Radiation Medicine Commons^™

Multiomics Characterization Of Methicillin-Resistant Staphylococcus Aureus (Mrsa) Isolates With Heterogeneous Intermediate Resistance To Vancomycin (Hvisa) In Latin America, Betsy E Castro, Rafael Rios, Lina P Carvajal, Mónica L Vargas, Mónica P Cala, Lizeth León, Blake Hanson, An Q Dinh, Oscar Ortega-Recalde, Carlos Seas, Jose M Munita, Cesar A Arias, Sandra Rincon, Jinnethe Reyes, Lorena Diaz

Faculty, Staff and Student Publications

BACKGROUND: Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) compromise the clinical efficacy of vancomycin. The hVISA isolates spontaneously produce vancomycin-intermediate Staphylococcus aureus (VISA) cells generated by diverse and intriguing mechanisms.

OBJECTIVE: To characterize the biomolecular profile of clinical hVISA applying genomic, transcriptomic and metabolomic approaches.

METHODS: 39 hVISA and 305 VSSA and their genomes were included. Core genome-based Bayesian phylogenetic reconstructions were built and alterations in predicted proteins in VISA/hVISA were interrogated. Linear discriminant analysis and a Genome-Wide Association Study were performed. Differentially expressed genes were identified in hVISA-VSSA by RNA-sequencing. The undirected profiles of metabolites were determined by liquid chromatography and …

Using Patient Flow Analysis With Real-Time Patient Tracking To Optimize Radiation Oncology Consultation Visits, Shane Mesko, Julius Weng, Prajnan Das, Albert C Koong, Joseph M Herman, Dorothy Elrod-Joplin, Ashley Kerr, Thomas Aloia, John Frenzel, Katy E French, Wendi Martinez, Iris Recinos, Abdulaziz Alshaikh, Utpala Daftary, Amy C Moreno, Quynh-Nhu Nguyen

Faculty, Staff and Student Publications

PURPOSE: Clinical efficiency is a key component of the value-based care model and a driver of patient satisfaction. The purpose of this study was to identify and address inefficiencies at a high-volume radiation oncology clinic.

METHODS AND MATERIALS: Patient flow analysis (PFA) was used to create process maps and optimize the workflow of consultation visits in a gastrointestinal radiation oncology clinic at a large academic cancer center. Metrics such as cycle times, waiting times, and rooming times were assessed by using a real-time patient status function in the electronic medical record for 556 consults and compared between before vs after …

Quantifying The Magnitude Of To Tal Dose Deviation Caused By Various Sources Of Error Among Iroc Phantom Irradiation Results, Sharbacha S. Edward

Dissertations and Theses (Open Access)

The Imaging and Radiation Oncology Core (IROC) phantoms are used as an end-to-end test of an institution’s radiotherapy processes, and for clinical trial credentialing. Phantoms are treated like patients, and evaluation of the doses received by the thermoluminescent dosimeters (TLDs) inside the phantom, reflects the accuracy with which an institution can image, plan and irradiate a phantom or patient. Recent phantom results show that among the hundreds of various IROC phantoms irradiated annually, 8-17% of institutions fail this test. The purpose of this work was to investigate the various types of errors that may occur during the treatment process and …

Infrastructure Development For Personalized Risk Prediction To Reduce Cardiovascular Disease In Childhood Cancer Survivors, Suman Shrestha

Dissertations and Theses (Open Access)

Although childhood cancer survivors have lengthy life expectancies, they run the risk of experiencing long-term health issues as a result of their treatment. The most frequent non-cancerous cause of morbidity and mortality for these survivors is cardiac disease. Radiation therapy (RT) has been linked in numerous cohort studies to a higher chance of developing a late cardiac disease in these survivors, and this risk rises with higher mean heart doses and increased RT exposure to larger cardiac volumes. Since, the heart is a heterogeneous organ made up of several distinct substructures, RT dose received by the entire heart does not …

