Radiation Medicine Commons^™

Patient-Reported Outcomes: Comparing Functional Avoidance And Standard Thoracic Radiation Therapy In Lung Cancer, Spencer Poiset, Joseph Lombardo, Edward Castillo, Richard Castillo, Bernard Jones, Moyed Miften, Brian Kavanagh, Adam Dicker, Cullen Boyle, Nicole Simone, Benjamin Movsas, Inga Grills, Chad Rusthoven, Yevgeniy Vinogradskiy, Lydia Wilson

Department of Radiation Oncology Faculty Papers

PURPOSE: Novel methods generate functional images using image processing techniques combined with four-dimensional computed tomography (4DCT) data (4DCT-ventilation). 4DCT-ventilation was implemented in a phase II, multicenter functional avoidance clinical trial. The work compares functional avoidance patient-reported outcomes (PROs) against historical standards.

METHODS: Patients with locally advanced lung cancer undergoing curative-intent chemoradiation were accrued. 4DCT-ventilation imaging was generated and functional avoidance treatment plans created reduced dose to functional lung. PRO instruments included Functional Assessment of Cancer Therapy Lung questionnaire and accompanying subscales (including the Trial Outcome Index [TOI]), EuroQol-5 Dimension (EQ-5D), and EQ-Visual Analog Scale (EQ-VAS). The average change from baseline …

Atypical Presentation Of Non-Small Cell Lung Carcinoma With Metastasis To Breast Tissue, Tylar P. Seckman, Diane Krutzler-Berry, Mohamed Ashal, Waqas Mahmud, Krista L. Denning, Logan M. Lawrence

Marshall Journal of Medicine

Malignant neoplasms of the lung commonly metastasize to lymph nodes, bone, brain, and liver via hematogenous and lymphatic routes. Much less commonly, metastasis occurs in the breast. Secondary metastatic disease of the breast is very rare, with a reported incidence ranging from 0.4-1.3%­­—with primary lung cancer being one of the most anomalous sources. This case details non-small cell lung cancer metastasis to the breast with proven primary contralateral lung origination. This atypical finding prompts medical professionals to consider these malignant cells' immunologic, histologic, and pathologic makeup to understand further and treat the neoplasm.

Deep Learning-Based Auto-Segmentation For Liver Yttrium-90 Selective Internal Radiation Therapy, Jun Li, Wookjin Choi, Rani Anne

Department of Radiation Oncology Faculty Papers

The aim was to evaluate a deep learning-based auto-segmentation method for liver delineation in Y-90 selective internal radiation therapy (SIRT). A deep learning (DL)-based liver segmentation model using the U-Net3D architecture was built. Auto-segmentation of the liver was tested in CT images of SIRT patients. DL auto-segmented liver contours were evaluated against physician manually-delineated contours. Dice similarity coefficient (DSC) and mean distance to agreement (MDA) were calculated. The DL-model-generated contours were compared with the contours generated using an Atlas-based method. Ratio of volume (RV, the ratio of DL-model auto-segmented liver volume to manually-delineated liver volume), and ratio of activity (RA, …

Developing Real-Time, Online Beam Control Of Uhdr Irradiators To Facilitate Flash Translational Investigations, Austin M. Sloop

Dartmouth College Ph.D Dissertations

The field of radiation oncology seeks novel techniques to increase the therapeutic ratio to treat malignancies while minimizing damage and toxicities in healthy tissues. While it was observed that delivering therapeutic doses at high dose rate could elicit lower biological effects over a half-century ago, the field of ultra-high dose rate (UHDR) radiation therapy (colloquially known as FLASH RT) has seen a resurgence in recent years due to an alignment of accelerator capability, dosimetric advances, and improved biotechnological techniques. This has opened the door to studying potential underlying mechanisms such that we may leverage the effects of FLASH tissue sparing …

Reduced Set-Shifting Processing Speed In Male Rats Following Low Dose (10 Cgy) Proton Exposure, Hui Ho Vanessa Chang, Gyutae Kim, Kyu-Sung Kim, Richard A. Britten

Center for Integrative Neuroscience and Inflammatory Diseases (CINID) Faculty Publications

