Health and Medical Physics Commons^™

Establishing A Comprehensive Framework For Sfrt Lattice Treatments: Optimization, Planning, And Clinical Evaluation, Gregory M. Gill

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spatially fractionated radiation therapy (SFRT) using lattice radiotherapy (LRT) has emerged as a promising treatment technique for bulky, nonresectable tumors by delivering spatially heterogeneous dose distributions consisting of high-dose vertices embedded within lower-dose regions. Although early clinical experiences have demonstrated potential therapeutic benefit, widespread clinical implementation of LRT remains limited due to the absence of standardized treatment planning workflows, consistent optimization strategies, and clearly defined evaluation metrics for heterogeneous dose distributions. The objective of this study is to develop and evaluate a structured framework to support efficient, reproducible, and safe clinical implementation of LRT.

To address these challenges, a comprehensive …

Theory, Experiments, And Image Recovery Algorithms For X-Ray Interferometry, Hunter C. Meyer

LSU Doctoral Dissertations

Purpose: X-ray grating interferometry is a form of X-ray phase contrast imaging capable of simultaneously measuring attenuation, differential-phase, and dark-field images arising from X-ray absorption, refraction, and small-angle scattering, respectively. These additional contrast mechanisms have potential clinical and industrial applications, particularly for lung tissue characterization and disease identification. As grating interferometers approach clinical viability, key challenges include reducing X-ray dose, mitigating mechanical instability, and correcting spectral artifacts resulting from beam hardening.

Methods: The modulated phase grating interferometer (MPGI) is a potential solution for reducing X-ray dose by eliminating the analyzer grating used in alternative interferometer designs, including the Talbot-Lau interferometer …

Exploring The Impact Of Adverse Childhood Experiences On Preventive Healthcare Utilization In Rural Georgia, Ryan R. Traylor

College of Graduate Studies: Theses & Dissertations

This study examines the relationship between Adverse Childhood Experiences (ACEs) and preventive healthcare use among adults in Georgia, specifically within rural populations facing structural barriers. Using 2023 Georgia Behavioral Risk Factor Surveillance System (BRFSS) data, the research analyzes associations between ACE exposure, rural residence, and preventive care outcomes, including physical exams and flu vaccinations. Guided by an intersectionally adapted version of Andersen’s Behavioral Model of Health Services Use, the study evaluates how predisposing factors, enabling resources, and perceived barriers relate to healthcare engagement. Logistic regression analyses assess the correlation of ACE exposure, cost barriers, provider access, and sociodemographics with preventive …

A Framework For Digital Energy Modulation And Translation In Projectional X-Ray Imaging, Richard R. Wargo

Theses and Dissertations

In projectional X-ray imaging, acquisition energy fundamentally influences subject contrast, image noise, and radiation dose. While dual-energy techniques exploit spectral differences to optimize contrast and enable material separation, acquiring multiple images of the same anatomy often requires additional exposures and increased system complexity.

This dissertation presents a framework for digital energy modulation (DEM), in which computational models are trained to translate projection images between energy domains without requiring additional X-ray acquisitions. DEM is conceived as a generalizable strategy for controlled contrast modulation in projection imaging, with potential applications in image optimization, radiation therapy alignment, and dual-energy applications.

The framework was …

Developing Reference Plans For Evaluating Global Clinical Trials Credentialing And Psqa Systems, Fre'etta M D Brooks, Mohammad Hussein, Jessica Lye, Christopher L Nelson, Nakamura Mitsuhiro, Mallory C Glenn, Patricia Diez, Rushil Patel, Maddison Shaw, Ileana Silvestre Patallo, Miriam Barry, Catharine H Clark, Joerg Lehmann, Stephen F Kry

Faculty, Staff and Student Publications

Purpose: To develop a practical framework for creating a diverse set of validated reference plans (varying in complexity) and implement a workflow to introduce beam modeling, calibration, and delivery errors into the reference cohort to test and compare various dosimetry audit methodologies.

