Massachusetts General Hospital

Contrast-enhanced single-energy CT (SECT) scans provide superior image contrast and better differentiation of the target volume and vascular structures compared to non-contrast CT scans at the cost of deteriorated dose calculation due to the high density of t...

Mechanistic models can help us understand why hadrons kill cells more effectively than photons. We used ChronoRepair, an agent-based model that tracks individual double-strand breaks (DSB) through detection, repair, and cell-fate decisions, to identify which...

Cone beam CTs at typical kV energies exhibit metal artifacts in IGRT patients with metal prosthetics. MV-CBCT, available on some linacs, reduces artifacts at the expense of soft tissue contrast-to-noise (CNR). As a remedy, we propose an AI network to convert...

Preclinical studies combining radiation with gadolinium-based AGuIX nanoparticles show potent radiosensitization effect. However, physics simulations to date show a lack of macroscopic dose enhancement. We address this by shifting from absorbed dose (D) to mi...

Structured education in artificial intelligence (AI) has become increasingly important for medical physicists as AI tools are integrated into clinical practice. To address this need, the AAPM Ad Hoc Advisory Committee on AI Boot Camps (AHAIBC) was established...

This educational session will address why dosimetry is central to modern radiopharmaceutical therapy. It will highlight how fixed-activity approaches emerged historically and why they are increasingly insufficient in the context of therapeutic precision, safe...

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 tetrahedral mesh-based tissue models at the macro and micro-scale of the International Commission on Radiological Protection (ICRP) adult female mesh-type reference computational phantom (MRCP) breast inclusive of tissue-specific vasculature models...

Slow energy switching remains a limitation in proton therapy. This study aims to design and optimize an energy degrader system to accelerate layer-to-layer dose delivery in compact proton therapy systems, thereby improving treatment efficiency, outcomes, and...

Cone-beam CT (CBCT) has rapidly expanded across diverse clinical applications, yet fleet-wide benchmarking of imaging performance remains challenging due to wide variation in acquisition hardware, reconstruction pipelines, and vendor-driven quality control (Q...

While image translation models like CycleGANs are increasingly used in medical imaging tasks, evaluating their training behavior remains challenging. Current practices often rely on batch-wise loss curves or selected visual outputs, both of which can be noisy...

Spine stereotactic body radiation therapy (SBRT) is an emerging standard of care for patients with symptomatic spinal metastatic disease. The accuracy of target volume delineation is of critical importance for safe and effective spine SBRT. The adjacent norma...

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 quantify organ-at-risk (OAR) sparing achievable using a hybrid approach combining conventional image-guided radiotherapy (IGRT) with a CT-guided online adaptive radiotherapy (CT-ART) cone-down boost for pelvic malignancies.

To evaluate longitudinal changes in structural MRI biomarkers across three radiotherapy timepoints in advanced cervical cancer and their association with treatment response and recurrence.

To quantify the impact of proton dose calculation methodology, including nuclear halo contributions, on secondary cancer risk for near-field organs following proton craniospinal irradiation.

To quantify the effect of interfractional anatomic variation on dose-averaged linear energy transfer (LETd) in head-and-neck intensity-modulated proton therapy (IMPT), and to determine whether daily adaptive proton therapy (APT) further alters LETd compared w...

Ensuring precise delivery of radiotherapy is paramount, especially in high dose rate settings where small deviations can create large, unplanned doses, jeopardizing patient safety and treatment outcome. Current dosimetry and QA methods operate on signals anal...

Current Y-90 radioembolization (RE) standard dosimetry assumes homogeneous microsphere distribution, ignoring patient-specific vasculature heterogeneity. We developed a framework to reproduce and augment patient-specific hepatic vascular models from cone-beam...

With the advent of pencil beam scanning in proton therapy, the necessity of a gantry has become less compelling. More broadly, gantry-less proton therapy systems offer a potential pathway to reduce system complexity, footprint, and cost, thereby improving pat...

The NCI Pediatric Proton and Photon Therapy Comparison Cohort aims to compare the risk of second malignancies in patients treated with proton versus photon radiotherapy. Using Monte Carlo (MC) simulations, normal tissue dose estimates were retrospectively cal...

To develop a fast and scalable computational framework for estimating DNA damage induced by X-ray irradiation while retaining track-structure fidelity and reducing computational cost.

Conventional dual-energy material decomposition methods suffer from significant noise amplification, which limits their clinical utility for tasks such as intra-fraction markerless tumor tracking. This study introduces PRISM, an open-source Julia framework sp...

Therapy Physics

Iatrogenic cognitive deficits are a major concern in neuro-radiotherapy, especially in pediatric cases. Compared to X-ray treatment modalities, proton and ion beam therapies show improved sparing of cognitive functions, for which optimal neuronal dendritic br...

Radiation therapy–associated cardiac arrhythmia is a clinically significant complication of thoracic RT, with important consequences for long-term cardiovascular health and treatment outcomes. Although arrhythmia risk evolves over time and is linked to cardia...

Therapy Physics

Clinical evidence generally suggests proton therapy can reduce treatment-related toxicity, especially in tumors near critical structures such as the brain, spinal cord, heart. This benefit is well established in pediatric cancers, where reducing radiation exp...