Quantitative Apparent Diffusion Coefficients From Peritumoral Regions As Early Predictors Of Response To Neoadjuvant Systemic Therapy In Triple-Negative Breast Cancer, Benjamin C Musall, Beatriz E Adrada, Rosalind P Candelaria, Rania M M Mohamed, Abeer H Abdelhafez, Jong Bum Son, Jia Sun, Lumarie Santiago, Gary J Whitman, Tanya W Moseley, Marion E Scoggins, Hagar S Mahmoud, Jason B White, Ken-Pin Hwang, Nabil A Elshafeey, Medine Boge, Shu Zhang, Jennifer K Litton, Vicente Valero, Debu Tripathy, Alastair M Thompson, Clinton Yam, Peng Wei, Stacy L Moulder, Mark D Pagel, Wei T Yang, Jingfei Ma, Gaiane M Rauch

Faculty, Staff and Student Publications

BACKGROUND: Pathologic complete response (pCR) to neoadjuvant systemic therapy (NAST) in triple-negative breast cancer (TNBC) is a strong predictor of patient survival. Edema in the peritumoral region (PTR) has been reported to be a negative prognostic factor in TNBC.

PURPOSE: To determine whether quantitative apparent diffusion coefficient (ADC) features from PTRs on reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) predict the response to NAST in TNBC.

STUDY TYPE: Prospective.

POPULATION/SUBJECTS: A total of 108 patients with biopsy-proven TNBC who underwent NAST and definitive surgery during 2015-2020.

FIELD STRENGTH/SEQUENCE: A 3.0 T/rFOV single-shot diffusion-weighted echo-planar imaging sequence (DWI).

ASSESSMENT: Three scans were …

Spinal Metastases And The Evolving Role Of Molecular Targeted Therapy, Chemotherapy, And Immunotherapy, Elena I Fomchenko, James C Bayley, Christopher Alvarez-Breckenridge, Laurence D Rhines, Claudio E Tatsui

Faculty, Staff and Student Publications

Metastatic involvement of the spine is a common complication of systemic cancer progression. Surgery and external beam radiotherapy are palliative treatment modalities aiming to preserve neurological function, control pain and maintain functional status. More recently, with development of image guidance and stereotactic delivery of high doses of conformal radiation, local tumor control has improved; however recurrent or radiation refractory disease remains a significant clinical problem with limited treatment options. This manuscript represents a narrative overview of novel targeted molecular therapies, chemotherapies, and immunotherapy treatments for patients with breast, lung, melanoma, renal cell, prostate, and thyroid cancers, which resulted in improved …

Multi-Organ Segmentation Of Abdominal Structures From Non-Contrast And Contrast Enhanced Ct Images, Cenji Yu, Chidinma P Anakwenze, Yao Zhao, Rachael M Martin, Ethan B Ludmir, Joshua S Niedzielski, Asad Qureshi, Prajnan Das, Emma B Holliday, Ann C Raldow, Callistus M Nguyen, Raymond P Mumme, Tucker J Netherton, Dong Joo Rhee, Skylar S Gay, Jinzhong Yang, Laurence E Court, Carlos E Cardenas

Faculty, Staff and Student Publications

Manually delineating upper abdominal organs at risk (OARs) is a time-consuming task. To develop a deep-learning-based tool for accurate and robust auto-segmentation of these OARs, forty pancreatic cancer patients with contrast-enhanced breath-hold computed tomographic (CT) images were selected. We trained a three-dimensional (3D) U-Net ensemble that automatically segments all organ contours concurrently with the self-configuring nnU-Net framework. Our tool's performance was assessed on a held-out test set of 30 patients quantitatively. Five radiation oncologists from three different institutions assessed the performance of the tool using a 5-point Likert scale on an additional 75 randomly selected test patients. The mean (± …

Radiation Therapy Induces Immunosenescence Mediated By P90rsk, Masaki Imanishi, Haizi Cheng, Sivareddy Kotla, Anita Deswal, Nhat-Tu Le, Eduardo Chini, Kyung Ae Ko, Venkata S K Samanthapudi, Ling-Ling Lee, Joerg Herrmann, Xiaolei Xu, Cielito Reyes-Gibby, Sai-Ching J Yeung, Keri L Schadler, Syed Wamique Yusuf, Zhongxing Liao, Roza Nurieva, El-Ad David Amir, Jared K Burks, Nicolas L Palaskas, John P Cooke, Steven H Lin, Michihiro Kobayashi, Momoko Yoshimoto, Jun-Ichi Abe

