[Validity of bone scintigraphy for radiotherapy treatment planning of the skeletal system]

Aim of this paper is to assess the validity of bone scanning for radiation therapy treatment planning in the skeletal system. Radiation therapy treatment planning in the skeletal system is based on plain film radiographs and bone scanning. Between January 1, 1993 and June 30, 1994, 228 patients were irradiated due to malignancies in the skeletal system. Included were bone metastases, lymphomas, sarcomas and bone invasion of neuroblastoma. The morphological display of the plain film radiographs and the bone scintigraphies were compared and modifications of the target volume due to the scan findings quantified. In 17 of 228 patients (7.5%) the target volume was modified by at least 2 cm due to tumor invasion depicted by radionuclide scanning only. Bone scintigraphy enables a sensitive display of bony invasion in skeletal malignancies. Because of a scan induced alteration of the target volume in 7.5% of the cases, bone scanning cannot be abandoned in RT treatment planning.