Bundeswehr Institute of Radiobiology, Neuherberg Str. 11, 80937, Munich, Germany.
Japan Self Defense Forces National Defense Medical College Research Institute, Tokorozawa, Japan.
Arch Toxicol. 2021 Jul;95(7):2335-2350. doi: 10.1007/s00204-021-03065-5. Epub 2021 May 18.
Radioactive iodine released in nuclear accidents may accumulate in the thyroid and by irradiation enhances the risk of cancer. Radioiodine uptake into the gland can be inhibited by large doses of stable iodine or perchlorate. Nutritional iodine daily intake may impact thyroid physiology, so that radiological doses absorbed by the thyroid as well as thyroid blocking efficacy may differ in Japanese with a very rich iodine diet compared to Caucasians. Based on established biokinetic-dosimetric models for the thyroid, we derived the parameters for Caucasians and Japanese to quantitatively compare the effects of radioiodine exposure and the protective efficacy of thyroid blocking by stable iodine at the officially recommended dosages (100 mg in Germany, 76 mg in Japan) or perchlorate. The maximum transport capacity for iodine uptake into the thyroid is lower in Japanese compared to Caucasians. For the same radioiodine exposure pattern, the radiological equivalent thyroid dose is substantially lower in Japanese in the absence of thyroid blocking treatments. In the case of acute radioiodine exposure, stable iodine is less potent in Japanese (ED = 41.6 mg) than in Caucasians (ED = 2.7 mg) and confers less thyroid protection at the recommended dosages because of a delayed responsiveness to iodine saturation of the gland (Wolff-Chaikoff effect). Perchlorate (ED = 10 mg in Caucasians) at a dose of 1000 mg has roughly the same thyroid blocking effect as 100 mg iodine in Caucasians, whereas it confers a much better protection than 76 mg iodine in Japanese. For prolonged exposures, a single dose of iodine offer substantially lower protection than after acute radioiodine exposure in both groups. Repetitive daily iodine administrations improve efficacy without reaching levels after acute radioiodine exposure and achieve only slightly better protection in Japanese than in Caucasians. However, in the case of continuous radioiodine exposure, daily doses of 1000 mg perchlorate achieve a high protective efficacy in Caucasians as well as Japanese (> 0.98). In Caucasians, iodine (100 mg) and perchlorate (1000 mg) at the recommended dosages seem alternatives in case of acute radioiodine exposure, whereas perchlorate has a higher protective efficacy in the case of longer lasting radioiodine exposures. In Japanese, considering protective efficacy, preference should be given to perchlorate in acute as well as prolonged radioiodine exposure scenarios.
在核事故中释放的放射性碘可能会在甲状腺中积累，并通过辐射增加癌症的风险。放射性碘进入腺体可以被大剂量的稳定碘或高氯酸盐抑制。营养碘的日常摄入量可能会影响甲状腺的生理功能，因此与摄入富含碘的日本相比，白人的甲状腺吸收辐射剂量以及甲状腺阻断效果可能会有所不同。基于甲状腺的已建立的生物动力学剂量模型，我们推导出了白人和日本人的参数，以定量比较放射性碘暴露的影响以及在官方推荐剂量（德国 100mg，日本 76mg）下稳定碘或高氯酸盐对甲状腺阻断的保护效果。日本人甲状腺摄取碘的最大转运能力低于白人。在没有甲状腺阻断治疗的情况下，对于相同的放射性碘暴露模式，日本人的放射性等效甲状腺剂量要低得多。在急性放射性碘暴露的情况下，日本人的稳定碘效果不如白人（ED=41.6mg），并且由于对腺体碘饱和的反应延迟（沃尔夫-恰克效应），在推荐剂量下对甲状腺的保护作用较小。高氯酸盐（白人 ED=10mg）在 1000mg 剂量下对甲状腺的阻断作用与白人的 100mg 碘大致相同，而与日本人的 76mg 碘相比，它提供了更好的保护。对于长时间暴露，单次碘剂量提供的保护作用远低于两组急性放射性碘暴露后的保护作用。每天重复给予碘可以提高疗效，而不会达到急性放射性碘暴露后的水平，并且在日本人中的保护作用仅略好于白人。然而，在持续放射性碘暴露的情况下，每天给予 1000mg 高氯酸盐可在白人和日本人中实现高保护效果（>0.98）。在白人中，在急性放射性碘暴露的情况下，推荐剂量的碘（100mg）和高氯酸盐（1000mg）似乎是替代选择，而在长时间放射性碘暴露的情况下，高氯酸盐具有更高的保护效果。在日本人中，考虑到保护效果，在急性和持续放射性碘暴露的情况下，应优先使用高氯酸盐。
