Radiation Medicine Commons^™

Craniospinal Irradiation Volumetric Modulated Arc Therapy (Vmat) Planning: A Dosimetric Contrast Utilizing Anterior Avoidance Sectors, Ashleigh M. Sammataro

Masters Projects

Purpose: Craniospinal irradiation (CSI) is essential for treating pediatric and adult central nervous system malignancies, yet it exposes large volumes of normal tissue to low‑dose radiation, contributing to significant long‑term toxicity. This study evaluated whether incorporating anterior‑avoidance sectors (AVD) into volumetric modulated arc therapy (VMAT) planning would improve normal tissue sparing while maintaining target coverage and plan quality.

Materials and Methods: 8 previously treated CSI patients were retrospectively replanned using two VMAT techniques: Full Arc and AVD. All patients were simulated supine with standardized immobilization and planned in Eclipse. Identical target volumes, optimization structures, and planning objectives were used for …

Study On The Accuracy Of Varian Eclipse Mlc Modeling When Mlcs Are Open Beyond The Jaw In Breast Cancer Patient Planning Using Aaa And Acuros With Both Dual-Isocentric Technique And Mono-Isocentric Technique., Amy Rogers

Masters Projects

Accurate dose delivery at the chest wall-supraclavicular (CW-SCV) junction remains an important challenge in breast irradiation, especially when multileaf collimator (MLC) leaves are intentionally opened beyond the collimator jaws to improve junction coverage. This study evaluated the dosimetric accuracy of the Varian Eclipse treatment planning system (TPS) at the CW-SCV junction using the Anisotropic Analytical Algorithm (AAA) and Acuros XB calculation algorithms with mono-isocentric and dual-isocentric treatment techniques. A prospective phantom-based study was performed using a solid water phantom and a Varian TrueBeam linear accelerator. Twenty-four unique three-dimensional conformal treatment plan configurations were created using combinations of beam energy (6 …

Optimizing Palliative Spine Radiation: A Dosimetric Comparison Of Hybrid Arc Therapy And Conventional Appa Techniques, Alaina Vaneaton

Masters Projects

This study aimed to evaluate the dosimetric impact of Hybrid Arc Palliative Radiation Therapy (HART) versus conventional anterior-posterior/posterior-anterior (APPA) beam arrangements for thoracic spine metastases. The primary objective was to assess differences in conformity, homogeneity, and organ-at-risk (OAR) sparing between the two techniques. A retrospective plan comparison was conducted using anonymized datasets from twenty patients previously treated with HART. Each case was replanned using a standard APPA technique, normalized to match the target coverage of the original HART plan within 0.1%. All plans were prescribed 20 Gy in 5 fractions. Plan quality was evaluated using conformity index (CI), homogeneity index …

Enhancing Target Dose Conformity While Effectively Sparing The Spinal Cord In Proton Arc Treatment Plans For Cervical Chordomas And Chondrosarcomas, Jon Blalock

Masters Projects

Cervical spinal chordomas and chondrosarcomas present significant therapeutic challenges due to their proximity to the spinal cord and resistance to conventional radiotherapy. This retrospective study investigated the capability of proton arc therapy (PAT) to maintain or improve adequate target coverage while reducing dose to the spinal cord for cervical spinal chordomas and chondrosarcomas over standard fixed beam intensity modulated proton therapy (IMPT). While both IMPT and PAT use pencil beam scanning (PBS) to with energy modulation to deliver dose in discrete layers, IMPT relies on a limited number of fixed beam angles, whereas PAT delivers dose over an arc trajectory. …

Comparison Of Left Breast Accelerated Partial Breast Irradiation Plans: Flattening Filter Free Vmat Vs. Standard Vmat In Deep Inspiration Breath Hold And Free Breathing Techniques, Monica Albeck

Masters Projects

This retrospective planning study compared dosimetric outcomes and treatment efficiency between flattening filter free (FFF) and standard volumetric modulated arc therapy (VMAT) plans for left breast accelerated partial breast irradiation (APBI) under deep inspiration breath hold (DIBH) and free-breathing (FB) conditions. Ten patients with early stage left breast cancer were replanned to create four plans each: FFF VMAT and standard VMAT in DIBH and FB. All plans prescribed 30 Gy in 5 fractions. Measures included planning target volume (PTV) coverage, mean heart dose, ipsilateral lung V30%, contralateral breast maximum dose, and monitor units (MUs). Statistical analysis used repeated-measures ANOVA with …

Evaluating Dosimetric Outcomes In A Prostate Rapid Plan Model: A Comparison Of Prostate Treatment Plans With And Without Standardized Planning Structures, Erica Wartman

Masters Projects

Abstract

Knowledge-based planning (KBP) using RapidPlan (RP) has demonstrated the ability to produce high quality radiation therapy treatment plans while reducing time. This study evaluated whether the inclusion of department specific standardized planning structures, including rings and other optimization tools, improves plan quality when using a prostate and lymph node RP model, or if the model alone is sufficient to provide a quality plan without the use of these additional planning structures.

