{"entity":{"id":"radioiodine-therapy","kind":"technology","name":"Radioiodine therapy and whole-body iodine scanning","aka":[],"tldr":"Using the thyroid's natural appetite for iodine to image and treat thyroid cancer with a radioactive form of it. The oldest theranostic, and now used more selectively than it was.","summary":"I-123 or low-activity I-131 scans map iodine-avid tissue; therapeutic I-131 ablates remnants or treats metastases. Randomised trials (HiLo, ESTIMABL1/2, IoN) have progressively reduced activity and then removed ablation for low-risk disease. Refractory disease (no uptake, or progression despite uptake) defines the population for kinase inhibitors; redifferentiation with MEK/BRAF inhibitors can restore uptake in selected patients.","status":"standard-of-care","asOf":"2026-09-07","wikipedia":"https://en.wikipedia.org/wiki/Isotopes_of_iodine#Iodine-131","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Isotopes_of_iodine#Iodine-131"}],"tags":[],"related":[],"cancers":["thyroid","papillary-thyroid-cancer","follicular-thyroid-cancer"],"sections":["radiopharma","radiation"],"technologies":["radioligand-therapy","spect"],"targets":[],"drugs":["radioactive-iodine"],"companies":[],"institutions":[],"pathways":[],"terms":["theranostics","rai-refractory"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"Thyroid cells take up iodine through the sodium-iodide symporter after TSH stimulation; the beta emission treats, the gamma emission images.","strengths":["Highly selective without any engineered targeting","Cheap, oral, curative in iodine-avid metastatic disease"],"limitations":["Dedifferentiated tumours lose uptake","Salivary toxicity; radiation precautions; second cancers at high cumulative activity"],"since":1946},"route":"/technologies/radioiodine-therapy/","neighbours":{"cancer":[{"id":"follicular-thyroid-cancer","kind":"cancer","name":"Follicular thyroid cancer","route":"/cancers/follicular-thyroid-cancer/"},{"id":"papillary-thyroid-cancer","kind":"cancer","name":"Papillary thyroid cancer","route":"/cancers/papillary-thyroid-cancer/"},{"id":"thyroid","kind":"cancer","name":"Thyroid cancer","route":"/cancers/thyroid/"}],"section":[{"id":"radiation","kind":"section","name":"Radiation Therapy","route":"/fronts/radiation/"},{"id":"radiopharma","kind":"section","name":"Radiopharmaceuticals & Theranostics","route":"/fronts/radiopharma/"}],"technology":[{"id":"radioligand-therapy","kind":"technology","name":"Radioligand therapy (beta emitters)","route":"/technologies/radioligand-therapy/"},{"id":"spect","kind":"technology","name":"SPECT & bone scan","route":"/technologies/spect/"}],"drug":[{"id":"radioactive-iodine","kind":"drug","name":"Radioactive iodine (I-131)","route":"/drugs/radioactive-iodine/"},{"id":"thyrotropin-alfa","kind":"drug","name":"Thyrotropin alfa","route":"/drugs/thyrotropin-alfa/"}],"term":[{"id":"low-risk-dtc","kind":"term","name":"Low-risk differentiated thyroid cancer (ATA risk)","route":"/terms/low-risk-dtc/"},{"id":"prrt-term","kind":"term","name":"PRRT (peptide receptor radionuclide therapy)","route":"/terms/prrt-term/"},{"id":"radioiodine-term","kind":"term","name":"Radioiodine therapy (I-131)","route":"/terms/radioiodine-term/"},{"id":"rai-refractory","kind":"term","name":"Radioiodine-refractory (RAI-R) thyroid cancer","route":"/terms/rai-refractory/"},{"id":"theranostics","kind":"term","name":"Theranostics","route":"/terms/theranostics/"},{"id":"thyroidectomy","kind":"term","name":"Thyroidectomy","route":"/terms/thyroidectomy/"}],"trial":[{"id":"astra","kind":"trial","name":"ASTRA","route":"/trials/astra/"},{"id":"estimabl2","kind":"trial","name":"ESTIMABL2","route":"/trials/estimabl2/"},{"id":"hilo","kind":"trial","name":"HiLo","route":"/trials/hilo/"},{"id":"ion-trial","kind":"trial","name":"IoN","route":"/trials/ion-trial/"}],"pairing":[{"id":"redifferentiation-rai","kind":"pairing","name":"MAPK inhibitor redifferentiation → radioiodine","route":"/pairings/redifferentiation-rai/"}]}}