Johns Hopkins University

Advances in ‘first-principles’ models of radiation response allow, in principle, for accurate mechanism-aware prediction of how biological effectiveness and effective linear quadratic (LQ) parameters change across various experimental and clinical conditions....

Proton therapy offers distinct dosimetric advantages for reirradiation (reRT) due to its finite range and Bragg peak, allowing potential tumor dose escalation with reduced normal tissue exposure compared to photon-based reRT. However, these benefits come with...

To reduce reliance on labor-intensive voxel-wise tumor masks by training CT segmentation models directly from routine radiology and pathology reports, enabling scalable detection and localization of tumors relevant to radiotherapy planning and incidental find...

To establish a large-scale, independent benchmark for evaluating auto-contouring AI with an emphasis on radiotherapy-relevant requirements: robustness to domain shift, calibration of confidence, and clinically meaningful failure modes beyond average Dice.

To provide a large, multicenter, longitudinal CT dataset with voxel-wise tumor annotations across multiple cancer sites to support development, benchmarking, and validation of AI models for radiotherapy target and organ-at-risk (OAR) segmentation under real-w...

To provide a large, diverse, and quality-controlled abdominal CT dataset with pancreas- and tumor-centric voxel-wise annotations to support benchmarking and development of AI models for pancreatic target segmentation and anatomy-aware evaluation relevant to r...

This session will present a structured, educational overview of how to perform patient-specific dosimetry in radiopharmaceutical therapy, using AAPM TG-381 as a reference framework. The first part will walk through generalizable dosimetry workflows—from imagi...

To develop and validate a log file-based patient quality assurance (LFQA) system for intensity modulated proton therapy (IMPT) using a GPU-accelerated pencil beam algorithm for dose reconstruction, permitting rapid log file upload, dose reconstruction, automa...

To develop a slice-specific CT organ dose library using Monte Carlo radiation transport simulations on a set of newborn, infant, and toddler (NIT) computational phantoms containing newly developed age-specific skeletal tissue models. This dose library forms t...

To create a large, quality-controlled abdominal CT atlas that enables radiotherapy auto-contouring research by providing standardized, voxel-wise annotations across diverse institutions and by supporting uncertainty-aware expert review and benchmarking.

Access to radiotherapy in low- and middle-income countries (LMICs) remains severely limited due to workforce shortages, infrastructure constraints, and workflow inefficiencies. Artificial intelligence (AI) has the potential to alleviate these pressures by sup...

Accurate estimation of microstructural parameters by Imaging Microstructural Parameters Using Limited Spectrally Edited Diffusion (IMPULSED) diffusion MRI, including cell size and intracellular volume fraction, is promising for monitoring radiation treatment...

Radiation therapy patient scheduling is highly complex due to stringent clinical and operational constraints, such as treatment continuity over a multi-fraction course, time for first fraction, etc. Current scheduling practice is largely manual and inefficien...

CyberKnife radiosurgery provides sub-millimeter targeting accuracy but relies on highly manual planning, often requiring several days and limiting throughput and consistency for time-sensitive cases. Currently, no commercial treatment planning system offers f...

To develop and evaluate an automated approach to intelligently interpret free-text, or natural language (NL), physician treatment directives and generate patient-specific prescriptions and clinical goals within a commercial treatment planning system (TPS) usi...

Tumor-treating-fields (TTFields) therapy uses alternating electric fields delivered via transducer arrays placed regionally close to the tumor site to non-invasively inhibit tumor growth. Although important insights into the mechanisms underlying the anticanc...

Physiologically based pharmacokinetic (PBPK) models used in radiopharmaceutical therapy (RPT) and theranostic digital twins are rapidly increasing in size and mechanistic detail, often containing tens to hundreds of parameters. While such models fit imaging a...

Photon-counting detector (PCD)–based cone-beam CT (CBCT) is gaining increasing interest for its potential to enable high-resolution and spectrally rich imaging. This study develops a tabletop PCD-CBCT system as a research platform and reports our progress in...

To evaluate a protocol-agnostic machine learning (PlanAI) (Sun Nuclear, Mirion Medical Company, Florida, USA)1 model for automated treatment planning in external-beam radiotherapy for thoracic cancer.

To implement a full abdominal motion model that combines respiration with gastrointestinal (GI) motility and quantify its interplay impact in pencil-beam scanning (PBS) proton therapy.

Quantitative image-based dosimetry for radiopharmaceutical therapy (RPT) increasingly relies on large, multi-organ mechanistic models of physiologically based pharmacokinetics (PBPK). While PBPK models often fit clinical data well, the extent to which their i...

We present a small-animal SPECT-CT system based on CZT imaging spectrometers and a rapidly switchable dual-FOV apertures. The system supports both total-body imaging and focused, high-resolution imaging. These capabilities address a key need in preclinical ra...

