An afterloading system for the intracavitary radiotherapy of cancer patients is described which works with a unique radiation source of 10 Ci 192Ir moving in steps of 1 cm. The times during which the source stops can be determined at a control panel. By using an intermediate piece of 10 cm, a total course of the source of 20 cm can be obtained. The course of the source can be calculated individually by a computer program. This program even takes into consideration an additional deep therapy if the position of the deep therapy field in the target volume is known. This method allows the adaptation of the total isodoses very precisely to the course of the tolerance doses.