[The place of ultrasonic diagnosis in radiotherapy]

1. Before starting radiotherapy ultrasonic investigation of the abdominal, retroperitoneal and pelvic area is mainly used to determine the stage of the disease, the tumour size and its relation to adjacent organs, as well as in the diagnosis of metastases. 2. During treatment, ultrasonography is useful in controlling the correct position of the treatment fields and the response of the tumour to treatment. 3. During follow up echography is helpful in controlling therapeutic results and in the early detection of tumour recurrence. At this point the procedure frequently replaces diagnostic X-ray control. 4. In regard to treatment planning, the outlines of the organs are directly transferred from the B-mode scan to the treatment plan. Hence, the position of the treatment fields and the isodose distribution can be exactly adjusted to e patient's anatomical requirements. Several examples are given to illustrate this procedure.