To overcome barriers in Intensity-Modulated Radiation Therapy (IMRT) research caused by reliance on proprietary optimization solvers (e.g., CPLEX) and fragmented software environments. We present the integration of a voxel down-sampling and fluence map optimi...

To investigate whether physics-based radiomics standardization can increase agreement in radiomics extracted from radiologist-annotated regions of diffuse lung disease (DLD) phenotypes across CT reconstruction kernels and radiation doses.

Radiopharmaceutical therapies (RPTs) effectively treat metastatic castration-resistant prostate cancer, yet injected radioactivities remain empirically prescribed. Although physiologically-based pharmacokinetic (PBPK) and pharmacodynamic (PD) models can separ...

In prostate-specific membrane antigen (PSMA)-targeted radiopharmaceutical therapy for metastatic castration-resistant prostate cancer, salivary glands often receive unintended high absorbed doses and are considered dose-limiting organs. For radiopharmaceutica...

The study aims to develop a parameterized brachytherapy source geometry modeling framework for GPU-based Monte Carlo particle transport simulation with an integrated DICOM workflow.

Diffusion-weighted MRI (dMRI) is promising for estimating tumor microenvironment characteristics from measured signals that encode the microscopic diffusion of water molecules constrained by cellular architecture. Estimation accuracy is compromised by low sig...

Ultra-high dose rate (FLASH) proton therapy generates positron-emitting radioisotopes, including C-11, O-15, and F-18, which decay via β⁺ emission. Each annihilation produces a pair of 511 keV photons naturally entangled in momentum and polarization. We evalu...

Computational nuclear oncology (CNO) methods are advancing rapidly but often developed in isolated tools and workflows that are difficult to reproduce, compare, and share. This fragmentation limits virtual studies and slows translation of physiologically base...

Quantitative 99mTc-sestamibi SPECT/CT is routinely used to distinguish benign kidney tumors from renal cell carcinoma. Standard clinical acquisitions typically use 360° orbits. However, a 180° posterior orbit can reduce scan time and patient discomfort. This...

Real-time, high-precision monitoring of tumor anatomy and microenvironment remains a critical unmet need in radiotherapy. Recent experimental studies have demonstrated that 511 keV photon pairs produced during positron annihilation are quantum entangled. Here...

Proton beam quality varies with depth in both monoenergetic and spread-out Bragg peak (SOBP) beams due to changes in track structure and local energy deposition. This study investigates hydroxyl radical-sensitive fluorescence as an intrinsic method to quantif...

To determine whether dense-fibrosis (FDense) measured with Late-Gadolinium-Enhanced-Inversion-Recovery ultrashort-echo-time (LGE-IR-UTE) MRI spatially correlates with R2* maps (a marker associated with hypoxia) in gynecologic-cancer patients during external-b...

To determine whether tumor descriptions in routine radiology reports can be converted into controllable priors for synthetic tumor generation in CT, and whether these report-conditioned synthetic tumors improve robustness of tumor detection and segmentation r...

Accurate estimation of lifetime dose accumulation in patients undergoing re-irradiation therapy is essential for assessing long-term toxicity risks and evaluating the effectiveness of multiple radiotherapy (RT) courses. Currently, no standardized practice exi...

While PET-CT imaging holds promise for simulation-free radiotherapy workflows, its inherent image resolution limits its use for accurate tumor and organ-at-risk (OAR) contouring. This study aims to enhance the spatial resolution of PET-CT by leveraging a reso...

Phase II and III clinical trials establish standards of care in radiation oncology; however, achieving equivalent clinical outcomes in routine practice depends on the reproducible implementation of trial protocols. We systematically evaluated whether publishe...

Radiation induced xerostomia is a common adverse sequela among head and neck cancer (HNC) patients with ~45,000 new cases treated with radiation in the US annually. Current guidelines focus on sparing the mean dose to the parotid glands to reduce xerostomia....

Photon-counting detectors (PCD) exhibit high sensitivity for scattered photons, enabling kilovoltage (kV) scattered X-ray imaging with potential for real-time tumor tracking for lung cancer radiotherapy. The performance in this application is strongly influen...

Diffusion MRI (dMRI) is a promising imaging modality for estimating tumor microenvironment parameters, providing valuable information for early treatment response assessment in radiotherapy. High noise levels in 1.5T MRI degrade parameter estimation accuracy....

Combining external-beam radiation therapy (EBRT) with radiopharmaceutical therapy (RPT) is gaining momentum as the two modalities complement each other from a radiation-biology perspective. EBRT delivers precise, high-dose radiation to bulky, image-defined le...

Clinical Trials Specialty Program

Clinical innovation is essential for advancing radiation therapy and is often led by clinically medical physicists. As the clinical and academic landscape evolves, establishing a research portfolio presents challenges and new opportunities for medical physici...

