What is an Octreotide scan?
An octreotide scan, also known as somatostatin receptor scintigraphy, is a test used to check the body for the presence of neuroendocrine tumor cells. This test is done in a Nuclear Medicine department, which is a type of radiology that uses radioactive materials to diagnose or treat diseases.
Neuroendocrine tumors originate from neuroendocrine cells, which are found throughout the body. As a result, neuroendocrine tumors can be found in many areas of the body, including the brain, thyroid, lungs and GI tract. Many neuroendocrine tumors have receptors on their surface for a hormone called somatostatin. When an octreotide scan is done, these receptors are targeted so that neuroendocrine tumor cells can be seen on the scan.
Octreotide scans are highly specialized and need radioactive material to be done. Not every center has the ability to do these scans.
What is this test used for?
This test is used to look for the presence of neuroendocrine cells throughout the body.
This scan may be used to visualize the primary neuroendocrine tumor during initial (diagnostic) testing. It may also be done at other times to check for tumor cells that have spread, or metastasized.
How is this test performed?
An IV is placed and an injection of octreotide with radioactive material attached to it (called "radiolabeled"), is given. The amount of radiation used is very small.
Octreotide is a drug very similar to somatostatin. Cells with somatostatin receptors on their surface will attract and attach to the radiolabeled octreotide. The radioactive material puts out a low dose of radiation that can be seen with a special scanner (similar to a CT scan).
About 4 hours after the injection, the patient will undergo a scan to look for cells that have taken up the octreotide.
The patient will lie flat, with a camera taking pictures above and below them. The scan evaluates the entire body. The scan will take an hour or longer.
The test requires multiple scans. The first set of scans are done on the day of the injection. A CT Scan done to create a 3D image of the body. The patient will return for additional scans per their provider’s directions.
The scanner's computer creates a figure of the patient on the screen. Any areas with increased octreotide uptake show up as a bright spot on the image.
How do I prepare for an octreotide scan?
If you are taking octreotide or somatostatin, you may need to stop the medication prior to the scan. You should discuss this with your provider.
If you are pregnant or nursing a baby, you should notify your doctor prior to the scan.
How do I interpret the results of an octreotide scan report?
Following the scan, the images are processed by a computer and read by a nuclear medicine physician. A report is created.
The report states the patient's name, date of birth, and indication (reason for the octreotide scan) at the top of the report. Radiology reports follow a standard outline, regardless of where they are obtained. Radiologists report both normal and abnormal findings in a very systematic approach. For this reason, it is very important to discuss the results with your doctor.
- The first paragraph often includes 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 generated for other medical professionals, the words used can be difficult to understand.
- Following the detailed results above, an “impression” generally follows. The impression is a summary of the findings, often given to answer the question asked by the ordering provider (the reason the scan was ordered in the first place). You should discuss the results with your care provider.