This month Ariamanesh and colleagues' article "Effect of Different 131I Dose Strategies for Treatment of Hyperthyroidism on Graves' Ophthalmopathy" presents evidence for personalizing dosimetry in patients treated with radioiodine for Grave Disease (GD) regarding the effect of different dose strategies ophthalmic complications. Initially and at 6 months and 12 months, 92 consenting participants with GD and no or inactive ophthalmopathy (clinical activity score; CAS < 3) underwent Snellen chart examination, measurement of proptosis, thyroid volume, and radioactive iodine uptake. Participants were prospectively randomized into 1 of 3 groups. In group 1, (n = 29) all the patients received fixed low dose (FLD) of 259 MBq of 131I, whereas in group 2, (n = 32) all the patients received fixed high dose (FHD) of 555 MBq, and in group 3, (n = 31) a calculated dose (CD) was administered to deliver 5.55 MBq/g (thyroid weight) of 131I.
Participants in CD received a mean activity of 240.5 MBq. The 3 groups were not significantly different regarding age, sex ratio, radioactive iodine uptake, smoking, visual acuity, and proptosis. The response rates 12 months after radioactive iodine therapy were 66.7%, 94.4%, and 92.9% in FLD, FHD, and CD groups, respectively (P = 0.05). Overall, CAS was increased significantly after treatment. Delta proptosis and delta CAS were increased significantly in FHD group compared with other groups (P < 0.05). The highest increment in proptosis was seen in FHD group.
The authors concluded that administration of 5.55 MBq/g of 131I has fewer ophthalmic complications compared with high fixed dose model and is more effective than low fixed dose strategy.