University of Wisconsin-Madison

The spread-out Bragg peak (SOBP) technique uses ridge filters to broaden the depth-dose profile, producing a dose distribution similar to a single-field-uniform(SFU) approach. In contrast, the single-energy pristine Bragg peak(SEPBP) approach relies on range...

Cherenkov Imaging is the method by which the light emitted from a patient’s skin during external beam radiation therapy can be imaged and used to verify dose delivery location. This is accomplished using an intensified CMOS camera time-gated to the linac puls...

Continuous glucose monitoring (CGM) provides high-resolution time-series data reflecting real-world glucose dynamics. However, most existing CGM analytics emphasize absolute glucose values, numerical thresholds, or food-centric interpretations, often overlook...

Ultra-high dose rate (UHDR) beams (40Gy/s) compromise the accuracy of conventional reference ion chambers (ICs) due to saturation effects. The Exradin A30 is an ultra-thin parallel-plate IC featuring a 0.3 mm nominal electrode spacing to enhance the charge co...

Patient instructions for radiation-related skin effects after fluoroscopy-guided interventional procedures are integral to substantial-dose follow-up programs. Patient-facing materials often exceed health-literacy targets, risking reduced comprehension and ad...

Fluoroscopy education and clinical literature dealing with videofluoroscopic swallowing studies commonly emphasize frame rate as the primary determinant of temporal resolution and diagnostic accuracy. However, frame integration or frame averaging, a fundament...

Cherenkov imaging enables non-invasive, real-time visualization of superficial dose during radiation therapy. In TSET using the Stanford standing technique, dose uniformity is highly sensitive to daily patient positioning. This study aims to experimentally de...

To integrate the first nozzle-mounted, quad-camera prompt gamma imaging (PGI) system on a clinical proton therapy gantry and to evaluate its efficacy for proton range verification under realistic treatment delivery conditions.

Coronary artery (CA) calcifications (CACs) connect upstream cardiovascular risks with downstream radiotherapy planning decisions, yet these powerful imaging biomarkers are underutilized in radiation oncology. We developed and validated an opportunistic screen...

Radiopharmaceuticals, Theranostics, and Nuclear Medicine

National shortages of clinical medical physicists underscore the need for scalable, hands-on learning opportunities. We sought to pilot a structured radiation oncology observership program that enhances clinical knowledge, builds confidence, supports career p...

Quantitative SPECT imaging of the alpha-emitters Ac-225 and Pb-212 is fundamentally limited by a low count rate and high-energy photon emissions that produce collimator penetration, septal scatter, and detector backscatter within clinically used photopeak win...

Half-value layer (HVL) is a common beam quality parameter, but physical measurement is often time-consuming and difficult. This work presents a faster spectral method for determining HVL for four sets of polyenergetic mammography beam qualities using a solid-...

Therapy Physics

To design and validate reliable treatment planning and delivery verification methods for TMPRT in the phase III NRG CC-017 trial, which compares TMPRT to standard radiotherapy in adults with newly diagnosed MGMT-unmethylated glioblastomas, with these methods...

To propose a clinically relevant, quantitative comparison of low-contrast edge definition on routine CT Head examinations.

To experimentally quantify the mechanical delivery errors of a pre-clinical Dynamical Collimation System (DCS) prototype for intensity modulated proton therapy (IMPT) and evaluate the dosimetric impact of these errors to the target coverage and organ sparing.

To assess the accurate delivery of iodinated contrast media (ICM) and saline flush volumes administered using piston-driven and peristaltic power injectors.

Quantitative Digital Subtraction Angiography (qDSA) is a method for determining blood velocity in which iodinated contrast agent is injected into pulsatile arterial blood flow and oscillations in contrast are tracked as they propagate downstream. qDSA aims to...

To develop a unified and fully automated desktop-based MRI coil QA application designed to minimize operator dependence and enhance workflow efficiency

To develop an automated framework that determines the number and placement of isocenters and target margins for extracranial stereotactic ablative radiotherapy (SABR) in polymetastatic disease, and evaluate lung dose tradeoffs versus uniform margins.