Methods: Sixteen IMRT and VMAT reference plans were created, using RayStation software, for four phantom geometries based on established credentialing cases from participating Global Harmonization Group (GHG) members. These reference plans were first validated in a multi-ion-chamber phantom. Nine dosimetric errors (perturbations) were introduced into the plans by modifying beam model and/or delivery parameters (MLC-offset, MLC-transmission, leaf-tip-width, PDD, …

Hyalinization-Based Pathologic Response And Immune Infiltration Following Neoadjuvant Radiotherapy With Or Without Immune-Checkpoint Blockade In Localized Undifferentiated Pleomorphic Sarcoma, R S Traweek, M Zoghbi, R Lazcano, B M Cope, A J Bishop, A Farooqi, D Mitra, A K Yoder, B A Guadagnolo, D R Ingram, K Wani, D Shamsutdinova, A J Lazar, W-L Wang, C P Scally, E Z Keung, K E Torres, K K Hunt, R Ratan, J A Livingston, M S Nakazawa, D M Araujo, S Patel, V Ravi, A P Conley, M A Zarzour, N Somaiah, C L Roland, E F Nassif Haddad

Faculty, Staff and Student Publications

BACKGROUND: Standard-of-care treatment of localized undifferentiated pleomorphic sarcoma (UPS) involves preoperative radiotherapy (RT) and surgery. Combination of RT with immune-checkpoint blockade (ICB) represents a promising new strategy.

METHODS: Our primary objective was to assess survival outcomes and pathologically documented response in patients receiving RT with or without ICB or chemotherapy.

RESULTS: In a retrospective cohort of 68 patients with primary or locally recurrent UPS who received neoadjuvant RT with or without ICB, the ICB group had greater tumor hyalinization than the non-ICB group (89% compared with 30%, P = 0.018). In the non-ICB group, 19/37 patients (51%) achieved hyalinization-based pathologic …

Aapm Task Group No 249b-Essentials And Guidelines For Clinical Medical Physics Residency Training Programs, Jonathon A Nye, Joseph P Dugas, William D Erwin, David P Gierga, Darryl G Kaurin, Stephanie M Leon, Ho-Ling Anthony Liu, Zheng Feng Lu, Alphonso W Magri, Lynn N Rill, Leah K Schubert, Beth A Schueler, Irina Vergalasova, John Vetter, Brian D Wichman, Amy Shu-Jung Yu, Dandan Zheng

Faculty, Staff and Student Publications

The establishment of guidelines and curriculum standards for medical physics residency training is a critical component of setting expectations and competencies for the profession. Since the last publication of these standards, residency training has become integrated into the eligibility criteria for most medical physics certification bodies. The rapid growth of medical physics requires periodic review of the curriculum to remove outdated approaches, update established knowledge, and add emerging technologies. The goal of this document is to provide a reference standard for residency training program directors, training mentors, and residents to guide creation and/or optimization of their program's curriculum. The document …

Dose Prediction Via Deep Learning To Enhance Treatment Planning Of Lung Radiotherapy Including Simultaneous Integrated Boost Techniques, Wenhua Cao, Mary Gronberg, Stephen Bilton, Hana Baroudi, Skylar Gay, Christopher Peeler, Zhongxing Liao, Thomas J Whitaker, Karen Hoffman, Laurence E Court

Faculty, Staff and Student Publications

Background: Recent studies have shown deep learning techniques are able to predict three-dimensional (3D) dose distributions of radiotherapy treatment plans. However, their use in dose prediction for treatments with varied prescription doses including simultaneous integrated boost (SIB), that is, using multiple prescription doses within the same plan, and benefit in improving plan quality should be validated.

Purpose: To investigate the feasibility and potential benefit of using deep learning to predict dose distribution of volumetric modulated arc therapy (VMAT) including SIB techniques and improve treatment planning for patients with lung cancer.

Methods: The dose prediction model was trained with 93 retrospective …

T2-Weighted Imaging Of Rectal Cancer Using A 3d Fast Spin Echo Sequence With And Without Deep Learning Reconstruction: A Reader Study, Dan Nguyen, Sarah Palmquist, Ken-Pin Hwang, Jingfei Ma, Usama Salem, Jia Sun, Xinzeng Wang, Jong Bum Son, Randy Ernst, Peng Wei, Harmeet Kaur, Nir Stanietzky

Faculty, Staff and Student Publications

Purpose: To compare image quality and clinical utility of a T2-weighted (T2W) 3-dimensional (3D) fast spin echo (FSE) sequence using deep learning reconstruction (DLR) versus conventional reconstruction for rectal magnetic resonance imaging (MRI).

