Lei Ren

Journal article Med Phys · July 2025 BACKGROUND: Projection interpolation can be used to reduce streak artifacts caused by sparse sampling in cone-beam computed tomography (CBCT) image reconstruction. Conventional analytical interpolation methods create additional blur and artifacts at locati ... Full text Link to item Cite

Finite Element Method-Based Hybrid MRI/CBCT Generation to Improve Liver Stereotactic Body Radiation Therapy Targets Localization Accuracy.

Journal article IEEE Trans Radiat Plasma Med Sci · March 2025 Cone-beam CT (CBCT) is commonly used in treatment imaging, but its limited soft tissue contrast presents challenges for liver tumor localization. As a result, indirect localization methods relying on the liver's boundary are commonly utilized, which have l ... Full text Link to item Cite

Author Correction: Identification of CT based radiomic biomarkers for progression free survival in head and neck squamous cell carcinoma.

Journal article Sci Rep · February 21, 2025 Full text Link to item Cite

Genomic Determinants Associated with Modes of Progression and Patterns of Failure in Metachronous Oligometastatic Castration-sensitive Prostate Cancer.

Journal article Eur Urol Oncol · February 2025 BACKGROUND AND OBJECTIVE: Oligometastatic castration-sensitive prostate cancer (omCSPC) represents an early state in the progression of metastatic disease for which patients experience better outcomes in comparison to those with higher disease burden. Desp ... Full text Link to item Cite

Multistage deep learning methods for automating radiographic sharp score prediction in rheumatoid arthritis.

Journal article Sci Rep · January 27, 2025 The Sharp-van der Heijde score (SvH) is crucial for assessing joint damage in rheumatoid arthritis (RA) through radiographic images. However, manual scoring is time-consuming and subject to variability. This study proposes a multistage deep learning model ... Full text Link to item Cite

Identification of CT based radiomic biomarkers for progression free survival in head and neck squamous cell carcinoma.

Journal article Sci Rep · January 8, 2025 This study addresses the limited noninvasive tools for Head and Neck Squamous Cell Carcinoma (HNSCC) progression-free survival (PFS) prediction by identifying Computed Tomography (CT)-based biomarkers for predicting prognosis. A retrospective analysis was ... Full text Link to item Cite

Mouse pancreatic tumor organoids reveal synergistic efficacy of low-dose anticancer drug and radiation combinations

Journal article Frontiers in Medicine · January 1, 2025 Background: Pancreatic cancer is the fourth-leading cause of cancer death in the United States, with a 5-year survival rate of only 13%. Most patients with locally advanced pancreatic cancer receive chemotherapy with or without radiation therapy (RT). Howe ... Full text Cite

Patient-specific deep learning for 3D protoacoustic image reconstruction and dose verification in proton therapy.

Journal article Med Phys · October 2024 BACKGROUND: Protoacoustic (PA) imaging has the potential to provide real-time 3D dose verification of proton therapy. However, PA images are susceptible to severe distortion due to limited angle acquisition. Our previous studies showed the potential of usi ... Full text Link to item Cite

Machine learning predicts conventional imaging metastasis-free survival (MFS) for oligometastatic castration-sensitive prostate cancer (omCSPC) using prostate-specific membrane antigen (PSMA) PET radiomics.

Journal article Radiother Oncol · October 2024 PURPOSE: This study investigated imaging biomarkers derived from PSMA-PET acquired pre- and post-metastasis-directed therapy (MDT) to predict 2-year metastasis-free survival (MFS), which provides valuable early response assessment to improve patient outcom ... Full text Link to item Cite

Enhanced Electroacoustic Tomography with Supervised Learning for Real-time Electroporation Monitoring.

Journal article Precis Radiat Oncol · September 2024 BACKGROUND: Nanosecond pulsed electric fields (nsPEF)-based electroporation is a new therapy modality potentially synergized with radiation therapy to improve treatment outcomes. To verify its treatment accuracy intraoperatively, electroacoustic tomography ... Full text Link to item Cite

A review on 4D cone-beam CT (4D-CBCT) in radiation therapy: Technical advances and clinical applications.

Journal article Med Phys · August 2024 Cone-beam CT (CBCT) is the most commonly used onboard imaging technique for target localization in radiation therapy. Conventional 3D CBCT acquires x-ray cone-beam projections at multiple angles around the patient to reconstruct 3D images of the patient in ... Full text Link to item Cite

Prostate-Specific Membrane Antigen PET Response Associates with Metastasis-Free Survival After Stereotactic Ablative Radiation in Oligometastatic Prostate Cancer

Journal article Advances in Radiation Oncology · July 1, 2024 Purpose: Emerging data suggest that metastasis-directed therapy (MDT) improves outcomes in patients with oligometastatic castration-sensitive prostate cancer (omCSPC). Prostate-specific membrane antigen positron emission tomography (PSMA-PET) can detect oc ... Full text Cite

Hybrid-supervised deep learning for domain transfer 3D protoacoustic image reconstruction.