Radiation oncology accreditation programs aim to promote safety and quality in radiotherapy using nationally recognized standards. This study evaluates the impact of the ASTRO Accreditation Program for Excellence (APEx) at a single institution across three su...

FLASH radiotherapy delivers curative dose to tumor at ultra-high dose rates (UHDR,>40Gy/s) while mitigating normal tissue toxicity. However, data on late-responding tissues are limited, halting its safe clinical translation. Owing to its steep dose–response a...

Quantitative imaging of 177Lu radioactivity in radiopharmaceutical therapy is desired to capture its time-dependent biodistribution for dosimetry. We propose a novel imaging system using photon-counting detector (PCD) for high-sensitivity quantitative activit...

Accurate calibration in photon-counting detectors (PCDs) for inhomogeneous pixel responses caused by charge sharing, pulse pile-up, and energy-dependent efficiency is the most critical and challenging task for PCD-based imaging applications. Conventional gain...

Personalized dosimetry in radiopharmaceutical therapy (RPT) is gaining strong interest because fixed-activity regimens often fail to capture the large variability in how patients respond to the treatment. Growing evidence shows clear dose–response relationshi...

Therapy Physics

Diagnostic and Interventional Radiology Physics

Professional

Therapy Physics

Time of flight (TOF) x-ray imaging is an emerging technology that combines high temporal resolution photon counting detector and very short x-ray pulses to provide additional information about photon interactions. For example, due to longer path lengths, scat...

To test whether commonly used pixel-wise CT reconstruction metrics reflect preservation of clinically relevant anatomy for radiotherapy imaging, and to develop an anatomy-centered, task-based evaluation and enhancement approach for sparse-view reconstruction.

Diagnostic and Interventional Radiology Physics

Patient motion estimation is essential for various X-ray imaging applications, and is typically formulated as an optimization problem. Solution using gradient-free methods often suffer from limited accuracy and high computational cost. Gradient-based approach...

To test whether a physics-informed “time-machine” tumor synthesis pipeline can generate realistic small pancreatic ductal adenocarcinoma (PDAC) targets on contrast-enhanced CT for training and stress-testing AI models intended to support CT-based target delin...

To explore the application of LLM agents for simulating clinical-team collaboration in prostate cancer radiotherapy treatment planning, integrating multidisciplinary expertise to automate end-to-end radiotherapy plan generation.

To develop and validate an auto-planning approach for robust intensity modulated proton therapy (IMPT) using a frontier large language model (LLM), ChatGPT-4o, in a clinical treatment planning system (TPS) for prostate cancer, automatically managing heterogen...

Accurate characterization of image quality (IQ) enables cohort stratification and optimization of downstream tasks in imaging and image analysis. A recent multi-institutional study curated CT images of an IQ phantom across diverse scanners and sites, capturin...

Automatic treatment planning and physician’s plan preference quantification are both critical tasks in High-dose-rate brachytherapy (HDRBT) of cervical cancer for rapidly generating high-quality plans meeting physician’s intent. This study employs inverse dee...

Radiopharmaceuticals, Theranostics, and Nuclear Medicine

αRPT is a promising treatment modality that is largely impervious to the mechanisms of resistance associated with chemotherapy, conventional radiotherapy, targeted (pathway-inhibition) therapies, and immunotherapy. Osteosarcoma (OS), which frequently expresse...

Track-structure Monte Carlo simulations are essential for modeling stochastic energy deposition at micro- and nanoscales relevant to radiobiology and for validating experiments in solid-state microdosimeters such as silicon-on-insulator (SOI) devices. However...

To evaluate the spatial resolution of an X-ray scatter imaging system utilizing a Photon Counting Detector (PCD) for real-time lung tumor tracking. Unlike transmission imaging, scatter imaging offers direct 3D tumor localization. This study quantifies the sys...

Monitoring real-time pancreatic target motion during radiotherapy is challenging. The diaphragm can be tracked by ultrasound; however, published findings on its correlation with abdominal motion are inconsistent. We aimed to develop a robust algorithm to asse...

To quantify the impact of gastrointestinal (GI) motility on pencil-beam scanning (PBS) proton therapy for abdominal cancers, and assess how fractionation and motion amplitude mitigate motility-induced interplay effects.

Intensity-modulated brachytherapy (IMBT) is an innovative technique aimed at achieving anisotropic dose distributions in brachytherapy. This study develops a fast dosimetric optimization method specifically for IMBT plans in cervical cancer.

To develop and validate an AI system that supports radiotherapy-relevant pancreatic target delineation by localizing and segmenting small pancreatic ductal adenocarcinoma (PDAC) and related anatomy on routine contrast-enhanced CT, and to benchmark performance...

Supercoiled plasmid DNA is widely used to study radiation-induced DNA damage. High-resolution atomic force microscopy (AFM) measurements of radiation-induced DNA fragment-length distributions have directly provided quantitative insights into radiation effects...

Therapy Physics