Faculty, Staff and Student Publications

Radiation therapy (RT) to the chest increases the patients’ risk of cardiovascular disease (CVD). A complete understanding of the mechanisms by which RT induces CVD could lead to specific preventive, therapeutic approaches. It is becoming evident that both genotoxic chemotherapy agents and radiation induce mitochondrial dysfunction and cellular senescence. Notably, one of the common phenotypes observed in cancer survivors is accelerated senescence, and immunosenescence is closely related to both cancer risk and CVD development. Therefore, suppression of immunosenescence can be an ideal target to prevent cancer treatment-induced CVD. However, the mechanism(s) by which cancer treatments induce immunosenescence are incompletely characterized. …

Comparison Of Pulmonary Function Changes Between Patients Receiving Neoadjuvant Chemotherapy And Chemoradiotherapy Prior To Minimally Invasive Esophagectomy: A Randomized And Controlled Trial, Xiaosang Chen, Mingjun Du, Han Tang, Hao Wang, Yong Fang, Miao Lin, Jun Yin, Lijie Tan, Yaxing Shen

Faculty, Staff and Student Publications

PURPOSE: Adequate pulmonary function is important for patients undergoing surgical resection of esophageal cancer, especially those that received neoadjuvant therapy. However, it is unknown if pre-operative radiation affects pulmonary function differently compared to chemotherapy. The purpose of this study was to compare changes in pulmonary function between patients undergoing minimally invasive esophagectomy (MIE) who received neoadjuvant chemotherapy or chemoradiotherapy.

METHODS: Between March 2017 and March 2018, esophageal cancer patients requiring neoadjuvant therapy were prospectively enrolled and randomly assigned to receive chemotherapy (CT) or chemoradiotherapy (CRT) before MIE. All patients received pulmonary function testing before and after the neoadjuvant therapy. Changes …

Optimisation Of Imaging Parameters During Ct Guided Interventional Procedures In Patients With Total Hip Arthroplasty, Anish Patel, Christine Azzopardi, Scott Evans, A Mark Davies, Steven James, Rajesh Botchu

Faculty, Staff and Student Publications

OBJECTIVE: To determine the optimal KV and mAs settings during CT guided injections in the presence of a total hip arthroplasty so that image quality is maintained whist keeping the dose as low as reasonably achievable.

METHODS: A total hip arthroplasty phantom with needles with differing gauges was scanned using different CT parameters (from low dose to high dose) and evaluating if this had any effect on needle conspicuity. Conspicuity was graded from 1 to 3 by 2 independent blinded reviewers.

RESULTS: Irrespective of the CT settings used (high dose or low dose parameters) needle conspicuity was not adversely affected …

Diagnostic Value Of Ultrasound In Children With Transverse Testicular Ectopia, Wei Zhou, Shoulin Li, Hao Wang, Jianchun Yin, Xiaodong Liu, Junhai Jiang, Guanglun Zhou, Jianguo Wen

Faculty, Staff and Student Publications

OBJECTIVE: The study aimed to investigate the diagnostic value of ultrasound in children's transverse testicular ectopia (TTE).

MATERIALS AND METHODS: We retrospectively studies all TTE cases diagnosed in our hospital from January 2017 to December 2021. All cases were evaluated by ultrasound examination and compared to physical examination and diagnostic laparoscopy results.

