of the structures of the chest and upper abdomen of human volunteers und ... Full text Cite

Refinement of motion correction strategies for lower-cost CT for under-resourced regions of the world

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 13, 2011 This paper describes a recently developed post-acquisition motion correction strategy for application to lower-cost computed tomography (LCCT) for under-resourced regions of the world. Increased awareness regarding global health and its challenges has enco ... Full text Cite

The feasibility of universal DLP-to-risk conversion coefficients for body CT protocols

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 13, 2011 The effective dose associated with computed tomography (CT) examinations is often estimated from dose-length product (DLP) using scanner-independent conversion coefficients. Such conversion coefficients are available for a small number of examinations, eac ... Full text Cite

XCAT/DRASIM: A realistic CT/human-model simulation package

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 13, 2011 The aim of this research is to develop a complete CT/human-model simulation package by integrating the 4D eXtended CArdiac-Torso (XCAT) phantom, a computer generated NURBS surface based phantom that provides a realistic model of human anatomy and respirato ... Full text Cite

Incorporation of a left ventricle finite element model defining infarction into the XCAT imaging phantom.

Journal Article IEEE Trans Med Imaging · April 2011 Featured Publication The 4D extended cardiac-torso (XCAT) phantom was developed to provide a realistic and flexible model of the human anatomy and cardiac and respiratory motions for use in medical imaging research. A prior limitation to the phantom was that it did not accurat ... Full text Link to item Cite

TH‐A‐214‐02: Organ Dose, Effective Dose, and Dose Conversion Coefficients in Adult CT: Comparison of Mathematical, XCAT, and ICRP Reference Phantoms

Conference Medical Physics · January 1, 2011 Purpose: To compare organ dose, effective dose, and dose conversion coefficients in adult CT estimated using three types of reference phantoms: (1) hermaphrodite mathematical phantom employed by the imPACT CT dose calculator, (2) reference male and female ... Full text Cite

Patient Specific Dosimetry Phantoms Using Multichannel LDDMM of the Whole Body.

Journal Article Int J Biomed Imaging · 2011 Featured Publication This paper describes an automated procedure for creating detailed patient-specific pediatric dosimetry phantoms from a small set of segmented organs in a child's CT scan. The algorithm involves full body mappings from adult template to pediatric images usi ... Full text Link to item Cite

Patient-specific radiation dose and cancer risk estimation in CT: part II. Application to patients.

Journal Article Med Phys · January 2011 Featured Publication PURPOSE: Current methods for estimating and reporting radiation dose from CT examinations are largely patient-generic; the body size and hence dose variation from patient to patient is not reflected. Furthermore, the current protocol designs rely on dose a ... Full text Link to item Cite

Patient-specific radiation dose and cancer risk estimation in CT: part I. development and validation of a Monte Carlo program.

Journal Article Med Phys · January 2011 Featured Publication PURPOSE: Radiation-dose awareness and optimization in CT can greatly benefit from a dose-reporting system that provides dose and risk estimates specific to each patient and each CT examination. As the first step toward patient-specific dose and risk estima ... Full text Link to item Cite

Dynamic multi-bed FDG PET imaging: Feasibility and optimization

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2011 Multi-Bed FDG PET/CT as applied to oncologic imaging is currently widely and routinely used for assessment of localized and metastatic disease involvement. In the past, based on conventional (single-bed) dynamic PET imaging, standard tracer kinetic modelin ... Full text Cite

Investigation of respiratory motion correction with and without motion correction of attenuation map in cardiac SPECT/CT in presence of non-rigid motion, an NCAT study

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2011 Respiratory motion combined with "respiratory creep" of the heart can introduce false cooling or affect the appearance of defects and thereby impact the diagnostic accuracy of cardiac PET or SPECT perfusion images. In this work we investigate the differenc ... Full text Cite

Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motions: A tool-set for investigating motion correction in 3D reconstruction

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2011 Patient respiratory and body motions occurring during emission tomography create artifacts in the images, which can mislead diagnosis. For example, in myocardial-perfusion imaging these artifacts can be mistaken for perfusion defects. Various software and ... Full text Cite

Estimation and correction of cardiac respiratory motion in SPECT in the presence of limited-angle effects due to irregular respiration.

