[Fast neutron therapy in the National Institute of Radiological Sciences; 10 years' experience and future study].

A total number of 1623 patients were treated with fast neutrons produced by bombarding a thick Beryllium target with 30 MeV deuterons between November 1975 and December 1987. The results of clinical trials with fast neutrons have shown that carcinoma of the salivary gland and the prostate and Pancoast tumor of the lung were indications for fast neutron therapy, and that the patients suffering from osteosarcoma, malignant melanoma and soft tissue sarcoma had indications for fast neutrons when fast neutrons were combined with surgery. Neither carcinoma of the pancreas nor glioblastoma multiforme had indications because of complications of normal tissues. High LET radiation therapy will be evaluated by using heavy ions characterized by Bragg peak combined with biological effects.