Scholars@Duke
Justus D Adamson

Justus D Adamson

Associate Professor of Radiation Oncology
Radiation Oncology
justus.adamson@duke.edu
Radiation Physics Red Zone Bas, Box 3295, Durham, NC 27710

Selected Publications

Clinical applicability of Linac-integrated CBCT based NIPAM 3D dosimetry: a dual-institutional investigation.

Journal Article Phys Med Biol · July 16, 2024 Objective.To develop and benchmark a novel 3D dose verification technique consisting of polymer gel dosimetry (PGD) with cone-beam-CT (CBCT) readout through a two-institution study. The technique has potential for wide and robust applicability through reli ... Full text Link to item Cite

Independent Monte Carlo dose calculation identifies single isocenter multi-target radiosurgery targets most likely to fail pre-treatment measurement.

Journal Article J Appl Clin Med Phys · June 2024 PURPOSE: For individual targets of single isocenter multi-target (SIMT) Stereotactic radiosurgery (SRS), we assess dose difference between the treatment planning system (TPS) and independent Monte Carlo (MC), and demonstrate persistence into the pre-treatm ... Full text Link to item Cite

Effects of Ataxia-Telangiectasia Mutated Variants on Radionecrosis and Local Control After Stereotactic Radiation Surgery for Non-Small Cell Lung Cancer Brain Metastases.

Journal Article Adv Radiat Oncol · January 2024 PURPOSE: Genetic variants affecting the radiation response protein ataxia-telangiectasia mutated (ATM) have been associated with increased adverse effects of radiation but also with improved local control after conventional radiation therapy. However, it i ... Full text Link to item Cite

Clinical Applications and Monte Carlo Validation of a fully integrated 3D dosimetry system

Conference Journal of Physics: Conference Series · January 1, 2024 A comprehensive 3D dosimetry system consisting of the ClearView™ 3D dosimeter, VistaScan™ optical CT scanner, and VistaAce™ analysis software is commercially available and has the potential to be a strong verification tool with widespread applications. The ... Full text Cite

A radiomics-incorporated deep ensemble learning model for multi-parametric MRI-based glioma segmentation.

Journal Article Phys Med Biol · September 13, 2023 Objective.To develop a deep ensemble learning (DEL) model with radiomics spatial encoding execution for improved glioma segmentation accuracy using multi-parametric magnetic resonance imaging (mp-MRI).Approach.This model was developed using 369 glioma pati ... Full text Link to item Cite

Generation, validation, and benchmarking of a commercial independent Monte Carlo calculation beam model for multi-target SRS.

Journal Article Z Med Phys · September 7, 2023 BACKGROUND: Dosimetric validation of single isocenter multi-target radiosurgery plans is difficult due to conditions of electronic disequilibrium and the simultaneous irradiation of multiple off-axis lesions dispersed throughout the volume. Here we report ... Full text Link to item Cite

A structured FMEA approach to optimizing combinations of plan-specific quality assurance techniques for IMRT and VMAT QA.

Journal Article Med Phys · September 2023 BACKGROUND: Many commercial tools are available for plan-specific quality assurance (QA) of radiotherapy plans, with their functionality assessed in isolation. However, multiple QA tools are required to review the full range of potential errors. It is impo ... Full text Link to item Cite

Investigation of a 3D dosimetry system utilizing radio-chromic gel and telecentric optical-CT readout.

Journal Article Med Phys · September 2023 BACKGROUND: Sophisticated modern radiation therapy treatments require comprehensive validation in 3D. PURPOSE: Investigation and characterization of a novel 3D dosimetry system consisting of ClearView radiochromic gel dosimeters (commercially available fro ... Full text Link to item Cite

Uncertainties in the dosimetric heterogeneity correction and its potential effect on local control in lung SBRT.

Journal Article Biomed Phys Eng Express · March 7, 2023 Objective. Dose calculation in lung stereotactic body radiation therapy (SBRT) is challenging due to the low density of the lungs and small volumes. Here we assess uncertainties associated with tissue heterogeneities using different dose calculation algori ... Full text Link to item Cite

Outcomes in Patients with Intact and Resected Brain Metastasis Treated with 5-Fraction Stereotactic Radiosurgery.

Journal Article Advances in radiation oncology · March 2023 PurposeHypofractionated stereotactic radiosurgery (HF-SRS) with or without surgical resection is potentially a preferred treatment for larger or symptomatic brain metastases (BMs). Herein, we report clinical outcomes and predictive factors followi ... Full text Cite

Virtual patient-specific QA with DVH-based metrics.