Journal Article Med Phys · December 2010 PURPOSE: One issue with amplitude binning list-mode studies in SPECT for respiratory motion correction is that variation in the patient's respiratory pattern will result in binned motion states with little or no counts at various projection angles. The red ... Full text Link to item Cite

Simulation of left ventricular dyssynchrony using the XCAT phantom

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2010 Multi-Harmonic Phase Analysis (MHPA) has been developed to quantify left-ventricular (LV) mechanical dyssynchrony with gated single photon emission tomography (SPECT) myocardial perfusion imaging (MPI). Although MHPA has shown promising clinical results, i ... Full text Cite

The new XCAT series of digital phantoms for multi-modality imaging

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2010 We developed a series of 4D Extended Cardiac-Torso (XCAT) phantoms for multimodality imaging research. Highly detailed whole-body anatomies for the initial adult male and female were previously defined for the XCAT using nonuniform rational b-spline (NURBS ... Full text Cite

Patient-specific radiation dose and cancer risk estimation in pediatric chest CT: A study in 30 patients

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · December 1, 2010 Radiation-dose awareness and optimization in CT can greatly benefit from a dose- reporting system that provides radiation dose and cancer risk estimates specific to each patient and each CT examination. Recently, we reported a method for estimating patient ... Full text Cite

Initial investigation into lower-cost CT for resource limited regions of the world

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · December 1, 2010 This paper describes an initial investigation into means for producing lower-cost CT scanners for resource limited regions of the world. In regions such as sub-Saharan Africa, intermediate level medical facilities serving millions have no CT machines, and ... Full text Cite

4D XCAT phantom for multimodality imaging research.

Journal Article Med Phys · September 2010 Featured Publication PURPOSE: The authors develop the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. METHODS: Highly detailed whole-body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B-spline (NURBS) an ... Full text Link to item Cite

Comparison of 3D OS-EM and 4D MAP-RBI-EM reconstruction algorithms for cardiac motion abnormality classification using a motion observer.

Journal Article IEEE Trans Nucl Sci · August 26, 2010 Using a heart motion observer, we compared the performance of two image reconstruction techniques, a 3D OS-EM algorithm with post Butterworth spatial filtering and a 4D MAP-RBI-EM algorithm. The task was to classify gated myocardial perfusion (GMP) SPECT i ... Full text Link to item Cite

Markerless lung tumor tracking and trajectory reconstruction using rotational cone-beam projections: a feasibility study.

Journal Article Phys Med Biol · May 7, 2010 Algorithms for direct tumor tracking in rotational cone-beam projections and for reconstruction of phase-binned 3D tumor trajectories were developed. The feasibility of the algorithm was demonstrated on a digital phantom, a physical phantom and two patient ... Full text Link to item Cite

Extension of the NCAT phantom for the investigation of intra-fraction respiratory motion in IMRT using 4D Monte Carlo.

Journal Article Phys Med Biol · March 7, 2010 The purpose of this work was to create a computational platform for studying motion in intensity modulated radiotherapy (IMRT). Specifically, the non-uniform rational B-spline (NURB) cardiac and torso (NCAT) phantom was modified for use in a four-dimension ... Full text Link to item Cite

RADAR realistic animal model series for dose assessment.

Journal Article J Nucl Med · March 2010 UNLABELLED: Rodent species are widely used in the testing and approval of new radiopharmaceuticals, necessitating murine phantom models. As more therapy applications are being tested in animal models, calculating accurate dose estimates for the animals the ... Full text Link to item Cite

Realistic Simulation of Regional Myocardial Perfusion Defects for Cardiac SPECT Studies.

Journal Article IEEE Nucl Sci Symp Conf Rec (1997) · 2010 The current 3D XCAT phantom allows users to manually define the regional myocardial perfusion defect (MPD) as a simple pie-shaped wedge region with reduced activity level in the myocardium of left ventricle. To more accurately and realistically model the M ... Full text Link to item Cite

Assessing the Susceptibility to Local Buckling at the Femoral Neck Cortex to Age-Related Bone Loss

Journal Article IFMBE Proceedings · December 1, 2009 To simulate bone adaptation, we used an engineering beam simulation of a one-legged stance and linearly thickened (young) or thinned (old) cortices until the maximum stress on the infero-medial neck surface was the same as in the middle-age version. Conseq ... Full text Cite

MCAT to XCAT: The Evolution of 4-D Computerized Phantoms for Imaging Research: Computer models that take account of body movements promise to provide evaluation and improvement of medical imaging devices and technology.

Journal Article Proc IEEE Inst Electr Electron Eng · December 2009 Recent work in the development of computerized phantoms has focused on the creation of ideal "hybrid" models that seek to combine the realism of a patient-based voxelized phantom with the flexibility of a mathematical or stylized phantom. We have been lead ... Full text Link to item Cite

Realistic X-ray CT simulation of the XCAT phantom with SINDBAD

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2009 An efficient simulation tool is developed to generate realistic X-ray CT images, including a good modeling of physics and a very detailed anthropomorphic model in a reasonable computing time. This simulation tool consists in a coupling of the existing X-ra ... Full text Cite

Evaluation of quantitative planar 90Y bremsstrahlung whole-body imaging.

