Radiation Medicine Commons^™

Evaluation Of An End-To-End Radiotherapy Treatment Planning Pipeline For Prostate Cancer, Mohammad Daniel El Basha, Court Laurence, Carlos Eduardo Cardenas, Julianne Pollard-Larkin, Steven Frank, David T. Fuentes, Falk Poenisch, Zhiqian H. Yu

Dissertations & Theses (Open Access)

Radiation treatment planning is a crucial and time-intensive process in radiation therapy. This planning involves carefully designing a treatment regimen tailored to a patient’s specific condition, including the type, location, and size of the tumor with reference to surrounding healthy tissues. For prostate cancer, this tumor may be either local, locally advanced with extracapsular involvement, or extend into the pelvic lymph node chain. Automating essential parts of this process would allow for the rapid development of effective treatment plans and better plan optimization to enhance tumor control for better outcomes.

The first objective of this work, to automate the treatment …

Proof-Of-Concept For Converging Beam Small Animal Irradiator, Benjamin Insley

Dissertations & Theses (Open Access)

The Monte Carlo particle simulator TOPAS, the multiphysics solver COMSOL., and

several analytical radiation transport methods were employed to perform an in-depth proof-ofconcept

for a high dose rate, high precision converging beam small animal irradiation platform.

In the first aim of this work, a novel carbon nanotube-based compact X-ray tube optimized for

high output and high directionality was designed and characterized. In the second aim, an

optimization algorithm was developed to customize a collimator geometry for this unique Xray

source to simultaneously maximize the irradiator’s intensity and precision. Then, a full

converging beam irradiator apparatus was fit with a multitude …

Photon Irradation And Cisplatin Enrich Cancer Stem Cells In Ovarian Cancer, Ashley Antonissen

Electronic Theses, Projects, and Dissertations

High Grade Serous Ovarian Cancer (HGSOC) has a 5-year survival rate of less than 50%. Ovarian cancer is one of the deadliest gynecological diseases and the 7th most common female cancer worldwide. Ovarian cancer patients generally have a poor prognosis despite the relatively successful treatments. When conventional cancer treatments, such as cisplatin chemotherapy and photon irradiation, are administered, residual cancer stem-like cells (CSCs) can survive, leading to CSC enrichment. CSCs are a small population of cancer cells that exhibit stem-like characteristics: quiescence (slowing of the cell cycle), differentiation, proliferation, and self-renewal to regenerate new CSCs. We hypothesized that providing cancer …

The Impact Of Simulated Image Acquisition Time Reduction On Image Quality And Parameters Of Myocardial Perfusion Imaging Using A Dedicated Cardiac Camera, Alireza Khatami

Electronic Thesis and Dissertation Repository

Heart disease is the second leading cause of death in Canada, highlighting the crucial role of early diagnosis in disease management. Myocardial perfusion imaging (MPI), is widely employed for this purpose, involves injecting a radiopharmaceutical into the body, imaging its distribution with a gamma camera, and revealing cardiac blood flow patterns. A significant challenge in MPI is the lengthy 8 to 10 minutes required for stress and rest imaging, potentially causing patient discomfort and compromising image quality due to movement. In a clinical study with 26 patients, post-processed data manipulation simulated a reduction in MPI imaging time. The findings indicated …

Comparative Analysis Of Rectum Delineation: Inter-Observer Agreement Among Treatment Planners Versus Auto Segmentation In A Single Institution, Haley Douglas

Culminating Experience Projects

Abstract

Introduction

The past 20 years have seen a continuous rise in the cancer patient population, resulting in staffing shortages, longer wait times for patients, and potentially lower-quality care. Artificial intelligence has been incorporated into the healthcare system and has provided ease with understaffing. Using AI technology to delineate structures can reduce planning time and variation between planners. The objective of this research is to assess the level of consistency in the rectum boundary delineation performed by different dosimetrists working at a single institution, as compared to the performance of the AutoContour software. This analysis will help determine the efficacy …

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 …

Dosimetric Evaluation Of Left-Sided Chest Wall Vmat Treatment With And Without Jaw Tracking; Dose Comparison Of Left Anterior Descending Artery Versus Heart Mean Dose, Jacqueline J. Emus

