You may have these tests to find where the cancer started (the primary tumour). Or they may check for any spread of the disease (secondaries or metastases).

What are nuclear medicine scans?

You may have these tests to find where the cancer started (the primary tumour). Or they may check for any spread of the disease (secondaries or metastases). The tests use a small amount of a radioactive substance called a tracer. The tracer shows up on scan pictures.

The dose of radioactivity from these scans is low. It is about the same amount you get from an x-ray. Almost all of it leaves your body within a week. The staff in the scanning department will tell you about any precautions you need to take after the scan.

If you plan on travelling abroad within three months of the scan, tell the doctor in the scanning department. They can give you a letter to show that you had a radioactive scan. This is because ports and airports have sensitive machines that pick up tiny amounts of radioactivity.

Octreotide scan

Neuroendocrine tumours often absorb a substance called octreotide. Doctors can attach a radioactive tracer to octreotide. This is so it can show up on scan pictures. They then inject the octreotide into the bloodstream. The scan pictures show areas of the body where radioactivity collects.

You will have three scans. You will have one on the day of the injection. You will then have two more over the next two days. You will have to keep still while the scanner takes pictures. Each scan takes about 30 minutes. You can go home between the scans.

An octreotide scan is sometimes called an Octreoscan or somatostatin receptor scintigraphy.

MIBG scan

NETs can also absorb a substance called MIBG. A radioactive tracer can be attached to MIBG, just like octreotide. This means you can have a scan that uses MIBG in a similar way to octreotide.

Ga68 PET-CT scan

This is similar to an octreotide scan, but more sensitive. You will have an injection containing the radioactive tracer gallium 68 DOTANOC. An hour later, you will have a PET/CT scan (see below). The scan takes about 30 to 45 minutes.

PET-CT scan

PET-CT scan is a combination of a CT scan, which takes a series of x-rays to build up a three-dimensional picture, and a positron emission tomography (PET) scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body.

About our information


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

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