Comparison of effects of 131I treatment for Graves' diseases in Asian countries

For the purpose to establish the standard therapy regimen of Graves' disease, an autoimmune hyperthyroidism, IAEA, since 1994, has been conducting a study on its treatment with 131I with certain conditions in 10 Asian countries to examine the effect, its dose dependency and area difference. The condition involves, in randomized patients, a low (50-60 Gy) and high (80-90 Gy) dose dependency. This report describes results (summarized in Japan) until the end of March 2000, of 573 patients receiving the treatment for more than 15 months in 9 countries. The 131I dose (Gy) is calculated by the Quimby equation: 14.7 x EHL (day) x U (%) x Dose (MBq)/W (g) x 3.7 x 100, where W is the thyroid weight determined by thyroid scintigraphy with 99mTc-pertechnetate; U, 24 hr iodine uptake by the organ determined by a tracer amount of 131I; and EHL, effective half life. Evaluation is done on clinical symptoms and thyroid hormones. There is no clear significant difference in doses at present; however, it is considered for the low dose to be suitable in China, India and Japan and for the high dose, in Bangladesh, Singapore and Thailand. (K.H.)