Ten previously treated Prostate+LN patients were replanned using the departmental RP model in Varian Eclipse treatment planning system.1 For each patient, two plans were created, one with standardized …

Evaluating Parotid Gland Dose Between Electronic Tissue Compensation And Field In Field Treatment Techniques For Parotid Sparing In Whole-Brain Radiotherapy, Joesph E. Bodgonas

Masters Projects

Purpose:

The parotid glands are essential to salivary function and patient quality of life, yet they are not routinely prioritized as organs at risk (OARs) during whole-brain radiotherapy (WBRT). With growing recognition of long-term side effects like xerostomia in patients with prolonged survival after WBRT, parotid-sparing techniques warrant investigation. This study compares radiation dose to the parotid glands using three different 3D conformal WBRT planning approaches: field-in-field (FiF) with blocking, electronic tissue compensation (eCOMP) without blocking, and eCOMP with blocking.

Methods and Materials:

A retrospective study was conducted on 20 patients previously treated with 3D conformal WBRT. Original eCOMP plans …

Evaluating Coplanar And Noncoplanar Treatment Plans For The Varian Halcyon And Varian Truebeam For Intact Prostate Patients., Ashley Coppage

Masters Projects

Prostate cancer is among the most treated malignancies with radiation therapy, where precise dose delivery is critical for tumor control and minimizing toxicity. VMAT is widely adopted due to its efficiency and conformity; however, the choice between coplanar and non-coplanar beam arrangements remains an area of ongoing investigation, especially with newer platforms like Halcyon and TrueBeam. This retrospective dosimetric study compares coplanar and non-coplanar volumetric modulated arc therapy (VMAT) treatment plans for intact prostate cancer patients using the Varian Halcyon and Varian TrueBeam systems. Plans were created using a standardized protocol within Eclipse v16.1, with all Halcyon plans employing coplanar …

A Comparative Study Of Vmat Beam Arrangements In Large Field Nodal Prostate Treatment Plans, Laura R. Black

Masters Projects

Treatment of extensive prostate and pelvic lymph node volumes for prostate cancer patients provide unique challenges related to limitations in multileaf collimator (MLC) design in many modern linear accelerators. A strategy to overcome this challenge is by restricting the field size, improving modulation as well as using overlapping arcs to ensure complete coverage of the target. Using too few arcs can result in suboptimal target coverage, while too many arcs can lead to prolonged time on the table, increasing the risk of patient movement and potential side effects that may compromise treatment accuracy. This study aims to evaluate the optimal …

Dosimetric Comparisons Of 6mv, 6fff, 10mv, And 10fff On Vmat Planning In Patients With Endometrial Cancer, Madisin M. Depas

Masters Projects

Purpose: This study aimed to evaluate the dosimetric and efficiency impacts of different photon beam energies—6MV, 6 flattening filter free (FFF), 10MV, and 10FFF—on volumetric modulated arc therapy (VMAT) plans for endometrial cancer, with attention to target coverage, organ at risk (OAR) sparing, and treatment efficiency.

Methods: A retrospective analysis was conducted on 25 patients with post-hysterectomy endometrial cancer. Each patient received four VMAT plans with varying energies. Planning metrics assessed included planning target volume (PTV) dose maximum (Dmax), conformity index (CI), heterogeneity index (HI), OAR doses (bladder, bowel, rectum), and total monitor units (MU). Correlations were drawn …

Dosimetric Effects Of Pinnacle³ Version 18.0 Advanced Auto-Planning Settings In Oropharyngeal Vmat Optimization, Emily Sanden

Masters Projects

This study evaluated the impact of Pinnacle³ version 18.0 auto-planning advanced settings modulation amount, monitor unit (MU) level, and dose fall-off priority on volumetric modulated arc therapy (VMAT) plan quality for bilateral oropharyngeal cancer. A total of 64 plans were generated using all possible combinations of low, medium, high, and very high settings for each parameter. A standardized base of tongue case was optimized once per plan using a single-time point approach, with planned target volume 1 (PTV1) (6996 cGy) and planned target volume 2 (PTV2) (5412 cGy) coverage evaluated. Each parotid gland, the spinal cord, brainstem, and the oral …

