Opinion Paper/CommentaryRadioiodine Therapy in Pediatric Differentiated Thyroid Cancer Dosimetry, Clinical Care, and Future ChallengesKumar, Praveen PhD; Damle, Nishikant Avinash MD; Bal, Chandrasekhar MD, DSc Author Information From the Department of Nuclear Medicine, All India Institute of Medical Science, New Delhi, India. Received for publication July 13, 2022; revision accepted September 4, 2022. Conflicts of interest and sources of funding: none declared. Correspondence to: Chandrasekhar Bal, MD, DSc, Department of Nuclear Medicine, All India Institute of Medical Science, New Delhi, India 110029. E-mail: [email protected]. Clinical Nuclear Medicine 48(2):p 158-167, February 2023. | DOI: 10.1097/RLU.0000000000004431 Buy Metrics Abstract Thyroid cancer is very rare in children. 131I therapy after thyroidectomy is established in pediatric differentiated thyroid cancer (DTC). Pediatric DTC guideline is silent on the optimum amount of 131I that could be safely and effectively administered to children who are more radiosensitive. Like adult DTC, children are also given 131I therapy empirically based either on age or body weight. Pediatric DTC guideline recommends that patient-specific dosimetry is important in children. Still, due to the low incidence rate and the practical difficulties of dosimetry, it has neither been established nor adopted in routine practice. This review article aims to discuss current approaches of 131I therapy in children and young adult patients with DTC and dosimetric data obtained by several investigators. Efforts are required to simplify dosimetric procedures and precise results, especially in determining lesion size. We prefer 3-dimensional dosimetry over planar dosimetry, where lesion size could be measured accurately. 124I PET/CT-based dosimetry is expected to give accurate dosimetric results. The most challenging aspect is that no randomized controlled trials are available to compare the empiric 131I therapy results versus dosimetry-based treatment outcomes in children and young adults. Suppose dosimetry-based 131I therapy could be shown to have better outcomes, namely, successful ablation rate, better disease-free survival, and lesser treatment-emergent adverse events than empirical 131I treatment. In that case, one can argue in favor of the former. Unfortunately, no convincing study is currently available. Thus, there is a need for a randomized control trial to settle this issue. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.