Dosimetric comparison of two type's applicator geometry in the three-dimensional computed tomography image-based intracavitary brachytherapy treatment planning of carcinoma uterine cervix

Background: The swift dose fall-off traits with distance from the applicators are the dominant advantage of brachytherapy. The differences in applicator designs will produce different dose distributions in intracavitary brachytherapy (ICBT) applications. Aim: The present study was aimed to find out the dosimetric differences for two type's applicators geometry in ICBT applications for carcinoma uterine cervix (Ca-Cx) performing three-dimensional computed tomography (3D-CT) image-based planning as per recent guidelines from the International Commission on Radiation Units and Measurements report-89. Materials and Methods: Retrospectively, 15 patients of Ca-Cx who have received ICBT treatment based on the 3D-CT image during 1st and 2nd fractions using fixed-geometry and flexible-geometry applicators respectively were selected for this study. For comparison of two type's applicators geometry the dose-volume parameters D100% and D90% of high-risk clinical target volume (HR-CTV), V400%, V200%, V150%, V100%, V50% (volume enclosing 400%, 200%, 150%, 100%, and 50% isodoseline of prescribed dose around target, respectively), and average point “A” dose were evaluated for target. While for organs at risk (bladder, rectum, and sigmoid colon) the dose-volume parameters D2cc, D1cc, and D0.1cc were recorded and evaluated. Results: Fixed-geometry applicator produces significantly lesser HR-CTV volume (P = 0.016