SU-E-T-426: Comparison of HDR Brachytherapy for Cervix Cancer Using an Adaptive Simulated Annealing Program and...

Area of Science:

• Radiation Oncology
• Medical Physics
• Gynecologic Oncology

Background:

• High dose rate (HDR) volumetric brachytherapy is crucial for advanced cervix carcinoma treatment.
• Local failure in cervix cancer is linked to high standardized uptake value (SUV) on FDG-PET scans.

Purpose of the Study:

• To evaluate an in-house adaptive simulated annealing (ASA) algorithm for boosting high SUV regions in cervix cancer brachytherapy.
• To compare ASA with the Oncentra® treatment planning system for potential improvement in local control.

Main Methods:

• Five cervix cancer cases underwent brachytherapy (tandem/ring and/or interstitial needles).
• MRI and PET images were fused with CTs to define high-risk clinical target volume (HR-CTV) and gross tumor volume (GTV) based on SUV.
• Treatment plans were generated using both ASA and Oncentra®, with dose-volume parameters compared.

Main Results:

• Physician deemed both ASA and Oncentra® plans acceptable in four out of five cases.
• Two ASA plans were preferred for better tumor coverage and organ sparing; two Oncentra® plans were preferred for lower organ doses.
• One ASA plan was rejected due to excessive bowel dose.

Conclusions:

• Both ASA and Oncentra® planning methods yield acceptable treatment plans for cervix carcinoma brachytherapy.
• Further research is necessary to ascertain the comparative advantages of each planning method.
• This study received partial funding from Varian Medical System Inc.