Measurement and calculation of local radiation doses in the vicinity of a positron emission tomograph (PET)

To assess the possible radiation dose from PET studies to personnel working in the vicinity of a PET scanner, local doses were measured with LiF thermoluminescence dosemeters at five different positions (maximum distance from the scanner 5.33 m) within the PET area, during a one year period. For the 692 clinical, and physical, PET measurements carried out during the same 12 month period the doses at the five positions were calculated and compared with the measured local doses. In the calculation, absorption and scattering of annihilation quanta was taken into account with geometry factors determined with a separate dose measurement using a strong 198 Au source of 11.26 GBq (304 mCi), centred in the field of view of the tomograph