Journal article Phys Med Biol · April 3, 2024 Objective. Protoacoustic imaging showed great promise in providing real-time 3D dose verification of proton therapy. However, the limited acquisition angle in protoacoustic imaging induces severe artifacts, which impairs its accuracy for dose verification. ... Full text Link to item Cite

TP53 structure-function relationships in metastatic castrate-sensitive prostate cancer and the impact of APR-246 treatment.

Journal article Prostate · January 2024 PURPOSE: Despite well-informed work in several malignancies, the phenotypic effects of TP53 mutations in metastatic castration-sensitive prostate cancer (mCSPC) progression and metastasis are not clear. We characterized the structure-function and clinical ... Full text Link to item Cite

Radiomic biomarkers of locoregional recurrence: prognostic insights from oral cavity squamous cell carcinoma preoperative CT scans

Journal article Frontiers in Oncology · January 1, 2024 Introduction: This study aimed to identify CT-based imaging biomarkers for locoregional recurrence (LR) in Oral Cavity Squamous Cell Carcinoma (OSCC) patients. Methods: Computed tomography scans were collected from 78 patients with OSCC who underwent surgi ... Full text Cite

Identification of CT-based non-invasive radiomic biomarkers for overall survival prediction in oral cavity squamous cell carcinoma.

Journal article Sci Rep · December 8, 2023 This study addresses the limited non-invasive tools for Oral Cavity Squamous Cell Carcinoma (OSCC) survival prediction by identifying Computed Tomography (CT)-based biomarkers to improve prognosis prediction. A retrospective analysis was conducted on data ... Full text Link to item Cite

Clinical and Genomic Differences Between Advanced Molecular Imaging-detected and Conventional Imaging-detected Metachronous Oligometastatic Castration-sensitive Prostate Cancer.

Journal article Eur Urol · December 2023 In metastatic castration-sensitive prostate cancer (mCSPC), disease volume plays an integral role in guiding treatment recommendations, including selection of docetaxel therapy, metastasis-directed therapy, and radiation to the prostate. Although there are ... Full text Link to item Cite

Radiation-induced acoustic signal denoising using a supervised deep learning framework for imaging and therapy monitoring.

Journal article Phys Med Biol · November 29, 2023 Radiation-induced acoustic (RA) imaging is a promising technique for visualizing the invisible radiation energy deposition in tissues, enabling new imaging modalities and real-time therapy monitoring. However, RA imaging signal often suffers from poor sign ... Full text Link to item Cite

Interpretable AI-assisted clinical decision making (CDM) for dose prescription in radiosurgery of brain metastases.

Journal article Radiother Oncol · October 2023 PURPOSE: AI modeling physicians' clinical decision-making (CDM) can improve the efficiency and accuracy of clinical practice or serve as a surrogate to provide initial consultations to patients seeking secondary opinions. In this study, we developed an int ... Full text Link to item Cite

On the correction of respiratory motion-induced image reconstruction errors in positron-emission tomography-guided radiation therapy

Journal article Physics and Imaging in Radiation Oncology · April 1, 2023 Background and purpose: Free breathing (FB) positron emission tomography (PET) images are routinely used in radiotherapy for lung cancer patients. Respiration-induced artifacts in these images compromise treatment response assessment and obstruct clinical ... Full text Cite

A feasibility study of enhanced prompt gamma imaging for range verification in proton therapy using deep learning.

Journal article Phys Med Biol · March 20, 2023 Background and objective. Range uncertainty is a major concern affecting the delivery precision in proton therapy. The Compton camera (CC)-based prompt-gamma (PG) imaging is a promising technique to provide 3Din vivorange verification. However, the convent ... Full text Link to item Cite

AI-assisted clinical decision making (CDM) for dose prescription in radiosurgery of brain metastases using three-path three-dimensional CNN

Journal article Clinical and Translational Radiation Oncology · March 1, 2023 Purpose: AI modeling physicians’ clinical decision-making (CDM) can improve the efficiency and accuracy of clinical practice or serve as a surrogate to provide initial consultations to patients seeking secondary opinions. In this study, we developed an AI ... Full text Cite

3Din vivodose verification in prostate proton therapy with deep learning-based proton-acoustic imaging.

Journal article Phys Med Biol · October 27, 2022 Dose delivery uncertainty is a major concern in proton therapy, adversely affecting the treatment precision and outcome. Recently, a promising technique, proton-acoustic (PA) imaging, has been developed to provide real-timein vivo3D dose verification. Howe ... Full text Link to item Cite

Fast four-dimensional cone-beam computed tomography reconstruction using deformable convolutional networks.

Journal article Med Phys · October 2022 BACKGROUND: Although four-dimensional cone-beam computed tomography (4D-CBCT) is valuable to provide onboard image guidance for radiotherapy of moving targets, it requires a long acquisition time to achieve sufficient image quality for target localization. ... Full text Link to item Cite

Patient-specific synthetic magnetic resonance imaging generation from cone beam computed tomography for image guidance in liver stereotactic body radiation therapy.

