Date Approved

7-26-2024

Graduate Degree Type

Project

Degree Name

Medical Dosimetry (M.S.)

Degree Program

Allied Health Sciences

First Advisor

Lee Culp

Academic Year

2023/2024

Abstract

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 increase planning efficiency. Patients were treated in the supine position with a separation of ≥ 22 cm. Comparative analysis of planning time, dose distribution, MUs, and placement of 105% hotspots within the lumpectomy site was conducted, with data analyzed using nonparametric paired sample Sign tests. The median planning time for auto-plans was significantly lower at 1.88 minutes compared to 44 minutes for manual plans (p=0.002). Auto-plans also required fewer MUs for both medial (230.5 MU vs. 281.5 MU, p=0.002) and lateral beams (217 MU vs. 262 MU, p=0.002). No significant differences were found in median hotspot, V16% for the ipsilateral lung, or the V95% for the lumpectomy between the two planning methods. However, the auto-plans demonstrated a slightly higher median V100% coverage for the lumpectomy (99% vs. 98%). Manual plans showed a higher success rate in placing the 105% hotspot within the lumpectomy cavity (40% vs. 30%). In conclusion, auto-planning with EZFluence significantly improves planning time and reduces MUs while maintaining comparable dose distributions to manual plans. Despite the need for potential manual adjustments to ensure optimal coverage and hotspot placement, EZFluence enhances planning efficiency, making it a valuable tool for dosimetrists, particularly in managing large breast patients undergoing hypofractionated WBI.

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