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The original targeted radiotherapy: thyroid cells soak up iodine, so radioactive iodine destroys leftover thyroid tissue and metastases while sparing everything else.
In use since 1946 for differentiated thyroid cancer; the archetype of theranostics (I-123 or I-131 scans image the same uptake). Roles: remnant ablation after thyroidectomy (now omitted in low-risk disease after ESTIMABL2, IoN, HiLo), adjuvant treatment of intermediate/high-risk disease, and treatment of iodine-avid metastases. Given after TSH stimulation (withdrawal or recombinant TSH). Salivary damage, secondary malignancy at high cumulative doses, and refractoriness in dedifferentiated tumours are the limits.
Ball-and-stick model from PubChem 2D record (no 3D conformer available). PubChem record
Sodium-iodide symporter (NIS) concentrates iodide in thyroid follicular cells; I-131 beta particles (mean path ~0.8 mm) irradiate the cell and neighbours; gamma emission enables imaging.
1.TSH stimulation upregulates the sodium-iodide symporter on thyroid cells
Source: www.thyroid.org/professionals/ata-professional-guidelines/. Doses are for orientation; the current label governs.
Given by infusion or injection in a clinic or hospital outpatient department, so it is a Part B drug: Medicare pays 80% after the Part B deductible and the patient owes 20% coinsurance, uncapped in Original Medicare unless a Medigap policy applies. Oral capsule or solution, but administered in nuclear medicine, so it is a Part B radiopharmaceutical rather than a Part D drug. Inpatient isolation for high-dose treatment is Part A.
Covered as a standard part of thyroid cancer care; higher doses for remnant ablation may need prior authorisation.
Sources: Medicare.gov: Chemotherapy · Medicare.gov: Prescription drugs (outpatient, Part B). Not medical or financial advice; verify with your plan.
Sources: NICE search: radioactive iodine (I-131). Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
First therapeutic use in thyroid cancer (Seidlin); formal approval followed
| Region | Year | Indication |
|---|---|---|
| US | 1951 | Hyperthyroidism and thyroid carcinoma (first radiopharmaceutical approval) |
| Adverse event |
|---|
| Sialadenitis / xerostomia |
Dose-dependent; common after repeated high-activity treatment. Rates read from the source. Blank cells mean the figure was not sourced, not that it is zero.
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Query for this drug: (TITLE:"Radioactive iodine" OR ABSTRACT:"Radioactive iodine" OR TITLE:"I-131" OR ABSTRACT:"I-131" OR TITLE:"Sodium iodide I-131" OR ABSTRACT:"Sodium iodide I-131") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Radioactive iodine (I-131), not a curated reading list.
Shares Radioiodine therapy (I-131), Radioiodine therapy and whole-body iodine scanning, Thyroglobulin, calcitonin and CEA in thyroid cancer follow-up, Thyroid cancer.
Shares MAPK inhibitor redifferentiation → radioiodine, Radioiodine therapy and whole-body iodine scanning, Thyroid cancer.
Shares Radioiodine-refractory (RAI-R) thyroid cancer, Radioiodine therapy and whole-body iodine scanning, Thyroglobulin, calcitonin and CEA in thyroid cancer follow-up, Thyroid cancer.
Shares ESTIMABL2, Radioligand therapy (beta emitters), Thyroid cancer.
Shares Low-risk differentiated thyroid cancer (ATA risk), Thyroid cancer.
Shares Radioiodine therapy (I-131), Radioiodine therapy and whole-body iodine scanning, Thyroid cancer.
Shares Thyroglobulin, calcitonin and CEA in thyroid cancer follow-up, Thyroid cancer (KEGG map), Thyroid cancer.
Shares Low-risk differentiated thyroid cancer (ATA risk), Thyroid cancer.