Date Approved

8-5-2025

Graduate Degree Type

Project

Degree Name

Medical Dosimetry (M.S.)

Degree Program

Health Professions

First Advisor

Kristen Vu

Second Advisor

Mubin Shaikh

Third Advisor

Sara Muellerleile

Academic Year

2024/2025

Abstract

Prostate cancer remains a significant cause of morbidity among men, and optimizing radiation therapy is crucial for balancing treatment efficiency, dosimetric precision, and patient costs. This retrospective cohort study evaluated 35 male patients aged ≥18 years with T1/T2 localized prostate cancer, comparing Stereotactic Body Radiotherapy (SBRT, 36.25 Gy in 5 fractions) and Hypofractionated Intensity-Modulated Radiotherapy (HYPO, 60 or 62 Gy in 20 fractions) using the Eclipse Treatment Planning System. The primary outcome was the Treatment

Efficiency Index (TEI), incorporating treatment duration, MU factor, dose conformity, and non- target tissue exposure. Secondary outcomes included planning target volume (PTV) coverage,

Conformality Index (CI), Homogeneity Index (HI), organ-at-risk (OAR) doses, integral dose, monitor unit (MU) efficiency, and patient-responsible costs. Results showed that SBRT achieved significantly higher TEI values (P < .0001), better CI (mean 1.22 vs. 1.35; P < .05), and improved HI (mean 0.12 vs. 0.15; P < .05). While SBRT delivered higher bladder doses (P < .001), it demonstrated lower integral dose (P = .0037) and reduced femoral head exposure (P < .001). Treatment costs were also lower with SBRT ($1,726.64 vs. $2,530.94; P < .001). MU efficiency did not differ significantly between modalities (P = .092). These findings support SBRT as a more efficient, conformal, and cost-effective option for localized prostate cancer, highlighting its potential as a preferred modality that balances efficiency, patient convenience, and affordability.

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