Impact Of Prostate Volume On Dose Fall-Off And Organ-At-Risk Exposure In Vmat For Prostate Cancer, Zhikang Jiang

Masters Projects

Prostate cancer remains one of the most prevalent malignancies among men, with radiotherapy, particularly VMAT—playing a central role in its management. VMAT allows for highly conformal dose delivery, but treatment planning must strike a careful balance between achieving steep dose gradients around the prostate and minimizing radiation exposure to nearby organs at risk (OARs), such as the bladder and rectum. This study aimed to evaluate how prostate volume influences dose fall-off characteristics and OAR dose exposure in VMAT treatment plans, providing insights into optimizing radiotherapy for patients with varying prostate sizes. A retrospective analysis was conducted on 50 prostate cancer …

Comparing Dosimetric Outcomes Of Static Imrt And Vmat In Accelerated Partial Breast Irradiation For Medially Located, Left-Sided Tumor Beds, Rani Jamil

Masters Projects

Abstract

Introduction: Accelerated partial breast irradiation (APBI) has emerged as a targeted alternative to whole-breast irradiation for early-stage breast cancer, particularly for patients with medially located, left-sided tumors. Static intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) offer advanced dose conformity, yet no direct comparisons between static IMRT and VMAT have been conducted specifically for medially located, left-sided APBI, a uniquely challenging anatomical subgroup. This study evaluates dosimetric differences between static IMRT and VMAT plans to determine which modality provides superior target coverage and organ-at-risk (OAR) sparing in left-sided APBI.

Methods: Ten patients with medially located left-sided breast …

Dosimetric Comparisons For Determining Optimal Arc Geometry In Multi Target Thoracic Vmat Sbrt Treatment Plans For Patients With Locally Advanced Inoperable Nsclc, Alexandrea M. Reeves

Masters Projects

Non-coplanar beam arrangements have been used for many years in radiation treatment planning. Their use has been known to show an increase in target conformity and gradient index. However, by using non-coplanar beam arrangements, the treatment planning time as well as the treatment delivery time can increase. Despite the increase in treatment planning and delivery complexity and time, previous studies have shown a decrease in OAR doses resulting in a desire to use non-coplanar beams. Previous studies have looked at various body sites and target locations, though no research has been found specifically studying non-coplanar beam arrangement in multi-target treatment …

Comparing And Evaluating Contralateral Breast Dose Relative To Median Ptv Tumor Bed Dose For Hypo-Fractionated Breast Treatments Using Import High Dose Constraints., Shannon J. Nordby

Masters Projects

This study is aimed to compare two different planning constraints for post-lumpectomy whole breast radiation treatments to evaluate whether or not the mean dose to the contralateral breast can be significantly reduced while maintaining plan quality for treatment. A total of 10 patients who had first undergone a lumpectomy were included into this study. Each patient’s initial treatment plan was created using a conventional approach with a mean dose constraint of < 600 cGy (Plan A) and then was replanned using the Import High protocol of a mean dose constraint, aiming to further push for a mean dose < 150 cGy (Plan B) to the contralateral breast. Both of these plans were analyzed for PTV coverage and dose to the surrounding critical structures. The results have shown that the contralateral mean dose was significantly reduced from an average of 216.32 in Plan A to 126.53 cGy in Plan B. All while meeting the target coverage of > 95% isodose line. Statistical testing showed a significant difference between the two planning techniques of lowering the contralateral dose (p < 0.0001), and normality testing supported the validity of the data analysis. In addition to a substantial dose reduction to the contralateral breast, Plan B maintained equal or improved dose constraint to other surrounding critical organs at risk, including the heart, lungs, spinal cord, and thyroid. The Import High protocol demonstrated consistent outcomes across diverse patient anatomies. These findings suggest that by using the Import High mean dose constraint, it is possible to maintain plan quality while reducing dose to the contralateral breast. This approach may help reduce the risk of long-term side effects and improve the patient’s overall outcomes in whole breast radiation treatments.

First Quantitative Investigation On The Dosimetric Perturbation From Dental Hardware In Spot-Scanning Proton Arc (Sparc®) Therapy And Planning Strategies In Head Neck Cancer Patient Population, Evan Harbert

Masters Projects

Purpose

There has been a tremendous interest in applying Spot-scanning Proton Arc (SPArc^®) to benefit head and neck cancer (HNC) patient population. However, the dental hardware materials effects on the beam distribution are not well understood, and placing spots through the dental hardware may cause an unnecessary degradation of target coverage if the material components differ from the nominal plan. The purpose of this study is to provide a quantitative dose perturbation analysis of the uncertainties caused by dental hardware and introduce a SPArc^® planning strategy to mitigate such impacts.