Space radiation (SR) exposure poses significant biomedical risks, including effects on the central nervous system (CNS). These risks are particularly relevant to cognitive function during long-duration space missions. One critical cognitive skill is decision-making, which requires attentional set-shifting (ATSET)—the ability to quickly assess problems, evaluate options, and select the best actions. Previous studies have shown that exposure to However, the impact of low LET (< 1 keV/μm) protons, which significantly contribute to the total radiation flux astronauts encounter within spacecraft, on ATSET performance is unknown. To address this gap, we evaluated the effects of cranial irradiation with 10 cGy of 100 MeV/n protons (LET = 0.732 keV/μm) on ATSET performance in male Sprague-Dawley rats. We also investigated whether concurrent exposure to variable gravity (hypergravity step-up, step down, purported to have the same effect as exposure to microgravity (another major spaceflight stressor) exacerbated SR-induced cognitive deficits. Our findings indicate that proton exposure alone significantly impaired ATSET performance, as evidenced by decreased processing speed while performing compound discrimination reversal and extra-dimensional shifting. Notably, no additive or synergistic effects were observed when hypergravity was combined with proton exposure. The impact that low-dose proton exposure has on CNS functionality, particularly in reducing processing speed during complex tasks, warrant further investigation. If similar cognitive deficits were to occur in astronauts exposed to galactic cosmic rays, mission success and safety could be significantly compromised.

A Knowledge-Based Planning Model To Identify Fraction-Reduction Opportunities In Brain Stereotactic Radiotherapy, Shane Mccarthy, William St. Clair, Damodar Pokhrel

Radiation Medicine Faculty Publications

Objective: To develop and validate a HyperArc-based RapidPlan (HARP) model for three-fraction brain stereotactic radiotherapy (SRT) plans to then use to replan previously treated five-fraction SRT plans. Demonstrating the possibility of reducing the number of fractions while achieving acceptable organs-at-risk (OAR) doses with improved target biological effective dose (BED) to brain lesions. Methods: Thirty-nine high-quality clinical three-fraction HyperArc brain SRT plans (24–27 Gy) were used to train the HARP model, with a separate 10 plans used to validate its effectiveness. Fifty-eight five-fraction HyperArc brain SRT plans (30–40 Gy) attempted to be retrospectively replanned for three fractions scheme using the HARP …

An Investigation Into The Feasibility And Efficacy Of Stereotactic Radiosurgery For 1–3 Cm Single Brain Lesions On The Ring-Mounted Halcyon Linac, Kristin J. Hazelwood, Shane Mccarthy, Josh Misa, David Castelvetere, William St. Clair, Damodar Pokhrel

Radiation Medicine Faculty Publications

Purpose: An evaluation of the accuracy, safety, and efficiency of the Halcyon ring delivery system (RDS) for stereotactic radiosurgery (SRS) treatment to relatively small (1–3 cm) brain lesions.

Methods: After completing the extensive in-house quality assurance checks including Winston–Lutz test and independent dose verification via MD Anderson IROC SRS head phantom irradiation on Halcyon, fifteen brain SRS patients previously treated with a single dose of 20 Gy on TrueBeam (6MV-FFF) with HyperArc geometry were retrospectively replanned on Halcyon (6MV-FFF). Plan quality metrics including conformity index (CI), gradient index (GI), gradient distance (GD), PTV coverage, gross tumor volume (GTV) dose, heterogeneity …

A Predictive Quality Assurance Model For Patient-Specific Gamma Passing Rate Of Hyperarc-Based Stereotactic Radiotherapy And Radiosurgery Of Brain Metastases, Shane Mccarthy, Brent Harrison, Damodar Pokhrel

Radiation Medicine Faculty Publications

Objective: Measurement-based patient specific quality assurance (PSQA) is an increasingly debated topic among medical physicists. Developments like online adaptive radiotherapy and same-day stereotactic treatments limit the time to do measurement-based PSQA. Herein, we develop a predictive machine learning model to supplement PSQA by predicting the gamma passing rate (GPR) per stereotactic arc. This streamlines PSQA, providing planners the insight to replan potentially sub-optimal plans, to mitigate machine time inefficiencies.