RESULTS: This study included 14 TTE patients in total, with a median age was 1.08 years. In the 14 TTE, physical examination found 10 TTE cases, of which nine testes were located in the opposite scrotum, one testis was located in the opposite groin, and the other four …

Artificial Intelligence For Radiation Oncology Applications Using Public Datasets, Kareem A Wahid, Enrico Glerean, Jaakko Sahlsten, Joel Jaskari, Kimmo Kaski, Mohamed A Naser, Renjie He, Abdallah S R Mohamed, Clifton D Fuller

Faculty, Staff and Student Publications

Artificial intelligence (AI) has exceptional potential to positively impact the field of radiation oncology. However, large curated datasets - often involving imaging data and corresponding annotations - are required to develop radiation oncology AI models. Importantly, the recent establishment of Findable, Accessible, Interoperable, Reusable (FAIR) principles for scientific data management have enabled an increasing number of radiation oncology related datasets to be disseminated through data repositories, thereby acting as a rich source of data for AI model building. This manuscript reviews the current and future state of radiation oncology data dissemination, with a particular emphasis on published imaging datasets, AI …

Distinguishing Intrathyroid Parathyroid Adenoma From Colloid Nodules And Papillary Thyroid Carcinomas Using Multiphasic Multidetector Computed Tomography, J Matthew Debnam, T Linda Chi, Michael Kwon, Jia Sun, Dawid Schellingerhout, Brandon T Golant, Salmaan Ahmed, Nancy D Perrier, Thinh Vu

Faculty, Staff and Student Publications

OBJECTIVE: The aim of the study is to determine whether multiphase multidetector computed tomography (4D-MDCT) can differentiate between intrathyroid parathyroid adenomas (ITPAs), colloid nodules, and papillary thyroid carcinoma (PTC).

METHODS: We studied 22 ITPAs, 22 colloid nodules, and 11 PTCs in 55 patients. Hounsfield unit (HU) values of the nodules were measured on 4D-MDCT in the precontrast, arterial, venous, and delayed phases. Raw HU values, phase with peak enhancement, and washout percentages between the phases were evaluated.

RESULTS: Regardless of size, all ITPAs (22/22) showed peak enhancement in the arterial phase, which was significantly greater than both colloid nodules (15/22) …

Development Of Advanced Mr-Guided Adaptive Radiation Therapy Methods For Head & Neck Cancers On The 1.5t Mr-Linac, Brigid Mcdonald

Dissertations and Theses (Open Access)

The 1.5T hybrid MRI/linear accelerator (MR-linac) has recently been introduced into clinical practice and used for the treatment of head and neck cancers (HNC). This device enables on-line adaptive radiation therapy (ART) based on anatomical changes throughout treatment and variations in patient position. This novel technology also has the potential for advanced ART strategies such as dose-optimized ART, in which the treatment plan is optimized based on the accumulated dose over previous fractions, or biological image-guided ART, in which the plan is adapted based on individual tumor response as measured through quantitative imaging techniques such as diffusion-weighted imaging (DWI). The …

Atr-Mediated Cd47 And Pd-L1 Upregulation Restricts Radiotherapy-Induced Immune Priming And Abscopal Responses In Colorectal Cancer, Cheng-En Hsieh, Cheng-En Hsieh

Dissertations and Theses (Open Access)

Radiotherapy of colorectal cancer (CRC) can prime adaptive immunity against tumor-associated antigen (TAA)-expressing CRC cells systemically. However, incidences of abscopal tumor remission are extremely rare, and the post-irradiation immune escape mechanisms in CRC remain elusive. We report that CRC cells utilize a common DNA repair signaling pathway — ATR/Chk1/STAT3 — to upregulate both CD47 and PD-L1 in response to radiotherapy, which through engagement of SIRPα and PD-1 suppresses the capacity of antigen-presenting cells to phagocytose them thereby preventing TAA cross-presentation and innate immune activation. This post-irradiation CD47 and PD-L1 upregulation can be observed across various human solid tumor cells. Concordantly, …

Integration Of Biomedical Imaging And Translational Approaches For Management Of Head And Neck Cancer, Abdallah Mohamed, Abdallah Mohamed

Dissertations and Theses (Open Access)

The aim of the clinical component of this work was to determine whether the currently available clinical imaging tools can be integrated with radiotherapy (RT) platforms for monitoring and adaptation of radiation dose, prediction of tumor response and disease outcomes, and characterization of patterns of failure and normal tissue toxicity in head and neck cancer (HNC) patients with potentially curable tumors. In Aim 1, we showed that the currently available clinical imaging modalities can be successfully used to adapt RT dose based-on dynamic tumor response, predict oncologic disease outcomes, characterize RT-induced toxicity, and identify the patterns of disease failure. We …

