The Use of Low Dose in Radioiodine Ablation of Well-Differentiated Thyroid Cancer

Remnant thyroid ablation after thyroidectomy with radioiodine (RAI, I-131) is considered the standard of care for low risk patients with well-differentiated thyroid cancer (WDTC). The choice of activity for therapy is usually empirically determined according to the tumor characteristics and the patient’s age. Many guidelines recommend a range of 1.1 to 3.7 GBq (30 to 100 mCi), although the choice between the extremes of this range remains controversial. Many studies, including retrospective systematic reviews and randomized multicenter trials, have compared results from using low versus high RAI doses. Data demonstrated similar successful ablation and recurrence rates in these groups, although there are no randomized trials to evaluate long-term outcomes. Until this has been addressed, the choice between 1.1 and 3.7 GBq dose for remnant ablation must be made according to the risk of each patient to maximize the efficacy of treatment, while minimizing unnecessary radiation.