SU-E-T-547: Rotating Shield Brachytherapy (RSBT) for Cervical Cancer

Area of Science:

• Gynecologic Oncology
• Radiation Oncology
• Medical Physics

Background:

• Advanced cervical cancer often requires complex brachytherapy techniques.
• Conventional brachytherapy includes intracavitary (IC) and intracavitary plus interstitial (IC+IS) methods.
• Electronic brachytherapy (eBT) offers a novel radiation source for brachytherapy.

Purpose of the Study:

• To compare rotating shield brachytherapy (RSBT) with an eBT source against conventional IC and IC+IS brachytherapy.
• To evaluate treatment planning system (TPS) simulations for these techniques in advanced cervical cancer patients.

Main Methods:

• Simulated brachytherapy plans (IC, IC+IS, RSBT) for 5 patients with bulky cervical cancer (>40cc).
• Utilized magnetic resonance imaging (MRI) for treatment planning.
• Compared 192Ir isotope sources for IC/IC+IS with the Xoft AxxentTM eBT source for RSBT.
• RSBT incorporated a 0.5 mm tungsten shield with variable angles.

Main Results:

• RSBT and IC+IS BT demonstrated superior dose conformity (D90) compared to IC BT.
• RSBT's advantage over IC+IS BT varied with shield angle, tumor shape, and applicator position.
• Increased delivery time was noted for RSBT with finer emission angles.

Conclusions:

• RSBT using eBT is a viable, less-invasive alternative for bulky cervical cancer.
• Optimizing RSBT parameters (shield angle) can enhance treatment outcomes.
• RSBT offers potential for improved efficacy with manageable increases in treatment time.