Journal article Precis Radiat Oncol · June 2022 OBJECTIVE: Despite its prevalence, cone beam computed tomography (CBCT) has poor soft-tissue contrast, making it challenging to localize liver tumors. We propose a patient-specific deep learning model to generate synthetic magnetic resonance imaging (MRI) ... Full text Link to item Cite

Dual-Intended Deep Learning Model for Breast Cancer Diagnosis in Ultrasound Imaging

Journal article Cancers · June 1, 2022 Automated medical data analysis demonstrated a significant role in modern medicine, and cancer diagnosis/prognosis to achieve highly reliable and generalizable systems. In this study, an automated breast cancer screening method in ultrasound imaging is pro ... Full text Cite

A geometry-guided multi-beamlet deep learning technique for CT reconstruction.

Journal article Biomed Phys Eng Express · May 13, 2022 Purpose. Previous studies have proposed deep-learning techniques to reconstruct CT images from sinograms. However, these techniques employ large fully-connected (FC) layers for projection-to-image domain transformation, producing large models requiring sub ... Full text Link to item Cite

Applications of Machine Learning to Improve the Clinical Viability of Compton Camera Based in vivo Range Verification in Proton Radiotherapy

Journal article Frontiers in Physics · April 11, 2022 We studied the application of a deep, fully connected Neural Network (NN) to process prompt gamma (PG) data measured by a Compton camera (CC) during the delivery of clinical proton radiotherapy beams. The network identifies 1) recorded “bad” PG events aris ... Full text Cite

Patient-specific deep learning model to enhance 4D-CBCT image for radiomics analysis.

Journal article Phys Med Biol · April 1, 2022 Objective.4D-CBCT provides phase-resolved images valuable for radiomics analysis for outcome prediction throughout treatment courses. However, 4D-CBCT suffers from streak artifacts caused by under-sampling, which severely degrades the accuracy of radiomic ... Full text Link to item Cite

Real-time Markerless Tracking of Lung Tumors based on 2-D Fluoroscopy Imaging using Convolutional LSTM.

Journal article IEEE Trans Radiat Plasma Med Sci · February 2022 PURPOSE: To investigate the feasibility of tracking targets in 2D fluor images using a novel deep learning network. METHODS: Our model design aims to capture the consistent motion of tumors in fluoroscopic images by neural network. Specifically, the model ... Full text Link to item Cite

The markerless lung target tracking AAPM Grand Challenge (MATCH) results.

Journal article Med Phys · February 2022 PURPOSE: Lung stereotactic ablative body radiotherapy (SABR) is a radiation therapy success story with level 1 evidence demonstrating its efficacy. To provide real-time respiratory motion management for lung SABR, several commercial and preclinical markerl ... Full text Link to item Cite

Enhancement of 4-D Cone-Beam Computed Tomography (4D-CBCT) Using a Dual-Encoder Convolutional Neural Network (DeCNN).

Journal article IEEE Trans Radiat Plasma Med Sci · February 2022 4D-CBCT is a powerful tool to provide respiration-resolved images for the moving target localization. However, projections in each respiratory phase are intrinsically under-sampled under the clinical scanning time and imaging dose constraints. Images recon ... Full text Link to item Cite

Prior image-guided cone-beam computed tomography augmentation from under-sampled projections using a convolutional neural network.

Journal article Quant Imaging Med Surg · December 2021 BACKGROUND: Acquiring sparse-view cone-beam computed tomography (CBCT) is an effective way to reduce the imaging dose. However, images reconstructed by the conventional filtered back-projection method suffer from severe streak artifacts due to the projecti ... Full text Link to item Cite

Multi-contrast four-dimensional magnetic resonance imaging (MC-4D-MRI): Development and initial evaluation in liver tumor patients.

Journal article Med Phys · December 2021 PURPOSE: To develop a novel multi-contrast four-dimensional magnetic resonance imaging (MC-4D-MRI) technique that expands single image contrast 4D-MRI to a spectrum of native and synthetic image contrasts and to evaluate its feasibility in liver tumor pati ... Full text Link to item Cite

A geometry-guided deep learning technique for CBCT reconstruction.

Journal article Phys Med Biol · July 30, 2021 Purpose.Although deep learning (DL) technique has been successfully used for computed tomography (CT) reconstruction, its implementation on cone-beam CT (CBCT) reconstruction is extremely challenging due to memory limitations. In this study, a novel DL tec ... 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

A phantom study of three-dimensional conformal radiation therapy and sliding window intensity-modulated radiation therapy based on 4D dose distribution

Journal article Chinese Journal of Radiation Oncology · March 15, 2021 Objective In this paper, based on the 4D dose distribution of the treatment plan, the effects of respiratory movement on the dose distribution of three-dimensional conformal radiation therapy (3DCRT) and sliding window intensity-modulated radiation therapy ... Full text Cite

4D radiomics: impact of 4D-CBCT image quality on radiomic analysis.

