[Some considerations on the avoidance of excess body burden in case of high dose 131I treatment: with special reference to the urination frequency].
In case of the treatment of metastatic thyroid cancer with radioiodine (131I), 3.7 GBq (100 mCi) or more is often repeatedly administered to the patient. Therefore, we must be aware of avoiding unnecessary exposure to the radioiodine except for the lesions to be treated. The administered radioiodine is excreted mainly through urinary system, resulting in an accumulation of the urine in the bladder for a certain period, which is highly concentrated with it. Based on this fact, we set one case having a particular pattern of the whole body retention curve. Then, two different modes of urination were considered; mode A indicates every 2 hour-urination x 6 times followed by every 6 hour-urination x 2 times, and mode B indicates every 6 hour-urination x 4 times. Focusing on the different amounts of urine in the bladder upon the different modes of urination, the radiation exposures from the urine to the neighboring organs, such as bladder wall, uterus, ovary and testis, and also to the whole body were calculated. As the results, it was found that the urination mode B would cause radiation exposure from the urine in the bladder twice as much as the urination mode A to the neighboring organs as well as to the whole body. This study will supply arguments for the necessity of frequent urination in the cases receiving radioiodine treatment for metastatic thyroid cancer.
Oyamada
H
H
Tokyo Eastern Blood Center, Japanese Red Cross Society.
Uchida
I
I
Koizumi
M
M
Kubo
A
A
Hashimoto
J
J
D001822:Body Burden; D004350:Drug Residues; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage*; D008297:Male; D010053:Ovary / Q000528:radiation effects; D019275:Radiopharmaceuticals / Q000008:administration & dosage*; D013737:Testis / Q000528:radiation effects; D013964:Thyroid Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D001743:Urinary Bladder / Q000528:radiation effects; D014554:Urination / Q000528:radiation effects*; D014599:Uterus / Q000528:radiation effects
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals