Medicine and Health Sciences Commons^™

Post-Modeling Adjustments And Delivered Dose Verification Of The 6fff Beam Model Commissioned For The Monaco Treatment Planning System, Grant C. Debevec

LSU Master's Theses

External beam radiation therapy has been shown to be an effective treatment method for tumors and abnormalities of the spine and vertebral region. Treating the spine using a stereotactic body radiation therapy (SBRT) technique can reduce toxicity to the spinal cord. The 6 MV flattening filter free (6FFF) beam model is currently used to plan and calculate dose for SBRT treatment plans, and the treatment plans are delivered using a linear accelerator (LINAC).

The commissioned beam model represents an invariant component of a LINAC. For volumetric modulated arc therapy (VMAT) treatment plans, the multileaf collimator (MLC) positions are changing throughout …

Development Of A Remote Dosimetric Audit Framework For Carbon Therapy, Paige Taylor

Dissertations & Theses (Open Access)

Carbon ion therapy is available at over a dozen institutions around the world and is being employed for treatment of cancer. The increased biological effect of carbon compared to conventional photon-based radiotherapy holds promise for the therapeutic benefit in historically radioresistant tumors. While ion chamber dosimetry has been used for day-to-day clinical measurements of absorbed dose, there are few options for remote dosimetry. The availability of such tools would support the development of a robust remote audit program for carbon ion therapy.

The Imaging and Radiation Oncology Core (IROC) conducts remote audits of photon and proton therapy. These audits are …

Improving Dose-Response Correlations For Locally Advanced Nsclc Patients Treated With Imrt Or Pspt, Yulun He

Dissertations & Theses (Open Access)

The standard of care for locally advanced non-small cell lung cancer (NSCLC) is concurrent chemo-radiotherapy. Despite recent advancements in radiation delivery methods, the median survival time of NSCLC patients remains below 28 months. Higher tumor dose has been found to increase survival but also a higher rate of radiation pneumonitis (RP) that affects breathing capability. In fear of such toxicity, less-aggressive treatment plans are often clinically preferred, leading to metastasis and recurrence. Therefore, accurate RP prediction is crucial to ensure tumor coverage to improve treatment outcome. Current models have associated RP with increased dose but with limited accuracy as they …

Automating The Radiation Therapy Treatment Planning Process For Pediatric Patients With Medulloblastoma, Soleil Hernandez

Dissertations & Theses (Open Access)

Over the past 50 years, pediatric cancer 5-year survival rates increased from 20% to 80% in high-income countries, however, these trends have not been mirrored in low-and-middle-income countries (LMICs). This is due in part to delayed diagnosis, higher rates of advanced disease at presentation and a growing lack of access to high quality medical personnel and technology necessary to deliver complex treatments.

The long-term goal of this study was to alleviate demanding workflows and increase global access to high-quality pediatric radiation therapy by harnessing the power of artificial intelligence to automate the radiation therapy treatment planning process for pediatric patients …

An Evaluation Of Methods To Reduce Inframammary Surface Dose In Prone Breast Irradiation, Seth Alvarado

Doctoral Dissertations

In cases of breast radiation treatments via external beam radiation therapy, the incidence of radiation dermatitis has been reported. In prior studies, this acute radiation side-effect has been correlated with the immobilization devices in cases of prone breast irradiation. They attribute this to the bolus effect that occurs with the interaction of the incident photon beam at different projections causing an increase in measured surface dose. The type of radiation planning technique, and patient positioning during the undertaking of these techniques, have also shown to influence this bolus effect. This study focuses on these factors in treatment planning in order …

An Evaluation Of Methods To Reduce Inframammary Surface Dose In Prone Breast Irradiation, Seth Alvarado

Culminating Experience Projects

In cases of breast radiation treatments via external beam radiation therapy, the incidence of radiation dermatitis has been reported. In prior studies, this acute radiation side-effect has been correlated with the immobilization devices in cases of prone breast irradiation. They attribute this to the bolus effect that occurs with the interaction of the incident photon beam at different projections causing an increase in measured surface dose. The type of radiation planning technique, and patient positioning during the undertaking of these techniques, have also shown to influence this bolus effect. This study focuses on these factors in treatment planning in order …

In-Phantom Film Measurements Of Two Treatment Planning Systems For Single-Fraction Spine Sbrt, Michael J. Taylor

LSU Master's Theses

Purpose: Treatment planning accuracy for spine stereotactic body radiation therapy (SBRT) varies depending on the dose calculation algorithm utilized in the treatment planning system (TPS). This project compared the end-to-end accuracy between spine SBRT plans calculated in a convolution-superposition based TPS (TPS_CS) and Monte Carlo based TPS (TPS_MC) with radiochromic film measurements. The hypothesis was that TPS_MC would calculate the dose gradient in the critical region between the vertebral body and the spinal cord more accurately than TPS_CS.

