Exposure of critical groups to nuclear medicine patients

When a radiopharmaceutical has been administered to a patient, assessment o f the risk to critical groups from emitted photon radiation is by measureme nt of the integral dose received by an individual, or by measurements of th e dose rate external to the patient coupled with appropriate occupancy fact ors. Estimations have been made from the available data of the dose to crit ical groups exposed to patients who have undergone diagnostic or therapeuti c procedures. These dose estimations can be used to assess the impact of th e proposed changes in statutory requirements, and to allow appropriate reco mmendations to be formulated. Two areas for consideration are that pregnant staff exposed to nuclear medicine patients will require an abdominal surfa ce dose limit lower than 2 mSv to restrict their foetal dose to 1 mSv, and the current UK restrictions for the behaviour of patients who have undergon e I-131 treatment are either already adequate or can even be relaxed in ord er to restrict the exposure of members of the public to the proposed lower dose limits. Agreement is needed on the value (e.g. 95th percentile) from a study of the dose to a number of individuals which should serve as the bas is for radiation protection recommendations. (C) 1998 Elsevier Science Ltd. All rights reserved.