To develop and validate a 3D deep learning autosegmentation model for prostate and OAR contouring on post-brachytherapy-catheter CT images for HDR prostate brachytherapy planning.

The Russian invasion of Ukraine has significantly disrupted radiation therapy (RT) services, highlighting the urgent need to replace Cobalt-60 machines and modernize infrastructure and training across 43 RT centers. In response, Help Ukraine Group (HUG) and R...

Accurate absorbed dose estimation is essential for radiotherapy and research. In ultra-high dose-rate (FLASH) beams, ~Gy doses are delivered in a few pulses, so small perturbations can bias monitoring. Beam current transformers (BCTs) are widely used for FLAS...

Accurate musculoskeletal (MSK) CT assessment relies on high spatial resolution, which can be compromised when extremities are positioned away from the scanner isocenter. The purpose of this study is to evaluate the effect of off-center positioning on spatial...

We report the first clinical implementation integrating a 6D upright treatment chair and a vertical CT system for image-guided proton therapy on a synchrotron-based fixed-beamline. This design aims to improve patient workflow and reduce the facility footprint...

Recent advances in cone-beam CT (CBCT) technology, such as large field of view and advanced iterative reconstruction algorithms, offer potential for using these on-board imagers for adaptive radiation therapy (ART). This study quantitatively characterizes the...

A modernized partial‑body Total Skin Electron Therapy (TSET) frame was designed, constructed, and prepared for commissioning at UW Health Eastpark Medical Center to replace an aging wooden structure and address the absence of commercially available systems me...

Cherenkov imaging is a technique used to observe surface dose deposition during radiation therapy. While proportional to dose, the imaged signal cannot derive absolute dose, due to the attenuation and inhomogeneity of human tissue optics. However, controlled,...

Cherenkov imaging enables real-time visualization of radiation delivery by capturing Cherenkov emission from patient tissue at the beam location. Although this signal can be compared to the expected dose distribution, no established method currently exists to...

We present advancements of single-molecule biodosimetry to measure radiation-induced DNA damage from α-emitting 225Ac. These results will be compared to β-emitting radionuclides to assess relative biological effectiveness (RBE) for radionuclide therapies.

Hypofractionated proton therapy for pancreatic cancer is limited by the proximity of radiosensitive abdominal organs. Single-energy Bragg peak (SEBP) proton delivery enables ultra-high dose-rate (UHDR) irradiation and may facilitate FLASH compatible treatment...

To experimentally determine the effective point of measurement (EPOM) shift of an Exradin A1SL ion chamber in kilovoltage x-ray beams (40-250 kVp) using water tank measurements.

To evaluate the accuracy of high-resolution radiochromic film dosimetry for characterizing peak and valley dose distributions in microbeam radiation therapy (MRT). This study aims to establish film as a benchmark for validating the spatial and dosimetric accu...

AAPM WGTG51 Report 374 emphasizes the importance of field barometer cross-calibration versus a reference barometer prior to reference dosimetry measurements. This work evaluates the validity of single-point calibration across altitudes and whether multi-point...

To examine the subjective and objective image quality (IQ) of a deep learning image reconstruction algorithm (Precise Image Quality Engine (PIQE)) in abdominal CT.

Accurate small‑field dosimetry on MR‑linacs remains challenging due to magnetic‑field–induced dose perturbations and steep dose gradients. In this study, the performance of a newly developed unshielded silicon diode has been evaluated for use in small-field d...

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.

Proton LATTICE radiotherapy (LRT), a spatially fractionated radiotherapy (SFRT), delivers high dose to intratumoral vertices while maintaining low valley dose. Single-field optimization (SFO) is robust in preserving peak-to-valley patterns but may increase en...

Cherenkov imaging offers real-time visualization and verification of external beam delivery during radiation therapy. However, the relationship between beam parameters and Cherenkov photon yield per unit dose remains underexplored, especially for small-fields...