Methods: 122 patients that had previously received HyperArc stereotactic radiosurgery/radiotherapy on a TrueBeam LINAC (Millenium 120 MLCs, 6MV-FFF) were used to generate a long short-term memory (LSTM) recurrent neural network to …

Automated Hippocampal Sparing Whole Brain Radiotherapy With Simultaneous Integrated Boost For Multiple Brain Metastases: Halcyon, Hyperarc On Truebeam, And Coplanar Truebeam, Shane Mccarthy, Ryan Clark, Anthony Magliari, William St. Clair, Damodar Pokhrel

Radiation Medicine Faculty Publications

Purpose: To demonstrate the ease and feasibility that hippocampal sparing whole brain (WB) simultaneous integrated boost (HSWB-SIB) plans can be generated using knowledge-based planning and Eclipse Scripting Application Programming Interface (ESAPI) for three different modalities, HyperArc on TrueBeam (TB-HA), a coplanar beam arrangement on TrueBeam (TB-Co), and the ring-mounted Halcyon LINAC (Hal).

Methods: Twelve patients with 2–14 brain metastases were retrospectively replanned for HSWB-SIB using a published HSWB RapidPlan model with modifications for the automated addition of SIB to metastases. Prescribed dose was 30 Gy to the WB planning target volume (PTV) and 50 Gy to the metastases in 10 …

Feasibility Of Treatment Planning With Hyperarc Stereotactic Radiosurgery Methods For Ocular Tumors, Chase Cochran, Shane Mccarthy, William St. Clair, Damodar Pokhrel

Radiation Medicine Faculty Publications

Purpose/objectives

Currently, ocular disease is primarily managed with COMS plaque brachytherapy. Various stereotactic radiosurgery (SRS) platforms have also been employed, yet widespread access remains a challenge. Herein, we demonstrate the feasibility of using the HyperArc SRS system to provide an additional platform for the treatment of ocular malignancies.

Materials/methods

Twenty previously treated COMS patients with ocular melanoma were selected for a retrospective HyperArc SRS planning study. The average gross tumor volume (GTV) derived from MRI was 1.19 ± 0.60 cc. Planning target volumes (PTV) were generated from a 2 mm expansion of the GTVs. HyperArc plans were created for a …

A Two-Hit Model Of Executive Dysfunction: Simulated Galactic Cosmic Radiation Primes Latent Deficits Revealed By Sleep Fragmentation, Richard A. Britten, Ella N. Tamgue, Paola Arriaga Alvarado, Arriyam S. Fesshaye, Larry D. Sanford

Department Radiation Oncology & Biophysics Faculty Publications

Future Artemis-class missions to Mars will expose astronauts to prolonged space radiation (SR), sleep disruption, and operational demands requiring greater autonomy, placing decision making and executive function at heightened risk. Both SR and sleep fragmentation (SF) independently impair cognition, yet their combined effects remain poorly understood. Using the Associative Recognition Memory and Interference (ARMIT) task, we assessed cognitive performance in male rats exposed to 10 cGy of Galactic Cosmic Ray simulation (GCRsim), SF, or both. Under well-rested conditions, GCRsim-exposed rats exhibited overt deficits in the C.1.2 stage, performing at chance when reinforcement contingencies shifted, consistent with impaired cognitive flexibility. In …

Machine Learning Models For Pancreatic Cancer Survival Prediction: A Multi-Model Analysis Across Stages And Treatments Using The Surveillance, Epidemiology, And End Results (Seer) Database, Aditya Chakraborty, Mohan D. Pant

Epidemiology, Biostatistics, & Environmental Health Faculty Publications

Background: Pancreatic cancer is among the most lethal malignancies, with poor prognosis and limited survival despite treatment advances. Accurate survival modeling is critical for prognostication and clinical decision-making. This study had three primary aims: (1) to determine the best-fitting survival distribution among patients diagnosed and deceased from pancreatic cancer across stages and treatment types; (2) to construct and compare predictive risk classification models; and (3) to evaluate survival probabilities using parametric, semi-parametric, non-parametric, machine learning, and deep learning methods for Stage IV patients receiving both chemotherapy and radiation. Methods: Using data from the SEER database, parametric models (Generalized Extreme Value, …

Demonstration Of An Enhanced Dosing Pattern For Debulking Large And Bulky Unresectable Tumors Via Differential Hole-Size Spatially Fractionated Radiotherapy, Joshua Misa, William St. Clair, Damodar Pokhrel

Radiation Medicine Faculty Publications

Purpose/objective

We propose a novel lattice deployment for spatially fractionated radiotherapy (SFRT) treatments. In this approach, a larger diameter high-dose sphere is centrally placed in the bulky tumor mass and surrounded by smaller diameter high-dose spheres.

