Indium In 111 pentetreotide
The original somatostatin receptor scan
Indium In 111 pentetreotide is octreotide joined to a DTPA chelator and labelled with indium-111. Approved as OctreoScan in 1994, it was the first widely used peptide-receptor imaging agent, showing neuroendocrine tumours on a gamma camera. Gallium-68 and copper-64 PET tracers have since proved more sensitive.
What is it?
Somatostatin receptor scintigraphy began with radiolabelled octreotide. The Rotterdam group's experience with more than 1,000 patients showed that many tumours, classically neuroendocrine ones, could be located this way, that granulomas and autoimmune processes also lit up, and that a positive scan often predicted response to octreotide treatment. They speculated that radiolabelled peptides could one day treat cancer, which is what lutetium-177 dotatate now does.
OctreoScan, approved in 1994, made the technique routine. In pulmonary carcinoid, SPECT/CT with it was more sensitive than contrast CT (96% against 87.5%); in bronchial carcinoids, 71% of patients had positive scans. Newer PET tracers outperform it: a systematic review found gallium-68 DOTATATE more sensitive in same-patient comparisons, and copper-64 DOTATATE found twice as many lesions in a 112-patient comparison (sensitivity 97% against 87%).
The label advises hydration and a mild laxative to reduce radiation dose, and because octreotide can cause severe hypoglycaemia in people with insulinoma, an intravenous glucose line is recommended when insulinoma is suspected. Hypersensitivity reactions, rarely including angioedema or anaphylaxis, have been reported. Its biological half-life is about six hours.
At a Glance
Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.
Half-Life: How Much Remains
The dataset records a half-life of biological half-life about 6 hours for Indium In 111 pentetreotide. After each half-life, half of what was in the circulation is gone, so about 3% remains after five. Real clearance varies with the person, the dose, the route and kidney or liver function; this is arithmetic on a published figure, not a dosing tool.
Published Research
Studies of indium-111 pentetreotide, from their PubMed abstracts.
The Rotterdam experience in over 1,000 patients
Scintigraphy with indium-111 DTPA-octreotide located tumours rich in somatostatin receptors and also granulomas and autoimmune processes; a positive scan often predicted a favourable response to octreotide, and the authors proposed radiolabelled peptides for therapy.
Pulmonary carcinoid
In 81 patients, SPECT/CT with indium-111 pentetreotide was positive in 50 of 55 with disease, with sensitivity of 96% against 87.5% for contrast CT and specificity of 92% against 97%.
Bronchial carcinoids
In 28 patients, 71% had OctreoScan-positive tumours, including 8 of 9 with carcinoid syndrome; the primary was positive in 13 of 16, and the scan found one primary that CT missed.
Against gallium-68 DOTATATE
A systematic review of 42 studies found gallium-68 DOTATATE more sensitive than indium-111 DTPA-octreotide in all three same-patient comparisons.
Against copper-64 DOTATATE
In 112 patients, sensitivity and accuracy were 87% and 88% for indium-111 DTPA-octreotide SPECT against 97% for copper-64 DOTATATE PET, which found twice as many lesions.
Side Effects & Contraindications
Reported Side Effects
From the label and studies above.
Contraindications & Cautions
Precautions from the OctreoScan label (DailyMed, effective February 21, 2022).
Legal Status
Indium In 111 pentetreotide is an approved prescription diagnostic in the US.
Frequently Asked Questions
?What is an OctreoScan?
A gamma-camera scan after an injection of indium-111-labelled octreotide, which binds somatostatin receptors on neuroendocrine tumours.
?Is OctreoScan still used?
It is still approved, but gallium-68 and copper-64 DOTATATE PET scans are more sensitive in head-to-head comparisons and have largely replaced it where available.
?Why is a glucose drip sometimes needed?
Octreotide can cause severe low blood sugar in people with insulinomas, so the label recommends an intravenous glucose line when insulinoma is suspected.
References
- [fda] US FDA, Drugs@FDA (openFDA): OCTREOSCAN, NDA 020314 (June 2, 1994). Read October 3, 2026.
- [fda-pi] FDA. OctreoScan (kit for indium In 111 pentetreotide) US prescribing information (DailyMed set 93d8f3b2-1216-41dc-a63d-0e812b33891d, effective February 21, 2022). Read October 3, 2026.
- [pubmed] Krenning EP, et al. "Somatostatin receptor scintigraphy with [111In-DTPA-D-Phe1]- and [123I-Tyr3]-octreotide: the Rotterdam experience with more than 1000 patients." Eur J Nucl Med, 1993;20(8):716-31. PMID: 8404961.
- [pubmed] Chiaravalloti A, et al. "111In-Pentetreotide SPECT/CT in Pulmonary Carcinoid." Anticancer Res, 2015;35(7):4265-70. PMID: 26124388.
- [pubmed] Granberg D, et al. "Octreoscan in patients with bronchial carcinoid tumours." Clin Endocrinol (Oxf), 2003;59(6):793-9. PMID: 14974924.
- [pubmed] Deppen SA, et al. "68Ga-DOTATATE Compared with 111In-DTPA-Octreotide and Conventional Imaging for Pulmonary and Gastroenteropancreatic Neuroendocrine Tumors: A Systematic Review and Meta-Analysis." J Nucl Med, 2016;57(6):872-8. PMID: 26769864.
- [pubmed] Pfeifer A, et al. "64Cu-DOTATATE PET for Neuroendocrine Tumors: A Prospective Head-to-Head Comparison with 111In-DTPA-Octreotide in 112 Patients." J Nucl Med, 2015;56(6):847-54. PMID: 25952736.
Sources & Citations
Studies were read from their PubMed records; regulatory sources are listed below, read October 3, 2026.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.