Journal Article J Appl Clin Med Phys · November 2022 We demonstrate a virtual pretreatment patient-specific QA (PSQA) procedure that is capable of quantifying dosimetric effect on patient anatomy for both intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). A machine learning ... Full text Link to item Cite

TARDIS: An updated artificial intelligence model to predict linear accelerator machine parameters at treatment delivery

Journal Article SoftwareX · July 1, 2022 We present an open-source artificial intelligence (AI) model that predicts machine parameters at treatment delivery using trajectory files from prior patients. Predictive models for IMRT and VMAT utilized a boosted and bagged tree, respectively, and predic ... Full text Cite

Development of a practical clinical application of NIPAM kV-CBCT dosimetry

Conference Journal of Physics: Conference Series · January 24, 2022 We report our progress towards developing a clinical application of NIPAM kV-CBCT dosimetry. The goal is to develop a practical kV-MV isocenter verification test for which the measurement and analysis can be carried out quickly (within an hour), and that e ... Full text Cite

Factors Associated With New-Onset Seizures Following Stereotactic Radiosurgery for Newly Diagnosed Brain Metastases.

Conference Adv Radiat Oncol · 2022 PURPOSE: Stereotactic radiosurgery (SRS) is a highly effective therapy for newly diagnosed brain metastases. Prophylactic antiepileptic drugs are no longer routinely used in current SRS practice, owing to a perceived low overall frequency of new-onset seiz ... Full text Link to item Cite

The Effect of Various Dose Normalization Strategies When Implementing Linear Boltzmann Transport Equation Dose Calculation for Lung Stereotactic Body Radiation Therapy Planning.

Journal Article Pract Radiat Oncol · 2022 PURPOSE: To explore implications of various plan normalizations when implementing a linear Boltzmann transport equation solver dose calculation algorithm (LBTE) for lung stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: Eighty-seven plans ... Full text Link to item Cite

Feasibility of a Novel 3D Dosimetry System for Commissioning of Single Isocenter Multitarget SRS Treatment

Conference INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS · 2022 Cite

Single isocenter SRS using CAVMAT offers improved robustness to commissioning and treatment delivery uncertainty compared to VMAT.

Journal Article J Appl Clin Med Phys · July 2021 PURPOSE: In this study, we evaluate and compare single isocenter multiple target VMAT (SIMT) and Conformal Arc Informed VMAT (CAVMAT) radiosurgery's sensitivity to uncertainties in dosimetric leaf gap (DLG) and treatment delivery. CAVMAT is a novel plannin ... Full text Link to item Cite

Hippocampal Avoidance in Multitarget Radiosurgery.

Journal Article Cureus · June 2021 Brain metastases are a common complication for patients diagnosed with cancer. As stereotactic radiosurgery (SRS) becomes a more prevalent treatment option for patients with many brain metastases, further research is required to better characterize the abi ... Full text Open Access Link to item Cite

A tool for patient-specific prediction of delivery discrepancies in machine parameters using trajectory log files.

Journal Article Med Phys · March 2021 PURPOSE: Multileaf collimator (MLC) delivery discrepancy between planned and actual (delivered) positions have detrimental effect on the accuracy of dose distributions for both IMRT and VMAT. In this study, we evaluated the consistency of MLC delivery disc ... Full text Link to item Cite

Outcomes in Patients With 4 to 10 Brain Metastases Treated With Dose-Adapted Single-Isocenter Multitarget Stereotactic Radiosurgery: A Prospective Study.

Journal Article Adv Radiat Oncol · 2021 PURPOSE: To examine the effectiveness and safety of single-isocenter multitarget stereotactic radiosurgery using a volume-adapted dosing strategy in patients with 4 to 10 brain metastases. METHODS AND MATERIALS: Adult patients with 4 to 10 brain metastases ... Full text Link to item Cite

On the use of trajectory log files for machine & patient specific QA.

Journal Article Biomed Phys Eng Express · December 4, 2020 Purpose:Trajectory log files are increasingly being utilized clinically for machine and patient specific QA. The process of converting the DICOM-RT plan to a deliverable trajectory by the linac control software introduces some uncertainty that is inherentl ... Full text Link to item Cite

Current multidisciplinary management of brain metastases.

Journal Article Cancer · April 1, 2020 Brain metastasis (BM), the most common adult brain tumor, develops in 20% to 40% of patients with late-stage cancer and traditionally are associated with a poor prognosis. The management of patients with BM has become increasingly complex because of new an ... Full text Link to item Cite

Comprehensive radiation and imaging isocenter verification using NIPAM kV-CBCT dosimetry.

Journal Article Med Phys · March 2020 PURPOSE: To develop and demonstrate a comprehensive method to directly measure radiation isocenter uncertainty and coincidence with the cone-beam computed tomography (kV-CBCT) imaging coordinate system that can be carried out within a typical quality assur ... Full text Link to item Cite

Application of TG-218 action limits to SRS and SBRT pre-treatment patient specific QA.

Journal Article J Radiosurg SBRT · 2020 AAPM TG-218 provides recommendations for standard IMRT pre-treatment QA without giving specifics for stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). In light of this, our purpose is to report our experience with applying TG-218 r ... Link to item Cite

Evaluation of UVA emission from x-ray megavoltage-irradiated tissues and phantoms.