Materials/methods

Thirty SFRT patients (10 head and neck [HN], 10 abdominal/pelvis, and 10 chest/lung cases) treated with an MLC-based crossfire method were retrospectively analyzed. Eleven differential hole-size lattice patterns were benchmarked against the clinically delivered SFRT plans (1 cm diameter cylinders, 2 cm spacing) and the standard uniform lattice pattern (1.5 cm diameter spheres, 3 cm spacing). These patterns varied in core diameter (C: …

In Vitro Α/Β Ratio Variations In Cervical Cancer, With Consequent Effects On Equivalent Dose In 2 Gy Fraction In High-Dose-Rate Brachytherapy, Cameron Thayer-Freeman, Brien Washington, Denise Fabian, Dennis C. Cheek, William St. Clair, Mark E. Bernard, Wei Luo

Radiation Medicine Faculty Publications

Purpose: To determine the distributions of published α/β values measured in vitro and the resulting uncertainties in the equivalent dose in 2 Gy fractions (EQD ₂ ) when applied to high-dose-rate brachytherapy (HDR-BT) for cervical cancer.

Methods and Materials: An analysis of 98 published α/β values from 31 papers was conducted, spanning 23 cervical cancer cell lines. Values were further divided into squamous cell carcinoma and adenocarcinoma histologies. Probability distributions were fit to histograms using the bootstrapped Kolmogorov-Smirnov goodness-of-fit test. Both average and most probable α/β values for cervical cancer were determined. The probability distributions were then applied to three …

Development And Clinical Validation Of Automated Same-Day Stereotactic Treatment Procedures For Multiple Brain Metastases And Recurrent Head And Neck Cancers, Shane Mccarthy

Theses and Dissertations--Radiation Medicine

As technology advances, more and more cancer patients are benefiting from the use of stereotactic radiosurgery and radiotherapy (SRS/SRT) to treat their disease. One such technology, Varian’s HyperArc high-definition radiosurgery module, a tool to help facilitate the treatment of brain metastases on a medical linear accelerator (LINAC), has been demonstrated to achieve comparable low dose spillage and target conformity compared to the current gold standard for intracranial malignancies, the Elekta Gamma Knife. Furthermore, due to HyperArc’s single-isocenter multiple lesion approach, the treatment can be delivered in a significantly shorter amount of time. Unfortunately, the manual process of creating these stereotactic …

A Fast Framework For Generating Radioactive Mixture Spectra And Its Application To Remote High-Performance Mixture Identification, Chiman Kwan, Bulent Ayhan, Adam Stavola, Kazi Aminul Islam, Hongfang Zhang, Jiang Li

Electrical & Computer Engineering Faculty Publications

Remote detection of radioactive materials in mixtures using handheld or portal detectors remains a challenge because of factors such as low concentration, environmental interference, sensor noise, and other complications. This work introduces a fast framework for generating realistic mixture spectra. Moreover, we present mixture isotope identification using data generated by the fast framework. Researchers have examined a range of conventional and recent algorithms within the fields of machine learning and deep learning. An application to uranium enrichment-level prediction has been included. Extensive simulation experiments validated the efficacy of the proposed framework.

Feasibility And Impact Of Knowledge-Based Automated Radiotherapy Treatment Planning In Low- And Middle-Income Countries, Awusi Kavuma, Solomon Kibudde, Yao Hao, Baozhou Sun

Faculty, Staff and Students Publications

Background and purpose: A high-quality treatment planning process is crucial in advanced radiotherapy techniques to ensure adequate dose to the target volume (TV) and sparing of organs at risk (OARs). This process often requires intensive labor, creating barriers for deployment in low- and middle-income countries (LMICs). We aimed to establish the feasibility of implementing knowledge-based auto-planning to facilitate clinical efficiency and increase patient throughput in an LMIC.

