most patients given RAI.Probably many patients given this treatment do in fact have some residual thyroid tissue that is either heavily damaged or reduced in amount so that it can not produce normal amounts of hormone. So far there is no evidence, in adults, that this residual radiated tissue will develop malignant change.
There is no certainty at this time that one approach is better than the other. It may be worth remembering that over 50% of patients given calculated modereate dose therapy remain euthyroid after ten years and can easily be surveyed at yearly intervals for hypothyroidism. When giving large doses of 131-I it is prudent to calculate the rads delivered to the gland (as above), which can reach 40-50,000. Such large doses of radiation can cause clinically significant radiation thyroiditis, and occasionally damage surrounding structures. And lastly, a speculation.
Practitioners comment that the incidence of serious ophthalmopathy seems to be less that in former decades. Prompt diagnosis and therapy might contribute to such a change. Another factor could be the more common ablation of the thyroid during therapy for Graves disease, since this should over time reduce exposure of patient’s immune system to thyroid antigens.
Lithium with RAI therapy– Although rarely used, RAI combined with lithium is safe and more effective than RAI alone in the cure of hyperthyroidism due to Graves’ disease, probably because it it causes greater retention of RAI within the thyroid gland.. Bogazzi et al (58.21)reported a study combining lithium with RAI therapy. MMI treatment was withdrawn 5 days prior to treatment, Two hundred ninety-eight patients were treated with RAI plus lithium (900 mg/d for 12 d starting 5 days prior to 131-I treatment) and 353 with RAI alone. RAI dosage was 260mCi/g estimated thyroid weight, corrected for RAIU (done on lithium).. All patients receive prednisone 0.5mg/kg/day, beginning on day 7 after RAI, tapering over 2 months. Patients treated with RAI plus lithium had a higher cure rate (91.0%) than those treated with RAI alone (85.0%, P = 0.030). In addition, patients treated with RAI plus lithium were cured more rapidly (median 60 d) than those treated with RAI alone (median 90 d, P = 0.000). Treatment with lithium inhibited the serum FT4 increase seen after methimazole withdrawal and RAI therapy.
Pretreatment with antithyroid drugs—
Patients are often treated directly after diagnosis, without prior therapy with antithyroid drugs. This is safe and common in patients with mild hyperthyroidsm and especially those without eye problems. However often physicians give antithyroid drugs before 131-I treatment in order to deplete the gland of stored hormone and to restore the FTI to normal before 131-I therapy. This offers several benefits. The possibility of 131-I induced exacerbation of thyrotoxicosis is reduced, the patient recovers toward normal health, and there is time to reflect on the desired therapy and review any concerns about the use of radioisotope for therapy. If the patient has been on antithyroid drug, it is discontinued two days before RAIU and therapy. Patients can be treated while on antithyroid drug, but this reduces the dose retained, reduces the post-therapy increment in hormone levels, and reduces the cure rate, so seems illogical(58.31) . When antithyroid drugs are discontinued the patient’s disease may exacerbate, and this must be carefully followed. Beta blockers can be given in this interim, but there is no reason for a prolonged interval between stopping antithyroid drug, and 131-I therapy, unless there is uncertainty about the need for the treatment.
Pretreatment with antithyroid drug does not appear in most studies to reduce the efficacy of 131-I treatment.  but the debate about the effect of antithyroid drug pretreatment on the efficacy of radioactive iodine therapy continues. In a recent study in which patients were on or off antithyroid therapy, which was discontinued four days before treatment, there was no effect on the efficacy of treatment at a one year endpoint (59.2). In