Personnel exposure from flood phantoms and point sources during quality assurance procedures

Nuclear medicine technologists routinely use flood phantoms containing 5 to 10 mCi (185-370 MBq) of Tc-99m to perform quality assurance tests on scintillation cameras. This paper presents the results of a study that measured the radiation exposure received by three individuals from a Tc-99m flood phantom during the daily performance of flood-field uniformity tests on three scintillation cameras. The extrapolated annual personnel exposure to the anterior trunk and the back of the hand were 172 mR and 220 mR, respectively. Additional measurements indicate that personnel performing these tests with a 10-mCi Co-57 flood disk source or a 200-muCi point source would receive approximately 25% and 1%, respectively, of the exposure from a 10-mCi Tc-99m flood phantom. These exposure levels should be considered when evaluating personnel radiation exposure in a nuclear medicine clinic.