Rapid clearance of advanced pelvic carcinomas by low dose rate 252Cf neutron therapy.

Californium 252 low dose rate intracavitary neutron implants combined with conventional external beam therapy for advanced pelvic tumors produced better local response than 137Cs in pelvic brachytherapy. Greater tumor regression was achieved by applying 252Cf while the maximum amount of tumor was present preceding or shortly after starting external beam therapy (12/14 or 86%). This schedule was more effective than similar neutron doses given after external beam irradiation.