Methods: The study included 50 patients with rectal cancer who underwent rectal MRI consecutively between July 7, 2020 and January 20, 2021 using a T2W 3D FSE sequence with DLR and conventional reconstruction. Three radiologists reviewed the two sets of images, scoring overall SNR, motion artifacts, and overall image quality on a 3-point scale and indicating clinical preference for DLR or conventional reconstruction based on those three …

Robust Automated Method Of Spatial Resolution Measurement In Radiotherapy Ct Simulation Images, Pavel Govyadinov, Rick R Layman, Tucker Netherton, Raymond Mumme, Aaron K Jones, Laurence E Court, Moiz Ahmad

Faculty, Staff and Student Publications

Background: Variation in imaging protocol, patient positioning, and the presence of artifacts can vary image quality in CT images used for radiotherapy planning. Automated methods for spatial resolution (SR) estimation exist but require further investigation and validation for wider adoption.

Purpose: To validated previously existing algorithm for SR estimation and introduce improvements that make it robust to patient positioning, CT protocol, site, and artifacts.

Method: A reference algorithm based on the previous gold standard was recreated and modified to improve robustness. The algorithms were tested on three different datasets: (1) a cylindrical ACR CT QC phantom scanned using a Siemens …

American Association Of Physicists In Medicine (Aapm) Chapter Climate Check: Mixed Methods Analysis Of Survey Responses, Ashley J Cetnar, Ghada Aldosary, Meghan C Koo, Holly Lincoln, Angélica Pérez-Andújar, Surendra Prajapati, Samantha J Simiele, Kristi R G Hendrickson

Faculty, Staff and Student Publications

Introduction: The American Association of Physicists in Medicine (AAPM) recently shared results and recommendations from its first Equity, Diversity, and Inclusion (EDI) Climate Survey, which was designed to assess the climate at the workplace, the AAPM organization, and the AAPM regional chapter level. This work further explores the status of EDI at the regional chapter level.

Methods: AAPM's EDI Survey was distributed to 5500 members and had a response rate of 25%. In the survey, three open-ended comment boxes were provided for feedback, including one for regional AAPM members. Sixty-four percent of respondents indicated they were part of a regional …

Clinical Use Of Gafchromic Ebt4 Film For In Vivo Dosimetry For Total Body Irradiation, Emily Draeger, Fada Guan, Min-Young Lee, Dae Yup Han, William Donahue, Zhe Jay Chen

Faculty, Staff and Student Publications

Purpose: In vivo dosimetry is a common requirement to validate dose accuracy/uniformity in total body irradiation (TBI). Several detectors can be used for in vivo dosimetry, including thermoluminescent dosimeters (TLDs), diodes, ion chambers, optically stimulated luminescent dosimeters (OSLDs), and film. TLDs are well established for use in vivo but required expertise and clinical system availability may make them impractical for multifractionated TBI. OSLDs offer quick readout, but recalls have restricted their use. The purpose of this work was to validate the newly available Gafchromic EBT4 film for TBI in vivo dosimetry.

Methods: Film calibration curves were created under standard conditions …

An Automated Treatment Planning Portfolio For Whole Breast Radiotherapy, Hana Baroudi, Leonard Che Fru, Deborah Schofield, Dominique L Roniger, Callistus Nguyen, Donald Hancock, Christine Chung, Beth M Beadle, Kent A Gifford, Tucker Netherton, Joshua S Niedzielski, Adam Melancon, Manickam Muruganandham, Meena Khan, Simona F Shaitelman, Sanjay Shete, Patricia Murina, Daniel Venencia, Sheeba Thengumpallil, Conny Vrieling, Joy Zhang, Melissa P Mitchell, Laurence E Court

Faculty, Staff and Student Publications

Background: Automation in radiotherapy presents a promising solution to the increasing cancer burden and workforce shortages. However, existing automated methods for breast radiotherapy lack a comprehensive, end-to-end solution that meets varying standards of care.

