THE IMPORTANCE OF TOMOGRAPHIC IMAGES TO ENSURE THE TREATMENT QUALITY IN GYNECOLOGICAL BRACHYTHERAPY

Introduction: Image-guided brachytherapy (IGBT) enables to evaluate dose distribution according to the patient’s anatomy, increases local control and minimizes normal tissue dose an advantage over 2D brachytherapy. With IGBT it is possible to verify that the insertion of the applicators was performed correctly. Magnetic resonance imaging (MRI) is considered the gold standard, but computed tomography (CT) images also provide improved planning aspects compared to planar images. Objectives. In this work we present cases of gynecological HDR brachytherapy, which the insertion planning tomographic images were essential for a decision making, since the determination of the treatment performance as well as to evaluate and ensure that the dose was properly delivered to the volume. Methodology: Four cases of cervical cancer patients undergoing gynecological brachytherapy in the radiotherapy department of the Brazilian Institute of Cancer Control (IBCC) - SP were selected. On patients A, B and C, the 30 ° tandem and Fletcher model ovoid were used, and on patient D was the tandem and cylinder, and patient A had a didelfo uterus with neoplasia in both uterus. The insertions were made in the gynecological position, and the supine tomographies performed on the Siemens Somatom Scope CT, the planning performed on the Brachyvision version 13.6 system, with automatic afterloading system and Gammamed® (Varian) applicators. Results: Patient A’s tomography showed that the applicator geometry was satisfactory in both uterus. After verification of the planning tomography of patient B it was found that the 30° tandem didnt cover CTV volume widely, the treatment was suspended and send for surgical rescue. Patient C had a fibroid and with imaging it was possible to check whether the PET capture lesion was being covered. On the case of patient D, the tomographic image showed that the insertion generated a false track and then repeated the insertion, avoiding inappropriate treatment. Conclusions The use of planning tomography for the four cases proved to be effective for assessing the quality of the insertion performed and the dose distribution obtained, ensuring adequate and safe dose deliveries to the patients. These data increase the importance of performing such images of this type in the brachytherapy routine.

Publication History

Article published online:
23 October 2019