Configuration analysis of the injection position and shape of the gel spacer in gynecologic brachytherapy

Purpose In this single-institution retrospective study, configuration analysis was performed to determine the optimal location and volume of hyaluronic acid gel spacer injection into rectovaginal or vesicovaginal septum for effective dose reduction (DR) organs at risk (OARs), rectum bladder. Methods materials 70 50 intracavitary brachytherapy treatment plans used only vaginal cylinders with spacers rectal bladder sides, respectively, whereas 28 did not use spacers. Correlation between geometrical parameters position 2-cm3 covering doses OARs each treatment. Results A higher DR predicted within ±5 mm ±2.5 in lateral-medial direction from midpoint on ±10 cranial–caudal side. There were correlations parameters: (p = 0.02) 0.04) sides; craniocaudal length side << 0.05); ventrodorsad thickness OAR 0.05) sides. no significant difference a ?10 cm3 that >> 0.05). Conclusions provides sufficient if its gravity point is cylinder applicator OAR, covers active applicator.