Topometry and dose planning in telegammatherapy of the prostatic carcinoma

A computer-aided technique is described of planning and irradiation for radical radiotherapy of local and local-regional stages of prostatic carcinoma. The technique provides a homogeneous dose distribution in the target volume and a considerable dose reduction in the high-risk organs, i.e., the rectum and the bladder. The optimal dose distribution is achieved by the arc of rotation from 240deg to 300deg. The field size varies between 7 and 10 cm. The isocentre is found for each patient individually according to his anatomical characteristics and the proliferation of the tumorous process. Thus, the dose for the dorsal wall of the rectum and the ventral part of the bladder is only 50 to 80% and for the femur neck below 50% of the tumor dose. Using the technique described, irradiation is easy and the accuracy of dose distributions meets the demands of radiotherapy. (L.O.). 3 figs., 5 refs