Journal Article Phys Med Biol · October 7, 2009 With high-dose administration of (90)Y labeled antibodies, it is possible to image (90)Y without an admixture of (111)In. We have earlier shown that it is possible to perform quantitative (90)Y bremsstrahlung SPECT for dosimetry purposes with reasonable ac ... Full text Link to item Cite

Improved Dynamic Cardiac Phantom Based on 4D NURBS and Tagged MRI.

Journal Article IEEE Trans Nucl Sci · October 1, 2009 We previously developed a realistic phantom for the cardiac motion for use in medical imaging research. The phantom was based upon a gated magnetic resonance imaging (MRI) cardiac study and using 4D non-uniform rational b-splines (NURBS). Using the gated M ... Full text Link to item Cite

Assessing the susceptibility to local buckling at the femoral neck cortex to age-related bone loss.

Journal Article Ann Biomed Eng · September 2009 Although it is known that long cortical bone structurally alter their area moment of inertia with age related bone loss maintaining their bending strength, the incidence of fragility fractures associated with cortical thinning still prevails. We hypothesiz ... Full text Link to item Cite

Methodology for generating a 3D computerized breast phantom from empirical data.

Journal Article Med Phys · July 2009 The initial process for creating a flexible three-dimensional computer-generated breast phantom based on empirical data is described. Dedicated breast computed-tomography data were processed to suppress noise and scatter artifacts in the reconstructed imag ... Full text Link to item Cite

Toward modeling of regional myocardial ischemia and infarction: Generation of realistic coronary arterial tree for the heart model of the XCAT phantom

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 22, 2009 A realistic 3D coronary arterial tree (CAT) has been developed for the heart model of the computer generated 3D XCAT phantom. The CAT allows generation of a realistic model of the location, size and shape of the associated regional ischemia or infarction f ... Full text Cite

Patient specific computerized phantoms to estimate dose in pediatric CT

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 16, 2009 We create a series of detailed computerized phantoms to estimate patient organ and effective dose in pediatric CT and investigate techniques for efficiently creating patient-specific phantoms based on imaging data. The initial anatomy of each phantom was p ... Full text Cite

Computerized 3D breast phantom with enhanced High-Resolution detail

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 15, 2009 We previously proposed a three-dimensional computerized breast phantom that combines empirical data with the flexibility of mathematical models1. The goal of this project is to enhance the breast phantom to include a more detailed anatomy than currently vi ... Full text Cite

Patient-specific dose estimation for pediatric abdomen-pelvisCT

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 15, 2009 The purpose of this study is to develop a method for estimating patient-specific dose from abdomen-pelvis CT examinations and to investigate dose variation across patients in the same weight group. Our study consisted of seven pediatric patients in the sam ... Full text Cite

Investigation of Respiratory Gating in Quantitative Myocardial SPECT.

Journal Article IEEE Trans Nucl Sci · February 1, 2009 The purpose of this study is to investigate optimal respiratory gating schemes using different numbers of gates and placements within the respiratory cycle for reduction of respiratory motion (RM) artifacts in myocardial SPECT. The 4D NCAT phantom with its ... Full text Link to item Cite

Evaluation of quantitative imaging methods for organ activity and residence time estimation using a population of phantoms having realistic variations in anatomy and uptake.

Journal Article Med Phys · February 2009 Estimating organ residence times is an essential part of patient-specific dosimetry for radioimmunotherapy (RIT). Quantitative imaging methods for RIT are often evaluated using a single physical or simulated phantom but are intended to be applied clinicall ... Full text Link to item Cite

Effectiveness of three alternative strategies in reducing the degrading impact of respiratory motion on the detection of small pulmonary nodules in SPECT imaging

Conference 2008 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (2008 NSS/MIC), VOLS 1-9 · January 1, 2009 Link to item Cite

Estimation and Correction of Irregular Respiratory motion of the Heart in Presence of Partial Angle Effects Due to Amplitude Binning in SPECT

Conference 2008 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (2008 NSS/MIC), VOLS 1-9 · January 1, 2009 Link to item Cite

The MCAT, NCAT, XCAT, and MOBY Computational Human and Mouse Phantoms

Chapter · January 1, 2009 Previous chapters have highlighted the two main categories of phantoms and the advantages and disadvantages of each. Brie y, existing computational phantoms involve a trade-off between realism and exibility, and this affects their applicability to imaging ... Full text Cite

Applications to Nuclear Medicine Imaging and Dosimetry Involving MCAT, NCAT, and MOBY Phantoms

Chapter · January 1, 2009 Recent advances in computer-generated phantoms, especially those described in Chapter 5, have found many important applications in medical imaging and dosimetry calculations. In medical imaging, a computer-generated phantom that realistically models the an ... Full text Cite