Purpose: This study aims to develop a complete portfolio of automated radiotherapy treatment planning for intact breasts, tailored to individual patient factors, clinical approaches, and available resources.

Methods: We developed five automated conventional treatment approaches and utilized an established RapidPlan model for volumetric arc therapy. These approaches include conventional tangents for whole breast treatment, two variants for supraclavicular nodes (SCLV) treatment with/without axillary nodes, and two …

Iroc Phantoms Accurately Detect Mlc Delivery Errors, Sharbacha S Edward, Julianne M Pollard-Larkin, Peter A Balter, Rebecca M Howell, Christine B Peterson, Stephen F Kry

Faculty, Staff and Student Publications

Purpose: We evaluated the impact of random and whole-bank multileaf collimator (MLC) delivery errors on dosimetric delivery accuracy in the Imaging and Radiation Oncology Core (IROC) phantom audits, as well as differences in delivery accuracy between the IROC phantom prescription and typical clinical fraction sizes.

Methods and materials: Plans were created for the IROC IMRT head and neck (H&N) and SBRT spine phantoms. MLC leaf errors were introduced into the plans: random shifts between -2 and 2 mm, and whole bank shifts of 0.5, 1, and 2 mm. Plans were recalculated and delivered on a Varian Truebeam, and the log …

Rapidbrachyivbt: A Dosimetry Software For Patient-Specific Intravascular Brachytherapy Dose Calculations On Optical Coherence Tomography Images, Maryam Rahbaran, Jonathan Kalinowski, Joseph M Decunha, Kevin J Croce, Brian A Bergmark, James M G Tsui, Phillip M Devlin, Shirin A Enger

Faculty, Staff and Student Publications

Background: Coronary artery disease is the most common form of cardiovascular disease. It is caused by excess plaque along the arterial wall, blocking blood flow to the heart (stenosis). A percutaneous coronary intervention widens the arterial wall with the inflation of a balloon inside the lesion area and leaves behind a metal stent to prevent re-narrowing of the artery (restenosis). However, in-stent restenosis may occur due to damage to the arterial wall tissue, triggering neointimal hyperplasia, producing fibrotic and calcified plaques and narrowing the artery again. Drug-eluting stents, which slowly release medication to inhibit neointimal hyperplasia, are used to prevent …

On The Acceptance, Commissioning, And Quality Assurance Of Electron Flash Units, Allison Palmiero, Kevin Liu, Julie Colnot, Nitish Chopra, Denae Neill, Luke Connell, Brett Velasquez, Albert C Koong, Steven H Lin, Peter Balter, Ramesh Tailor, Charlotte Robert, Jean-François Germond, Patrik Gonçalves Jorge, Reiner Geyer, Sam Beddar, Raphael Moeckli, Emil Schüler

Faculty, Staff and Student Publications

Background and purpose: FLASH or ultra-high dose rate (UHDR) radiation therapy (RT) has gained attention in recent years for its ability to spare normal tissues relative to conventional dose rate (CDR) RT in various preclinical trials. However, clinical implementation of this promising treatment option has been limited because of the lack of availability of accelerators capable of delivering UHDR RT. Commercial options are finally reaching the market that produce electron beams with average dose rates of up to 1000 Gy/s. We established a framework for the acceptance, commissioning, and periodic quality assurance (QA) of electron FLASH units and present an …

Open-Chest Cardiac Ultrasound-Mediated Imaging With A Vacuum Coupler, Nilesh Mathuria, Krithik Vishwanath, Giorgio Brero, Blake C Fallon, Antonio Martino, Richard C Willson, Carly S Filgueira, Richard R Bouchard

Faculty, Staff and Student Publications

BACKGROUND: A fundamental obstacle for the preclinical development of ultrasound-(US) mediated cardiac imaging remains cardiac motion, which limits interframe correlation during extended acquisition periods.

PURPOSE: To address this need, we present the design and implementation of a 3D-printed vacuum coupler that stabilizes a US transducer on the epicardial surface of the heart for feasibility assessment and development of advanced, cardiac, US-mediated imaging approaches.