Journal article Phys Med Biol · February 11, 2021 PURPOSE: To investigate the impact of 4D-CBCT image quality on radiomic analysis and the efficacy of using deep learning based image enhancement to improve the accuracy of radiomic features of 4D-CBCT. MATERIAL AND METHODS: In this study, 4D-CT data from 1 ... Full text Link to item Cite

Building a patient-specific model using transfer learning for four-dimensional cone beam computed tomography augmentation.

Journal article Quant Imaging Med Surg · February 2021 BACKGROUND: We previously developed a deep learning model to augment the quality of four-dimensional (4D) cone-beam computed tomography (CBCT). However, the model was trained using group data, and thus was not optimized for individual patients. Consequentl ... Full text Link to item Cite

Respiratory deformation registration in 4D-CT/cone beam CT using deep learning.

Journal article Quant Imaging Med Surg · February 2021 BACKGROUND: To investigate the feasibility of using a supervised convolutional neural network (CNN) to register phase-to-phase deformable vector field of lung 4D-CT/4D-cone beam CT for 4D dose accumulation, contour propagation, motion modeling, or target v ... Full text Link to item Cite

Enhancing digital tomosynthesis (DTS) for lung radiotherapy guidance using patient-specific deep learning model.

Journal article Phys Med Biol · January 26, 2021 Digital tomosynthesis (DTS) has been proposed as a fast low-dose imaging technique for image-guided radiation therapy (IGRT). However, due to the limited scanning angle, DTS reconstructed by the conventional FDK method suffers from significant distortions ... Full text Link to item Cite

Intensity non-uniformity correction in MR imaging using residual cycle generative adversarial network.

Journal article Phys Med Biol · November 27, 2020 Correcting or reducing the effects of voxel intensity non-uniformity (INU) within a given tissue type is a crucial issue for quantitative magnetic resonance (MR) image analysis in daily clinical practice. Although having no severe impact on visual diagnosi ... Full text Link to item Cite

Adaptive respiratory signal prediction using dual multi-layer perceptron neural networks.

Journal article Phys Med Biol · September 14, 2020 To improve the prediction accuracy of respiratory signals by adapting the multi-layer perceptron neural network (MLP-NN) model to changing respiratory signals. We have previously developed an MLP-NN to predict respiratory signals obtained from a real-time ... Full text 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

Motion robust 4D-MRI sorting based on anatomic feature matching: A digital phantom simulation study.

Journal article Radiat Med Prot · March 2020 PURPOSE: Motion artifacts induced by breathing variations are common in 4D-MRI images. This study aims to reduce the motion artifacts by developing a novel, robust 4D-MRI sorting method based on anatomic feature matching and applicable in both cine and seq ... Full text Link to item Cite

Volumetric cine magnetic resonance imaging (VC-MRI) using motion modeling, free-form deformation and multi-slice undersampled 2D cine MRI reconstructed with spatio-temporal low-rank decomposition.

Journal article Quant Imaging Med Surg · February 2020 BACKGROUND: The purpose of this study is to improve on-board volumetric cine magnetic resonance imaging (VC-MRI) using multi-slice undersampled cine images reconstructed using spatio-temporal k-space data, patient prior 4D-MRI, motion modeling (MM) and fre ... Full text Link to item Cite

A multi-scale framework with unsupervised joint training of convolutional neural networks for pulmonary deformable image registration.

Journal article Phys Med Biol · January 13, 2020 To achieve accurate and fast deformable image registration (DIR) for pulmonary CT, we proposed a Multi-scale DIR framework with unsupervised Joint training of Convolutional Neural Network (MJ-CNN). MJ-CNN contains three models at multi-scale levels for a c ... Full text Link to item Cite

Clinical implementation of AI technologies will require interpretable AI models.

Journal article Med Phys · January 2020 Full text Link to item Cite

Augmentation of CBCT Reconstructed From Under-Sampled Projections Using Deep Learning.

Journal article IEEE Trans Med Imaging · November 2019 Edges tend to be over-smoothed in total variation (TV) regularized under-sampled images. In this paper, symmetric residual convolutional neural network (SR-CNN), a deep learning based model, was proposed to enhance the sharpness of edges and detailed anato ... Full text Link to item Cite

Daily edge deformation prediction using an unsupervised convolutional neural network model for low dose prior contour based total variation CBCT reconstruction (PCTV-CNN).

Journal article Biomed Phys Eng Express · October 2019 PURPOSE: Previously we developed a PCTV method to enhance the edge sharpness for low-dose CBCT reconstruction. However, the iterative deformable registration method used for deforming edges from planning-CT to on-board CBCT is time-consuming and user-depen ... Full text Link to item Cite

SPARE: Sparse-view reconstruction challenge for 4D cone-beam CT from a 1-min scan.

