Radiation dose to the bladder wall from 2-[18F]fluoro-2-deoxy-D-glucose in adult humans

Accurate determination of the radiation dose to the bladder wall from 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) is important because the bladder is the critical organ in radiotracer studies using 2-[18F]FDG. The radiation dose to the bladder wall from injected 2-[18F]FDG was estimated using both a dynamic bladder model and the conventional MIRD model. The dynamic model takes into account the excretion rate, the varying size of the bladder, the volume at injection, and an estimated bladder time activity curve. Our data from 302 adult subjects in a five-year period indicate that when the bladder is large at the time of injection, the dose to the bladder is greatly reduced. The absorbed dose of the bladder based on the dynamic model for an initial volume of 450 ml is 0.16 +/- 0.06 rad/mCi, while that for an initial volume of 200 ml is calculated to be 0.37 +/- 0.18 rad/mCi. The MIRD model estimates an average value of 0.35 +/- 0.16 rad/mCi for the 302 cases.