Materials and methods: We evaluated 60 randomly selected VMAT manual plans (VMPs), including 10 for each of the following sites: head and neck, oesophagus, breast, prostate, cervical, and rectal cancers. Using the same …

Percutaneous Stenting As Treatment For Chylothorax From Superior Vena Cava Syndrome: A Case Report, Arta Kasaeian, Taylor Hoffman, Mohammad Ghasemi Rad, David Wynne, David Léon

Faculty, Staff and Students Publications

Superior vena cava syndrome is a condition that results from obstruction of the superior vena cava, the etiology of which can be benign or malignant. The impaired venous return can cause facial and upper extremity swelling, dyspnea, and neurologic symptoms. Chylothorax is a rare complication of superior vena cava syndrome. We report a case of a 69-year-old male with end-stage renal disease, who developed both a chylothorax and a contralateral simple pleural effusion secondary to superior vena cava syndrome. He was successfully treated with percutaneous endovascular stenting.

Three-Dimensional Deep Learning Normal Tissue Complication Probability Model To Predict Late Xerostomia In Patients With Head And Neck Cancer, Hung Chu, Suzanne P M De Vette, Hendrike Neh, Nanna M Sijtsema, Roel J H M Steenbakkers, Amy Moreno, Johannes A Langendijk, Peter M A Van Ooijen, Clifton D Fuller, Lisanne V Van Dijk

Faculty, Staff and Student Publications

Purpose: Conventional normal tissue complication probability (NTCP) models for patients with head and neck cancer are typically based on single-value variables, which, for radiation-induced xerostomia, are baseline xerostomia and mean salivary gland doses. This study aimed to improve the prediction of late xerostomia by using 3-dimensional information from radiation dose distributions, computed tomography imaging, organ-at-risk segmentations, and clinical variables with deep learning (DL).

Methods and materials: An international cohort of 1208 patients with head and neck cancer from 2 institutes was used to train and twice validate DL models (deep convolutional neural network, EfficientNet-v2, and ResNet) with 3-dimensional dose distribution, …

Lyrical Stillness, Madhav Patel

HCA Healthcare Journal of Medicine

“Lyrical Stillness” is a poem I wrote during my radiation oncology rotation, during which I was provided the opportunity to learn more about multidisciplinary cancer care while delving deeper into radiotherapy. Cancer can be an overwhelming disease process physically, psychologically, and emotionally. Patients undergoing treatment often experience stress and anxiety with the uncertainty of their prognoses. In this poem, I describe a patient receiving radiation therapy whom I enjoyed speaking to about his favorite hobby: bird watching. During his subsequent radiation treatment sessions, I decided to play a CD of mockingbirds singing in a tropical forest, in the hopes it …

Analysis Of Impulsive Differential Equation Models Of Cell Populations Undergoing Radiation Therapy, Abigail D'Ovidio Long

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Radiation therapy is a mode of treatment which is implemented for approximately 50% of cancer patients. Treatment needs to be able to kill cancer cells, but also do minimal damage to surrounding healthy tissue. We propose two main impulsive differential equation models of radiation therapy to capture the periodic nature of the treatment. These models build off of previous studies using clinical data to ensure biological relevance. The first model incorporates only cancer cell populations, and we provide parameter relationships which theoretically ensure treatment outcomes of cancer eradication, cancer approaching a carrying capacity, and cancer approaching a periodic solution. We …

Novel Cuprotosis-Related Gene Signature: A Prognostic Indicator And Regulator Of The Glioma Immune Microenvironment, Dongming Gao, Youyuan Bao, Wenyin Shi, Lei Li, Liang Gao

Department of Radiation Oncology Faculty Papers

Background: Glioma is a primary malignant brain tumor with a poor prognosis. Glioma-related biomarkers need to be identified to enable the personalized treatment of and predict the prognosis of glioma patients. Cuproptosis is an unusual mechanism of cell death, and is closely associated with disease progression and the immune-microenvironment of the tumor. However, the function of cuproptosis in glioma is still unclear, therefore the aim of this study was to investigate the role of cuproptosis-related genes in gliomas.