Journal article Med Phys · September 2019 PURPOSE: Currently, four-dimensional (4D) cone-beam computed tomography (CBCT) requires a 3-4 min full-fan scan to ensure usable image quality. Recent advancements in sparse-view 4D-CBCT reconstruction have opened the possibility to reduce scan time and do ... Full text Link to item Cite

Predicting real-time 3D deformation field maps (DFM) based on volumetric cine MRI (VC-MRI) and artificial neural networks for on-board 4D target tracking: a feasibility study.

Journal article Phys Med Biol · August 21, 2019 To predict real-time 3D deformation field maps (DFMs) using Volumetric Cine MRI (VC-MRI) and adaptive boosting and multi-layer perceptron neural network (ADMLP-NN) for 4D target tracking. One phase of a prior 4D-MRI is set as the prior phase, MRIprior. Pri ... Full text Link to item Cite

MRI-based treatment planning for liver stereotactic body radiotherapy: validation of a deep learning-based synthetic CT generation method.

Journal article Br J Radiol · August 2019 OBJECTIVE: The purpose of this work is to develop and validate a learning-based method to derive electron density from routine anatomical MRI for potential MRI-based SBRT treatment planning. METHODS: We proposed to integrate dense block into cycle generati ... Full text Link to item Cite

MRI-based treatment planning for proton radiotherapy: dosimetric validation of a deep learning-based liver synthetic CT generation method.

Journal article Phys Med Biol · July 16, 2019 Magnetic resonance imaging (MRI) has been widely used in combination with computed tomography (CT) radiation therapy because MRI improves the accuracy and reliability of target delineation due to its superior soft tissue contrast over CT. The MRI-only trea ... Full text Link to item Cite

Enhancing liver tumor localization accuracy by prior-knowledge-guided motion modeling and a biomechanical model.

Journal article Quant Imaging Med Surg · July 2019 BACKGROUND: Pre-treatment liver tumor localization remains a challenging task for radiation therapy, mostly due to the limited tumor contrast against normal liver tissues, and the respiration-induced liver tumor motion. Recently, we developed a biomechanic ... Full text Link to item Cite

Low dose cone-beam computed tomography reconstruction via hybrid prior contour based total variation regularization (hybrid-PCTV).

Journal article Quant Imaging Med Surg · July 2019 BACKGROUND: Previously, we developed a prior contour based total variation (PCTV) method to use edge information derived from prior images for edge enhancement in low-dose cone-beam computed tomography (CBCT) reconstruction. However, the accuracy of edge e ... Full text Link to item Cite

Technical Note: Imaging dose resulting from optimized procedures with limited-angle intrafractional verification system during stereotactic body radiation therapy lung treatment.

Journal article Med Phys · June 2019 PURPOSE: The limited-angle intrafractional verification (LIVE) system was developed to track tumor movement during stereotactic body radiation therapy (SBRT). However, the four-dimensional (4D) MV/kV imaging procedure results in additional radiation dose t ... Full text Link to item Cite

First clinical retrospective investigation of limited projection CBCT for lung tumor localization in patients receiving SBRT treatment.

Journal article Phys Med Biol · May 8, 2019 To clinically investigate the limited-projection CBCT (LP-CBCT) technology for daily positioning of patients receiving breath-hold lung SBRT radiation treatment and to investigate the feasibility of reconstructing fast 4D-CBCT from 1 min 3D-CBCT scan. Elev ... Full text Link to item Cite

Iterative inversion of deformation vector fields with feedback control.

Journal article Med Phys · July 2018 PURPOSE: Often, the inverse deformation vector field (DVF) is needed together with the corresponding forward DVF in four-dimesional (4D) reconstruction and dose calculation, adaptive radiation therapy, and simultaneous deformable registration. This study a ... Full text Link to item Cite

A Novel method to generate on-board 4D MRI using prior 4D MRI and on-board kV projections from a conventional LINAC for target localization in liver SBRT.

Journal article Med Phys · July 2018 PURPOSE: On-board MRI can provide superb soft tissue contrast for improving liver SBRT localization. However, the availability of on-board MRI in clinics is extremely limited. On the contrary, on-board kV imaging systems are widely available on radiotherap ... Full text Link to item Cite

Low dose CBCT reconstruction via prior contour based total variation (PCTV) regularization: a feasibility study.

Journal article Phys Med Biol · April 19, 2018 PURPOSE: compressed sensing reconstruction using total variation (TV) tends to over-smooth the edge information by uniformly penalizing the image gradient. The goal of this study is to develop a novel prior contour based TV (PCTV) method to enhance the edg ... Full text Link to item Cite

Monte Carlo analysis of beam blocking grid design parameters: Scatter estimation and the importance of electron backscatter.

Journal article Med Phys · March 2018 PURPOSE: Beam blocking grids provide a simple and direct measurement of the scattered photon signal which degrades image quality in x-ray imaging systems, such as cone-beam CT (CBCT). This study evaluates the scatter estimation accuracy of the beam blockin ... Full text Link to item Cite

Image acquisition optimization of a limited-angle intrafraction verification (LIVE) system for lung radiotherapy.