Methods: Single-fraction spine SBRT treatments following RTOG 0631 and local institutional guidelines were planned in …

Nanoparticles For Biomedical Applications, Joseph Kim

Dissertations & Theses (Open Access)

This thesis presents development and evaluation of the potential of three new nanoparticles for biomedical applications. With the rapid growth of the field of nanoscience, researchers have explored developing nanoparticles for various biomedical applications, including imaging, therapy, and drug delivery. This thesis demonstrates the development of two C­₆₀ fullerene based nanoparticles and one boron based nanoparticle to answer key questions related to their biological potential.

In the first part of the thesis, we describe synthesis and characterization of a pure boron nanoparticle containing asolectin phospholipid-based liposome construct prepared using a water-in-oil emulsion method, as a novel alternative agent for …

Targeting Prostate Cancer Through High Dose Rate Brachytherapy, Christopher Smith

Electronic Thesis and Dissertation Repository

While prostate cancer is not typically an aggressive disease, it can be lethal for some patients. Treatment of the disease has proven to be effective; however, when the disease recurs locally it does so most commonly at the site of the dominant intraprostatic lesion (DIL). An effective treatment method for prostate cancer is high dose rate brachytherapy (HDR-BT). This is a radiation therapy where a radioactive seed is interstitially inserted into the patient to deliver the radiation dose. It was the goal of this work to utilize preprocedural imaging and pathological data from radical prostatectomy specimens to investigate methods to …

The Importance Of Dna Repair Capacity To (And A Model To Predict) Cell Radiosensitivity To Ions, David B. Flint, David B. Flint

Dissertations & Theses (Open Access)

Radiation therapy with ions has a number of advantages over conventional radiation therapy with photons, including favorable depth-dose distributions, greater relative biological effectiveness (RBE) and a lesser dependence on a number of biological factors known to affect radiosensitivity to photons, including DNA repair capacity. Thus, it is expected that an additional benefit of using ions is that they mitigate the great heterogeneities in treatment responses commonly observed in photon therapies.

However, by analyzing the cell survival of human cancer cell lines exposed to clinically relevant photon, proton, and carbon ion beams, we show there is not significantly less relative variability …

Developing A Presimulation Protocol For Prostate Cancer Patients Undergoing Radiotherapy, Jennifer Wieworka

Walden Dissertations and Doctoral Studies

Inadequate preparation of prostate cancer patients undergoing radiation therapy (RT) can damage healthy tissue and cause long-term complications. Proper setup can reduce side effects. Currently, there are no standardized guidelines to help prepare patients for prostate radiation. Guidelines will help nurses coordinate care and manage symptoms for these patients. The purpose of this doctoral project was to address the gap in practice of the lack of a standardized process for implementing presimulation interventions for patients with prostate cancer undergoing RT by developing an evidence-based clinical practice guideline (CPG). The practice question for this project focused on the best practices contributing …

Bypassing The Blood-Brain Barrier: A Physical And Pharmacological Approach For The Treatment Of Metastatic Brain Tumors, Samuel A. Sprowls

Graduate Theses, Dissertations, and Problem Reports

This dissertation (a) provided an in depth literature review of methods to disrupt the BBB/BTB and improve therapeutic distribution to brain tumors, (b) evaluated the use of azacitidine as a single agent therapy for the treatment of brain metastasis of breast cancer and a potential molecular mechanism by which brain tropic cells are sensitized to hypomethylating agents, (c) determined the impact cannabidiol has on P-glycoprotein mediated efflux at the blood-brain barrier and its potential for use as a single agent treatment for metastatic brain tumors, (d) developed a preclinical radiation therapy protocol for use in small animals and in vitro …

