Potential third-party radiation exposure from outpatients treated with {sup 131}I for hyperthyroidism

Thirty-three hyperthyroid patients treated with radioiodine (mean administered activity 414 MBq, range 163-555) were studied to determine if pretreatment dosimetry could be used to give radiation protection advice that could assure compliance with the effective dose constraints suggested by the European Commission. Effective doses to travelers, co-workers, and sleeping partners were estimated by integrating the effective dose rate-versus-time curve obtained by fitting the dose rates measured several times after radioiodine administration to a biexponential function. The mean estimated effective doses to travelers, co-workers, and sleeping partners were 0.11 mSv (0.05-0.24), 0.24 mSv (0.07-0.52), and 1.8 mSv (0.6-4.1), respectively. The best correlation was found between effective dose (D) in mSv and maximum activity (AU{sub max}) in MBq taken up in the thyroid: D{sub traveler}=0.0005*(AU{sub max})+0.04 (r=0.88,p