John Stephen Ginn

Journal Article J Appl Clin Med Phys · January 2026 PURPOSE: To develop a knowledge-based deep model for sCT generation from a single MR volume in LINAC-based frameless SRS, enabling the MR-only workflow without extra CT simulation. METHODS: A total of 139 patients were included in the study, with 120 used ... Full text Link to item Cite

A Radiogenomic Deep Ensemble Learning Model for Identifying Radionecrosis Following Brain Metastases (BM) Stereotactic Radiosurgery in Patients With Non-small Cell Lung Cancer BM.

Journal Article Adv Radiat Oncol · August 2025 PURPOSE: Stereotactic radiosurgery (SRS) is widely used for brain metastases (BM), but the risk of radionecrosis poses a challenge in post-SRS management. Given the lack of noninvasive imaging methods for distinguishing radionecrosis from recurrence, we ai ... Full text Link to item Cite

Feasibility of Stereotactic Body Radiation Therapy for Pancreatic Tumors Abutting Organs at Risk Using Magnetic Resonance Guided Adaptive Radiation Therapy.

Journal Article Int J Radiat Oncol Biol Phys · July 1, 2025 PURPOSE: Stereotactic body radiation therapy (SBRT) has historically been contraindicated in patients with tumors abutting gastrointestinal (GI) organs due to risk of toxicity. Adaptive magnetic resonance (MR) guided SBRT (MRgSBRT) is an increasingly used ... Full text Link to item Cite

Real-time 3D MR guided radiation therapy through orthogonal MR imaging and manifold learning.

Journal Article Med Phys · March 2025 BACKGROUND: In magnetic resonance image (MRI)-guided radiotherapy (MRgRT), 2D rapid imaging is commonly used to track moving targets with high temporal frequency to minimize gating latency. However, anatomical motion is not constrained to 2D, and a portion ... Full text Link to item Cite

Uncertainty quantification in multi-parametric MRI-based meningioma radiotherapy target segmentation.

Journal Article Front Oncol · 2025 PURPOSE: This work investigates the use of a spherical projection-based U-Net (SPU-Net) segmentation model to improve meningioma segmentation performance and allow for uncertainty quantification. METHODS: A total of 76 supratentorial meningioma patients tr ... Full text Link to item Cite

Dosimetric predictors of acute and late gastrointestinal toxicities in stereotactic online adaptive magnetic resonance-guided radiotherapy (SMART) for locally advanced pancreatic adenocarcinoma

Conference Radiotherapy and Oncology · November 1, 2024 Background and purpose: A retrospective evaluation of dosimetric predictors and leveraged dose-volume data for gastrointestinal (GI) toxicities for locally-advanced pancreatic cancer (LAPC) treated with daily stereotactic MRI-guided online-adaptive radioth ... Full text Cite

Dosimetric predictors of acute and late gastrointestinal toxicities in stereotactic online adaptive magnetic resonance-guided radiotherapy (SMART) for locally advanced pancreatic adenocarcinoma.

Journal Article Radiother Oncol · November 2024 BACKGROUND AND PURPOSE: A retrospective evaluation of dosimetric predictors and leveraged dose-volume data for gastrointestinal (GI) toxicities for locally-advanced pancreatic cancer (LAPC) treated with daily stereotactic MRI-guided online-adaptive radioth ... Full text Link to item Cite

A Dose Accumulation Assessment of Alignment Errors During Spatially Fractionated Radiation Therapy.

Journal Article Pract Radiat Oncol · 2024 PURPOSE: Spatially fractionated radiation therapy (SFRT) techniques produce high-dose peaks and low-dose valleys within a tumor. Lattice stereotactic body radiation therapy (SBRT) is a form a SFRT delivered across 5 fractions. Because of the high spatial d ... Full text Link to item Cite

Knowledge-based adaptive planning quality assurance using dosimetric indicators for stereotactic adaptive radiotherapy for pancreatic cancer.

Journal Article Radiother Oncol · May 2023 INTRODUCTION: We aimed to develop knowledge-based tools for robust adaptive radiotherapy (ART) planning to determine on-table adaptive DVH metric variations or planning process errors for stereotactic pancreatic ART. We developed volume-based dosimetric id ... Full text Link to item Cite

Implementing stereotactic accelerated partial breast irradiation using magnetic resonance guided radiation therapy.

Journal Article Radiother Oncol · November 2021 INTRODUCTION: Accelerated partial breast irradiation (APBI) seeks to reduce irradiated volumes and radiation exposure for patients while maintaining acceptable clinical outcomes. Magnetic resonance image-guided radiotherapy (MRgRT) provides excellent soft- ... Full text Link to item Cite

A motion prediction confidence estimation framework for prediction-based radiotherapy gating.

Journal Article Med Phys · August 2020 PURPOSE: Motion prediction can compensate for latency in image-guided radiotherapy and has been an active area of research. However, motion predictions are subject to error and variations. We have developed and evaluated a novel motion prediction confidenc ... Full text Link to item Cite

An image regression motion prediction technique for MRI-guided radiotherapy evaluated in single-plane cine imaging.

Journal Article Med Phys · February 2020 PURPOSE: To develop and evaluate a novel motion prediction method for magnetic resonance image (MRI)-guided radiotherapy applications. This method, which we deem "image regression," predicts future tissue motion based on a weighted combination of previousl ... Full text Link to item Cite

Multislice motion modeling for MRI-guided radiotherapy gating.

Journal Article Med Phys · February 2019 PURPOSE: On-board magnetic resonance imaging (MRI) greatly enhances real-time target tracking capability during radiotherapy treatments. However, multislice and volumetric MRI techniques are frame rate limited and introduce unacceptable latency between the ... Full text Link to item Cite

Online target volume estimation and prediction from an interlaced slice acquisition - A manifold embedding and learning approach

Chapter · January 1, 2019 In radiotherapy it is critical to have access to real-time volumetric information to support online dose calculation and motion management. MRI-guidance offers an online imaging platform but is restricted by image acquisition speed. This work alleviates th ... Full text Cite

Model-Interpolated Gating for Magnetic Resonance Image-Guided Radiation Therapy.

Journal Article Int J Radiat Oncol Biol Phys · November 15, 2018 PURPOSE: To develop and validate a technique for radiation therapy gating using slow (≤1 frame per second) magnetic resonance imaging (MRI) and a motion model. Proposed uses of the technique include radiation therapy gating using T2-weighted images and con ... Full text Link to item Cite

Characterization of spatial distortion in a 0.35 T MRI-guided radiotherapy system.

Journal Article Phys Med Biol · June 7, 2017 Spatial distortion results in image deformation that can degrade accurate targeting and dose calculations in MRI-guided adaptive radiotherapy. The authors present a comprehensive assessment of a 0.35 T MRI-guided radiotherapy system's spatial distortion us ... Full text Link to item Cite

Dosimetric validation of a magnetic resonance image gated radiotherapy system using a motion phantom and radiochromic film.

Journal Article J Appl Clin Med Phys · May 2017 PURPOSE: Magnetic resonance image (MRI) guided radiotherapy enables gating directly on the target position. We present an evaluation of an MRI-guided radiotherapy system's gating performance using an MRI-compatible respiratory motion phantom and radiochrom ... Full text Link to item Cite

A clinical and time savings evaluation of a deep learning automatic contouring algorithm.

Journal Article Med Dosim Automatic contouring algorithms may streamline clinical workflows by reducing normal organ-at-risk (OAR) contouring time. Here we report the first comprehensive quantitative and qualitative evaluation, along with time savings assessment for a prototype dee ... Full text Link to item Cite