Methods: We examined the relationship between cuproptosis and glioma using the clinical and expression data of glioma tumors from The Cancer Genome …

Optimization Processes Of Clinical Chelation-Based Radiopharmaceuticals For Pathway-Directed Targeted Radionuclide Therapy In Oncology, Katsumi Tomiyoshi, Lydia J. Wilson, Firas Mourtada, Jennifer Sims Mourtada, Yuta Namiki, Wataru Kamata, David J. Yang, Tomio Inoue

Department of Radiation Oncology Faculty Papers

Targeted radionuclide therapy (TRT) for internal pathway-directed treatment is a game changer for precision medicine. TRT improves tumor control while minimizing damage to healthy tissue and extends the survival for patients with cancer. The application of theranostic-paired TRT along with cellular phenotype and genotype correlative analysis has the potential for malignant disease management. Chelation chemistry is essential for the development of theranostic-paired radiopharmaceuticals for TRT. Among image-guided TRT,

Isolation, Discrimination, And Feeling “Constant Guilt”: A Mixed-Methods Analysis Of Female Physicians’ Experience With Fertility, Family Planning, And Oncology Careers, Sarah Marion, Shraddha M Dalwadi, Aleksandra Kuczmarska-Haas, Erin F Gillespie, Michelle S Ludwig, Emma B Holliday, Bridgette Thom, Fumiko Chino, Anna Lee

Faculty, Staff and Students Publications

Introduction: Family planning among female physicians is harmed by high risks of infertility, workload burden, poor family leave policies, and gender discrimination. Many women report feeling unsupported in the workplace, despite national policies to protect against unfair treatment.

Methods: This secondary analysis applied a modified version of the rigorous and accelerated data reduction technique to conduct a thematic analysis of comments to an open-ended prompt. Comments were coded by multiple trained researchers then grouped and merged into illustrative themes via qualitative techniques.

Results: Of 1004 responses to the quantitative survey, 162 physicians completed the open-ended prompt. Initial codes (n = …

Conference Report: Review Of Clinical Implementation Of Advanced Quantitative Imaging Techniques For Personalized Radiotherapy, Yevgeniy Vinogradskiy, Houda Bahig, Nicholas Bucknell, Jeffrey Buchsbaum, Hui-Kuo George Shu

Department of Radiation Oncology Faculty Papers

The topic of quantitative imaging in radiation therapy was presented as a "Masterclass" at the 2023 annual meeting of the American Society of Radiation Oncology (ASTRO). Dual-energy computed tomography (CT) and single-positron computed tomography were reviewed in detail as the first portion of the meeting session, with data showing utility in many aspects of radiation oncology including treatment planning and dose response. Positron emission tomography/CT scans evaluating the functional volume of lung tissue so as to provide optimal avoidance of healthy lungs were presented second. Advanced brain imaging was then discussed in the context of different forms of magnetic resonance …

Validation Of An Artificial Intelligence-Based Prognostic Biomarker In Patients With Oligometastatic Castration-Sensitive Prostate Cancer, Jarey H. Wang, Matthew P. Deek, Adrianna A. Mendes, Yang Song, Amol Shetty, Soha Bazyar, Kim Van Der Eecken, Emmalyn Chen, Timothy N. Showalter, Trevor J. Royce, Tamara Todorovic, Huei-Chung Huang, Scott A. Houck, Rikiya Yamashita, Ana P. Kiess, Daniel Y. Song, Tamara Lotan, Theodore Deweese, Luigi Marchionni, Lei Ren, Amit Sawant, Nicole L. Simone, Alejandro Berlin, Cem Onal, Andre Esteva, Felix Y. Feng, Phuoc T. Tran, Philip Sutera, Piet Ost

Department of Radiation Oncology Faculty Papers

BACKGROUND: There is a need for clinically actionable prognostic and predictive tools to guide the management of oligometastatic castration-sensitive prostate cancer (omCSPC).