Journal Article Phys Med Biol · November 21, 2019 RECA (Radiotherapy enhanced with Cherenkov photo-activation) is a proposed treatment where the anti-cancer drug psoralen is photo-activated in situ by UVA (Ultraviolet A, 320-400 nm) Cherenkov light (CL) produced directly by the treatment beam itself. In t ... Full text Link to item Cite

Postoperative Five-Fraction Radiosurgery for Resected Brain Metastases

Conference International Journal of Radiation Oncology*Biology*Physics · September 2019 Full text Cite

Feasibility of radiosurgery dosimetry using NIPAM 3D dosimeters and x-ray CT

Conference Journal of Physics: Conference Series · August 29, 2019 We investigated the feasibility of using N-isopropylacrylamide (NIPAM) dosimeters with x-ray CT to verify radiosurgery dose. Dosimeters were prepared at one facility and shipped to a second facility for irradiation. A simulation CT was acquired and plans p ... Full text Cite

Delivered Dose Distribution Visualized Directly With Onboard kV-CBCT: Proof of Principle.

Journal Article Int J Radiat Oncol Biol Phys · April 1, 2019 PURPOSE: To demonstrate proof of principle of visualizing delivered 3-dimensional (3D) dose distribution using kilovoltage (kv) cone beam computed tomography (CBCT) mounted onboard a linear accelerator. We apply this technique as a unique end-to-end verifi ... Full text Link to item Cite

Predicting intracranial progression following stereotactic radiosurgery for brain metastases: Implications for post SRS imaging.

Journal Article J Radiosurg SBRT · 2019 PURPOSE: Follow-up imaging after stereotactic radiosurgery (SRS) is crucial to identify salvageable brain metastases (BM) recurrence. As optimal imaging intervals are poorly understood, we sought to build a predictive model for time to intracranial progres ... Link to item Cite

The effect of MLC leaf width in single-isocenter multi-target radiosurgery with volumetric modulated arc therapy.

Journal Article J Radiosurg SBRT · 2019 PURPOSE: Single-isocenter multi-target (SIMT) volumetric modulated arc therapy (VMAT) is primarily limited to linear accelerators utilizing 2.5 mm leaf width MLCs. We explore feasibility of applying this technique to linear accelerators utilizing MLCs with ... Open Access Link to item Cite

Technical Note: On maximizing Cherenkov emissions from medical linear accelerators.

Journal Article Med Phys · July 2018 PURPOSE: Cherenkov light during MV radiotherapy has recently found imaging and therapeutic applications but is challenged by relatively low fluence. Our purpose is to investigate the feasibility of increasing Cherenkov light production during MV radiothera ... Full text Link to item Cite

In Reply to Pratx and Kapp.

Journal Article Int J Radiat Oncol Biol Phys · June 1, 2018 Full text Link to item Cite

Enhancing Radiation Therapy Through Cherenkov Light-Activated Phototherapy.

Journal Article Int J Radiat Oncol Biol Phys · March 1, 2018 PURPOSE: This work investigates a new approach to enhance radiotherapy through a photo therapeutic agent activated by Cherenkov light produced from the megavoltage photon beam. The process is termed Radiotherapy Enhanced with Cherenkov photo-Activation (RE ... Full text Open Access Link to item Cite

Characterization of Water-Clear Polymeric Gels for Use as Radiotherapy Bolus.

Journal Article Technol Cancer Res Treat · December 2017 Our purpose was to investigate polymeric gels for use as a highly transparent radiotherapy bolus and determine the relevant physical and dosimetric properties. We first quantified tensile properties (maximum stress, strain, and Young modulus) for various p ... Full text Link to item Cite

Enhancing Radiation Therapy Through Cherenkov Light-Activated Phototherapy from Clinical Megavoltage Treatment Beams

Conference International Journal of Radiation Oncology*Biology*Physics · October 2017 Full text Cite

Utilizing a diagnostic kV imaging system for x-ray psoralen activated cancer therapy (X-PACT)

Journal Article Biomedical Physics and Engineering Express · May 25, 2017 X-ray psoralen activated cancer therapy (X-PACT) is a new therapeutic approach that has been shown to induce tumor cell apoptosis and cytotoxicity in vitro, and slow tumor growth in BALB/c mice with syngeneic 4T1 tumors. X-PACT is accomplished by injection ... Full text Cite

An in-house protocol for improved flood field calibration of TrueBeam FFF cine imaging.

Journal Article J Appl Clin Med Phys · January 2017 PURPOSE: TrueBeams equipped with the 40 × 30 cm2 Electronic Portal Imaging Devices (EPIDs) are prone to image saturation at the image center when used with flattening filter free (FFF) photon energies. While cine imaging during treatment may not saturate b ... Full text Link to item Cite

Triphasic contrast enhanced CT simulation with bolus tracking for pancreas SBRT target delineation.

Journal Article Pract Radiat Oncol · 2017 PURPOSE: Bolus-tracked multiphasic contrast computed tomography (CT) is often used in diagnostic radiology to enhance the visibility of pancreas tumors, but is uncommon in radiation therapy pancreas CT simulation, and its impact on gross tumor volume (GTV) ... Full text Link to item Cite

Single fraction stereotactic radiosurgery for multiple brain metastases.

