Iodine Symporter Targeting with 124I/131I Theranostics

Theranostics, a modern approach combining therapeutics and diagnostics, is among the most promising concepts in nuclear medicine for optimizing and individualizing treatments for many cancer entities. Theranostics has been used in clinical routines in nuclear medicine for more than 60 y-as I-131 for diagnostic and therapeutic purposes in thyroid diseases. In this minireview, we provide a survey of the use of 2 different radioiodine isotopes for targeting the sodium-iodine symporter in thyroid cancer and non-thyroidal neoplasms as well as a brief summary of theranostics for neuroendocrine neoplasms and metastatic castration-refractory prostate cancer. In particular, we discuss the role of I-124-based dosimetry in targeting of the sodium-iodine symporter and describe the clinical application of I-124 dosimetry in a patient who had radioiodine-refractory thyroid cancer and who underwent a redifferentiation treatment with the mitogen-activated extracellular signal-related kinase kinase inhibitor trametinib.