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...

Therapy Physics

Clinical Trials Specialty Program

Interactive, educational, hands-on session (60 min total). The first part focuses on participant interaction with the web demo; the second part provides an expert synthesis of results. Emphasis is on building intuition rather than promoting a single workflow....

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...

AAPM Task Group 430 aims to comprehensively evaluate organ and effective dose (ED) estimations from whole body CT data to support recommendations for DLP-to-ED conversions factors and their associated uncertainties. Accurate whole-body organ segmentation is c...

Radiopharmaceutical therapy (RPT) is re-shaping how radiation is used to combat cancer since it provides a way to deliver radiation systemically. Due to its impactful clinical applications, RPT has been approved by the FDA to treat patients with metastatic ca...

ESTRO–AAPM Joint Program in Trial Design for Medical Physicists: Moving Past QA into Clinical Trials for Oncologic Outcomes and Biomarker Applications puts physicists at the center of evidence generation. This panel‑workshop reframes the physicist’s role from...

Though digital breast tomosynthesis has been standard of care for over 15 years, the image acquisition parameters, especially the acquisition angles, encompass a wide range of variations. A question that warrants further investigation is the image quality tra...

The recent clinical trials to evaluate novel dose and fractionations, including for non-malignant conditions, may change the clinical role and scope of RT practice. Clinical trials are ongoing to evaluate the use of RT to treat non-malignant conditions such a...

This session will review the current status and expansion of MIDRC as a unique, large-scale source of curated and harmonized imaging data spanning multiple modalities and body regions. MIDRC’s resources are specifically designed to meet the AI community’s cri...

Therapy Physics

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...

Therapy Physics

As artificial intelligence becomes increasingly integral to clinical oncology and clinical trials, medical physicists are uniquely positioned to lead the development of the robust system architectures required to integrate AI safely and effectively. This sess...

The mechanism responsible for the “FLASH-effect”, the observed healthy tissue sparing without impacting tumor control when irradiating at ultra-high dose-rates is still highly debated. After a decade of research, several hypotheses emerged, yet, none can expl...

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...

As precision oncology evolves, the goal is for RPT to be viewed as a bridge between nuclear medicine, radiation oncology and medical oncology for the benefit of patients with cancer. However, challenges remain related to items, such as “turf wars” between dep...

Diagnostic and Interventional Radiology Physics

Breast cancer prevention strategies rely upon effective tools to identify "at risk" women who are more likely to develop breast cancer. Risk-stratified screening has been proposed to optimize screening for patients and better use resources, which is equally i...

This is an one-hour session with the speaker nominated and elected by the Ultrasound Subcommittee of the AAPM. This C-Z lectureship program during the coming AAPM Annual Meeting in July 2026 has been approved by AAPM.

Therapy Physics

Radiopharmaceuticals, Theranostics, and Nuclear Medicine

Diagnostic and Interventional Radiology Physics

Interest in Y-90 dosimetry for liver radioembolization has grown rapidly as clinical evidence demonstrates a clear relationship between absorbed dose, treatment response, and toxicity. Historically, activity prescriptions were based on simplified empirical or...

Radiopharmaceuticals, Theranostics, and Nuclear Medicine

IM/TH- Radiopharmaceutical Therapy

At the subcellular scale, Monte Carlo track-structure (MCTS) has demonstrated good accuracy for modeling the initial radiation-induced biological damage by providing a detailed characterization of the spatiotemporal complex structure of ionizing radiation. At...

Spectral imaging confers several benefits such as material decomposition, increased soft tissue contrast, and metal artifact reduction. Novel methods currently under evaluation for adoption to linac onboard imaging include a kV dual-layer imager investigated...

A recent controversial study in NEJM reported associations between hematologic malignancy and low estimated bone marrow dose (≤1 mGy) from pediatric CT. Accurate interpretation of such findings requires a clear understanding of uncertainty in organ dose estim...

In the rapidly developing field of radiopharmaceuticals, the skeleton poses a uniquely daunting challenge to any effort to safely employ these powerful tools. The skeleton’s wide distribution throughout the body as well as its variability make dose difficult...

Radiation-induced lymphopenia (RiL) worsens survival in glioblastoma by impairing anti-tumor immunity. Reducing dose to circulating lymphocytes (CLs) may help mitigate RiL. Because IMRT and VMAT differ in their dynamic delivery time, they may alter blood expo...

This session will present a structured debate on single versus multiple timepoint dosimetry in radiopharmaceutical therapy, highlighting both technical and clinical perspectives. A speaker from the nuclear medicine/imaging side will discuss the benefits and r...

Therapy Physics

This session will focus on the specific considerations involved in clinical trials of alpha-particle radiopharmaceutical therapies. Unlike beta emitters, alpha-emitter therapies bring unique characteristics, short particle range, high linear energy transfer,...

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...

Alzheimer’s disease (AD) progression can be monitored with longitudinal PET imaging. Changes in amyloid and tau; two characteristic AD proteins, are measured using [11C]PiB and [18F]AV1451, similar to how serial imaging with [18F]FDG is used to clinically ass...

Therapy Physics

Diagnostic and Interventional Radiology Physics