Doi Suhail AR, Loutfi Issa, Al-Shoumer Kamal AS
Endocrinology, Mubarak Al Kabeer Teaching Hospital & Faculty of Medicine, Kuwait University, Jabriya, Kuwait.
BMC Nucl Med. 2001;1(1):1. doi: 10.1186/1471-2385-1-1.
The current status of radioiodine-131 (RaI) dosimetry for Graves' hyperthyroidism is not clear. Recurrent hyperthyroidism and iatrogenic hypothyroidism are two problems which interact such that trying to solve one leads to exacerbation of the other. Optimized RaI therapy has therefore begun to be defined just in terms of early hypothyroidism (ablative therapy) as physicians have given up on reducing hypothyroidism. METHODS: Optimized therapy is evaluated both in terms of the greatest separation of cure rate from hypothyroidism rate (non-ablative therapy) or in terms of early hypothyroidism (ablative therapy) by mathematical modeling of outcome after radioiodine and critically discussing the three common methods of RaI dosing for Graves' disease. RESULTS: Cure follows a logarithmic relationship to activity administered or absorbed dose, while hypothyroidism follows a linear relationship. The effect of including or omitting factors in the calculation of the administered I-131 activity such as the measured thyroid uptake and effective half-life of RaI or giving extra compensation for gland size is discussed. CONCLUSIONS: Very little benefit can be gained by employing complicated methods of RaI dose selection for non-ablative therapy since the standard activity model shows the best potential for cure and prolonged euthyroidism. For ablative therapy, a standard MBq/g dosing provides the best outcome in terms of cure and early hypothyroidism.
131碘（RaI）治疗格雷夫斯甲亢的剂量测定现状尚不清楚。复发性甲亢和医源性甲减是两个相互影响的问题，试图解决其中一个会导致另一个问题恶化。因此，由于医生已放弃降低甲减发生率，优化的RaI治疗开始仅根据早期甲减（消融治疗）来定义。
通过对放射性碘治疗后的结果进行数学建模，并批判性地讨论格雷夫斯病常用的三种RaI给药方法，从治愈率与甲减发生率的最大分离度（非消融治疗）或早期甲减（消融治疗）方面评估优化治疗。
治愈率与给药活度或吸收剂量呈对数关系，而甲减发生率呈线性关系。讨论了在计算给药I-131活度时纳入或忽略如测量的甲状腺摄取率、RaI有效半衰期等因素，或对腺体大小给予额外补偿的影响。
对于非消融治疗，采用复杂的RaI剂量选择方法获益甚微，因为标准活度模型显示出治愈和延长甲状腺功能正常期的最佳潜力。对于消融治疗，标准的每克兆贝可剂量在治愈和早期甲减方面提供了最佳结果。
