Fundamental aspects of neutron radiotherapy with a 252Cf source, 1

Californium-252 (252Cf) is a man-made radionuclide (half-life 2.65 years) which emits a mixture of neutrons and gamma rays. It is used in radiotherapy as an alternative to radium and extends the potential benefits of neutrons to interstitial and intracavitary applications. One of the principal problems in the use of 252Cf for brachytherapy applications is the protection for the medical, nursing and technical staff involved. We adapt a complex and sophisticated after-loading technique in order to use 252Cf (135 μg) clinically. The apparatus consists of the following 6 sections; (1) source, (2) applicator (3) source container, (4) guiding tube, (5) control cabinet and (6) treatment couch. The dose equivalent rate of the surface of the container and the concrete barrier is much smaller than permissible dose levels. We get a conclusion that problem of the protection is within safety limit while this afterloading system is used. (auth.)