Radioactive iodine (I-131)
The original targeted radiotherapy: thyroid cells soak up iodine, so radioactive iodine destroys leftover thyroid tissue and metastases while sparing everything else.
Overview
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.
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. Connects to Somatostatin receptor 2.
- PSMA / SSTR-positive cell
1.TSH stimulation upregulates the sodium-iodide symporter on thyroid cells
- Route
- Oral capsule or solution
- Schedule
- 1.1 GBq (30 mCi) for remnant ablation (HiLo); 3.7-7.4 GBq for adjuvant or metastatic treatment; low-iodine diet and TSH stimulation beforehand
- Monitoring
- Post-therapy whole-body scan; thyroglobulin; salivary and marrow function
Source: www.thyroid.org/professionals/ata-professional-guidelines/. Doses are for orientation; the current label governs.
- Medicare
- Part B (clinician-administered)
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.
- Commercial insurance
- covered on label
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.
- Notes
- Standard of care for differentiated thyroid cancer for 80 years; delivered through NHS nuclear medicine departments (BTA guideline). No TA.
- NHS England
- Routinely funded for the appraised indication (or via managed access)
Sources: NICE search: radioactive iodine (I-131). Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
Compare all products across the US, EU, UK, Japan, China and Australia →
- 1946ApprovalUS
First therapeutic use in thyroid cancer (Seidlin); formal approval followed
Approvals
| 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.
Trials
topTrials recruiting now
Country and place are remembered in this browser only. A postcode is sent to OpenStreetMap's Nominatim service to find coordinates when you press the button; nothing else leaves your device.
Landmark trials
Latest papers
topQuery 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 (radiopharmaceutical OR radioligand OR radionuclide OR theranostic OR "nuclear medicine" OR "molecular imaging" OR radiotracer OR scintigraphy OR 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.
Similar pages
not linked directly; found by shared links- AgentThyrotropin alfa
Shares NIS (sodium-iodide symporter), Graves' disease and hyperthyroidism, Radioiodine therapy (I-131), Radioiodine therapy and whole-body iodine scanning.
- AgentIobenguane I-131 (therapeutic)
Shares Radioiodine therapy (I-131), Iodine-123, Iodine-131, Radioligand therapy (beta emitters).
- TermPRRT (peptide receptor radionuclide therapy)
Shares Radioiodine therapy and whole-body iodine scanning, Theranostics, Somatostatin receptor 2, Radioligand therapy (beta emitters).
- InstitutionAll India Institute of Medical Sciences, New Delhi
Shares Board of Radiation and Isotope Technology, Radioligand therapy (beta emitters).
- TrialASTRA
Shares Radioiodine therapy and whole-body iodine scanning, Thyroid cancer.
- AgentIobenguane I-123 (cardiac use)
Shares PDRadiopharma, Iodine-123.
- Key paperRadiopharmaceutical therapy in cancer: clinical advances and challenges
Shares Theranostics, Iodine-131, Radioligand therapy (beta emitters).
- PersonDale L. Bailey
Shares Iodine-124, Iodine-131.