Radiation dose reduction due to bladder voiding prior to scanning, measured from patients undergoing positron emission tomography-computed tomography imaging using ¹⁸F-Fludeoxyglucose

The objective of this work was to experimentally measure the radiation dose rate reduction factor due to bladder voiding from patients undergoing PET/CT imaging studies using F-18 (FDG) by directly measuring the dose rate immediately before and after voiding, and compare the results with the current scientific literature. The radiation dose rate was measured using ionization chamber located at one meter distance from the interior patient body surface in standing position at the waste level. The same measurement is repeated after voiding and the dose reduction ratio was calculated. The bladder voiding effect had a dose rate reduction factor of about 12% between dose rates measured before and after voiding. We have measured dose rates at one meter from 50 patients and found an average dose rate per unit activity of 94.3 μSv/hr/GBq. Our results are in agreement with the current published data. The presented data can be applied in radiation protection optimization procedures, especially for the protection of the caregivers of patients undergoing FDG PET/CT imaging who are considered as a source of external radiation to others. The provided information will benefit medical physicists working in nuclear medicine and radiation safety policy makers. (author)