Impact Of Immunotherapy On The Survival Of Pancreatic Adenocarcinoma Patients: An Analysis Of The National Cancer Database, Saber A. Amin

Theses & Dissertations

Pancreatic adenocarcinoma (PDAC) represents 7.2% of all cancer deaths, and by 2030, it will become the second leading cause of death due to cancer. The median overall survival (OS) is 17-23 months in resectable and 4-6 months in metastatic PC [8-9]. The 5-year survival of resectable PC is 22%, and unresectable PC is 8%. A majority of patients treated with standard treatments such as surgery, chemotherapy, and radiation therapy eventually succumb to the disease due to widespread micrometastases at the time of diagnosis. Due to the minimal effect of the current treatments, novel treatment strategies such as immunotherapeutics have been …

Characterization Of Treatment Planning System Photon Beam Modeling Errors In Iroc Houston Phantom Irradiations, Mallory Glenn

Dissertations & Theses (Open Access)

In radiation therapy, proper commissioning of the treatment planning system’s (TPS) dose calculation algorithm is critical because any errors in this process impact all treatment plans prepared in the system. Previously, TPS errors have been identified as a major cause for poor phantom irradiation performance, which may also mean that patients are treated suboptimally. The purpose of this work was to investigate the TPS beam modeling developed by the radiotherapy community to understand where inconsistencies may arise, which variables are most susceptible to variations, and in what way changing these variables can alter dose calculations.

Using the Imaging and Radiation …

A Comparison Between Rectal Dose In Prostate Radiotherapy Patients Treated With Spaceoar Hydrogel Present Versus Patients Treated Without Spaceoar Hydrogel., David Desano

Culminating Experience Projects

Introduction: External beam radiation therapy is a common treatment option for prostate cancer patients with localized disease. Radiation-induced side effects associated with the rectum can impact a patient’s ability to complete treatment or affect the quality of life years after radiation treatment. Spaceoar hydrogel has been developed to reduce radiation dose to nearby pelvis structures, and therefore decreasing potential side effects.

Methods: A total of 20 patients who received definitive radiation therapy to the prostate and seminal vesicles were selected and placed into 2 groups (10 spaceoar, 10 non-spaceoar). The individuals’ age ranged from 60 to 79 years old with …

Towards Optimizing Quality Assurance Outcomes Of Knowledge-Based Radiation Therapy Treatment Plans Using Machine Learning, Phillip Douglas Hardenbergh Wall

LSU Doctoral Dissertations

Knowledge-based planning (KBP) techniques have been shown to provide improvements in plan quality, consistency, and efficiency for advanced radiation therapies such as volumetric modulated arc therapy (VMAT). While the potential clinical benefits of KBP methods are generally well known, comparatively less is understood regarding the impact of using these systems on resulting plan complexity and pre-treatment quality assurance (QA) measurements, especially for in-house KBP systems. Therefore, the overarching purpose of this work was to assess QA implications with using an in-house KBP system and explore data-driven methods for mitigating increased plan complexity and QA error rates without compromising dosimetric plan …

Novel Detection And Treatment Strategies For Pancreatic Ductal Adenocarcinoma, Joseph Carmicheal

Theses & Dissertations

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies with an estimated 5-year survival rate of less than 9%. The high lethality of PDAC is due to two primary reasons: the discovery of PDAC at later stages, with locally invasive or metastatic disease present at the time of initial diagnosis as well as the lack of efficacious therapeutic interventions that significantly impact survival. In this dissertation, we sought to discover and test novel detection and treatment strategies for PDAC. Firstly, serum EVs were investigated as potential non-invasive liquid biopsy biomarkers, to serve as a means of early cancer …

Human Factor Associations With Safety Events In Radiation Therapy, Sheri M. Weintraub

Health Sciences Program Student Theses, Dissertations and Capstones

One important connection for all human beings is that we have a shared need for health care and are at some risk of experiencing medical error. Errors documented in the field of radiation therapy have included tragic levels of suffering and even death from preventable mistakes. Efforts to improve patient safety include an approach called incident learning that makes use of information about known errors to inform safetyimprovement strategy. The complexity of human contributing factors challenges those safety improvements. The problem addressed by this dissertation study is that radiation therapy puts patients at risk, and the incident learning systems designed …

