50. Dose diminution to bladder and rectal points during high dose rate inlracavitary brachytherapy of cervical carcinoma by utilizing balloon catheters to displace critical structures

Purpose: To ascertain the potential for dose reduction to bladder and rectal points by utilizing intravaginal Foley balloon catheters as a mechanism for structural displacement during Tandem and Ovoid (TNO) High-Dose Rate Intracavitary Brachytherapy (HDR) of the uterine cervix. Methods and Materials: In 15 patients, 2 Foley balloons were placed intravaginally, with one balloon placed superior to the tandem and one inferior, as close to the TNO flange as patient geometry allowed. A series of 41 consecutive digitized treatment plans were assessed with and without liquid contrast inflation of Foley catheter balloons. Planning X-rays were acquired and digitized. Software calculated dose was then defined for 2 bladder and 2 rectal points, both with and without Foley balloon inflation. Results were then assessed utilizing parametric statistical analysis. Results: Collectively and between equivalent points, a statistically significant (P = .01) diminution in calculated dose was observed with inflation of intracavitary balloon catheters. Conclusion: The advantages available from dose reduction using intracavitary balloon catheters include decreased HDR induced organ toxicity, case-by case customizability, and low cost of implementation. As such, further exploration of this technique is warranted.