Lymphocyte Depletion Rate As A Biomarker Of Radiation Dose To Circulating Lymphocytes During Fractionated Partial-Body Radiation Therapy, Susannah G Ellsworth, Anirudh Yalamanchali, Tim Lautenschlaeger, Stuart A Grossman, Clemens Grassberger, Steven H Lin, Radhe Mohan

Faculty, Staff and Student Publications

Purpose: Radiation causes exponential depletion of circulating lymphocyte populations; in turn, radiation-induced lymphopenia is associated with worse survival for many solid tumors, possibly owing to attenuated antitumor immune responses. Identifying reliable and reproducible methods of calculating the radiation dose to circulating immune cells may facilitate development of techniques to reduce the risk and severity of radiation-induced toxic effects to circulating lymphocytes.

Methods and materials: Patient-specific lymphocyte loss rates were derived from a clinical data set including 684 adult patients with solid tumors. Multivariable linear regression was used to model the relationship between the lymphocyte loss rate and physical parameters of …

Multiagent Chemotherapy And Stereotactic Body Radiation Therapy In Patients With Unresectable Pancreatic Adenocarcinoma: A Prospective Nonrandomized Controlled Trial, Colin S Hill, Lauren Rosati, Hao Wang, Hua-Ling Tsai, Jin He, Amy Hacker-Prietz, Daniel A Laheru, Lei Zheng, Shuchi Sehgal, Vincent Bernard, Dung T Le, Timothy M Pawlik, Matthew J Weiss, Amol K Narang, Joseph M Herman

Faculty, Staff and Student Publications

PURPOSE: In a prospective multicenter study, gemcitabine monotherapy followed by stereotactic body radiation therapy (SBRT) was well tolerated with outcomes comparable to chemoradiation for locally advanced pancreatic cancer (LAPC). Recent trials have reported improved survival with multiagent chemotherapy (MA-CTX) alone. This prospective trial explored whether SBRT could be safely delivered after MA-CTX. Herein, we report the long-term outcomes of adding SBRT after MA-CTX in LAPC patients and evaluate whether genetic profiles of specimens obtained before SBRT influence outcomes.

METHODS AND MATERIALS: This prospective nonrandomized controlled phase 2 trial enrolled 44 LAPC and 4 locally recurrent patients after multidisciplinary evaluation between …

The Potential Of Biology-Guided Radiation Therapy In Thoracic Cancer: A Preliminary Treatment Planning Study, Steven N Seyedin, Rostem Bassalow, Osama R Mawlawi, Lehendrick M Turner, Roshal R Patel, Samuel R Mazin, Oluwaseyi M Oderinde, Yevgen Voronenko, Cody A Wages, Peter D Olcott, Joe Y Chang, Peter A Balter, James W Welsh

Faculty, Staff and Student Publications

PURPOSE: We investigated the feasibility of biology-guided radiotherapy (BgRT), a technique that utilizes real-time positron emission imaging to minimize tumor motion uncertainties, to spare nearby organs at risk.

METHODS: Volumetric modulated arc therapy (VMAT), intensity-modulated proton (IMPT) therapy, and BgRT plans were created for a paratracheal node recurrence (case 1; 60 Gy in 10 fractions) and a primary peripheral left upper lobe adenocarcinoma (case 2; 50 Gy in four fractions).

RESULTS: For case 1, BgRT produced lower bronchus V40 values compared to VMAT and IMPT. For case 2, total lung V20 was lower in the BgRT case compared to VMAT …

Three-Dimensional (3d) Anatomic Location, Extension, And Timing Of Severe Osteoradionecrosis Of The Mandible, Lucas G Sapienza, Justin J Thomas, Weiyuan Mai, Alexander N Hanania, Sandeep Hunjan, Vlad C Sandulache, Albert C Chen

Faculty, Staff and Students Publications

BACKGROUND: The purpose of this study was to describe the topography, extension (volume), and timing of severe osteoradionecrosis (ORN) that required mandible resection in patients previously treated for head and neck cancer at a high-volume Veterans Affairs Medical Center.