The Vanderbilt University Reference Adult and Pediatric Phantom Series

Chapter · January 1, 2009 Anthropomorphic computational phantoms used for dose calculations in nuclear medicine for the past 30 years have used the stylized anatomical computational phantoms that were originally developed for the Medical Internal Radiation Dose (MIRD) committee of ... Full text Cite

Summary and Future Needs Related to Computational Phantoms

Chapter · January 1, 2009 A PhD candidate is often asked to include in the dissertation a section called “future work.” This task requires the student to go beyond the data-based scientific process and predict what future developments might follow. “Crystal ball gazing, " however, ... Full text Cite

Incorporating patient-specific variability in the simulation of realistic whole-body ¹⁸F-FDG distributions for oncology applications

Journal Article Proceedings of the IEEE · January 1, 2009 The purpose of the work described in this paper was the development of a framework for the creation of a realistic positron emission tomography (PET) simulated database incorporating patient-specific variability. The ground truth used was therefore based o ... Full text Cite

Patient-specific dose estimation for pediatric chest CT.

Journal Article Med Phys · December 2008 Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and d ... Full text Link to item Cite

Banding artifact reduction for cardiac CT

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2008 One of problems with the current cardiac CT imaging is the banding artifacts, i.e., horizontal shifts in multiplanar reformatted (MPR) or three-dimensional (3-D) images. In this work, we propose a novel gating method that does not rely on electro-cardiogra ... Full text Cite

Estimation and correction of irregular respiratory motion of the heart in presence of partial angle effects due to amplitude binning in SPECT

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2008 Respiratory motion combined with the "respiratory creep" of the heart can affect the appearance of defects and even conceal them, thereby impacting the diagnostic accuracy of cardiac PET or SPECT perfusion images. Several groups have investigated the use o ... Full text Cite

Effectiveness of three alternative strategies in reducing the degrading impact ofrespiratory motion on the detection of small pulmonary nodules in SPECT imaging

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2008 The objective of this investigation is to determine the effectiveness of three methods in reducing the impact of respiratory motion on the detection of small solitary pulmonary nodules in single photon emission computed tomographic imaging. Based on our pr ... Full text Cite

Realistic CT simulation using the 4D XCAT phantom.

Journal Article Med Phys · August 2008 The authors develop a unique CT simulation tool based on the 4D extended cardiac-torso (XCAT) phantom, a whole-body computer model of the human anatomy and physiology based on NURBS surfaces. Unlike current phantoms in CT based on simple mathematical primi ... Full text Link to item Cite

Accurate event-driven motion compensation in high-resolution PET incorporating scattered and random events.

Journal Article IEEE Trans Med Imaging · August 2008 With continuing improvements in spatial resolution of positron emission tomography (PET) scanners, small patient movements during PET imaging become a significant source of resolution degradation. This work develops and investigates a comprehensive formali ... Full text Link to item Cite

System matrix modelling of externally tracked motion.

Journal Article Nucl Med Commun · June 2008 BACKGROUND AND AIM: In high-resolution emission tomography imaging, even small patient movements can considerably degrade image quality. The aim of this work was to develop a general approach to motion-corrected reconstruction of motion-contaminated data i ... Full text Link to item Cite

Three-dimensional computer generated breast phantom based on empirical data

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · May 14, 2008 The goal of this work is to create a detailed three-dimensional (3D) digital breast phantom based on empirical data and to incorporate it into the four-dimensional (4D) NCAT phantom, a computerized model of the human anatomy widely used in imaging research ... Full text Cite

SU‐GG‐J‐93: Feasibility Study On Artifact Reduction Using Dual Energy Digital Tomosynthesis

Conference Medical Physics · January 1, 2008 Purpose: We propose a simulation study to examine the feasibility of incorporating dual energy (DE) subtraction with digital tomosynthesis (DTS) to help reduce DTS reconstruction artifacts. Method and Materials: We have previously investigated the incorpor ... Full text Cite

SU‐GG‐J‐94: Feasibility Study On the Efficacy of Dual Energy Cine Imaging in Radiation Therapy for Lung Cancer

Conference Medical Physics · January 1, 2008 Purpose: Modern IMRT plans have necessitated improved image localization techniques. In the lungs, internal target volumes (ITVs) are often generated from 4DCT images; however, the patient must be properly localized daily for this to work effectively. In t ... Full text Cite

TH‐D‐AUD A‐08: A Method for Generating Large Datasets of Patient Geometries for Radiotherapy Treatment Planning Studies

Conference Medical Physics · January 1, 2008 Purpose: Radiotherapy treatment planning studies often require the use of large patient CT datasets to extract conclusions of statistical significance. However, due to various reasons such as difficulties in acquiring a larger set of CT scans and in segmen ... Full text Cite