Culminating Experience Projects

Radiation therapy has significantly improved breast cancer survival rates; however, it can still lead to long-term side effects, particularly affecting the heart. Left-side breast cancer patients face higher risks due to the proximity of the heart to the treatment area. To mitigate cardiac toxicity, various strategies, including jaw tracking and Volumetric Modulated Arc Therapy (VMAT), have been proposed. This study investigates the dosimetric impact of VMAT plans with and without jaw tracking on the left anterior descending artery (LAD) dose and heart mean dose in post-mastectomy breast cancer patients. Ten patients previously treated with VMAT were evaluated, and the results …

The Development Of Artificial Intelligence-Based Tools For Expert Peer Review Of Radiotherapy Treatment Plans, Mary Gronberg

Dissertations & Theses (Open Access)

Creating a patient-specific radiation treatment plan is a time-consuming and operator-dependent manual process. The treatment planner adjusts the planning parameters in a trial-and-error fashion in an effort to balance the competing clinical objectives of tumor coverage and normal tissue sparing. Often, a plan is selected because it meets basic organ at risk dose thresholds for severe toxicity; however, it is evident that a plan with a decreased risk of normal tissue complication probability could be achieved. This discrepancy between “acceptable” and “best possible” plan is magnified if either the physician or treatment planner lacks focal expertise in the disease site. …

A Quantitative Dosimetric Comparison Of Dibh Vmat And Static-Imrt Apbi Treatments: Evaluating Large Left Sided Lumpectomy Cavities Located Near The Chest Wall, Christopher Jordan Clifton

Culminating Experience Projects

Abstract

Introduction

The main purpose of this study was to determine whether there was a significant difference between the dose distributions when comparing static-IMRT and VMAT plans for patients with large left sided lumpectomy cavities located near the chest wall while utilizing DIBH. Thorough planning and statistical analysis was performed to determine whether there was a clear advantage for either treatment technique to better benefit patient outcomes.

Methods

Ten female patients with large left sided lumpectomy cavities were selected to be retrospectively planned using both static-IMRT and VMAT plans. Each patient fell within the ASTRO eligibility criteria for APBI treatments. …

A Dosimetric Comparison Of Jaw Tracking Versus Non-Jaw Tracking Using 6mv Vmat Treatment Beams In Prostate Patients With Involved Lymph Nodes, Rebecca Todd

Culminating Experience Projects

Introduction:

Jaw tracking is the process of the collimator jaws dynamically following the multileaf collimators during modulated therapy. Jaw tracking can be used throughout the dosimetry treatment planning process for IMRT and VMAT treatment plans. It can reduce a patient’s OAR dose by reducing low dose spillage from MLC interleaf leakage. This study aims to investigate if jaw tracking reduces OAR dose while maintaining PTV coverage in prostate patients with involved lymph nodes using 6MV VMAT treatment planning technique.

Methods:

This is a quantitative study of 10 patients. For each patient, two plans were created, one plan using a non-jaw …

Dosimetric Significance Of Manual Density Overrides In Oropharyngeal Cancer, Thomas Lo Greco

Culminating Experience Projects

Kilovoltage computed tomography plays a crucial role in radiotherapy planning. However, the presence of high-density metallic objects can introduce streaking artifacts in CT scans, resulting in inaccurate dose calculations by the treatment planning software. Previous studies have explored manual density overrides and artifact reduction algorithms individually to enhance dose calculation accuracy, but their combined application on patient plans within a treatment planning system remains unexplored.

This research aims to assess the necessity of manual density overrides when an artifact reduction algorithm is already employed to address dental artifacts in oropharyngeal cancer treatment plans. A total of 20 previously treated volumetric …

Intensity Modulated Bolus Electron Conformal Therapy (Im-Bect): Methods For Quality Assurance Of Prime Intensity Modulators And Evaluation Of Planned Im-Bect Dose Distributions, Andrew S. Mcguffey

LSU Doctoral Dissertations

Purpose: Intensity-modulated bolus electron conformal therapy (IM-BECT) shapes homogeneous dose distributions to superficial, irregularly-shaped target volumes, avoiding nearby critical structures. This dissertation provides research useful for translating IM-BECT to the radiotherapy clinic by: (1) developing and testing a factory quality assurance (QA) method for fabricated Passive Radiotherapy Intensity Modulator for Electrons (PRIME) devices and (2) verifying an IM-BECT planning and delivery process using end-to-end tests.

