drugsAgentApproved

Indium-111 pentetreotide

aka 111In-pentetreotide, OctreoScan

The original nuclear medicine scan for finding neuroendocrine tumours, used before PET scans like Ga-68 DOTATATE became available. It is still FDA-approved but has largely been superseded because PET gives sharper pictures with less radiation.

OctreoScan (kit for the preparation of indium In-111 pentetreotide) was approved by FDA in 1994 (NDA 020314) and is still marketed, now by Curium, as a two-vial kit that the radiopharmacy combines before injection. It is indicated for scintigraphic localisation of primary and metastatic neuroendocrine tumours bearing somatostatin receptors, at a recommended dose of 111 MBq (3 mCi) for planar imaging or 222 MBq (6 mCi) for SPECT.

OctreoScan was the standard-of-care functional imaging test for neuroendocrine tumours for roughly two decades, but head-to-head studies have consistently shown that the newer PET tracers (68Ga-DOTATATE, 68Ga-DOTATOC, 64Cu-DOTATATE) detect more lesions with better spatial resolution and lower radiation dose, and most guideline bodies (SNMMI, ENETS) now favour SSTR-PET where it is available. OctreoScan remains relevant where PET access is limited, and it has a long track record: the label carries specific precautions for insulinoma patients, who can develop severe hypoglycaemia with unlabelled octreotide co-administration, and the finished radiopharmaceutical must be used within six hours of preparation.

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Ball-and-stick model from PubChem 2D record (no 3D conformer available). PubChem record

Pentetreotide (DTPA-octreotide)

PubChem holds the unlabelled ligand, so the radionuclide itself is not in this drawing.

See it in action

Pentetreotide is an octreotide derivative conjugated to the chelator DTPA; once labelled with indium-111 it binds somatostatin receptor subtype 2 on neuroendocrine tumour cells. Because indium-111 is a gamma emitter rather than a positron emitter, imaging is by SPECT (or SPECT/CT) rather than PET. Connects to Somatostatin receptor 2.

Left: the molecule; no solved complex yet.

1. Where it connects: Somatostatin receptor 2

No solved complex yet: the molecule alone, which binds Somatostatin receptor 2.

2. Step by step

auto-advancing · hover to pause

1.Indium-111 pentetreotide slips into a pocket on Somatostatin receptor 2.

Modality

SPECT tracer

Mechanism

Brand / code

OctreoScan

Dosing & schedule

Route: Intravenous injection, after radiolabelling the kit
Schedule: 111 MBq (3 mCi) for planar imaging; 222 MBq (6 mCi) for SPECT imaging; use within 6 hours of preparation

Source: www.accessdata.fda.gov/drugsatfda_docs/label/2022/020314Orig1s000Lbl.pdf. Doses are for orientation; the current label governs.

Regulatory

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Approvals

Region	Year	Indication
US	1994	Scintigraphic localisation of primary and metastatic neuroendocrine tumours bearing somatostatin receptors

Trials

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ClinicalTrials.gov · phase 2/3

refreshed 2026-10-19

4 studies0 recruiting3 Phase 22 Phase 3

Search “Indium-111 pentetreotide” on ClinicalTrials.gov →

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Indium-111 pentetreotide

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