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 …

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 …

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.

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

Faculty, Staff and Students Publications

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

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

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 …

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 …

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

Masters 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 …

Feasibility Of Using Ring-Mounted Halcyon Linac For Single-Isocenter/Two-Lesion Lung Stereotactic Body Radiation Therapy, Damodar Pokhrel, Aaron Webster, Richard Mallory, Justin Visak, Mark E. Bernard, Ronald C. Mcgarry, Mahesh Kudrimoti

Radiation Medicine Faculty Publications

PURPOSE: To demonstrate the plan quality and delivery efficiency of volumetric-modulated arc therapy (VMAT) with the Halcyon Linac ring delivery system (RDS) in the treatment of single-isocenter/two-lesion lung stereotactic body radiation therapy (SBRT).

MATERIALS/METHODS: Sixteen previously treated non-coplanar VMAT single-isocenter/two-lesion lung SBRT plans delivered with SBRT-dedicated C-arm TrueBeam Linac were selected. Prescribed dose was 50 Gy to each lesion over five fractions with treatment delivery every other day and AcurosXB algorithm as the final dose calculation algorithm. TrueBeam single-isocenter plans were reoptimized for Halcyon Linac with coplanar geometry. Both TrueBeam and Halcyon plans were normalized for identical combined target coverage …

Structural Shielding Considerations For Vmat, Ana Lucia Dieguez

LSU Master's Theses

Introduction: As noted in National Council on Radiation Protection and Measurements (NCRP) Report 151, the medical physicist or other qualified expert has the responsibility to keep abreast of any new technology or treatment method that could potentially impact structural shielding design. Volumetric arc therapy (VMAT) became prevalent after the publication of Report 151 and thus was not explicitly addressed in Report 151. If the shielding-related characteristics of VMAT differ enough from the expectations of Report 151, especially in the circumstance of a vault utilized exclusively for VMAT, a shielding design based on Report 151 could potentially be inadequate. The …

Development And Clinical Validation Of Knowledge-Based Planning Models For Stereotactic Body Radiotherapy Of Early-Stage Non-Small-Cell Lung Cancer Patients, Justin David Visak

Theses and Dissertations--Radiation Medicine

Lung stereotactic body radiotherapy (SBRT) is a viable alternative to surgical intervention for the treatment of early-stage non-small-cell lung cancer (NSCLC) patients. This therapy achieves strong local control rates by delivering ultra-high, conformal radioablative doses in typically one to five fractions. Historically, lung SBRT plans are manually generated using 3D conformal radiation therapy, dynamic conformal arcs (DCA), intensity-modulated radiation therapy, and more recently via volumetric modulated arc therapy (VMAT) on a C-arm linear accelerator (linac). Manually planned VMAT is an advanced technique to deliver high-quality lung SBRT due to its dosimetric capabilities and utilization of flattening-filter free beams to improve …

Development Of A Robust Treatment Delivery Framework For Stereotactic Body Radiotherapy (Sbrt) Of Synchronous Multiple Lung Lesions, Lana Catherine Critchfield

Theses and Dissertations--Radiation Medicine

Stereotactic body radiation therapy (SBRT) of lung tumors uses high doses of radiation to deliver high biological effective doses (BED) in very few fractions (1-5). With the use of highly conformal fields to cover the tumor without depositing large doses to non-cancerous structures, this technique has proven time and again to be successful at achieving high local control. However, frequently patients receiving SBRT are elderly with multiple medical comorbidities who may not tolerate long treatment times. Furthermore, many patients present with oligometastatic or multiple primary lung tumors. The success of SBRT on oligometastatic lung disease relies on physician experience with …