METHODS: The vacuum coupler was 3D printed with biocompatible resins and secured with a standard intraoperative suction aspirator. US-mediated imaging (i.e., B-mode and photoacoustic [PA] imaging) was performed in an open-chest porcine model with and without the …

Imaging Lung Tumor Motion Using Integrated-Mode Proton Radiography-A Phantom Study Towards Tumor Tracking In Proton Radiotherapy, Ryan Fullarton, Mikaël Simard, Lennart Volz, Allison Toltz, Savanna Chung, Christoph Schuy, Daniel G Robertson, Gary Royle, Sam Beddar, Colin Baker, Christian Graeff, Charles-Antoine Collins-Fekete

Faculty, Staff and Student Publications

BACKGROUND: Motion of lung tumors during radiotherapy leads to decreased accuracy of the delivered dose distribution. This is especially true for proton radiotherapy due to the finite range of the proton beam. Methods for mitigating motion rely on knowing the position of the tumor during treatment.

PURPOSE: Proton radiography uses the treatment beam, at an energy high enough to traverse the patient, to produce a radiograph. This work shows the first results of using an integrated-mode proton radiography system to track the position of moving objects in an experimental phantom study; demonstrating the potential of using this method for measuring …

Molecular Modification Of Queen Bee Acid And 10-Hydroxydecanoic Acid With Specific Tripeptides: Rational Design, Organic Synthesis, And Assessment For Prohealing And Antimicrobial Hydrogel Properties, Song Hong, Sachin B. Baravkar, Yan Lu, Abdul Razak Masoud, Qi Zhao, Weilie Zhou

School of Medicine Faculty Publications

Royal jelly and medical grade honey are traditionally used in treating wounds and infections, although their effectiveness is often variable and insufficient. To overcome their limitations, we created novel amphiphiles by modifying the main reparative and antimicrobial components, queen bee acid (hda) and 10-hydroxyl-decanoic acid (hdaa), through peptide bonding with specific tripeptides. Our molecular design incorporated amphiphile targets as being biocompatible in wound healing, biodegradable, non-toxic, hydrogelable, prohealing, and antimicrobial. The amphiphilic molecules were designed in a hda(hdaa)-aa1-aa2-aa3 structural model with rational selection criteria for each moiety, prepared via Rink/Fmoc-tBu-based solid-phase peptide synthesis, and structurally verified by NMR and LC–MS/MS. …

Customized Feminine Hygiene Wash Containing Postbiotics From Lactobacillus Spp. To Treat Urinary Tract Infections (Uti), Veena G. Nair

Theses and Dissertations

Probiotics, which support host health by maintaining normal microbial flora, offer a promising approach for preventing recurrent infections. To evaluate the prophylactic potential of vaginal probiotics against urinary tract infections (UTIs), we conducted a study on 54 healthy South Indian women aged 18–40 who visited the Obstetrics and Gynaecology outpatient clinic at Trichy SRM Medical College and Research Centre between June and July 2022. Vaginal swabs were collected following ethical guidelines, and commensal microbiota were isolated for probiotic characterization, with the broader objective of developing a customized feminine hygiene wash enriched with vaginal postbiotics.

Lactobacilli cell-free supernatant (CFS) demonstrated potent …

Resilience And Reality: Exploring The Lived Experiences Of People Living With Hiv In Texas During The Covid-19 Pandemic – A Qualitative Study., Ahmed F. Alanazi

Social Work Dissertations - Archive

This study investigated the lived experiences of individuals living with HIV (PLWH) in the Dallas-Fort Worth (DFW) area of Texas during the COVID-19 pandemic, using an Interpretative Phenomenological Analysis (IPA) framework. The research examined the intersection of health, social dynamics, and psychological resilience among PLWH, who faced compounded vulnerabilities due to systemic inequities and the dual public health crises of HIV and COVID-19. Through semi-structured interviews with ten participants from diverse backgrounds, the study captured the profound impacts of disrupted healthcare systems, heightened stigma, and social isolation on this marginalized population. The findings reveal that the pandemic exacerbated existing inequities …