Journal article Med Phys · January 2018 PURPOSE: Limited-angle intrafraction verification (LIVE) has been previously developed for four-dimensional (4D) intrafraction target verification either during arc delivery or between three-dimensional (3D)/IMRT beams. Preliminary studies showed that LIVE ... Full text Link to item Cite

Principal component reconstruction (PCR) for cine CBCT with motion learning from 2D fluoroscopy.

Journal article Med Phys · January 2018 PURPOSE: This work aims to generate cine CT images (i.e., 4D images with high-temporal resolution) based on a novel principal component reconstruction (PCR) technique with motion learning from 2D fluoroscopic training images. METHODS: In the proposed PCR m ... Full text Link to item Cite

Accelerating volumetric cine MRI (VC-MRI) using undersampling for real-time 3D target localization/tracking in radiation therapy: a feasibility study.

Journal article Phys Med Biol · December 14, 2017 PURPOSE: To accelerate volumetric cine MRI (VC-MRI) using undersampled 2D-cine MRI to provide real-time 3D guidance for gating/target tracking in radiotherapy. METHODS: 4D-MRI is acquired during patient simulation. One phase of the prior 4D-MRI is selected ... Full text Link to item Cite

Clinical Study of Orthogonal-View Phase-Matched Digital Tomosynthesis for Lung Tumor Localization.

Journal article Technol Cancer Res Treat · December 2017 BACKGROUND AND PURPOSE: Compared to cone-beam computed tomography, digital tomosynthesis imaging has the benefits of shorter scanning time, less imaging dose, and better mechanical clearance for tumor localization in radiation therapy. However, for lung tu ... Full text Link to item 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

Dosimetric Analysis of Microscopic Disease in SBRT for Lung Cancers.

Journal article Technol Cancer Res Treat · December 2017 OBJECTIVE: The objective of this study is to theoretically and experimentally evaluate the dosimetry in the microscopic disease regions surrounding the tumor under stereotactic body radiation therapy of lung cancer. METHODS: For simplicity, the tumor was c ... Full text Link to item Cite

Respiratory signal prediction based on adaptive boosting and multi-layer perceptron neural network.

Journal article Phys Med Biol · August 3, 2017 To improve the prediction accuracy of respiratory signals using adaptive boosting and multi-layer perceptron neural network (ADMLP-NN) for gated treatment of moving target in radiation therapy. The respiratory signals acquired using a real-time position ma ... Full text Link to item Cite

Reducing scan angle using adaptive prior knowledge for a limited-angle intrafraction verification (LIVE) system for conformal arc radiotherapy.

Journal article Phys Med Biol · May 7, 2017 The purpose of this study is to develop an adaptive prior knowledge guided image estimation technique to reduce the scan angle needed in the limited-angle intrafraction verification (LIVE) system for 4D-CBCT reconstruction. The LIVE system has been previou ... Full text Link to item Cite

Estimating 4D-CBCT from prior information and extremely limited angle projections using structural PCA and weighted free-form deformation for lung radiotherapy.

Journal article Med Phys · March 2017 PURPOSE: To investigate the feasibility of using structural-based principal component analysis (PCA) motion-modeling and weighted free-form deformation to estimate on-board 4D-CBCT using prior information and extremely limited angle projections for potenti ... Full text Link to item Cite

Markerless Four-Dimensional-Cone Beam Computed Tomography Projection-Phase Sorting Using Prior Knowledge and Patient Motion Modeling: A Feasibility Study.

Journal article Cancer Transl Med · 2017 AIM: During cancer radiotherapy treatment, on-board four-dimensional-cone beam computed tomography (4D-CBCT) provides important patient 4D volumetric information for tumor target verification. Reconstruction of 4D-CBCT images requires sorting of acquired p ... Open Access Link to item Cite

Sensitivity of 3D Dose Verification to Multileaf Collimator Misalignments in Stereotactic Body Radiation Therapy of Spinal Tumor.

Journal article Technol Cancer Res Treat · December 2016 PURPOSE: This study aimed to detect the sensitivity of Delt 4 on ordinary field multileaf collimator misalignments, system misalignments, random misalignments, and misalignments caused by gravity of the multileaf collimator in stereotactic body radiation t ... Full text Link to item Cite

Scatter Reduction and Correction for Dual-Source Cone-Beam CT Using Prepatient Grids.

Journal article Technol Cancer Res Treat · June 2016 PURPOSE: Scatter significantly limits the application of the dual-source cone-beam computed tomography by inducing scatter artifacts and degrading contrast-to-noise ratio, Hounsfield-unit accuracy, and image uniformity. Although our previously developed in ... Full text Link to item Cite

A Technique for Generating Volumetric Cine-Magnetic Resonance Imaging.