Journal Article Adv Radiat Oncol · 2017 INTRODUCTION: Due to the neurocognitive side effects of whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS) is being used with increasing frequency. The use of SRS is expanding for patients with multiple (>4) brain metastases (BM). This s ... Full text Open Access Link to item Cite

Single-Fraction Radiosurgery for 4 or More Brain Metastases.

Journal Article Int J Radiat Oncol Biol Phys · October 1, 2016 Full text Open Access Link to item Cite

Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery.

Journal Article Med Phys · October 2016 PURPOSE: The recent development of multifocal stereotactic radiosurgery (SRS) using a single isocenter volumetric modulated arc theory (VMAT) technique warrants a re-examination of the quality assurance (QA) tolerances for routine mechanical QA recommended ... Full text Link to item Cite

WE-FG-BRA-01: Cancer Treatment Utilizing Photo-Activation of Psoralen with KV X-Rays.

Journal Article Med Phys · June 2016 PURPOSE: This work investigates X-PACT (X-ray Psoralen Activated Cancer Therapy): a new approach for the treatment of cancer. X-PACT utilizes psoralen, a potent anti-cancer therapeutic with immunogenic anti-cancer potential. Psoralen therapies have been li ... Full text Link to item Cite

SU-C-204-06: Monte Carlo Dose Calculation for Kilovoltage X-Ray-Psoralen Activated Cancer Therapy (X-PACT): Preliminary Results.

Journal Article Med Phys · June 2016 PURPOSE: X-PACT is an experimental cancer therapy where kV x-rays are used to photo-activate anti-cancer therapeutics through phosphor intermediaries (phosphors that absorb x-rays and re-radiate as UV light). Clinical trials in pet dogs are currently under ... Full text Link to item Cite

SU-F-T-283: A Novel Device to Enable Portal Dosimetry for Flattening Filter Free Beams.

Journal Article Med Phys · June 2016 PURPOSE: Varian's electronic portal imaging device (EPID) based portal dosimetry tool is a popular and effective means of performing IMRT QA. EPIDs for older models of the TrueBeam accelerator utilize a 40cmx30cm Image Detection Unit (IDU) that saturates a ... Full text Link to item Cite

SU-G-TeP4-01: A High Resolution Pre-Treatment VMAT QA Technique Based On EPID for Single Isocenter Multiple Mets Stereotactic Radiosurgery.

Journal Article Med Phys · June 2016 PURPOSE: For multiple mets radiosurgery, it is advantageous to use VMAT with a single isocenter for the ease in planning and efficiency in delivery. Insightful pre-treatment QA for these cases is difficult to obtain because (1) target size is often small a ... Full text Link to item Cite

SU‐C‐202‐07: Protocol and Hardware for Improved Flood Field Calibration of TrueBeam FFF Cine Imaging

Conference Medical Physics · June 2016 Purpose:Flattening filter free photon energies are commonly used for high dose treatments such as SBRT, where localization accuracy is essential. Often, MV cine imaging may be employed to verify correct localizati ... Full text Cite

On the sensitivity of TG-119 and IROC credentialing to TPS commissioning errors.

Journal Article J Appl Clin Med Phys · January 8, 2016 We investigate the sensitivity of IMRT commissioning using the TG-119 C-shape phantom and credentialing with the IROC head and neck phantom to treatment planning system commissioning errors. We introduced errors into the various aspects of the commissionin ... Full text Open Access Link to item Cite

Physics considerations for single-isocenter, volumetric modulated arc radiosurgery for treatment of multiple intracranial targets.

Conference Pract Radiat Oncol · 2016 OBJECTIVE: Our purpose was to address challenges associated with single-isocenter radiosurgery for multiple intracranial targets (SIRMIT) including increased sensitivity to rotational uncertainties (resulting from distance of the targets from isocenter) as ... Full text Link to item Cite

Adaptive planning using positron emission tomography for locally advanced lung cancer: A feasibility study.

Journal Article Pract Radiat Oncol · 2016 PURPOSE: To evaluate the feasibility of adaptive planning using positron emission tomography-computed tomography (PET-CT) in locally advanced non-small cell lung cancer. METHODS AND MATERIALS: Patients with locally advanced non-small cell lung cancer recei ... Full text Link to item Cite

On the sensitivity of TG-119 and IROC credentialing to TPS commissioning errors.

Journal Article J Appl Clin Med Phys · January 2016 We investigate the sensitivity of IMRT commissioning using the TG-119 C-shape phantom and credentialing with the IROC head and neck phantom to treatment planning system commissioning errors. We introduced errors into the various aspects of the commissionin ... Full text Link to item Cite

X-Ray Psoralen Activated Cancer Therapy (X-PACT).

