Impact Assessment on the Calculation of Administered Doses with the Use of IGABT in Each Brachytherapy Session Versus Brachytherapy Based on Single 3D Scan

Gynecological brachytherapy is a fundamental component of the comprehensive treatment for endometrial and cervix cancer. In order to plan the treatment, it is necessary to know, through the use of tomography (CT) or magnetic resonance imaging (MRI), the location of the tumor and nearby organs at risk (such as rectum, bladder and sigmoid colon). Image Guided Adaptive Brachytherapy (IGABT) is a highly personalized method that implies acquiring a new image at each treatment session; it can contribute to improve the survival rate in these types of pathologies while reducing the risk of complications, offering a high quality, effective and safe treatment. The comparative study was performed on a sample of 60 patients treated in three sessions. In each case, the planning criteria of the first session were replicated in the following ones, in order to identify its impact on the variation of doses delivered to the organs at risk and clinical volumes and thus justify the use of IGABT for gynecological tumors. In most cases, results showed a decrease in the dose delivered to the clinical volume and a great variability in the dose delivered to the organs at risk, showing that it is not possible to state whether replicating the first session in the following ones will complete a treatment in accordance with the dose specifications of the EMBRACE II protocol.