Radiation protection issues associated with nuclear medicine out-patients.

This paper reviews the published data relating to the radiation hazards associated with nuclear medicine outpatients. It is discussed both in the context of the current UK advice as well as potential guidelines following the recommendations in ICRP 60. For diagnostic studies there is little need for restrictions. The main exceptions are for a prolonged journey home by public transport with high levels of 99Tcm and for the situation of an outpatient given 111In who has to look after a fretful infant. The main problem occurs following the administration of 131I therapy for thyrotoxicosis. The principal hazards are associated with external exposure; radiation doses from ingestion due to contamination are small. Restrictions should only be necessary for administered activities greater than 400 MBq (e.g. public transport, return to work, sleeping with partner). With such restrictions it is considered that 131I therapy for thyrotoxicosis can continue to be given on an outpatient basis.