Radiation dosimetry for the adult female and fetus from iodine-131 administration in hyperthyroidism.
Through a study of the iodine kinetics of 127 patients, we have developed radiation dose estimates to major organs and the fetus for patients with varying degrees of hyperthyroidism. We observed a negative correlation between maximum thyroid uptake and biologic half-time of iodine in the thyroid and used this correlation to predict the biologic half-time at fixed values of maximum thyroid uptake. Dose estimates to the bladder, gonads, marrow, thyroid, uterus, and whole body were estimated for maximum thyroid uptakes from 20% to 100%. Bladder dose varied from 0.6 to 1.0 mGy/MBq and dose to the uterus varied from 0.036 to 0.063 mGy/MBq under different model assumptions. Dose estimates to the fetus and fetal thyroid were approximated at all stages of pregnancy. Average fetal dose was a maximum between 0 and 2 mo of pregnancy, with the maximum ranging from 0.048 mGy/MBq to 0.083 mGy/MBq, depending on model assumptions. Some radiation risks for irradiation of the fetus and the fetal thyroid are discussed.
Stabin
M G
MG
Medical Sciences Division, Oak Ridge Associated Universities, Tennessee 37831-0117.
Watson
E E
EE
Marcus
C S
CS
Salk
R D
RD
D000328:Adult; D005260:Female; D005333:Fetus; D006801:Humans; D006980:Hyperthyroidism / Q000378:metabolism / Q000532:radiotherapy*; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008875:Middle Aged; D011247:Pregnancy; D011829:Radiation Dosage; D013961:Thyroid Gland / Q000196:embryology / Q000378:metabolism*
D007457:Iodine Radioisotopes