RT Journal Article SR Electronic T1 Iodine Symporter Targeting with 124I/131I Theranostics JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 34S OP 38S DO 10.2967/jnumed.116.186866 VO 58 IS Supplement 2 A1 James Nagarajah A1 Marcel Janssen A1 Philipp Hetkamp A1 Walter Jentzen YR 2017 UL http://jnm.snmjournals.org/content/58/Supplement_2/34S.abstract AB 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 131I 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 nonthyroidal 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 124I-based dosimetry in targeting of the sodium–iodine symporter and describe the clinical application of 124I 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.