Journal Article PLoS One · 2016 This work investigates X-PACT (X-ray Psoralen Activated Cancer Therapy): a new approach for the treatment of solid cancer. X-PACT utilizes psoralen, a potent anti-cancer therapeutic with current application to proliferative disease and extracorporeal photo ... Full text Open Access Link to item Cite

A Prospective Study of Adaptive Planning Utilizing Interim PET-CT for Locally Advanced Lung Cancer

Conference International Journal of Radiation Oncology*Biology*Physics · November 2015 Full text Cite

Utilizing knowledge from prior plans in the evaluation of quality assurance.

Journal Article Phys Med Biol · June 21, 2015 Increased interest regarding sensitivity of pre-treatment intensity modulated radiotherapy and volumetric modulated arc radiotherapy (VMAT) quality assurance (QA) to delivery errors has led to the development of dose-volume histogram (DVH) based analysis. ... Full text Link to item Cite

SU-E-J-223: A BOLD Contrast Imaging Sequence to Evaluate Oxygenation Changes Due to Breath Holding for Breast Radiotherapy: A Pilot Study.

Journal Article Med Phys · June 2015 PURPOSE: To develop a robust MRI sequence to measure BOLD breath hold induced contrast in context of breast radiotherapy. METHODS: Two sequences were selected from prior studies as candidates to measure BOLD contrast attributable to breath holding within t ... Full text Link to item Cite

SU-E-T-93: Activation of Psoralen at Depth Using Kilovoltage X-Rays: Physics Considerations in Implementing a New Teletherapy Paradigm.

Journal Article Med Phys · June 2015 PURPOSE: Psoralen is a UV-light activated anti-cancer biotherapeutic used for treating skin lesions (PUVA) and advanced cutaneous T-cell lymphoma (ECP). To date psoralen has not been used to treat deep seated tumors due to difficulty in generating UV-light ... Full text Link to item Cite

Treatment Planning and Delivery of Whole Brain Irradiation with Hippocampal Avoidance in Rats.

Journal Article PLoS One · 2015 BACKGROUND: Despite the clinical benefit of whole brain radiotherapy (WBRT), patients and physicians are concerned by the long-term impact on cognitive functioning. Many studies investigating the molecular and cellular impact of WBRT have used rodent model ... Full text Link to item Cite

On the feasibility of polyurethane based 3D dosimeters with optical CT for dosimetric verification of low energy photon brachytherapy seeds.

Journal Article Med Phys · July 2014 PURPOSE: To investigate the feasibility of and challenges yet to be addressed to measure dose from low energy (effective energy <50 keV) brachytherapy sources (Pd-103, Cs-131, and I-125) using polyurethane based 3D dosimeters with optical CT. METHODS: The ... Full text Link to item Cite

TU-C-BRE-05: Clinical Implications of AAA Commissioning Errors and Ability of Common Commissioning ' Credentialing Procedures to Detect Them.

Journal Article Med Phys · June 2014 PURPOSE: To test the ability of the TG-119 commissioning process and RPC credentialing to detect errors in the commissioning process for a commercial Treatment Planning System (TPS). METHODS: We introduced commissioning errors into the commissioning proces ... Full text Link to item Cite

TU-C-BRE-07: Quantifying the Clinical Impact of VMAT Delivery Errors Relative to Prior Patients' Plans and Adjusted for Anatomical Differences.

Journal Article Med Phys · June 2014 PURPOSE: There is increased interest in the Radiation Oncology Physics community regarding sensitivity of pre-treatment IMRT/VMAT QA to delivery errors. Consequently, tools mapping pre-treatment QA to the patient DVH have been developed. However, the quant ... Full text Link to item Cite

Evaluating radiation-induced white matter changes in patients treated with stereotactic radiosurgery using diffusion tensor imaging: a pilot study.

Journal Article Technol Cancer Res Treat · February 2014 Stereotactic radiosurgery (SRS) has been an effective treatment method for brain tumors; however, few data are available regarding radiation-induced white matter (WM) damage by SRS. In this work, diffusion tensor imaging (DTI) was used to investigate WM ch ... Full text Link to item Cite

A novel technique for VMAT QA with EPID in cine mode on a Varian TrueBeam linac.

Journal Article Phys Med Biol · October 7, 2013 Volumetric modulated arc therapy (VMAT) is a relatively new treatment modality for dynamic photon radiation therapy. Pre-treatment quality assurance (QA) is necessary and many efforts have been made to apply electronic portal imaging device (EPID)-based IM ... Full text Link to item Cite

SU-E-T-353: Feasibility of 3D Dosimetry for Prostate LDR: Monte Carlo Simulations of Pd-103,I-125, and Cs-131 Seeds in Deformable PRESAGE.

Journal Article Med Phys · June 2013 PURPOSE: Recent innovations in 3D dosimetry include deformable polyurethane dosimeters (PRESAGE) and high resolution optical CT (∼50 microns). These developments enable 3D dosimetry in deformation conditions present during prostate LDR brachytherapy. Howev ... Full text Link to item Cite

SU-E-T-196: Pretreatment Patient Clinical Objective IMRT Quality Assurance Using a 3D Diode Array.

