A mathematical model of optimized radioiodine-131 therapy of Graves' hyperthyroidism

BMC Medical Physics

Table 2 Suggested FixA Ral regimen for optimized non-ablative dosing

Thyroid grade	Standard	Expected
	activity	Outcome of therapy
0	185 Mbq	85% cure and less than
Not easily visible even with neck
extension. Just palpable (Est 10 g)		10% hypothyroid at 1
I	259 MBq	year.
Visible only with neck extension but easily
Palpable (Est 20 g)
II	370 MBq
Visible without neck extension (Est 40 g)
III	444 MBq
Visible easily from afar (Est 80 g)

Adapted from the data of Zaini et al 1992 [68]. Only palpation was used to decide dosing in this study. The assumption made is that grades I - II goiters have median weights of 20–40 g [76], with the grade 0 goiter having a median weight of about 8 g [76,77] and grade III goiters a median weight of 80–100 g. [76] This regimen needs to be formally evaluated, especially in a study that uses a more accurate method of thyroid size assessment.