Journal article Int J Radiat Oncol Biol Phys · June 1, 2016 PURPOSE: The purpose of this study was to develop a techique to generate on-board volumetric cine-magnetic resonance imaging (VC-MRI) using patient prior images, motion modeling, and on-board 2-dimensional cine MRI. METHODS AND MATERIALS: One phase of a 4- ... Full text Link to item Cite

An interprojection sensor fusion approach to estimate blocked projection signal in synchronized moving grid-based CBCT system.

Journal article Med Phys · January 2016 PURPOSE: A preobject grid can reduce and correct scatter in cone beam computed tomography (CBCT). However, half of the signal in each projection is blocked by the grid. A synchronized moving grid (SMOG) has been proposed to acquire two complimentary projec ... Full text Link to item Cite

Dosimetric verification of lung cancer treatment using the CBCTs estimated from limited-angle on-board projections.

Journal article Med Phys · August 2015 PURPOSE: Lung cancer treatment is susceptible to treatment errors caused by interfractional anatomical and respirational variations of the patient. On-board treatment dose verification is especially critical for the lung stereotactic body radiation therapy ... Full text Link to item Cite

Preliminary clinical evaluation of a 4D-CBCT estimation technique using prior information and limited-angle projections.

Journal article Radiother Oncol · April 2015 BACKGROUND AND PURPOSE: A technique has been previously reported to estimate high-quality 4D-CBCT using prior information and limited-angle projections. This study is to investigate its clinical feasibility through both phantom and patient studies. MATERIA ... Full text Link to item Cite

A limited-angle intrafraction verification (LIVE) system for radiation therapy.

Journal article Med Phys · February 2014 PURPOSE: Currently, no 3D or 4D volumetric x-ray imaging techniques are available for intrafraction verification of target position during actual treatment delivery or in-between treatment beams, which is critical for stereotactic radiosurgery (SRS) and st ... Full text Link to item Cite

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

Journal article Med Phys · December 2013 PURPOSE: To develop a technique to estimate onboard 4D-CBCT using prior information and limited-angle projections for potential 4D target verification of lung radiotherapy. METHODS: Each phase of onboard 4D-CBCT is considered as a deformation from one sele ... Full text Link to item Cite

Respiration-phase-matched digital tomosynthesis imaging for moving target verification: a feasibility study.

Journal article Med Phys · July 2013 PURPOSE: To develop a respiration-phase-matched digital tomosynthesis (DTS) technique to monitor moving targets, and to evaluate its accuracy for various imaging parameters and anatomical characteristics. METHODS: Previously developed 3D-DTS techniques, re ... Full text Link to item Cite

Evaluation of multiple image-based modalities for image-guided radiation therapy (IGRT) of prostate carcinoma: a prospective study.

Journal article Med Phys · April 2013 Featured Publication PURPOSE: Setup errors and prostate intrafraction motion are main sources of localization uncertainty in prostate cancer radiation therapy. This study evaluates four different imaging modalities 3D ultrasound (US), kV planar images, cone-beam computed tomog ... Full text Link to item Cite

Commissioning and dosimetric characteristics of TrueBeam system: composite data of three TrueBeam machines.

Journal article Med Phys · November 2012 Featured Publication PURPOSE: A TrueBeam linear accelerator (TB-LINAC) is designed to deliver traditionally flattened and flattening-filter-free (FFF) beams. Although it has been widely adopted in many clinics for patient treatment, limited information is available related to ... Full text Link to item Cite

Implementation of dual-energy technique for virtual monochromatic and linearly mixed CBCTs.

Journal article Med Phys · October 2012 Featured Publication PURPOSE: To implement dual-energy imaging technique for virtual monochromatic (VM) and linearly mixed (LM) cone beam CTs (CBCTs) and to demonstrate their potential applications in metal artifact reduction and contrast enhancement in image-guided radiation ... Full text Link to item Cite

Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in cone-beam computed tomography (CBCT).

Journal article Med Phys · August 2012 Featured Publication PURPOSE: To evaluate the feasibility of a synchronized moving grid (SMOG) system to remove scatter artifacts, improve the contrast-to-noise ratio (CNR), and reduce image lag artifacts in cone-beam CT (CBCT). METHODS: The SMOG system proposed here uses a ra ... Full text Link to item Cite

Imaging system QA of a medical accelerator, Novalis Tx, for IGRT per TG 142: our 1 year experience.

Journal article J Appl Clin Med Phys · July 5, 2012 American Association of Physicists in Medicine (AAPM) task group (TG) 142 has recently published a report to update recommendations of the AAPM TG 40 report and add new recommendations concerning medical accelerators in the era of image-guided radiation th ... Full text Open Access Link to item Cite

SU-E-T-104: Commissioning and Dosimetric Characteristics of TrueBeam System: Composite Data of Three TrueBeam Machines.

Journal article Med Phys · June 2012 INTRODUCTION: A TrueBeam linear accelerator (TB-LINAC) is designed to deliver standard flattened and flattening-filter-free (FFF) beams. In our institute, three TB-LINAC units are installed. In this work, composite data of the three units and multi-unit co ... Full text Link to item Cite

Clinical commissioning and use of the Novalis Tx linear accelerator for SRS and SBRT.

