Presentation of therapy scheme and irradiation technique of short-term contact radiotherpy of the carcinoma of the cervix

Since April 1983 patients with gynecologic tumors have been irradiated with the HDR afterloading method at the University Hospital of Cologne. The therapy scheme for the carcinoma of the cervix consists of a combination of intracavitary contact irradiation and external radiotherapy. Brachytherapy is preponderant in an early stage of tumor extension, whereas teletherapy contributes more to the total dose in advanced stages. At first, the pelvis is totally exposed to a homogenous irradiation, so the shrunken tumor can more easily be arrived by curietherapy. The therapy scheme is described for the different tumor stages with its dosages, fractionations, and treatment pauses. Besides the use of special multiple-way applicators, the risk organs are protected by collimating with a block the middle part of the external irradiation field as soon as the maximum permissible dose is reached. A special block shape minimizes the dose irregularities at the field borders. The total physical dose at point A is about 60 Gy. The high dose rate of HDR afterloading has to be considered when calculating the biologic efficient dose. Here the dose rate factor furnishes a rough relation to the established radium dosage. (orig.)