A Multiple X-Ray-Source Array (Mxa) System With A Planar Two-Dimensional Source Distribution For Digital Breast Tomosynthesis, Alejandro Sisniega, Andrew M Hernandez, Shadi A Shakeri, Elizabeth A Morris, John M Boone, Jeffrey H Siewerdsen, Paul R Schwoebel

Faculty, Staff and Student Publications

Background: Digital breast tomosynthesis (DBT) has outpaced digital mammography in clinical adoption in the United States; however, substantial technological limitations remain to image quality in DBT, including undersampling from a one-dimensional (1D) scan geometry, x-ray source motion during acquisition, and patient motion artifacts from long exam times.

Purpose: A thermionic cathode x-ray system employing two-dimensional (2D, planar) multiple x-ray-source arrays (MXA) is proposed to improve DBT image quality.

Methods: A 1D MXA, consisting of a linear array of thermionic cathodes was used to simulate a 2D MXA. The 1D MXA included 11 focal spots separated by a distance of Δd …

Promotion And Tenure For Medical Physicists Should Be Based On Article Specific Measures And Not On Journal Impact Factor, Samantha Hedrick, Jinzhong Yang, Yi Rong

Faculty, Staff and Student Publications

No abstract provided.

Interpreting The Biological Effects Of Protons As A Function Of Physical Quantity: Linear Energy Transfer Or Microdosimetric Lineal Energy Spectrum?, Fada Guan, Lawrence Bronk, Matthew Kerr, Yuting Li, Leslie A Braby, Mary Sobieski, Xiaochun Wang, Xiaodong Zhang, Clifford Stephan, David R Grosshans, Radhe Mohan

Faculty, Staff and Student Publications

The choice of appropriate physical quantities to characterize the biological effects of ionizing radiation has evolved over time coupled with advances in scientific understanding. The basic hypothesis in radiation dosimetry is that the energy deposited by ionizing radiation initiates all the consequences of exposure in a biological sample (e.g., DNA damage, reproductive cell death). Physical quantities defined to characterize energy deposition have included dose, a measure of the mean energy imparted per unit mass of the target, and linear energy transfer (LET), a measure of the mean energy deposition per unit distance that charged particles traverse in a medium. The …

Nanoscale Gold Nanoparticle (Gnp)-Laden Tumor Cell Model And Its Use For Estimation Of Intracellular Dose From Gnp-Induced Secondary Electrons, Sandun Jayarathna, Amrit Kaphle, Sunil Krishnan, Sang Hyun Cho

Faculty, Staff and Student Publications

Background: Gold nanoparticles (GNPs) accumulated within tumor cells have been shown to sensitize tumors to radiotherapy. From a physics point of view, the observed GNP-mediated radiosensitization is due to various downstream effects of the secondary electron (SE) production from internalized GNPs such as GNP-mediated dose enhancement. Over the years, numerous computational investigations on GNP-mediated dose enhancement/radiosensitization have been conducted. However, such investigations have relied mostly on simple cellular geometry models and/or artificial GNP distributions. Thus, it is at least desirable, if not necessary, to conduct further investigations using cellular geometry models that properly reflect realistic cell morphology as well as …

Automatic Vessel Attenuation Measurement For Quality Control Of Contrast-Enhanced Ct: Validation On The Portal Vein, Kevin Mccoy, Sujay Marisetty, Dominique Tan, Corey T Jensen, Jeffrey H Siewerdsen, Christine B Peterson, Moiz Ahmad

Faculty, Staff and Student Publications

Background: Adequate image enhancement of organs and blood vessels of interest is an important aspect of image quality in contrast-enhanced computed tomography (CT). There is a need for an objective method for evaluation of vessel contrast that can be automatically and systematically applied to large sets of CT exams.

Purpose: The purpose of this work was to develop a method to automatically segment and measure attenuation Hounsfield Unit (HU) in the portal vein (PV) in contrast-enhanced abdomen CT examinations.