The development and application of a realistic simulation dataset for simultaneous cardiac and respiratory gated ECT/CT

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2007 We have developed and evaluated a realistic simulation dataset for simultaneous cardiac and respiratory gated ECT/CT using the 4D NURBS-based Cardiac-Torso (NCAT) Phantom and Monte Carlo simulation methods. To include both cardiac and respiratory motions s ... Full text Cite

Enhanced 4D heart model based on high resolution dual source gated cardiac CT images

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2007 We have developed a new 4D heart model for use in the 4D NCAT phantom that, through modification of parameters that define it, is capable of modeling a wide variety of beating heart motions, normal and abnormal. High-resolution gated cardiac CT data of a h ... Full text Cite

Modeling respiratory motion variations in the 4D NCAT phantom

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2007 The current 4D NCAT phantom includes a flexible, parameterized respiratory model based on respiratory-gated CT data of a normal subject. A limitation of this model is that it is based on only one realization of the normal respiratory motion. The data upon ... Full text Cite

Modeling respiratory motion variations in the 4P NCAT phantom

Effect of respiratory motion on abdominal C-arm CT angiography using the 4D NCAT phantom

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2007 With the recent advancement of C-arm angiographic techniques in acquiring the 3D rotational angiography, the system has the ability to reconstruct the CT-like transaxial slices of the scan volume, but at lower image quality compared to those reconstructed ... Full text Cite

Onboard SPECT for Biological Target Localization

Conference International Journal of Radiation Oncology*Biology*Physics · November 2007 Full text Cite

Image-domain motion compensated time-resolved 4D cardiac CT

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · October 15, 2007 Two major problems with the current electrocardiogram-gated cardiac computed tomography (CT) imaging technique are a large patient radiation dose (10-15 mSv) and insufficient temporal resolution (83-165 ms). Our long-term goal is to develop new time resolv ... Full text Cite

Image-domain material decomposition using photon-counting CT

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · October 15, 2007 Novel CdTe photon counting x-ray detectors (PCXDs) have been developed for very high count rates [1-4] suitable for x-ray micro computed tomography (μCT) scanners. It counts photons within each of J energy bins. In this study, we investigate use of the dat ... Full text Cite

Impact of respiratory motion on the detection of small pulmonary nodules in SPECT imaging.

Journal Article IEEE Nucl Sci Symp Conf Rec (1997) · 2007 The objective of this investigation is to determine the impact of respiratory motion on the detection of small solitary pulmonary nodules (SPN) in single photon emission computed tomographic (SPECT) imaging. We have previously modeled the respiratory motio ... Full text Link to item Cite

Normal and pathological NCAT image and phantom data based on physiologically realistic left ventricle finite-element models.

Journal Article IEEE Trans Med Imaging · December 2006 The four-dimensional (4-D) NURBS-based cardiac-torso (NCAT) phantom, which provides a realistic model of the normal human anatomy and cardiac and respiratory motions, is used in medical imaging research to evaluate and improve imaging devices and technique ... Full text Link to item Cite

Compensating for patient respiration in PET/CT imaging with the registered and summed phases (RASP) procedure

Journal Article 2006 3rd IEEE International Symposium on Biomedical Imaging: From Nano to Macro - Proceedings · November 17, 2006 PET/CT imaging has introduced new challenges in accurate quantitation of lung nodules due to respiratory motion and mismatches in CT-based attenuation correction (CTAC). We used Monte Carlo simulations to investigate how respiratory-correlated CTAC can be ... Cite

Development of a computer-generated model for the coronary arterial tree based on multislice CT and morphometric data

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 30, 2006 A detailed four-dimensional model of the coronary artery tree has great potential in a wide variety of applications especially in biomedical imaging. We developed a computer generated three-dimensional model for the coronary arterial tree based on two data ... Full text Cite

Toward time resolved 4D cardiac CT imaging with patient dose reduction; estimating the global heart motion

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 30, 2006 Coronary artery imaging with multi-slice helical computed tomography is a promising noninvasive imaging technique. The current major issues include the insufficient temporal resolution and large patient dose. We propose an image reconstruction method which ... Full text Cite

Effect of heart rate on CT angiography using the enhanced cardiac model of the 4D NCAT

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 30, 2006 We investigate the effect of heart rate on the quality and artifact generation in coronary artery images obtained using multi-slice computed tomography (MSCT) with the purpose of finding the optimal time resolution for data acquisition. To perform the stud ... Full text Cite

Optimization of gated liver FDG PET with non-uniform respiration

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2006 The objective of this research is to optimize and characterize the respiratory gated reconstruction protocol in liver FDG PET scans with non-uniform respiration using Monte-Carlo simulations. Assuming externally-tracked motion information and NCAT respirat ... Full text Cite