Conference Med Phys · June 2013 PURPOSE: To evaluate the accuracy and sensitivity of a patient clinical objective IMRT QA tool using a 3D diode array. METHODS: A 3D QA device (Delta4, Scandidos Inc.) with 2 orthogonal diode array planes was used for IMRT QA. The diode spacing is 5mm in c ... Full text Link to item Cite

WE-G-108-08: A Novel Technique for VMAT QA with EPID in Cine Mode On Varian TrueBeam.

Conference Med Phys · June 2013 PURPOSE: Volumetric modulated arc therapy (VMAT) is a relatively new treatment modality for dynamic photon radiation therapy. Pre-treatment quality assurance (QA) is necessary and many efforts have been taken to apply electronic portal imaging device (EPID ... Full text Link to item Cite

WE-G-108-06: Evaluating Pre-Treatment IMRT & VMAT QA Techniques Quantitatively Using Receiver Operating Characteristic (ROC) Analysis.

Journal Article Med Phys · June 2013 PURPOSE: Pre-treatment IMRT and VMAT QA techniques are often commissioned without knowledge of their sensitivity to clinically relevant delivery errors. The purpose of this work is to develop a method to quantify the sensitivity and specificity of pre-trea ... Full text Link to item Cite

SU-E-T-560: A Method to Determine Optimal Dynamic MLC Parameters for Varian Truebeam with Millennium MLC and HDMLC.

Conference Med Phys · June 2013 PURPOSE: Correct MLC modeling is essential to the accurate IMRT delivery. Most TPSs use simplified models with parameters of leaf transmission (LT) and dynamic leaf gap (DLG). The common way to determine them is through extrapolation from measurements. In ... Full text Link to item Cite

Towards comprehensive characterization of Cs-137 Seeds using PRESAGE® dosimetry with optical tomography.

Conference J Phys Conf Ser · 2013 We describe a method to directly measure the radial dose and anisotropy functions of brachytherapy sources using polyurethane based dosimeters read out with optical CT. We measured the radial dose and anisotropy functions for a Cs-137 source using a PRESAG ... 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 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

Multicatheter Vaginal Balloon Brachytherapy: One Year's Clinical Experience

Conference International Journal of Radiation Oncology*Biology*Physics · November 2012 Full text Cite

Urinary Catheterization Increases the Dose to Bowel During Vaginal Brachytherapy

Conference International Journal of Radiation Oncology*Biology*Physics · November 2012 Full text Cite

Can Standard Radiation Therapy Quality Assurance (QA) Detect Potential Delivery Errors?

Conference International Journal of Radiation Oncology*Biology*Physics · November 2012 Full text Cite

Independent verification of gantry angle for pre-treatment VMAT QA using EPID.

Journal Article Phys Med Biol · October 21, 2012 Featured Publication We propose a method to incorporate independent verification of gantry angle for electronic portal imaging device (EPID)-based pre-treatment quality assurance (QA) of clinical volumetric modulated arc therapy (VMAT) plans. Gantry angle is measured using pro ... 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 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 Open Access Link to item Cite

Commissioning a CT-compatible LDR tandem and ovoid applicator using Monte Carlo calculation and 3D dosimetry.

Journal Article Med Phys · July 2012 Featured Publication PURPOSE: To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T&O) applicator using Monte Carlo calculation and 3D dosimetry. METHODS: For geometric characterization, we quantif ... Full text Link to item Cite

SU-D-213AB-05: Commissioning a CT Compatible LDR T&O Applicator Using Analytical Calculation with ID and 3D Dosimetry.

Journal Article Med Phys · June 2012 PURPOSE: To determine the characteristics of a new commercially available CT-compatible LDR Tandem and Ovoid (T&O) applicator using 3D dosimetry. METHODS: We characterized source attenuation through the asymmetric gold shielding in the buckets by measuring ... Full text 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

Preoperative single fraction partial breast radiotherapy for early-stage breast cancer.

Journal Article Int J Radiat Oncol Biol Phys · January 1, 2012 Featured Publication PURPOSE: Several recent series evaluating external beam accelerated partial breast irradiation (PBI) have reported adverse cosmetic outcomes, possibly related to large volumes of normal tissue receiving near-prescription doses. We hypothesized that deliver ... 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 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

Contour based respiratory motion analysis for free breathing CT.

Journal Article Comput Biol Med · October 2011 Featured Publication We propose a method to quantify superior-inferior (SI) motion of a rigid target using the 3D contour from free-breathing CT (FBCT). The technique utilizes similarity between 2D contours (Jaccard Index) and a population based density function for probabilit ... Full text Link to item Cite

Dosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance.

