Octreotide Scan

Authors: Ms Maria Triantafillou*
                            Dr Dee Nandurkar *

What is an octreotide scan?

An octreotide scan is used to detect and monitor treatment of neuroendocrine tumours, which arise from cells that produce hormones that are carried in the bloodstream. Many of these tumours are benign (non-cancerous), but some are malignant and can spread around the body. Sometimes the abnormal hormones produced by these tumours can produce a variety of unusual symptoms depending on where the tumours are located.

To detect these tumours, a small amount of harmless medication, a radiopharmaceutical (see InsideRadiology: Nuclear Medicine), is injected into a vein in the arm, followed by a whole-body scan to take pictures or images. The same images are also taken the next day, but no further injection is given on the second visit.

Why would my doctor refer me to have this scan?

If your doctor is concerned that you may have a neuroendocrine tumour, they may refer you for an octreotide scan to help detect whether a tumour is present.

If you are known to have a neuroendocrine tumour, an octreotide scan can help determine whether your treatment is working.

How do I prepare for an octreotide scan?

It is important that you let staff at the hospital or radiology facility where you are having the scan done know if you are (or think you could be) pregnant or are breast-feeding.

This scan may not be suitable for pregnant women because of the radiation dose to the growing foetus. Please discuss this with your doctor.

If you are currently on octreotide therapy or certain other medications (e.g. somatostatin), you may be required to stop treatment temporarily for the scan. The safety and duration of stopping treatment will be discussed with your doctor and the nuclear medicine physician in consultation with you.

Women who are breast-feeding and people who are the primary or sole carer of small children may need to make special preparations for after the scan, to stop breast-feeding and to avoid close contact with young children for a short time. This is due to the small amount of radioactivity your body may release for a while after the scan. Talk to your referring doctor or the nuclear medicine facility where you will have the scan for details. The Australian Radiation Protection and Nuclear Safety Agency has recommendations about breast-feeding and close contact with children after nuclear medicine tests.

Drink plenty of fluids before and throughout this scan, and up to 1 day after having the scan. This encourages the elimination of the radioactive material that is not absorbed by the body and is also useful for taking clearer images. If your doctor is concerned that the tumour is in your abdomen, you may be given a mild laxative the evening before the scan and the evening after the first scan to improve the quality of the images. If you have symptoms of diarrhoea or loose motions, then the laxative may not be necessary.

What happens during an octreotide scan?

The scan begins with an injection of a small amount of harmless radioactive material (radiopharmaceutical) into a vein in your arm. You will be asked to return in 4 hours for a scan of your whole body.

You will be asked to remove any metal belongings before the scan, such as keys and jewellery. The scan involves lying on a special bed with cameras (called detectors) moving close to you, but they will not touch you. This takes approximately 20–30 minutes. It is very important that you remain still during the scan. If you know you will have difficulty in remaining still, discuss this with the medical radiation technologist before the start of the scan.

This preliminary set of images will be shown to the nuclear medicine physician (specialist doctor), and if required, another set of three-dimensional pictures called a SPECT-CT will be taken. This will take an additional 20–30 minutes. You will be asked to return the next day when the same set of images will be taken. You will not receive another injection for these images.

Are there any after effects of an octreotide scan?

The amount of radiopharmaceutical you receive is very small. There are no after effects from having an octreotide scan.

You will need to drink plenty of fluids before and throughout this scan, and up to 1 day after having the scan to encourage the elimination of any radioactive material that has not been absorbed by the body.

If you are breast-feeding or caring for young children, see the “How do I prepare” section for more information about special precautions you may need to take.

How long does an octreotide scan take?

An octreotide scan consists of three sessions:

• The first session on the first morning can take up to 1 hour. The nuclear medicine technologist will discuss the scan with you and a small plastic tube will be inserted into your arm (called an intravenous cannula). The radiopharmaceutical will then be injected through the cannula into your bloodstream.
• A wait of approximately 4 hours is required after the injection to allow the radiopharmaceutical to circulate in your blood. You will be asked to return to the radiology facility after 4 hours for your scan. The scan can take up to 1 hour, and then you will be able to leave the facility.
• You will be asked to return the next day (day 2) for another scan similar to the day before, also taking up to 1 hour. You will not need another injection. A small number of people may be asked to return again for a third consecutive day, but this is rare.

What are the risks of an octreotide scan?

The amount of radiopharmaceutical used is quite small. It has no effect on how you feel, and the radiation exposure is safe and should not result in any short- or long-term hazardous effects (see InsideRadiology: Radiation Risk of Medical Imaging for Adults and Children).

What are the benefits of an octreotide scan?

Neuroendocrine tumours can be difficult to identify. The octreotide scan can detect the presence of these tumours in the body and their location. Any differences in scan results between two or more octreotide scans can help determine whether treatment is having an effect on the tumour.

Who does the octreotide scan?

The nuclear medicine technologist will prepare the radiopharmaceutical, give the injection and carry out your scan.

The nuclear medicine physician (specialist doctor) will interpret your scan images and issue a report to your referring doctor. The physician may speak to you during your scan if additional information about your condition is required.

Where is an octreotide scan done?

In a hospital or private radiology clinic nuclear medicine department.

When can I expect the results of my octreotide scan?

After completing your scan, your referring doctor generally will receive the written report within 24 hours.

It is important that you discuss the results with the doctor who referred you, either in person or on the telephone, so that they can explain what the results mean for you.

Further information about octreotide scan:

It is important if you have had any previous X-rays or scans to bring them along, as this may help with the interpretation of your octreotide scan.

*The author has no conflict of interest with this topic.

Page last modified on 31/8/2018.