Toward time resolved cardiac CT images with patient dose reduction: Image-based motion estimation

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2006 Two major problems with the current electrocardiogram-gated cardiac CT imaging technique are a large patient radiation dose and insufficient temporal resolution. Our long-term goal is to develop new time resolved and low dose cardiac CT imaging techniques ... Full text Cite

System matrix modeling of externally tracked motion

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2006 In high resolution emission tomography imaging, even small patient movements can considerably degrade image quality. This work investigates an approach to motion compensated reconstruction of motion-contaminated data, thus applicable to any scanner in the ... Full text Cite

Investigation of equal magnitude respiratory gating in quantitative myocardial SPECT

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2006 The purpose of this study is to investigate the effectiveness of respiratory gating in myocardial SPECT using different numbers of gates where each gate contains an equal magnitude of heart and diaphragm motion. The 4D NURBS-based Cardiac-Torso (NCAT) phan ... Full text Cite

RTNCAT (Real Time NCAT): Implementing Real Time physiological movement of voxellized phantoms in GATE

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2006 GATE figures among existing MC simulation codes for emission tomography applications. Although it allows working with voxellized activity distributions it does not enable the incorporation of physiological motion in a real time sense for such distributions ... Full text Cite

Cardiac motion estimation from gated emission computed tomography images

Journal Article IEEE Nuclear Science Symposium Conference Record · January 1, 2006 Quantitative description of the cardiac left ventricle (LV) motion is desirable to assist in detecting myocardial motion abnormalities. It has been recognized that the torsion component of the LV movement is considerably more difficult to track than its ra ... Full text Cite

Study of parameters characterizing space-time Gibbs priors for 4D MAP-RBI-EM in gated myocardial perfusion SPECT

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2005 We investigate the optimal parameters of the 4D space-time Gibbs priors used in the 4D MAP-RBI-EM method for application to gated myocardial perfusion (GMP) SPECT. The Gibbs prior can be defined by a clique structure, the derivative of a generalized potent ... Full text Cite

Effect of respiratory motion in CT-based attenuation correction in SPECT using different CT scanners and protocols

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2005 Artifacts can arise in reconstructed SPECT images using CT-based attenuation correction (CTAC) due to patient respiratory motion. We investigate the extent of these artifacts using different CT scanners ranging from single-slice to state-of-the-art multi-s ... Full text Cite

A Monte Carlo and physical phantom evaluation of quantitative In-111 SPECT.

Journal Article Phys Med Biol · September 7, 2005 Accurate estimation of the 3D in vivo activity distribution is important for dose estimation in targeted radionuclide therapy (TRT). Although SPECT can potentially provide such estimates, SPECT without compensation for image degrading factors is not quanti ... Full text Link to item Cite

Dynamic imaging of allogeneic mesenchymal stem cells trafficking to myocardial infarction.

Journal Article Circulation · September 6, 2005 BACKGROUND: Recent results from animal studies suggest that stem cells may be able to home to sites of myocardial injury to assist in tissue regeneration. However, the histological interpretation of postmortem tissue, on which many of these studies are bas ... Full text Link to item Cite

Validation of the 4D NCAT simulation tools for use in high-resolution x-ray CT research

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · August 25, 2005 We validate the computer-based simulation tools developed in our laboratory for use in high-resolution CT research. The 4D NURBS-based cardiac-torso (NCAT) phantom was developed to provide a realistic and flexible model of the human anatomy and physiology. ... Full text Cite

Fast modelling of the collimator-detector response in Monte Carlo simulation of SPECT imaging using the angular response function.

Journal Article Phys Med Biol · April 21, 2005 Interactions of incident photons with the collimator and detector, including septal penetration, scatter and x-ray fluorescence, are significant sources of image degradation in applications of SPECT including dual isotope imaging and imaging using radioiso ... Full text Link to item Cite

An observer study methodology for evaluating detection of motion abnormalities in gated myocardial perfusion SPECT.

Journal Article IEEE Trans Biomed Eng · March 2005 To address the task of detecting nonischemic motion abnormalities from animated displays of gated myocardial perfusion single photon emission computed tomography data, we performed an observer study to evaluate the difference in detection performance betwe ... Full text Link to item Cite

Elastic image mapping for 4-D dose estimation in thoracic radiotherapy.

