Octreotide scan

An octreotide scan is a type of nuclear medicine test that helps detect neuroendocrine tumors (NETs). Also called a somatostatin receptor scintigraphy or SRS, this procedure is especially useful in identifying NETs that have spread to the liver.

Octreotide is a hormone used to treat some types of cancer, particularly those stemming from carcinoid tumors.

During this procedure, a small amount of octreotide combined with a radioactive material called indium-111 is injected into a vein. Using a special camera, your team is able to see how octreotide attaches to a tumor and pinpoint its location.

A NET is caused by abnormal neuroendocrine cells. Your body’s neuroendocrine system has cells throughout various parts of the body, such as in the intestines, lungs and stomach. They work like nerve cells, but also as cells that make hormones, and they help control the speed in which food moves through your gut.

In addition to the octreotide scan, other tests used to help diagnose NETs include:

• Barium X-ray
• Biopsy
• Blood and urine tests
• Computed tomography (CT) scan
• Positron emission tomography (PET) scan
• Magnetic resonance imaging (MRI)

How to prepare for an octreotide scan

If your care team recommends an octreotide scan, there are a few steps you may take to prepare. These tips also apply to a variety of nuclear medicine tests.

• Inform your care team about any medications you take, including over-the-counter drugs, vitamins and herbal supplements. For some nuclear medicine tests, you must avoid certain drugs beforehand.
• Ask your care team if you’re able to eat or drink before the test. You may have to drink more water in advance of an octreotide scan.
• Let your care team know if you’ve had any problems during a previous nuclear medicine scan.
• Tell your care team if you’re pregnant. An octreotide scan isn’t meant for pregnant women because of the dose of radiation given. If you’re breastfeeding, you may have an octreotide scan if you stop breastfeeding and avoid contact with young children and infants for the time period that your doctor tells you.
• If you’re using octreotide as a cancer treatment, your doctor may ask you to stop this medication in advance, as it could interfere with the results.

What to expect from an octreotide scan

You may need to make up to three visits to a nuclear medicine department to complete the octreotide scan.

• Initially, a small dose of octreotide along with the radioactive material (called a tracer) is injected into a vein.
• The technologist may then ask you to return within about four hours. When you return, expect to have several images done with a special type of camera. There’s no pain associated with the imaging.
• The technologist may ask you to return in 24 to 48 hours to complete additional imaging.

Benefits and risks of an octreotide scan

An octreotide scan is used to help detect the size, location and possible spread of NETs.

Nuclear medicine scans use only a very small dose of radioactive material, so the risk of toxicity or an allergic reaction is also low. However, it’s possible to feel pain or swelling where the radioactive material was injected.

The radioactive material used with an octreotide scan loses its radioactivity and leaves your body via your urine or stool over the following few days. Ask your care team about any precautions to take during this time period, such as having to avoid being close to children or pregnant women. You’ll likely be asked to drink a lot of water to help flush the material out of your body.

Reviewing the results of an octreotide scan

Talk to your doctor about the results from your octreotide scan as well as any other diagnostic tests. These tests may help your doctor describe the tumor to help determine evidence-informed treatment moving forward. Make sure to have any questions ready to ask your care team about the results, including:

• Do you know the stage of cancer?
• Can you explain what that stage means for me?
• Can the cancer be removed with surgery?
• What happens next?