Journal article J Appl Clin Med Phys · May 10, 2012 The purpose of this study was to perform comprehensive measurements and testing of a Novalis Tx linear accelerator, and to develop technical guidelines for com-missioning from the time of acceptance testing to the first clinical treatment. The Novalis Tx ( ... Full text Link to item Cite

Development and clinical evaluation of a three-dimensional cone-beam computed tomography estimation method using a deformation field map.

Journal article Int J Radiat Oncol Biol Phys · April 1, 2012 Featured Publication PURPOSE: To develop a three-dimensional (3D) cone-beam computed tomography (CBCT) estimation method using a deformation field map, and to evaluate and optimize the efficiency and accuracy of the method for use in the clinical setting. METHODS AND MATERIALS ... Full text Link to item Cite

Imaging system QA of a medical accelerator, Novalis Tx, for IGRT per TG 142: Our 1 year experience

Journal article Journal of Applied Clinical Medical Physics · January 1, 2012 Featured Publication American Association of Physicists in Medicine (AAPM) task group (TG) 142 has recently published a report to update recommendations of the AAPM TG 40 report and add new recommendations concerning medical accelerators in the era of image-guided radiation th ... Full text Cite

Advances in treatment techniques: arc-based and other intensity modulated therapies.

Journal article Cancer J · 2011 Featured Publication Treatment planning and radiation delivery techniques have advanced significantly during the past 2 decades. The development of the multileaf collimator has changed the scope of radiotherapy. The dynamic conformal arc technique emerged from traditional cone ... Full text Link to item Cite

A TCP model incorporating setup uncertainty and tumor cell density variation in microscopic extension to guide treatment planning.

Journal article Med Phys · January 2011 Featured Publication PURPOSE: Tumor control probability (TCP) models have been proposed to evaluate and guide treatment planning. However, they are usually based on the dose volume histograms (DVHs) of the planning target volume (PTV) and may not properly reflect the substanti ... Full text Link to item Cite

Combining scatter reduction and correction to improve image quality in cone-beam computed tomography (CBCT).

Journal article Med Phys · November 2010 Featured Publication PURPOSE: The authors propose a combined scatter reduction and correction method to improve image quality in cone-beam computed tomography (CBCT). Although using a beam-block approach similar to previous techniques to measure the scatter, this method differ ... Full text Link to item Cite

Clinical evaluation of positioning verification using digital tomosynthesis and bony anatomy and soft tissues for prostate image-guided radiotherapy.

Journal article Int J Radiat Oncol Biol Phys · January 1, 2009 Featured Publication PURPOSE: To evaluate on-board digital tomosynthesis (DTS) for patient positioning vs. two-dimensional (2D) radiography and three-dimensional cone beam (CBCT). METHODS AND MATERIALS: A total of 92 image sessions from 9 prostate cancer patients were analyzed ... Full text Link to item Cite

A novel digital tomosynthesis (DTS) reconstruction method using a deformation field map.

Journal article Med Phys · July 2008 Featured Publication We developed a novel digital tomosynthesis (DTS) reconstruction method using a deformation field map to optimally estimate volumetric information in DTS images. The deformation field map is solved by using prior information, a deformation model, and new pr ... Full text Link to item Cite

Automatic registration between reference and on-board digital tomosynthesis images for positioning verification.

Journal article Med Phys · February 2008 Featured Publication The authors developed a hybrid multiresolution rigid-body registration technique to automatically register reference digital tomosynthesis (DTS) images with on-board DTS images to guide patient positioning in radiation therapy. This hybrid registration tec ... Full text Link to item Cite

Evaluation of Image Enhancement Method on Target Registration Using Cone Beam CT in Radiation Therapy.

Journal article Clin Med Oncol · 2008 An intensity based six-degree image registration algorithm between cone-beam CT (CBCT) and planning CT has been developed for image-guided radiation therapy (IGRT). CT images of an anthropomorphic chest phantom were acquired using conventional CT scanner a ... Full text Link to item Cite

Accelerating reconstruction of reference digital tomosynthesis using graphics hardware.

Journal article Med Phys · October 2007 Featured Publication The successful implementation of digital tomosynthesis (DTS) for on-board image guided radiation therapy (IGRT) requires fast DTS image reconstruction. Both target and reference DTS image sets are required to support an image registration application for I ... Full text Link to item Cite

Evaluation of three types of reference image data for external beam radiotherapy target localization using digital tomosynthesis (DTS).

Journal article Med Phys · August 2007 Featured Publication Digital tomosynthesis (DTS) is a fast, low-dose three-dimensional (3D) imaging approach which yields slice images with excellent in-plane resolution, though low plane-to-plane resolution. A stack of DTS slices can be reconstructed from a single limited-ang ... Full text Link to item Cite