Journal Article Radiat Prot Dosimetry · 2005 PURPOSE: Demonstrate the path integration of a four-dimensional (4-D) dose distribution onto the 3-D anatomy. MATERIALS AND METHODS: A computer-generated 4-D thoracic phantom with a lung tumour was constructed. Eight respiratory phases were generated. A ra ... Full text Link to item Cite

Physiologically realistic LV models to produce normal and pathological image and phantom data

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2004 The cardiac model of the 4D NCAT phantom was enhanced by incorporating a physiological basis from which to realistically model left ventricular (LV) motion defects. A finite element mechanical model of the LV was developed to simulate deficits in contracti ... Cite

Development and validation of a Monte Carlo simulation tool for multi-pinhole microSPECT

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2004 The purpose of this study is to develop and validate a Monte Carlo simulation (MCS) tool for investigation and evaluation of multi-pinhole microSPECT imaging. This simulation tool is based on a combination of SimSET and MCNP-4b Monte Carlo codes. It allows ... Cite

A mathematical observer study for the evaluation and optimization of compensation methods for myocardial SPECT using a phantom population that realistically models patient variability

Journal Article IEEE Transactions on Nuclear Science · February 1, 2004 The goal of this study was to develop and apply a population of phantoms that realistically models patient variability and use it to optimize and evaluate different compensation methods used during reconstruction process with respect to defect detection in ... Full text Cite

Development of a 4-D digital mouse phantom for molecular imaging research.

Journal Article Mol Imaging Biol · 2004 PURPOSE: We develop a realistic and flexible 4-D digital mouse phantom and investigate its usefulness in molecular imaging research. METHODS: Organ shapes were modeled with non-uniform rational B-spline (NURBS) surfaces based on high-resolution 3-D magneti ... Full text Link to item Cite

Extension of the 4D NCAT phantom to dynamic X-ray CT simulation

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2003 The 4D NCAT phantom, developed to provide a realistic model of the human anatomy and physiology, is widely used in SPECT imaging research, but lacks anatomical details for application to high-resolution imaging such as x-ray CT and MRI. At the same time, c ... Cite

A study of the effect of cardiac gating in myocardial SPECT using the 4D NCAT

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2003 The purpose of the study is to investigate the effect of cardiac gating in myocardial SPECT obtained from different gating schemes and image reconstruction methods using the 4D NURBS-based Cardiac-Torso (NCAT) phantom. We generated 144 phantoms over a card ... Cite

A mathematical observer study for evaluation of a model-based compensation method for crosstalk in simultaneous dual isotope SPECT

Journal Article IEEE Nuclear Science Symposium Conference Record · December 1, 2003 We have previously developed a model-based method to compensate for the crosstalk in simultaneous acquisition of Tc-99m stress and Tl-201 rest myocardial perfusion SPECT. The purpose of this study is to evaluate the performance of this method in terms of a ... Cite

Development of a Dynamic Model for the Lung Lobes and Airway Tree in the NCAT Phantom

Journal Article IEEE Transactions on Nuclear Science · January 1, 2003 The four-dimensional (4-D) NCAT phantom was developed to realistically model human anatomy based on the visible human data and cardiac and respiratory motions based on 4-D tagged magnetic resonance imaging and respiratory-gated CT data from normal human su ... Full text Cite

Impact of respiratory motion on the detection of solitary pulmonary nodules with SPECT tumor imaging of NeoTect

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2002 We have previously modeled the respiratory motion of solitary pulmonary nodules (SPN) based on the change of location of anatomic structures within the lungs identified on breath-held CT images of volunteers acquired at two different stages of respiration. ... Cite

A Simulation Study of the Effect of Gating Scheme on Respiratory Motion Blurring in FDG Lung PET

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2002 In this study, different respiratory gating schemes in FDG Lung PET were studied using a modified 4D NURBS based CArdiac Torso (NCAT) phantom and Monte Carlo simulation methods. A sphere-shaped lesion with 7 mm in diameter was placed at the bottom of the r ... Cite

CT-PET Image Fusion using the 4D NCAT Phantom with the Purpose of Attenuation Correction

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2002 The purpose of this study is to improve CT-based attenuation correction of 3D PET data using an attenuation map derived from non-rigidly transformed 3D CT data. Utilizing the 4D NURBS-based cardiac-torso (NCAT) phantom with a realistic respiratory model ba ... Cite

Development of a Dynamic Model for the Lung Lobes and Airway Tree in the NCAT Phantom

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2002 The 4D NCAT phantom was developed to realistically model human anatomy based on the Visible Human data and cardiac and respiratory motions based on 4D tagged MRI and respiratory-gated CT data from normal human subjects. Currently, the 4D NCAT phantom does ... Cite

Evaluation and Optimization of Compensation Methods for Myocardial SPECT using a Set of Realistic Phantoms that Include Patient Variability

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2002 The goal of this study was to evaluate and optimize different compensation methods used during reconstruction process with respect to defect detection in myocardial SPECT images. Various combinations of attenuation, detector response and scatter compensati ... Cite

Identification of candidate genes for Parkinson disease (PD)by the convergence of genetic linkage and association data with gene expression in the substantia nigra.

