Innovative use of balloon applicators for gynecological high dose rate brachytherapy

Introduction: The use of balloon brachytherapy devices for High Dose Rate (HDR) partial breast irradiation is well established. Alternatively, balloon applicators can be used for HDR brachytherapy treatment of gynecological malignancies. This includes treatment for (1) post operative endometrial cancer and (2) inoperable endometrial cancer.Here, we describe the clinical and dosimetric methodology for these two treatment sites. Materials and Methods: Balloon devices were used as applicators for vaginal vault irradiation for patients treated post-operatively and for treatment of the uterusfor those with inoperable endometrial cancer. Patients were treated with a Varian iX Ir-192 high dose rate brachytherapy source.Three dimensional treatment planning was done with BrachyVision 8.2 and was based on CT scans acquired for each treatment fraction. Results: For irradiation of the vaginal vault, the use of a balloon applicator reduces the frequency of air gaps between the vaginal mucosa and the applicator as compared to a standard segmented cylinder applicator.It provides excellent radiation dose coverage of the target area with acceptable doses to the bladder and the rectum.For treatment of the uterine serosa, the dose distribution is similar to that obtained through the use of Simon-Heyman capsules while maintaining the ease of a single-entry applicator. It also provides a more reproducible treatment because the volume of the balloon is easily duplicated from fraction to fraction.The insertion and removal of the applicator in both treatment sites is well tolerated. Conclusion: The use of balloon applicators in gynecological sites is a clinically feasible and safe method of patient treatment.Balloon applicators offer the simplicity of a single-entry, single channel tool. The applicator itself is patient specific based on the fill volume of the balloon and can be the same from fraction to fraction, or can adapt if the patient anatomy changes.The dose distributions obtained are similar to conventional treatment devices.Other treatment sites may also benefit from the use of a balloon applicator.