Comparaison entre Stump Cylinder et moule personnalisé, effet de la forme de l’applicateur sur la distribution de dose
The purpose of this study was to compare the efficacy of two applicators used in high dose rate vaginal brachytherapy. The first is the Stump Cylinder used in the "brachycenter" department at the Middle East Institute of Health in Lebanon and the second is the custom mold used in the radiotherapy department at Tenon Hospital in France. A comparison of the clinical target volume and the doses received by the rectum and bladder was performed in order to determine the best method of treatment and to optimize the dose distribution. 95 patients were treated in both departments. The average values of the D95% dose received by the CTV were respectively 89.43% for the Stump Cylinder and 110.16% for the custom mold. The conformity index was 0.84 for the Stump Cylinder while it was 0.97 for the custom mold, which ensures a better dose distribution. For the rectum, the maximum dose D2cc taken by volume was 71.23% for the Stump Cylinder and 79.51% for the custom mold. The bladder was better protected with Stump Cylinder with a D2cc value of 65.81% against 94.88% for the custom mold. The underdosing obtained using the Stump Cylinder was due to the shape of upper part of the cylinder which was not conform with the shape of the vaginal vault in women. A better protection of the organs at risk was observed with the Stump Cylinder since the dose taken by the rectum and bladder using a custom mold can reach the tolerance limits.