Radiotheragnostics paradigm for radioactive iodine (Iodide) management of differentiated thyroid cancer

This review of radioactive iodide treatment (RAIT) extends from historical origins to its modern utili-zation in differentiated thyroid cancer (DTC). The principles embedded in the radiotheragnostics (RTGs) paradigm are detailed. The diverse approaches in current practice are addressed, and this broad variability represents a major weakness that erodes our specialty’s trust-based relationship with patients and referring physicians. The currently develop-ing inter-specialty collaboration should be hailed as a positive change. It promises to clarify the target-based terminology for RAIT. It defines RAIT of post total thyroidectomy (PTT), presumably benign thyroid as ‘rem-nant ablation’ (RA). ‘Adjuvant treatment’ (AT) referrers to RAIT of suspected microscopic DTC that is inher-ently occult on diagnostic imaging. RAIT directed at DTC lesion(s) overtly seen on diagnostic imaging is termed ‘treatment of known disease’ (TKD). It was recently recognized that a ‘recurrent’ DTC is actually occult residual DTC in the majority of cases. Thy-roglobulin with remnant uptake concord (TRUC) method (aka Tulchinsky method) was developed to validate that a benign remnant in the post-thyroidectomy neck bed, as quantified by the RAI uptake, is concordant with a measured thyroglobulin (Tg) level at the time of the initial post-thyroidectomy evaluation. It allows recognition of occult residual DTC contribution to post-thyroidectomy Tg. Case examples demonstrate the application of the TRUC method for a logical selection of a specific RAIT category, using imaging-guided identification and management of RAI-avid versus RAI-nonavid residual DTC, i.e. the radiotheragnostics paradigm.