Diagnostic thyroid procedures and corresponding radiation doses in Manitoba: 1981-1985.
Data on nuclear medicine thyroid examinations performed in Manitoba (population 1 million) from 1981-1985 were collected, with more detailed demographic data obtained on 1,100 consecutive patients between June 1987 and January 1988. An average of 2,081 patients were examined per year, 81% female and 19% male, representing 8.4% of all nuclear medicine procedures. Typical administered activity and associated HE per patient were 238.0 MBq and 1.5 mSv for 99mTc, 7.4 MBq and 1.2 mSv for 123I, and 0.33 MBq and 3.9 mSv for 131I. Based on NCRP risk estimates with explicit corrections for age, sex, and radionuclide used, it is estimated that the rate of thyroid cancer induction is unlikely to exceed 0.56 y-1, of which about 10% would be fatal. This estimate is about a factor of 4 less than that generated using more generally applicable radiation protection risk estimates averaged over both sexes and all ages in the general population. The replacement of 131I with the present mix of radiotracers used for thyroid evaluation has resulted in a reduction of the estimated population detriment by a factor of 3.6.
Huda
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Department of Medical Physics, Manitoba Cancer Treatment and Research Foundation, Winnipeg, Canada.
Gordon
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Greenberg
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ID
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology; D011159:Population Surveillance; D011877:Radionuclide Imaging / Q000706:statistics & numerical data*; D012306:Risk; D013670:Sodium Pertechnetate Tc 99m; D013959:Thyroid Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D013960:Thyroid Function Tests / Q000706:statistics & numerical data*; D013964:Thyroid Neoplasms / Q000453:epidemiology
D007457:Iodine Radioisotopes; D013670:Sodium Pertechnetate Tc 99m