[Cf-252 neutron therapy of cervical carcinoma: topometrical radiotherapy planning using an afterloading technic and...

The introduction of the afterloading technique with Cf-252 sources of high dose rate into the clinical practice has made necessary a topometrical radiation treatment planning (RTP) with increased accuracy in order to keep the risk of post-irradiation complications as low as possible. The possibilities of computerized tomography (CT) for topometrical RTP have been examined on 20 patients with histologically verified carcinoma of the cervix (stage Ia and Ib). The systematic use of the methods provides comprehensive information on anatomical relations and the localization of the applicator on all levels required for physical RTP. Thus, it was revealed that the cervix is enclosed by the bladder and that the distance from the dorsal wall of the bladder to the applicator in the cervical canal is, as a rule, not or little dependent on the level of bladder filling. By controlling the level of bladder filling it may be possible to reduce radiation load on the ileum, and thus to diminish the risk of radiation damage in case of intracavitary brachytherapy with Cf-252.