MATERIALS AND METHODS: The records from a reference hyperbaric oxygen clinic were retrospectively analyzed (n = 50, 2018-2021). Inclusion criteria were: I) severe ORN defined as progressive ORN that required resection; II) pathologic confirmation of ORN; and III) availability of pre-operative CT-imaging. Using a radiotherapy (RT) imaging software, we performed a detailed volumetric (3D) analysis of the bone involvement by ORN. …

Automation Of Radiation Treatment Planning For Cervical Cancer, Dong Joo Rhee

Dissertations and Theses (Open Access)

Cervical cancer is one of the most common cancer in low- and middle-income countries (LMICs). The mortality rate can be reduced if radiation treatment becomes widely available. However, due to the lack of radiation treatment facilities and human resources, many cervical cancer patients in Africa are not able to receive timely treatments or advanced therapies. To increase the availability of radiation treatment in low-and middle-income countries (LMICs) including African countries, many attempts have been made to reduce the cost of medical linear accelerators. However, increasing the number of treatment machines would not instantly resolve the issues, as there would be …

Advancement Of A 3d Computational Phantom And Its Age Scaling Methodologies For Retrospective Dose Reconstruction Studies, Aashish Gupta

Dissertations and Theses (Open Access)

We have used a 3D age-scalable computational phantom for over two decades for retrospective dose reconstruction studies of childhood cancer survivors (CCS) treated with 2D historic radiotherapy (RT). However, our phantom and its age scaling functions (ASF) must be updated so that it can be used in studies that include survivors treated with contemporary RT. We aimed to implement our phantom and its age scaling functions in DICOM format and determine the feasibility of applying our ASFs to accurately scale the whole-body CT-based anatomies.

In the implementation study, we developed Python scripts that model the phantom and ASFs in a …

Conditional Survival Among Patients With Oropharyngeal Cancer Treated With Radiation Therapy And Alive Without Recurrence 5 Years After Diagnosis, Kristina R Dahlstrom, Juhee Song, Peter F Thall, Clifton D Fuller, Katherine A Hutcheson, Faye M Johnson, G Brandon Gunn, Jack Phan, Steven J Frank, William H Morrison, Renata Ferrarotto, David I Rosenthal, Erich M Sturgis, Adam S Garden

Faculty, Staff and Students Publications

BACKGROUND: Risk of recurrence among patients with oropharyngeal cancer (OPC) who survive 5 years is low. The goal of this study was to assess long-term survival of patients with OPC alive without recurrence 5 years after diagnosis.

METHODS: This study included newly diagnosed patients with OPC, who had been treated with radiation and were alive without recurrence 5 years after diagnosis. Overall survival (OS) probabilities beyond 5 years were estimated using the Kaplan-Meier method. Factors associated with OS were determined using Bayesian piecewise exponential survival regression. Standardized mortality ratios for all-cause death were estimated controlling for study year, age, and …

Nuclear-Targeted Gold Nanoparticles Enhance The Effects Of Radiation Therapy With And Without Liposomal Delivery, Maureen Aliru

Dissertations and Theses (Open Access)

Less that 10% of pancreatic cancer patients are eligible for curative resection, and clinical trials evaluating chemoradiation in locally advanced patients with unresectable disease have been largely disappointing. New and creative therapeutic approaches are needed to address the unment need for treatment options. The objective of this thesis is to advance radiosensitization of treatment-resistant densely desmoplastic pancreatic cancer using nanoparticles to surmount biological barriers to effective particle distribution for DNA-targeting.

Clinical translation of radiosensitizing nanoparticles has stalled owing to technical challenges. Current strategies to use AuNPs for radiosensitization require large quantities of gold, kilovoltage x-rays, immediate irradiation after intravenous administration, …

Ms211: Obit For Bishop Hearn, Armin Weinberg

Works on Radiation Effects: 1990-2020

Obit for Bishop Hearn in Sept 9, 2020 Houston Chronicle, He was instrumental in asking Armin to help engage in the work supported by AIHA to compliment his Methodist interest in Kazakhstan. Without him the project would not have begun nor ended . Because of him TMH provided multiple years of support that complimented the AIHA funding and allow Armin to bring many other resources to their effort. A truly warm, respectful and supportive leader. See more at Armin Weinberg, PhD Papers and its finding aid.

