Quality assurance aspects in planning brachytherapy for gynecological cancer

In the Institute of Oncology and Radiology in Kiev we have used the Nucletron NPS brachytherapy planning system since 1988. We have planed the radiotherapy 230 gynecological cancer patients (cervical and endometrial carcinoma, stage T2-3NxMO). There are many aspects of quality assurance in planning intracavitary therapy in gynecology: target dose and volume specification, reconstruction of the positions of applicator and sources relative to reference points, topography of organs at risk, optimization of dose-fractionation schemes. All patients have been treated using the Selectron-LDR (caesium 137) unit and cobalt-60 machine. We used a new dose-time fractionation schemes for LDR, which were not traditional for national standard protocols. In all 230 cases, treatment planning was undertaken and doses to Manchester points A and B, to rectal and bladder points were calculated. Anatomical topography was obtained using orthogonal radiographs, hysterography, ultrasound imaging. Treatment techniques for brachytherapy (cancer of the cervix): dose per fraction of 23;17;13Gy to p.A, to total of 53 Gy, one fraction every 10-12 days, dose rate to p.A 0.23-0.25 Gy/hour. For verification the accuracy of treatment planning and dose delivery we have compared the calculated doses to in vivo measured doses (rectum). These measurements we made with 27012 clinical dosemeter (former GDR). The results have been analysed and will be presented at the Meeting