Methods: The IM-BECT planning and delivery process determines beam parameters and treatment devices (cutout, bolus, PRIME device) using .decimal’s (Sanford, FL) ElectronRT (eRT) planning system; calculates dose using a pencil-beam redefinition algorithm modified for PRIME …

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 …

Multiparametric Magnetic Resonance Imaging Artificial Intelligence Pipeline For Oropharyngeal Cancer Radiotherapy Treatment Guidance, Kareem Wahid

Dissertations & Theses (Open Access)

Oropharyngeal cancer (OPC) is a widespread disease and one of the few domestic cancers that is rising in incidence. Radiographic images are crucial for assessment of OPC and aid in radiotherapy (RT) treatment. However, RT planning with conventional imaging approaches requires operator-dependent tumor segmentation, which is the primary source of treatment error. Further, OPC expresses differential tumor/node mid-RT response (rapid response) rates, resulting in significant differences between planned and delivered RT dose. Finally, clinical outcomes for OPC patients can also be variable, which warrants the investigation of prognostic models. Multiparametric MRI (mpMRI) techniques that incorporate simultaneous anatomical and functional information …

The Safe And Effective Clinical Deployment Of Artificial Intelligence Tools, Kelly Nealon

Dissertations & Theses (Open Access)

18 million new cancer cases are diagnosed each year. Roughly half of these patients will be treated with radiation therapy, a complex technique that requires an interdisciplinary team of clinical staff and expensive equipment to be delivered safely. Cancer centers in Low- and Middle-Income Countries (LMIC) have an especially difficult time meeting the demands of radiation therapy as the complexity of treatment techniques increase, with only 37% of patients in these regions having access to the care they need. Artificial Intelligence (AI) based tools are being developed to simplify the treatment planning and quality assurance processes to increase the number …

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 …

Improving Radiotherapy Workflow: Evaluation And Implementation Of Deep Learning Auto-Segmentation In A Multi-User Environment, And Development Of Automatic Contour Quality Assurance System, Jingwei Duan

Theses and Dissertations--Radiation Medicine

Radiotherapy is a frequently used therapeutic modality for cancer patients. Accurately contouring of tumors and organs at risk (OARs) is critical for developing optimal treatment plans in radiotherapy, especially after the implementation of Intensity-modulated radiation therapy (IMRT) and Stereotactic Body Radiation Therapy (SBRT). The manual contouring process is time-consuming and suffers from inter-observer variations. However, manual contouring is often hindered by laborious clinical duties, leading to reduced effectiveness, and increased segmentation errors due to fatigue. Additionally, online adaptive radiation therapy(ART), which has been shown to benefit patient outcomes, places higher demands on contouring and quality assurance (QA) speed.

Recently, deep …

A Learning Health System For Radiation Oncology, Rishabh Kapoor

Theses and Dissertations

The proposed research aims to address the challenges faced by clinical data science researchers in radiation oncology accessing, integrating, and analyzing heterogeneous data from various sources. The research presents a scalable intelligent infrastructure, called the Health Information Gateway and Exchange (HINGE), which captures and structures data from multiple sources into a knowledge base with semantically interlinked entities. This infrastructure enables researchers to mine novel associations and gather relevant knowledge for personalized clinical outcomes.

The dissertation discusses the design framework and implementation of HINGE, which abstracts structured data from treatment planning systems, treatment management systems, and electronic health records. It utilizes …

Characterization And Investigation Of Cold Atmospheric Plasma And Its Effects On Cancer Cell Biology, Thomas M. Ritrosky

Theses and Dissertations

Modern cancer treatment uses radiation therapy in over 50% of patient cases. It is an e↵ective way of treating tumors because the mechanisms of cell killing are well known through the damage that ionizing radiation does to DNA. The amount of radiation can be tracked through measuring the dose of the clinical photon or electron beam used. However, there are limitations in the usage of radiation therapy, for example, a tumor can create hypoxic areas that become radioresistant leading to complete ine↵ectiveness of further radiation treatment. This project looks into the application of cold atmospheric plasma as an adjuvant therapy …

Analysis Of Biologically Effective Dose For Retroactive Yttrium-90 Trans-Arterial Radioembolization Treatment Optimization, Mj Lindsey

CMC Senior Theses

Trans-arterial radioembolization (TARE) is a protracted modality of radiation therapy where radionuclides labeled with Yttrium-90 (⁹⁰Y) are inserted inside a patient's hepatic artery to treat hepatocellular carcinoma (HCC). While TARE has been shown to be a clinically effective and safe treatment, there is little understanding of the radiobiological relationship between absorbed dose and tissue response, and thus there is no dosimetric standard for treatment planning. The Biologically Effective Dose (BED) formalism, derived from the Linear-Quadratic model of radiobiology, is used to weigh the absorbed dose by the time pattern of delivery. BED is a virtual dose that can …

