Radiation safety issues in the maintenance of cyclotron targets for the production of 11C

In this paper we present the method used for disassembly and cleaning of gas targets used in the routine production of 11C for clinical use in PET. The most activated component of a target are the Havar foils, that are the principal radioactive waste resulting. Radionuclides produced in the foils, like 57Co, 56Co, 58Co, 54Mn, have been found also in the powder and liquids resulting from the cleaning of the inner walls of the targets, as well as 7Be, resulting from the 14N(p,2α)7Be. Proper operation is needed to reduce radiation dose to the hands of the operator and also to avoid inhalation of contaminated aerosols during the cleaning procedure. (author)