Development Of Fully Balanced Ssfp And Computer Vision Applications For Mri-Assisted Radiosurgery (Mars), Jeremiah Sanders

Dissertations and Theses (Open Access)

Prostate cancer is the second most common cancer in men and the second-leading cause of cancer death in men. Brachytherapy is a highly effective treatment option for prostate cancer, and is the most cost-effective initial treatment among all other therapeutic options for low to intermediate risk patients of prostate cancer. In low-dose-rate (LDR) brachytherapy, verifying the location of the radioactive seeds within the prostate and in relation to critical normal structures after seed implantation is essential to ensuring positive treatment outcomes.

One current gap in knowledge is how to simultaneously image the prostate, surrounding anatomy, and radioactive seeds within the …

Adjuvant Therapy In Adrenocortical Carcinoma: Reflections And Future Directions, Sara Bedrose, Marilyne Daher, Lina Altameemi, Mouhammed Amir Habra

Faculty, Staff and Students Publications

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy with high risk of recurrence despite macroscopically complete surgical resection. The main predictors of ACC recurrence include advanced disease stage, incomplete surgical resection, cortisol production, certain genetic alterations, and high proliferation rate (Ki-67 proliferation index). Mitotane has been the mainstay adjuvant therapy of ACC. However, the use of mitotane is based on retrospective and occasionally conflicting evidence. As mitotane levels can take a few months before reaching therapeutic levels, there is an emerging practice of combining platinum-based chemotherapy with mitotane in the adjuvant setting. Retrospective data indicate that radiotherapy is an …

Modeling Proton Relative Biological Effectiveness Using Monte Carlo Simulations Of Microdosimetry, Mark A. Newpower

Dissertations and Theses (Open Access)

Proton therapy is a radiotherapy modality that can offer a better physical dose distribution when compared to photon radiotherapy by taking advantage of the Bragg peak, a narrow region of rapid energy loss. Proton therapy is also known to offer an enhanced relative biological effectiveness (RBE) compared to photons. In the current clinical standard, RBE is fixed at 1.1 at all points along the proton beam, meaning protons are assumed to require 10% less dose than photons to achieve target coverage and organ at risk (OAR) sparing. However, there is mounting clinical evidence, and a significant number of in vitro …

Fasting Reduces Intestinal Radiotoxicity Enabling Dose-Escalated Radiotherapy For Pancreatic Cancer, Marimar De La Cruz Bonilla

Dissertations and Theses (Open Access)

Surgical resection is the only potentially curative treatment for pancreatic cancer, but only 15-20% of patients have resectable tumors. In unresectable cases, stereotactic body radiotherapy (SBRT) may be used to give tumor-directed radiotherapy (RT). Unfortunately, this can cause severe gastrointestinal (GI) toxicity due to proximity of the pancreatic head to the duodenum. Protecting the intestine from the toxic side-effects of radiation may enable dose-escalation that could achieve more effective local control of disease. We and others have previously shown that a fast of 24 hours protects mice from lethal doses of the DNA-damaging agent etoposide. In this study, we demonstrate …

Development Of Automated Radiotherapy Treatment Planning For Cervical And Breast Cancer For Resource-Constrained Clinics, Kelly Kisling

Dissertations and Theses (Open Access)

Globally, cancer rates are on the rise, especially in low- and middle-income countries (LMICs). However, many of these countries lack access to radiotherapy, which is due in part to a substantial shortage of the staff necessary to deliver safe and effective radiotherapy. This staff shortage could be mitigated by the automation of the radiation treatment planning process. To this end, we developed automated planning for cervical and postmastectomy breast cancer radiotherapy, the two most common types of cancer in women in many LMICs.

For radiotherapy of cervical cancer in resource-constrained clinics, the recommended treatment technique is a four-field box. We …