Date Approved

8-8-2025

Graduate Degree Type

Project

Degree Name

Medical Dosimetry (M.S.)

Degree Program

Health Professions

First Advisor

Kristen Vu

Second Advisor

Richard Hammond

Academic Year

2024/2025

Abstract

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 planning structures and one without. Planning target volumes (PTVs), and organs at risk (OAR) sparing were evaluated and compared amongst the two treatment plans for each patient. Dose-volume histograms (DVHs) and clear check constraints were both evaluated. Statistical analysis included paired t-tests, sign tests, and signed rank tests with a significant p value of (P< .05).

Results showed that plans created without standardized planning structures demonstrated significantly improved OAR sparing for the bladder, rectum, and femoral heads across multiple dose metrics. PTV coverage at the 5040 cGy level was also superior in these plans, while no significant differences were observed at higher dose levels (6300 cGy and 7000 cGy).

These findings suggest that a well-trained RP model can achieve equal or superior plan quality without additional optimization structures. Eliminating these aids may streamline workflows, reduce planner variability, and conserve resources without compromising plan quality.

Key words: Organs at risk (OAR), Planning target volume (PTV), Rapid Plan (RP), Knowledge based plan (KBP), Dose volume histogram (DVH)

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