Construction of storage, remote afterloader, and treatment facility for californium-252 medical sources, and radiation protection survey

This paper describes the design and construction of a shielded facility for storage and treatment of up to about 100 μg of 252Cf seed assemblies, after-loading cells and tubes, and a remote afterloader for 252Cf tubes, and radiation protection survey of the completed facility. Applicability of the Guide by Stoaddrd and Hootman for the spherical shields was confirmed by the present design calculations and radiation protection survey. However, for local shielding such as the bedside shielding, which is preferable rather than structural shielding for protection against radiation from brachytherapy sources, the Guide cannot be applied, because scattered neutrons from the floor, ceiling, and wall may reach behind the shield. By using the remote after loader, radiation exposure to staff for the intracavitary therapy may be reduced significantly, while by the present afterloading technique for the interstitial therapy neutron dose to the therapist is 1 to 2 mrem/μg of 252Cf implanted. In the future, remote interstitial implantation method will be needed. (auth.)