A Dosimetric Comparison of Brachytherapy Sources for Endometrial Cancer: an Electronic Brachytherapy and an Iridium-192 Source with Multichannel Cylinders and a Three-Dimensional Technique

Ir192 vaginal brachytherapy (IBT) is commonly used for patients with postoperative endometrial cancer (EC). We devised a novel multichannel vaginal applicator that could be equipped with an electronic brachytherapy (EBT) device. We aimed to explore the differences in physical parameters between the EBT and IBT. This retrospective study included 20 EC patients who received adjuvant IBT from March 1, 2023, to May 1, 2023. Multichannel vaginal cylinders were used, and three-dimensional plans were generated. We designed an electronic multichannel vaginal applicator model and simulated a three-dimensional EBT plan. In order to ensure comparability, D90 of the CTV for the EBT plan was normalized to be equivalent to that of the IBT plan for the same patient. Twenty EBT plans were compared with 20 IBT plans. Results showed, the mean D90 value of clinical target volume (CTV) was 536.1 cGy for both treatment plans. For the mean dose of CTV, the EBT was significantly greater (738.3 vs. 684.3 cGy, p = 0.000). There was no significant difference in CTV coverage between the EBT and IBT plans. For high-dose areas (V200