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

Dissertations & 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 …

A Quantitative Investigation Of Treating Lung Tumors With Dynamic Conformal Arcs Vs. Vmat For Lung Sbrt Plans, Shawn Loutos

Culminating Experience Projects

Introduction

This study aims to investigate the comparisons in dynamic conformal arc, VMAT (no ASC), forced MU limitations (ASC), or a 50/50 hybrid arc (ASC) in how they can improve a lung SBRT case where the tumor is abutting a dose critical structure. The goal of this research is to investigate multiple treatment techniques in an attempt to increase the dose constraint pass rate. The variables in comparison are how well different plan iterations can successfully meet constraints as well as pass a 0.5 modulation complexity score (MCS).

Methods

10 previously treated patients were used in this study who exhibited …

Deep Inspiration And End Exhale Breathhold Evaluation For The Treatment Of Locally Advanced Pancreatic Adenocarcinoma Using The Viewray Mridian Linactm, Tatum Mcglynn

Culminating Experience Projects

Introduction

Radiation therapy has been limited in the treatment of locally advanced pancreatic cancer. This is due to the dose tolerance to nearby organs at risk and breathing motion. Advancements in radiation treatment technology have now allowed pancreatic patients to be treated to higher doses in fewer fractions using stereotactic body radiotherapy treatment. With the use of MRI-guided treatments, using the ViewRay MRIdian linac, doses can be escalated using online adaptive treatment planning and real time tracking. However, there has yet to be an optimal breathhold technique investigated that can aid in this process.

Methods

Five patients that had been …

Dosimetric Comparison Of Static Imrt And Vmat Apbi Treatment Planning In The Prone Position For Breast Conservation Therapy, Kelly A. Foucher

Culminating Experience Projects

Introduction

Prevalence of early-stage breast cancer is increasing with the aid of preventative screenings and early diagnosis. The standard of care is transforming from conventional approaches with long treatment regimens towards hypofractionation and tissue sparing techniques. Based on studies over the past ten years, there are reasons to consider a partial-breast, hypo fractionated treatment option in the supine position. In practice, aPBI is often produced using several static intensity modulated beams to control dose to the normal breast tissue and limit dose to the heart and lungs. Patients may also be treated in the prone treatment setup in order to …

Effects Of Ezfluence Planning Software On Dosimetric Parameter Compliance For Early-Stage Breast Cancer, Jackie Loomis

Culminating Experience Projects

Each year over 2 million women are given a breast cancer diagnosis and over half a million women succumb to the disease yearly. As technology advances in the world of radiation oncology, automated planning softwares, such as Radformation’s EZFluence, are being utilized to streamline the treatment planning process. This study was designed to investigate whether the automated plans are dosimetrically equivalent to traditionally planned 3D field in field tangential plans. Is there a disadvantage to using these automated softwares? Three different dosimetrists with varying backgrounds replanned 27 previously treated breast cancer patients and an assortment of comparisons were ran between …

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

Dissertations & 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 …

A Quantitative Investigation At Dose To Tissue When Using Physical Constraints Versus Biological Based Constraints In Pancreatic Carcinoma Patients, Kelly R. Alley

Culminating Experience Projects

Introduction

The purpose of this study was to compare dose to organs at risk as well as PTV coverage. Physical objectives, biological objectives, and a combination of the two were utilized to compare which technique provided the best coverage of the PTV while also preserving the greatest amount of healthy tissue.

Methods

Each randomly selected patient had three separate plans created for them. The first plan used only physical based constraints in the form of upper objectives. The second plan used only biological based constraints in the form of gEUD objectives. The third plan used a combination of both upper …

Development Of A Novel Rodent Model Of Radiation-Induced Implant Capsular Contracture, Tanya Delyzer

Electronic Thesis and Dissertation Repository

Radiation-induced implant capsular contracture is a challenging complication of post-mastectomy breast reconstruction. The objective of this thesis was to establish a novel rodent model that replicates the critical properties of this complication. Retired breeder female Sprague-Dawley rats underwent surgery with custom smooth silicone implants placed under the right 4^th mammary fat pad. Half these rats received 26Gy of ionizing radiation to the implant and fat pad. Radiated implants had both higher Baker grades of capsular contracture and Kumar scores denoting radiation-induced fibrosis. Irradiated capsules showed increased Masson’s trichrome staining and significantly higher hydroxyproline to total protein ratio compared to …

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 …

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 & 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, …