Ultra-high-dose-rate (UHDR) proton irradiation may spare normal tissue (FLASH effect), but PBS proton dose rate is limited by machine constraints (minimum MU/spot and dwell time). Intra-field interruptions can leave sub-threshold MU for remaining delivery, de...

To investigate whether ultra-high dose rate (UHDR) electron beams induce a FLASH effect, quantified through differential gene expression in the plant species Arabidopsis thaliana.

To quantify dose delivered from a scanning microbeam x-ray irradiator using partial-volume techniques with thermoluminescent dosimeters (TLD-100) chips and to improve dosimetry in systems with small fields.

Heterotopic flank xenografts are widely used for preclinical head and neck cancer (HNC), despite hypothesized microenvironmental differences relative to orthotopic tumors. Tumor hypoxia is a major determinant of radiation response and arises from complex inte...

To develop and validate a physics‑informed model that converts trabecular bone attenuation (HU) measured at non‑standard tube potentials into 120‑kVp–equivalent CT numbers.

Proton density fat fraction (PDFF) is widely used as a quantitative MRI biomarker in clinical care. Accurate PDFF measurement requires robust quality control, commonly performed using phantom-based assessment. This work evaluates an automated algorithm for qu...

FLASH radiotherapy reduces skin damage in vivo from ultra-high dose rate (UHDR) irradiation relative to conventional dose rates (CDR), while preserving tumor tissue damage. The macroscopic FLASH tissue sparing effect has not yet been robustly reproduced in la...

This study was to examine the complimentary damage mechanisms and their potential synergy between conventional/ultrahigh dose rate radiotherapy (CDR/UHDR RT) and photodynamic therapy (PDT). FLASH radiotherapy produces a significant reduction in radiation-indu...

Traditionally, CT scanner spatial resolution is characterized using non-clinically optimized scan modes (axial scans, with dose levels and kernels not suited for real patients). In this study, we demonstrate a clinically motivated approach for exploring how r...

The FLASH radiotherapy effect is the reduction of radiation-induced normal tissue damage with Ultra-High Dose Rate (UHDR) irradiation, relative to Conventional Dose Rates (CDR), while preserving tumor tissue damage. However, the underlying mechanism remains u...

Radiopharmaceutical therapy (RPT) delivers targeted radiation to cancer cells. Patient‑specific dosimetry can help estimate dose and predict treatment outcome. However, tumor segmentation approaches vary across institutions, introducing uncertainty into dose...

The goal of this project was to investigate whether the FLASH effect can be preserved when an ultra-high-dose-rate (UHDR) delivery is split into multiple beams (2, 4 or 6), all delivered within a time window (5 sec) that was previously shown to preserve the s...

To evaluate a MR-CT deformable registration workflow using a novel 3D-printed anthropomorphic phantom that enables controlled, known lumbar spine deformation, with assessment of geometric accuracy and quantitative integrity of MR fat-fraction (FF).

Cardiotoxicity is a devastating complication of cancer treatment. Notably, the heart is complex and dose to cardiac substructures (CS) have been strongly linked to radiation-induced cardiac morbidity. The physicist-led, NIH-funded “THE cARdiac Radiation Thera...

Targeted alpha therapy (TAT) produces fundamentally different dose-response behavior than beta-emitting therapy because energy deposition occurs from rare, short-ranged, high-LET particle traversals. Under typical TAT administered activities, many cells recei...

Professional

Therapy Physics

Therapy Physics

In radiation oncology, phase I clinical trials often test the new capabilities of a treatment machine, a novel radiopharmaceutical drug, or an untested clinical indication of radiation therapy. These trials require significant physics investment of time and e...

Respiratory-induced interplay effects in spot-scanning proton therapy can lead to dose degradation for lung cancer patients treated under free-breathing conditions. While motion mitigation techniques such as deep-inspiration breath-hold or abdominal compressi...

Leadership

Clinical Trials Specialty Program

Diagnostic and Interventional Radiology Physics

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...

To advance the qDSA algorithm beyond mean velocity estimations by quantifying systolic and diastolic waveform parameters using 2D image-derived features.

