[Contact therapy in the pharynx and oral cavity areas: after-loading technic, irradiation planning and results]

The contact irradiation in the region of pharynx and mouth with an afterloading unit is presented. Twelve patients with recurrent carcinomas of the squamous cell epithelium have been treated. A stable and reproducible positioning of the source probes in the tumor region is made possible by special applicator prostheses which are adapted to the post-operative situation. The irradiation scheme is based on the transformation of the source co-ordinates from the stereoradiographic localization system into the co-ordinate system of the computed tomogram. At least three fixed metal points which are inserted in the applicator prostheses and visualized by stereoradiography as well as by computed tomography serve as mutual reference points for both co-ordinate systems. The source positioning in the tumor region is optimized by CT irradiation planning. Three cases are presented in order to describe the principles of the method. Preliminary results are discussed.