Analysis of information sources in references of the Wikipedia article "ヨウ素131" in Japanese language version.
The increased risk of thyroid cancer after thyroid irradiation in childhood has been recognized for nearly 50 yr (119).
Thus, a major concern of iodine-131 therapy relates to the risks of thyroid and nonthyroid cancers. Not surprisingly, this issue has been the focus of several long term follow-up studies involving more than 60,000 patients (56, 120–123). Studies of the effects of external radiation, diagnostic iodine- 131 use, and environmental radioiodine and g-ray exposure have also provided important insights regarding the risks of radiation exposure and thyroid carcinomas (26, 28, 124–128). These studies show that the risk of thyroid cancer is increased with exposure to low or moderate levels of external radiation. In contrast, thyroid cancer risks are much lower after high level irradiation that results in thyroid cell death or reduced capacity of cells to divide (128, 129).
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The large scale epidemiological surveys of the CTSG involving 36,050 patients in the United States (56) and the Swedish cohort studies (16, 121, 141) have provided considerable information about the relative cancer risks after iodine-131 therapy. After treatment of Graves’ disease in adults with iodine-131, which exposes the thyroid gland to high levels of radiation, rates of thyroid cancer and thyroid cancer mortality were not increased (56, 121, 141, 160).
Follow-up data involving children in the CTSG showed that thyroid adenomas developed in 30% of the patients treated in one center with low doses of iodine-131 (50 mCi/g) estimated to result in thyroid exposure of 2500 cGy (56, 88). Yet, in the other centers where children were treated with higher doses of iodine-131 (100–200 mCi/g), the incidence of thyroid neoplasms was not increased (56).