METHODS: This is a multicenter retrospective study to assess the prognostic and predictive performance of a multimodal artificial intelligence biomarker (MMAI; the ArteraAI Prostate Test) in men with omCSPC (n = 222). The cohort also included 51 patients from the STOMP and ORIOLE phase 2 clinical trials which randomized patients to observation versus metastasis-directed therapy (MDT). MMAI scores were computed from digitized histopathology slides and clinical variables. Overall survival (OS) and time to castration-resistant prostate cancer (TTCRPC) were …

Durable Local Control With Hypofractionated Radiation Therapy For Unresectable Or Metastatic Melanoma, Sydney A Keatts, Aya F Salem, David M Swanson, Ahsan S Farooqi, Andrew J Bishop, Rodabe N Amaria, Jennifer L Mcquade, Isabella C Glitza Oliva, Adi Diab, Roi Weiser, Sarah B Fisher, Ryan P Goepfert, Merrick I Ross, B Ashleigh Guadagnolo, Devarati Mitra

Faculty, Staff and Student Publications

BACKGROUND AND PURPOSE: As patients with advanced melanoma live longer in the context of systemic therapy advancements, better strategies for durable control of bulky tumors are needed. In this study, we evaluated if dose-escalated hypofractionated radiation therapy (HFRT) can provide durable local control and improve tumor-associated symptoms in patients with unresectable or bulky metastatic melanoma for whom stereotactic ablative radiotherapy (RT) approaches are not feasible due to tumor size or location.

MATERIALS AND METHODS: We retrospectively reviewed 49 patients with unresectable or bulky metastatic melanoma who were treated to a total of 53 tumor targets with 12-17 fractions HFRT at …

Personalized Brachytherapy: Applications And Future Directions, Piyush Pathak, Justin J Thomas, Arjit Baghwala, Chengfeng Li, Bin S Teh, Edward B Butler, Andrew M Farach

Faculty, Staff and Students Publications

Brachytherapy offers a highly conformal and adaptive approach to radiation therapy for various oncologic conditions. This review explores the rationale, applications, technological advances, and future directions of personalized brachytherapy. Integration of advanced imaging techniques, 3D-printed applicators, and artificial intelligence are rapidly enhancing brachytherapy delivery and efficiency, while genomic tests and molecular biomarkers are refining patient and dose selection. Emerging research on combining brachytherapy with immunotherapy offers unique synergistic potential, and technologies such as intensity-modulated and shielded brachytherapy applicators present novel opportunities to further optimize dose distributions. Despite these promising advances, the field faces challenges including a need to train more …

Atr Inhibition Radiosensitizes Cells Through Augmented Dna Damage And G2 Cell Cycle Arrest Abrogation, Scott J Bright, Mandira Manandhar, David B Flint, Rishab Kolachina, Mariam Ben Kacem, David Kj Martinus, Broderick X Turner, Ilsa Qureshi, Conor H Mcfadden, Poliana C Marinello, Simona F Shaitelman, Gabriel O Sawakuchi

Faculty, Staff and Student Publications

Ataxia telangiectasia and Rad3-related protein (ATR) is a key DNA damage response protein that facilitates DNA damage repair and regulates cell cycle progression. As such, ATR is an important component of the cellular response to radiation, particularly in cancer cells, which show altered DNA damage response and aberrant cell cycle checkpoints. Therefore, ATR's pharmacological inhibition could be an effective radiosensitization strategy to improve radiotherapy. We assessed the ability of an ATR inhibitor, AZD6738, to sensitize cancer cell lines of various histologic types to photon and proton radiotherapy. We found that radiosensitization took place through persistent DNA damage and abrogated G2 …

Source Model Parameters For Beam Commissioning Of Scanning Proton Therapy Treatment Planning System: Multi-Institutional Survey And Analysis, Chih-Wei Chang, Liyong Lin, Lei Dong, Heng Li, Jan Po Schuemann, Jiajian Shen, Xuanfeng Ding

Conference Presentation Abstracts

Purpose: To create a beamline-specific repository of source model parameters and beam commissioning data for scanning proton therapy (PT) treatment planning system (TPS).

Methods: We surveyed 28 PT centers, collecting beam commissioning source model parameters of diverse beamlines from different vendors: Hitachi, IBA, Varian, Mevion. Parameters included (i) beam meterset calibration in protons per MU, (ii) in-air spot size at isocenter in terms of standard deviation in x- (crossline, σ_x) and y- (inline, σ_y) directions, (iii) in-air angular spread at isocenter in x-direction (θ_x) and y-direction (θ_y). We plotted each parameter as …