Exploring The Roles Of Long Non-Coding Rnas In Glioblastoma Tumor Recurrence And Therapy Resistance, Christian Tyler Stackhouse

All ETDs from UAB

ABSTRACT Glioblastoma (GBM) is the most common and devastating primary CNS brain tumor with a median survival time of around 14 months. Most patients succumb to re-current disease which is often more malignant than the primary tumor and is frequently therapy resistant. There have not been significant advances in the treatment of GBM despite decades of research. This is partly due to the lack of accurate preclinical models and of the focus on primary rather than recurrent tumors. We created a 350 gene custom GBM-specific panel which contains 16 molecular signatures including molecular sub-typing signatures. We have demonstrated concordance of …

The Impact Of Exercise During Radiation Therapy For Breast Cancer Patients, Diane Yu

Walden Dissertations and Doctoral Studies

Breast cancer is one of the leading causes of death among women. In 2017, breast, lung and bronchus, prostate, and colorectal cancers accounted for almost 50% of all new cancer cases in the United States. Breast conservation therapy with lumpectomy (i.e., surgery) and adjuvant radiation therapy is commonly used as treatment for early stage breast cancer. However, side effects such as pain and poor sleep quality can affect quality of life for breast cancer patients undergoing radiation treatment. The main purpose of this quantitative study, using the health belief model (HBM) theoretical framework, was to investigate the correlations between the …

Investigation Of Stereotactic Body Radiation Therapy Delivery Accuracy On An Elekta Linear Accelerator, Addie Barron

LSU Master's Theses

Purpose: This work investigated the delivery accuracy of high-dose lung and spine stereotactic treatments delivered with the Elekta Infinity and Versa HD platforms. The accuracy of these platforms will be used for consideration in implementing a spine stereotactic radiosurgery (SSRS) program at Mary Bird Perkins Cancer Center.

Methods: A geometric phantom was used to perform Winston-Lutz type tests that assessed the relevant degrees of freedom (gantry, collimator, and couch) of the delivery system. A lung stereotactic body radiation therapy (SBRT) and spine SRS treatment plan were generated for use in end-to-end testing. Delivery accuracy was tested using a novel diode …

Optimization Of Decision Making In Personalized Radiation Therapy Using Deformable Image Registration, Jason Vickress

Electronic Thesis and Dissertation Repository

Cancer has become one of the dominant diseases worldwide, especially in western countries, and radiation therapy is one of the primary treatment options for 50% of all patients diagnosed. Radiation therapy involves the radiation delivery and planning based on radiobiological models derived primarily from clinical trials. Since 2015 improvements in information technologies and data storage allowed new models to be created using the large volumes of treatment data already available and correlate the actually delivered treatment with outcomes. The goals of this thesis are to 1) construct models of patient outcomes after receiving radiation therapy using available treatment and patient …

Design & Delivery Of Automated Winston-Lutz Test For Isocentric & Off-Axis Delivery Stability Utilizing Truebeam Developer Mode & Electronic Portal Imaging Device, Mahmoud Mohammad Yaqoub

UNLV Theses, Dissertations, Professional Papers, and Capstones

The uncertainties in treatment delivery cannot be ignored in radiation therapy. Thus, the quality assurance QA tests are very important task of the medical physicist in clinical practice. Assuring the coincidence between the mechanical isocenter of the Linear Accelerator (LINAC) and its radiation beams isocenter is one of the most important qualities need to be tested, and the Winston Lust (WL) test is the

most popular technique to perform this task, especially for the treatment modalities which need high precision in beam delivery such as the stereotactic radiosurgery/stereotactic body radiotherapy (SRS/SBRT). The linear accelerator-based SRS/SBRT is a well-established method in …

Development Of 3d-Printed Patient Specific Bolus For Clinical Use In Total Scalp Irradiation, Garrett Baltz

Dissertations & Theses (Open Access)

Total scalp irradiation (TSI) is a specialized radiation therapy technique that aims to deliver a uniform dose to the entire scalp. Original electron-based TSI techniques had limited homogeneity due to hot and cold spots created at field junctions due to the multiple matched fields that were required to treat the entire scalp. The transition to photon volumetric-modulated arc therapy based TSI techniques has improved homogeneity, to the point where non-conformal bolus is now a limiting factor. Bolus is required to build-up full dose to the scalp surface in total scalp irradiation. Creating bolus that is conformal to the scalp is …