Journal Article Int J Radiat Oncol Biol Phys · June 1, 2011 Featured Publication PURPOSE: To quantify the dosimetric effect and margins required to account for prostate intrafractional translation and residual setup error in a cone beam computed tomography (CBCT)-guided hypofractionated radiotherapy protocol. METHODS AND MATERIALS: Pro ... Full text Link to item Cite

WE‐E‐BRB‐07: EPID Based Verification of Delivered Fluence for VMAT with High Angular Resolution

Conference Medical Physics · January 1, 2011 Purpose: In VMAT, the dose rate, MLC position, and gantry angle change simultaneously, it is important they follow their predefined trajectories to ensure correct dose delivery. Our purpose is to develop an efficient VMAT QA strategy using EPID that is cap ... Full text Cite

Treatment Plan Optimization for Adaptive Radiation Therapy

Chapter · January 1, 2011 In current standard radiation therapy process, patient anatomy is represented by the snapshot of computed tomography (CT) images at the simulation for treatment planning. The planned radiation dose distribution, obtained from either three-dimensional (3D) ... Full text Cite

Prostate intrafraction motion assessed by simultaneous kilovoltage fluoroscopy at megavoltage delivery I: clinical observations and pattern analysis.

Journal Article Int J Radiat Oncol Biol Phys · December 1, 2010 Featured Publication PURPOSE: To describe prostate intrafraction motion using kilovoltage fluoroscopy at treatment delivery for a hypofractionated radiotherapy protocol. METHODS AND MATERIALS: Kilovoltage images were acquired during treatment delivery, as well as pre- and post ... Full text Link to item Cite

Prostate intrafraction motion assessed by simultaneous kV fluoroscopy at MV delivery II: adaptive strategies.

Journal Article Int J Radiat Oncol Biol Phys · December 1, 2010 Featured Publication PURPOSE: To investigate potential benefits of adaptive strategies for managing prostate intrafractional uncertainties when interfraction motion is corrected online. METHODS AND MATERIALS: Prostate intrafraction motion was measured using kV fluoroscopy duri ... Full text Link to item Cite

Maximum intensity projection (MIP) imaging using slice-stacking MRIa).

Journal Article Med Phys · November 2010 Featured Publication PURPOSE: To evaluate the feasibility of acquiring maximum intensity projection (MIP) images using a novel slice-stacking MRI (SS-MRI) technique. METHODS: The proposed technique employed a steady state acquisition sequence to image multiple axial slices. At ... Full text Link to item Cite

Variation of Clinically Relevant Dose Indices for 3DCRT of Lung with Respect to Dose Calculation Algorithm

Conference International Journal of Radiation Oncology*Biology*Physics · November 2010 Full text Cite

SU‐GG‐I‐140: Maximum Intensity Projection (MIP) Imaging Using Multi‐Slice Cine MRI

Conference Medical Physics · January 1, 2010 Purpose: To propose a novel method of acquiring Maximum Intensity Projection (MIP) images using multi‐slice cine MRI, termed as MRI‐MIP, and to evaluate its feasibility in quantifying motion magnitude. Materials and Methods: MRI‐MIP images are acquired usi ... Full text Cite

SU‐GG‐T‐483: Does Breath‐Hold Immobilization Affect Tumor Radioresistance in Breast?

Conference Medical Physics · January 1, 2010 Purpose: A 15–30s Breath Hold (BH) is often used in radiation therapy for breast cancer patients to minimize heart dose, however its effect on tumor oxygenation and radiosensitivity is unknown. The purpose of this study is to utilize published data on the ... Full text Cite

Adaptive Management of Intrafraction Motion in Online Image Guided Prostate Cancer Radiotherapy

Conference International Journal of Radiation Oncology*Biology*Physics · November 2009 Full text Cite

Inferences about prostate intrafraction motion from pre- and posttreatment volumetric imaging.

Journal Article Int J Radiat Oncol Biol Phys · September 1, 2009 Featured Publication PURPOSE: To evaluate the ability of rectal filling, bladder filling, and prostate localization from pre- and posttreatment volumetric imaging to predict prostate intrafraction motion. METHODS AND MATERIALS: Pre- and posttreatment cone beam computed tomogra ... Full text Link to item Cite

Optimizing monoscopic kV fluoro acquisition for prostate intrafraction motion evaluation.

Journal Article Phys Med Biol · January 7, 2009 Featured Publication Monoscopic kV imaging during radiotherapy has been recently implemented for prostate intrafraction motion evaluation. However, the accuracy of 3D localization techniques from monoscopic imaging of prostate and the effect of acquisition parameters on the 3D ... Full text Link to item Cite

SU‐FF‐T‐620: Assessment of Dose Reconstruction Methods for Prostate Image Guided Radiotherapy Protocols

Conference Medical Physics · January 1, 2009 Purpose: Many dosimetric evaluations of prostate intrafraction motion disregard effects of treatment duration and translations of the surrounding body per fraction. However the probability of motion has been shown to increase with time and image guidance s ... Full text Cite

TU‐C‐303A‐08: A Hybrid Strategy Using Discriminant Analysis for Prostate Intrafraction Motion Management

Conference Medical Physics · January 1, 2009 Purpose: Prostate intrafraction motion has been shown to be patient specific; however most current compensation strategies are population wide. We evaluate the feasibility of applying margins based on a subpopulation of patients with similar intrafraction ... Full text Cite

Prostate intrafraction motion evaluation using kV fluoroscopy during treatment delivery: a feasibility and accuracy study.