Adaptive radiation therapy (ART) for proton therapy relies on routine offline CT simulations for updated anatomy. To facilitate online proton ART, we present our high‑fidelity regularized Brownian Bridge (rBBrg) framework to perform deterministic cross-modali...

Intensity-modulated proton therapy (IMPT) plan optimization is time-intensive due to its high dimensionality and the inherent non-convexity of clinical dosimetric constraints. Conventional algorithms like projected gradient descent (PGD) often require extensi...

Development of next-generation neutron capture therapy (NCT) agents demands rigorous preclinical testing to verify targeting efficacy, safety, and therapeutic gain under clinically relevant irradiation conditions. This work proposes a preclinical, accelerator...

Upright patient positioners coupled with diagnostic-quality vertical CTs at treatment isocenter introduce significant opportunities for online adaptive particle therapy. However, limited upright data constrains our ability to rigorously test and optimize this...

Diagnostic and Interventional Radiology Physics

Focused on the "fringes" of Medical Physics - in line with AAPM strategic plan - expanding beyond the current boundaries of Medical Physics. Collecting non-traditional science that belongs/should belong to medical physics. Fun, stimulating, and thought-provok...

Catheter position uncertainty produces dosimetric error in HDR prostate brachytherapy, with reported displacements between planning and delivery of up to 5-7mm. Current inverse planning methods optimize dwell times for fixed catheter positions without account...

The Liberty Vision Y-90 ophthalmic applicator (LV-90) is an FDA approved HDR source for episcleral brachytherapy to treat ocular tumors and benign growths. It is an attractive option for patients because it does not require episcleral sutures, muscle relocati...

Focal dose escalation to the dominant intraprostatic lesion (GTV) improves biochemical control but is limited by urethral toxicity. 177Lu-PSMA radiopharmaceutical therapy (RPT) offers a targeted boost, yet its spatial heterogeneity in uptake leaves GTV sub-re...

Therapy Physics

In digital radiography (DR), the Exposure Index (EI) and Deviation Index (DI) provide standardized feedback on whether image receptor exposure is appropriately matched to patient size and clinical task. However, systematic, context-aware analysis of EI and DI...

Material quantification in spectral CT assumes a known voxel background, such as water in iodine maps or hydroxyapatite in bone edema maps. These assumptions are never met in vivo, where voxels typically contain mixtures of tissues with differing effective at...

With advances in Targeted Alpha Therapy (TAT) preclinical and clinical research, the importance for accurate and traceable dosimetry with sub-organ resolution becomes critical. Current limitations in verifying imaging resolution and activity quantification hi...

To design and fabricate a 3D-printed anthropomorphic phantom of the lumbar spine and pelvis to evaluate and improve the quantitative accuracy of SPECT/CT imaging and dosimetry for bone marrow and vertebral body lesions.

Quantitative Lu-177 SPECT imaging requires balancing statistical precision with clinically feasible acquisition times. Conventional reconstruction relies on triple-energy-window (TEW) scatter correction and is therefore effectively limited to the 208 keV phot...

To validate a high-throughput workflow for quantifying liver proton-density fat-fraction (PDFF), using a novel two-door/two-bed MRI suite and a focused, AI-assisted, motion-insensitive chemical-shift-encoded (CSE) MRI protocol.

Accurate patient-specific dosimetry is essential for safety and efficacy in radiopharmaceutical therapy (RPT). Yet standardized approaches for commissioning dosimetry workflows are not well established. This work presents a framework for dosimetric validation...

Therapy Physics

Accurate absorbed dose determination for alpha emitting sources remains challenging due to short particle ranges and sensitivity to source geometry. This work presents a practical framework for direct absorbed dose to water measurements from a plated 241Am so...

Diagnostic and Interventional Radiology Physics

Individuals with Down syndrome (DS) are at high risk of developing Alzheimer's Disease, partially driven by trisomy 21-related overproduction of amyloid precursor protein and plaque (Aβ) development. Tau neurofibrillary tangles typically follow Aβ and obey si...