High-Throughput Mapping Of The Biological Effects Of Particle Therapy, Lawrence Bronk

Dissertations & Theses (Open Access)

Radiation therapy is an essential tool in the cure of many cancer patients. Charged particle based radiation therapies are gaining momentum as the physical dose distributions of ions are superior to standard photons due their limited range. Additionally, charged particle radiation has been shown to have linear energy transfer (LET) specific relative biological effectiveness (RBE) when compared to photons. It is essential to employ accurate biophysical models for particle beams in order to maximize the therapeutic potential of particle therapy through the introduction of biologically optimized treatment planning. The development of such models requires the support of large amounts of …

Improvements In Four-Dimensional And Dual Energy Computed Tomography, Rachael M. Martin

Dissertations & Theses (Open Access)

Dual energy and 4D computed tomography (CT) seek to address some of the limitations in traditional CT imaging. Dual energy CT, among other purposes, allows for the quantification and improved visualization of contrast materials, and 4D CT is often used in radiation therapy applications as it allows for the visualization and quantification of object motion. While much research has been done with these technologies, areas remain for potential improvement, both in preclinical and clinical settings, which will be explored in this dissertation. Preclinical dual energy cone-beam CT (CBCT) can benefit from wider separation between the peak energy of the two …

Relationship Between Admission Criteria And Program Completion In A Radiation Therapy Program, Adrienne Mae Dougherty

Walden Dissertations and Doctoral Studies

Poor completion rates in the radiation therapy associate's degree program offered through a community college did not meet the standards set by the college and damaged the program's reputation. The relationship between admission criteria and program completion was not known. The purpose of this study was to determine if there were any relationships between the admission criteria (GPA in prerequisite courses, interview scores, writing sample scores, and preadmission testing scores) and students' completion of a radiation therapy associate's degree program. This correlational study used 2 stages of Tinto's retention theory: (a) recruitment and admission to college and (b) pre-entry assessment …

An Algorithm To Improve Deformable Image Registration Accuracy In Challenging Cases Of Locally-Advanced Non-Small Cell Lung Cancer, Christopher L. Guy

Theses and Dissertations

A common co-pathology of large lung tumors located near the central airways is collapse of portions of lung due to blockage of airflow by the tumor. Not only does the lung volume decrease as collapse occurs, but fluid from capillaries also fills the space no longer occupied by air, greatly altering tissue appearance. During radiotherapy, typically administered to the patient over multiple weeks, the tumor can dramatically shrink in response to the treatment, restoring airflow to the lung sections which were collapsed when therapy began. While return of normal lung function is a positive development, the change in anatomy presents …

Radiation Therapy Medical Physics Review – Delivery, Interactions, Safety, Feasibility, And Head To Head Comparisons Of The Leading Radiation Therapy Techniques, Cielle Collins

Honors Theses and Capstones

Radiation therapy uses high energy radiation to kill cancer cells. Radiation therapy for cancer treatment can take the form of photon therapy (using x-rays and gamma rays), or charged particle therapy including proton therapy and electron therapy. Within these categories, numerous methods of delivery have been developed. For example, a certain type of radiation can be administered by a machine outside of the body, called external-beam radiation therapy, or by a “seed” placed inside of the body near cancer cells, called internal radiation therapy or brachytherapy. Approximately half of all cancer patients receive radiation therapy, and the form of radiation …

Re-Optimization Of Radiation Therapy Dose To The Prostate Using Cbct: Reducing Dose To Organs At Risk, R. Charles Keider Jr.

Masters Theses

Cancer of the prostate is the second most common cancer among American males. The prostate is small gland, located in the pelvis, posterior to the bladder and anterior/inferior to the rectum. Due to this location when irradiating the prostate the normal tissue organs at risk are the bladder and rectum. Negative effects seen when these structures are irradiated can include; bladder stricture, dysuria, hematuria, diarrhea, rectal bleeding, and proctitis.

In order to eliminate or reduce these negative effects more precise and accurate treatment techniques have been employed. Intensity Modulated Radiation Therapy (IMRT) has been successful in achieving greater precision when …