Treatment with californium-252

Radiotherapy with 252Cf for intractable or radioresistant cancer is discussed. Results obtained between 1974 and 1977 by the Japanese Foundation for Cancer Research showed that the first cures (cancer disappeared within 3 months) were observed in 24 of 44 patients irradiated with 500 to 2800 rad of neutron. This irradiation was particularly effective for cancer of the head and the neck and for cancer of the cervix uteri in 2 patients, malignant melanoma in 1, and skin cancer in 1. But it was not effective for esophageal cancer. Neutron irradiation was ineffective in doses of 300 to 500 rad but was effective in doses of more than 1000 rad in many cases. Severe side effects were observed in only one patient irradiated with more than 1400 rad of neutron. Irradiation in doses up to 1500 rad seems to be possible. The exposure dose for operators can be decreased by one third if the method of filling is done by hand. Remote control-type after-loading apparatuses for irradiation of tissue are now being developed. However, in the future, delayed disturbances and the type of disease to which this treatment can be applied should be studied. (Tsunoda, M.)