Methods and Materials

A published in-house developed …

A Dosimetric Comparison Of Treatment Techniques For Stereotactic Body Radiotherapy For Pancreatic Patients, Kameron Lemley

Masters Projects

Stereotactic body radiotherapy (SBRT) is utilized in radiation therapy to deliver ablative radiation doses to tumor volumes while achieving high conformity and minimal dose to surrounding critical structures. This treatment technique allows for faster dose fall-off which allows tighter treatment margins. SBRT for pancreatic cancer has been investigated for its efficacy and has proven to be an effective treatment choice for neoadjuvant radiation therapy. Since pancreatic cancer is extremely aggressive with a high mortality rate, it is important to have a treatment option that can reduce cost and increase convenience for the patient while simultaneously providing a conformal treatment plan. …

Retrospective Dosimetric Comparison Of Radiation Therapy Treatment Using Hybrid-Vmat Technique For Esophageal Cancer, Colleen Cozzie

Masters Projects

Abstract

Introduction

Esophageal cancer is the fifth most common gastrointestinal cancer in the United States. As oncology treatment includes radiation as a standard of care, it is vital to examine effective treatment delivery options. Understanding the dosimetric differences between VMAT and hybrid-VMAT can help providers choose the most appropriate care plan for patients undergoing esophageal irradiation. The purpose of this study was to evaluate if VMAT or hybrid-VMAT delivery would be the superior planning method for patients with planning target volumes greater than ten centimeters. Adequately covering the tumor volume while sparing dose to adjacent critical structures is the goal …

Comparative Plan Analysis: Helical Tomotherapy Vs. Linac Vmat For Lower Extremity Sarcomas, Marie E. Dibona

Masters Projects

Abstract

Introduction

Soft tissue sarcomas (STS) affect about 13,500 people annually in the United States, and those in the lower extremities present unique challenges in radiation therapy due to the wide variability in tumor sizes, sometimes exceeding 30cm. Traditional treatment involves C-Arm linear accelerators using Volumetric Modulated Radiation Therapy (VMAT), which provides precise targeting while sparing nearby organs. Helical Tomotherapy (HT) is another option, delivering radiation in a helical pattern with a binary MLC for a uniform dose distribution. However, no studies have compared VMAT and HT for lower extremity sarcomas of different sizes. This study aims to compare these …

Can Simultaneous Integrated Boost Provide Better Dosimetric Coverage Compared To Sequential Boost In Prone Breast Treatment Of Large Breast Volumes?, Kinze Kraft

Masters Projects

Introduction: This study investigates the dosimetric differences between sequential boost (SeB) and simultaneous integrated boost (SIB) techniques in prone breast radiotherapy for patients with large breast volumes, utilizing a 3D-CRT planning technique. Prone positioning in radiotherapy has shown to be effective in reducing heart and lung doses, yet limited research exists to compare overall plan quality between SeB and SIB using this technique. This analysis aims to evaluate whether SIB provides better dosimetric coverage and reduced dose to organs at risk (OARs) compared to SeB in prone breast radiotherapy.

Methods: A retrospective analysis was conducted on data from ten patients …

A Quantitative Investigation Into Isotropic Variations Of Treatment Planning Isocenters To Model Patient Misalignment During Radiation Therapy Delivery And Its Impact On Evaluated Dose Metrics For Hypofractionated Dibh Left Breast Cancer Patients, Mckenzie Gemeiner

Masters Projects

Introduction

This research was conducted for carcinoma of the left breast without nodal involvement using the 3D deep inspiration breath hold (DIBH) treatment technique. Limiting dose to healthy tissues is crucial in radiation treatment planning. The impact of dosimetric uncertainty due to isotropic variations on constraints and goals is often overlooked. This study investigates dose metric differences due to inherent patient misalignment modeled by isotropic variations in treatment planning.

