Internal dosimetry for intake of 18FDG using spot urine sample.

In nuclear medicine, workers handle unsealed radioactive materials. Among the materials, (18)FDG is the most widely used in PET/CT technique. Because of the short half-life of (18)F, it is very challenging to monitor internal exposure of nuclear medicine workers using in vitro bioassay. Thus, the authors developed the new in vitro bioassay methodology for short half-life nuclides. In the methodology, spot urine sample is directly used without normalisation to 1-d urine sample and the spot urinary excretion function was newly proposed. In order to estimate the intake and committed dose for workers dealing (18)FDG, biokinetic models for FDG was also developed. Using the new methodology and biokinetic model, the in vitro bioassay for workers dealing (18)FDG was successfully performed. The authors expect that this methodology will be very useful for internal monitoring of workers who deal short-lived radionuclides in the all field as well as the nuclear medicine field.