In Phantom and In-Vivo Measurements of the Absorbed Dose in the Treatment of Cervical- Uterine Cancer Using Low Dose Rate

Intracavitary Brachytherapy is one of the most used methods for the treatment of the cervical-uterine cancer treatment, which is the main cause of cancer women death. This treatment consists in the insertion of low rate dose Cs sources into the patient. The most used system for the treatment dose planning is that of Manchester. This planning is based on sources, which are considered fixed during the treatment. However, the experience has shown that, during the treatment, the sources could be displaced from its initial position, changing the dose from that previously prescribed. For this reason, it is necessary to make measurements of the absorbed dose to the surrounding organs (mainly bladder and rectum). This paper presents the results of measuring the absorbed dose using home-made LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters (TLD). Measurements were carried out in-vivo, during 20 minutes at the beginning and at the end of the treatments, comparing with those measurements performed at the Manchester A point in a phantom human-like. Results showed that the absorbed dose to the critical organs changes significantly with the movement of the patient during the treatment.