Methods

10 patient subjects were randomly selected with carcinoma of the left breast without nodal involvement, each using the 3D hypofractionated, deep inspiration breath hold (DIBH) technique. All plans had 24 …

A Quantitative Investigation Into The Daily Variation Of Bladder And Rectum Volumes Among Prostate Cancer Patients Receiving Radiation And When It Violates Dose Constraints At Any Given Fraction., Joseph Pape

Masters Projects

When planning radiation therapy treatments for prostate cancer, the bladder and rectum are important organs at risk (OAR). The purpose of this retrospective study was to establish guidelines for bladder and rectal volumes for men receiving hypofractionated radiation therapy to their prostate and seminal vesicles. Ten patients were included in the study and radiation doses to the bladder and rectum were recorded based on the daily change in the OAR volumes. The bladder and rectal volumes were contoured on each patient’s daily treatment CBCT and those volumes were compared to that on the treatment planning CT. The results showed that …

A Comparative Analysis Of Helical Tomotherapy Planning With Active Versus Total Bone Marrow Sparing Using Dual-Energy Computed Tomography, April E. Premo

Masters Projects

Purpose: This study aims to compare helical tomotherapy (HT) plans using active bone marrow (ABM) sparing contouring versus traditional bone marrow (BM) sparing contouring using dual-energy computed tomography (DECT) in the treatment of gynecologic (GYN) cancers. The goal is to evaluate the effects of using ABM contours in optimization on organs at risk (OAR) and planning target volumes (PTVs).

Methods: The study involved creating HT plans for GYN cancer patients, utilizing both ABM and BM contouring techniques. DECT was used to distinguish between active and inactive bone marrow. Dosimetric comparisons were made between BM and ABM sparing plans. Statistical analyses …

Plan Comparison Of Hybrid Dynamic Conformal Arc Therapy (Hdcat) And 3-Dimensional Conformal Radiation Therapy (3dcrt) In Palliative Treatment Of Thoracic Spine Tumors, Maria Juchartz

Masters Projects

Abstract

Introduction

When cancer spreads from its place of origin to a new location, it is termed ‘metastatic’. Metastatic cancer is often not curable, however palliative care can be given. One common method of palliation is in the form of radiation therapy. A common site of metastasis is in the thoracic spine, which has several nearby organs that can make treatment planning difficult. These treatments often consist of three-dimensional conformal radiotherapy methods. The purpose of this study was to compare the traditional 3DCRT techniques to a hybrid dynamic conformal arc technique. HDCAT has been used in previous studies, however none …

A Retrospective Quantitative Investigation Into Prostate Radiation Treatment Among Patients With Rectal Gas At Simulation, And How It Affects Planning: A South Florida Context., Soufiane Mansouri

Masters Projects

This study examines the effect of Hounsfield Unit (HU) correction of air in rectal tissue on dose distribution during prostate cancer radiation therapy planning. Ten patients treated between 2023 and 2024, of which received 70 Gray (Gy) in 28 fractions, were retrospectively analyzed. Inclusion criteria included the presence of rectal gas during simulation and noncompliance with pre-simulation preparation instructions. Statistical tests, including a standard t-test and a sign test, were used to compare dose planning without HU correction to planning with HU-corrected rectal gas to tissue, focusing on differences in rectal doses and planned target volume doses. Radiation therapy plans …

A Clinical Comparison With The Flattening Free Filter Technique For Lung Stereotactic Body Radiotherapy Using Functional Lung Planning, Addison Gucwa

Masters Projects

Abstract

Introduction

Lung cancer remains the leading cause of cancer incidence and mortality worldwide. Advances in stereotactic body radiation therapy have demonstrated survival rates comparable to surgery, however, they come with a higher risk of developing radiation pneumonitis. The aim of this study was to explore the possibility of minimizing the risk of lung toxicities after stereotactic body radiation therapy to lung tumors with the use of functional lung planning and flattening filter free beams.

Materials and Methods

This retrospective study analyzed treatment planning data from ten patients previously treated with SBRT for inoperable lung tumors. Functional lung volumes were …

A Retrospective Quantitative Comparison Of Auto-Planning Vs. Manual-Planning For Large Breast Patients, Olivia R. Smiley

Masters Projects

Breast cancer is the most prevalent cancer among women in the United States, with many patients undergoing whole breast irradiation (WBI) following lumpectomy. Dosimetrists face challenges in planning WBI for patients with large breasts due to issues related to hotspots, dose uniformity, and extended planning times. Auto-planning tools like EZFluence, which use artificial intelligence, offer potential improvements in planning efficiency and dose distribution. This retrospective quantitative study compares auto-planning using EZFluence with manual planning for 10 large breast patients, aiming to reduce hotspots, achieve a more homogeneous dose, minimize doses to organs at risk (OARs), reduce monitor units (MUs), and …

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

Masters 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 …

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

Masters 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 …

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

Masters 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 …