Absorbed dose to the adult male and female brain from 18F-fluorodeoxyglucose

The absorbed doses to adult male and female brains from 18F-fluorodeoxyglucose were investigated. A total of eight male and six female patients undergoing clinical positron tomography brain scans were included in this study. This patient population allowed for a comparison of the absorbed dose to the brain in men and women. For each patient, time-activity curves for the brain were generated, yielding cumulated activity measurements for the entire organ. From these cumulated activities the average residence times for both male and female subjects were calculated and then multiplied by the S-values from the MIRDOSE 3.1 software program for absorbed dose estimates. The average absorbed dose per administered activity to the adult male brain was found to be 4.2 x 10(-2) mGy MBq(-1), which is lower than that found for the adult female brain of 5.3 x 10(-2) mGy MBq(-1). Six of the male and all six female subjects were each studied on two separate occasions, allowing for an analysis of within-subject variability. The average variation in the self-dose for all 12 patients was found to be within 14%, suggesting that in most cases this method of obtaining a single dose estimate is precise.