Ga-68 Dotatate Scan

What is a Ga-68 Dotatate scan?

A Ga-68 dotatate scan is a test used to check your body for a specific kind of cancer cell called neuroendocrine tumor (NET) cells. Neuroendocrine tumors come from neuroendocrine cells, which are found throughout the body. NETs can be found in many parts of the body, such as the brain, thyroid, lungs, and GI (gastrointestinal) tract.

About 70-90% of NETs have receptors on their surface for a hormone called somatostatin. Octreotide is a protein that attaches to the somatostatin receptor. Ga-68 is a type of radiotracer – a radioactive material that is attached to octreotide for the Ga-68 dotatate scan. With the octreotide attached to the radioactive Ga-68 dotatate, it enters the body and attaches to the somatostatin receptors on NET cells. A PET scan is then done to see the areas where the Ga-68 dotatate has been attached.

The Ga-68 dotatate scan has taken the place of octreotide scans in most cancer centers because it can find more areas of NET. This scan is highly specialized and not every center can do this type of scan.

What is this test used for?

This test is used to look for NET cells throughout the body.

This scan may be used during your initial (diagnostic) testing to find the main tumor or to look at where the NET has spread. It may also be done at other times to check how the treatment is working, or if tumor cells have spread (metastasized).

How is this test done?

You will have this test done in the Nuclear Medicine department. Nuclear medicine is a type of radiology that uses radioactive materials to diagnose or treat diseases. You will have an IV (intravenous, into a vein) placed. The Ga-68 dotatate “radioactive tracer” will be given through your IV. The amount of radiation used is very small.

Cells with somatostatin receptors on their surface will attract and attach to the Ga-68 dotatate. You will then have a PET scan, which can find the radiation that is put off by the Ga-68 dotatate. The test takes about 2 hours.

The computer makes a figure of your body on the screen. Any areas with a higher amount of Ga-68 will show up as a bright spot on the image. It is important to remember that the tracer goes through many areas of the body. This causes some areas to show up on the scan that are not always NET. It is important to review the report with your provider to understand it.

How do I get ready for a Ga-68 dotatate scan?

If you are taking octreotide or somatostatin, you may need to stop the medication prior to the scan. You should talk about this with your provider. You do not need to fast (avoid eating) before the test. Drink plenty of water before the test. You should drink 1 liter of fluid during the 2 hours before the test. Keep drinking plenty of water for a few hours following the test to help wash the radiotracer out of your body.

If you are pregnant or nursing a baby, you should tell your provider before the scan.

How do I read the results of the scan report?

Following the scan, the images are processed by a computer and read by a nuclear medicine physician. A report is made with the results.

Radiology reports follow a standard outline, no matter where they are done. Radiologists report both normal and abnormal findings. For this reason, it is very important to go over the results with your provider.

• The first paragraph often has the technical information about the scan (for example, how much radiolabeled octreotide was given, whether the whole body was scanned, etc.).
• The middle paragraphs describe the findings, both normal and abnormal. Because reports are written for other medical professionals, the words used can be hard to understand.
• Following the detailed results above, an “impression” often follows. The impression is an overview of the findings. You should talk about the results with your care provider.