Methods: Input CT images were processed by a vessel enhancing filter to determine candidate PV segmentations. Multiple machine learning (ML) classifiers …

Quantitative Evaluation Of 90y-Pet/Ct And 90y-Spect/Ct-Based Dosimetry Following Yttrium-90 Radioembolization, Srinivas Cheenu Kappadath, Eric Courtney Henry, Benjamin P Lopez, Armeen Mahvash

Faculty, Staff and Student Publications

Background: Following yttrium-90 radioembolization (90Y-RE), 90Y-PET/CT and 90Y-SPECT/CT imaging provide the means to calculate the voxelized absorbed dose distribution. Given the widespread use of the two imaging modalities and lack of well-established standardized dosimetry protocols for 90Y-RE, there is a clinical need to systematically investigate and evaluate differences in the performance of voxel-based dosimetry between 90Y-PET/CT and 90Y-SPECT/CT.

Purpose: To quantitatively analyze and compare 90Y-PET/CT and 90Y-SPECT/CT-based dosimetry following 90Y-RE.

Methods: 90Y-PET/CT and 90Y-SPECT/CT imaging was acquired for 35 patients following 90Y-RE with TheraSphere for the treatment of unresectable hepatocellular carcinoma. Dosimetry was performed using the local deposition method with …

Landmark-Based Auto-Contouring Of Clinical Target Volumes For Radiotherapy Of Nasopharyngeal Cancer, Carlos Sjogreen, Tucker J Netherton, Anna Lee, Moaaz Soliman, Skylar S Gay, Callistus Nguyen, Raymond Mumme, Ivan Vazquez, Dong Joo Rhee, Carlos E Cardenas, Mary K Martel, Beth M Beadle, Laurence Edward Court

Faculty, Staff and Student Publications

Background: The delineation of clinical target volumes (CTVs) for radiotherapy for nasopharyngeal cancer is complex and varies based on the location and extent of disease.

Purpose: The current study aimed to develop an auto-contouring solution following one protocol guidelines (NRG-HN001) that can be adjusted to meet other guidelines, such as RTOG-0225 and the 2018 International guidelines.

Methods: The study used 2-channel 3-dimensional U-Net and nnU-Net framework to auto-contour 27 normal structures in the head and neck (H&N) region that are used to define CTVs in the protocol. To define the CTV-Expansion (CTV1 and CTV2) and CTV-Overall (the outer envelope of …

Evaluating The Relationship Between Magnetic Resonance Image Quality Metrics And Deep Learning-Based Segmentation Accuracy Of Brain Tumors, Rajarajeswari Muthusivarajan, Adrian Celaya, Joshua P Yung, James P Long, Satish E Viswanath, Daniel S Marcus, Caroline Chung, David Fuentes

Faculty, Staff and Student Publications

Background: Magnetic resonance imaging (MRI) scans are known to suffer from a variety of acquisition artifacts as well as equipment-based variations that impact image appearance and segmentation performance. It is still unclear whether a direct relationship exists between magnetic resonance (MR) image quality metrics (IQMs) (e.g., signal-to-noise, contrast-to-noise) and segmentation accuracy.

Purpose: Deep learning (DL) approaches have shown significant promise for automated segmentation of brain tumors on MRI but depend on the quality of input training images. We sought to evaluate the relationship between IQMs of input training images and DL-based brain tumor segmentation accuracy toward developing more generalizable models …

Evaluating Automatically Generated Normal Tissue Contours For Safe Use In Head And Neck And Cervical Cancer Treatment Planning, Raphael Douglas, Adenike Olanrewaju, Raymond Mumme, Lifei Zhang, Beth M Beadle, Laurence Edward Court

Faculty, Staff and Student Publications

Purpose: Volumetric-modulated arc therapy (VMAT) is a widely accepted treatment method for head and neck (HN) and cervical cancers; however, creating contours and plan optimization for VMAT plans is a time-consuming process. Our group has created an automated treatment planning tool, the Radiation Planning Assistant (RPA), that uses deep learning models to generate organs at risk (OARs), planning structures and automates plan optimization. This study quantitatively evaluates the quality of contours generated by the RPA tool.

Methods: For patients with HN (54) and cervical (39) cancers, we retrospectively generated autoplans using the RPA. Autoplans were generated using deep-learning and RapidPlan …