Is 99mtechnetium (Pertechnetate) more efficient in clinical evaluation of thyroid lesions compared to 123iodine? A scoping review

Background: This research aims to find out which radiopharmaceutical is more efficient to evaluate thyroid lesions, such as hyperthyroidism, Graves' disease (GD), or even cold or hot thyroid nodule identification (is 99mtechnetium [99mTc] or 123iodine [123I] suitable in this case?). Materials and Methods: An extensive computerized search was done by the authors, revealing 61 studies in total. 49 studies were excluded for various reasons, so only 12 were eligible for inclusion in this review. Results: Majority of the studies suggested that the use of 99mTc over 123I. 99mTc is a suitable choice to evaluate thyroid disorders. However, 123I can be broadly used in assessing thyroid functions, detecting malignancy and causes of thyrotoxicosis, calculating therapeutic dosages of 131I, and identifying cold or hot lesions effectively due to its superior accumulation in thyroid. Conclusion: 99mTc is a nonphysiologic compound widely used to evaluate thyroid abnormalities, and it has a noticeably low biodistribution in the thyroid. On the other hand, 123I is an organic compound with excellent biodistribution that is used to gather further information on thyroid functions and susceptibility and prevalence of toxic adenoma, GD, and cold or hot thyroid nodule evaluation.