Conference AMERICAN JOURNAL OF HUMAN GENETICS · October 1, 2002 Link to item Cite

Study of the efficacy of respiratory gating in myocardial SPECT using the new 4-D NCAT phantom

Journal Article IEEE Transactions on Nuclear Science · June 1, 2002 Respiratory motion can cause artifacts in myocardial single photon emission computed tomography (SPECT) images, which can lead to the misdiagnosis of cardiac diseases. One method to correct for respiratory artifacts is through respiratory gating. We study ... Full text Cite

Study of the efficacy of respiratory gating in myocardial SPECT using the new 4D NCAT phantom

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2001 Respiratory motion can cause artifacts in myocardial SPECT images, which can lead to the misdiagnosis of cardiac diseases. One method to correct for respiratory artifacts is through respiratory gating. We study the effectiveness of respiratory gating throu ... Cite

Modeling the respiratory motion of solitary pulmonary nodules for investigating SPECT tumor imaging

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2001 We have modeled the respiratory motion of solitary pulmonary nodules (SPN) based on the change of location of anatomic structures in the lungs determined from breath-held CT images of volunteers acquired at two different stages of respiration. The resultin ... Cite

Modeling respiratory mechanics in the MCAT and spline-based MCAT phantoms

Journal Article IEEE Transactions on Nuclear Science · February 1, 2001 Respiratory motion can cause artifacts in myocardial SPECT and computed tomography (CT). We incorporate models of respiratory mechanics into the current 4D MCAT and into the next generation spline-based MCAT phantoms. In order to simulate respiratory motio ... Full text Cite

Simulating patient-specific heart shape and motion using SPECT perfusion images with the MCAT phantom

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2001 The spline-based Mathematical Cardiac Torso (MCAT) phantom is a realistic software simulation designed to simulate single photon emission computed tomographic (SPECT) data. It incorporates a heart model of known size and shape; thus, it is invaluable for m ... Full text Cite

Development of an interactive software application to model patient populations in the 4D NURBS-based Cardiac Torso phantom

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · December 1, 2000 The 4D NURBS-based Cardiac Torso (NCAT) phantom was developed to provide a realistic and flexible computerized torso phantom to be used in medical imaging research. The organ shapes in the NURBS-based phantom are modeled with non-uniform rational b-splines ... Cite

Effects of upward creep and respiratory motion in myocardial SPECT

Journal Article IEEE Transactions on Nuclear Science · January 1, 2000 In this study, we investigate the effects of two patient involuntary motions, namely upward creep (UC) and respiratory (RSP) motion, in myoeardial SPECT images. A new realistic torso phantom was developed based on data from the Visual Human Project and usi ... Full text Cite

Effects of upward creep and respiratory motion in myocardial SPECT

Journal Article IEEE Transactions on Nuclear Science · 2000 In this study, we investigate the effects of two patient involuntary motions, namely upward creep (UC) and respiratory (RSP) motion, in myoeardial SPECT images. A new realistic torso phantom was developed based on data from the Visual Human Project and usi ... Cite

Namic heart phantom

Journal Article IEEE Transactions on Nuclear Science · December 1, 1999 We develop a realistic computerized heart phantom for use in medical imaging research. This phantom is a hybrid of realistic patient-based phantoms and flexible geometry-based phantoms. The surfaces of heart structures are defined using non-uniform rationa ... Full text Cite

Monte Carlo optimization of 4D smoothing methods for gated myocardial perfusion SPECT

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 1999 In this paper, we develop a technique for optimizing space-time smoothing methods proposed for gated myocardial perfusion SPECT. Gated SPECT synchronizes image acquisition with an ECG signal so that a time loop of 3D SPECT images is acquired. The optimizat ... Cite

Next generation MCAT: A realistic spline-based torso phantom

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 1999 We develop a realistic computerized torso phantom for use in medical imaging research. The phantom has the potential to model anatomical variations and patient motion more realistically than phantoms based on simple geometric primitives. Structures are def ... Cite

Realistic spline-based dynamic heart phantom

Journal Article IEEE Nuclear Science Symposium and Medical Imaging Conference · January 1, 1999 We develop a realistic computerized heart phantom for use in medical imaging research. This phantom is a hybrid of realistic patient-based phantoms and flexible geometry-based phantoms. The surfaces of heart structures are defined using non-uniform rationa ... Cite

Pattern of vascular resistance contributes to blood flow heterogeneity

Journal Article FASEB Journal · December 1, 1996 The blood flow patterns in vascular networks becomes heterogeneous when the resistances of sister vessels become unequal. We determined in theory effects on flow heterogeneity for two types of resistance inequalities: (1) left-hand sisters drawn randomly f ... Cite