Journal Article Med Phys · May 2008 Featured Publication Margin reduction for prostate radiotherapy is limited by uncertainty in prostate localization during treatment. We investigated the feasibility and accuracy of measuring prostate intrafraction motion using kV fluoroscopy performed simultaneously with radio ... Full text Link to item Cite

TU‐C‐351‐03: Can Pre‐ and Post‐Imaging Determine Prostate Intrafraction Motion?

Conference Medical Physics · January 1, 2008 Purpose: Recent studies of prostate intrafraction motion have been inconclusive. One cine‐MRI study demonstrated that pre‐treatment rectal filling status is a significant predictor of intrafraction motion magnitude. However, studies using the Calypso syste ... Full text Cite

TU‐FF‐A3‐05: Optimizing KV Fluoro Acquisition for Prostate Intrafraction Motion Evaluation

Conference Medical Physics · January 1, 2008 Purpose: Commercially available gantry mounted kV imagers are currently restricted to manual fluoroscopy acquisitions with fixed mAs & frame rate, limiting use of fluoroscopy for prostate intrafraction motion measurement. For consideration in future acquis ... Full text Cite

Does group B streptococcal infection contribute significantly to neonatal sepsis in Antigua and Barbuda?

Journal Article West Indian Med J · December 2007 Group B streptococcus is the most common cause of neonatal sepsis in the United States of America (USA). This study was undertaken to determine the contribution of group B streptococcus to neonatal septicaemia in Antigua and Barbuda. From 1994 to 2002, the ... Link to item Cite

WE‐E‐M100F‐07: Prostate Intrafraction Motion Measurement Using KV Fluoroscopy During Treatment Delivery

Journal Article Medical Physics · January 1, 2007 Purpose: Margin reduction for prostate radiotherapy is limited by uncertainty in prostate localization during treatment. We investigate the feasibility and accuracy of measuring prostate intrafraction motion using kV fluoroscopy performed simultaneously wi ... Full text Cite

Long-path measurements of ultrasonic attenuation and velocity for very dilute slurries and liquids and detection of contaminates.

Journal Article Ultrasonics · December 22, 2006 Featured Publication The objective was to use multiple paths through the slurry to determine the lowest concentration that provided accurate attenuation measurements and to measure the velocity of sound through an effective long path. Ultrasonic attenuation measurements were o ... Full text Link to item Cite

Measurement of the viscosity-density product using multiple reflections of ultrasonic shear horizontal waves.

Journal Article Ultrasonics · December 22, 2006 Featured Publication We have developed an on-line computer-controlled sensor, based on ultrasound reflection measurements, to determine the product of the viscosity and density of a liquid or slurry for Newtonian fluids and the shear impedance of the liquid for non-Newtonian f ... Full text Link to item Cite

Measurement of the viscosity-density product using a quartz wedge

Journal Article AIP Conference Proceedings · April 9, 2005 The on-line measurement of the viscosity-density product is accomplished by analyzing the multiple reflections of an ultrasonic shear horizontal (SH) wave within a quartz wedge. Many echoes are observed as the ultrasound is reflected from the two sides (in ... Full text Cite

Development of enhanced ultrasonic imaging for in situ inspection of a tension-stressed, threaded fastener

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · 2000 A laboratory system was developed that utilized an ultrasonic pulse-echo technique to detect very small cracks emanating from the thread root of a tensile-stressed fastener. Primary benefits were 1) the ability to inspect the fastener without its removal f ... Cite

Is a single isocenter sufficient for volumetric modulated arc therapy radiosurgery when multiple itracranial metastases are spatially dispersed?

Journal Article Med Dosim Previous work demonstrated improved dosimetry of single isocenter volumetric modulated arc therapy (VMAT) of multiple intracranial targets when they are located ≤ 4cm from isocenter because of narrower multileaf collimators (MLCs). In follow-up, we sought ... Full text Link to item Cite

Hippocampal dose from stereotactic radiosurgery for 4 to 10 brain metastases: Risk factors, feasibility of dose reduction via re-optimization, and patient outcomes.

Conference Med Dosim This study aimed to report hippocampal dose from single-fraction stereotactic radiosurgery (SRS) for 4 to 10 brain metastases and determine feasibility of hippocampal-sparing SRS. Patients with 4 to 10 brain metastases receiving single-isocenter, multi-tar ... Full text Link to item Cite

Radiosurgery treatment planning using conformal arc informed volumetric modulated arc therapy.

Journal Article Med Dosim Linac based radiosurgery to multiple metastases is commonly planned with volumetric modulated arc therapy (VMAT) as it effectively achieves high conformality to complex target arrangements. However, as the number of targets increases, VMAT can struggle to ... Full text Link to item Cite