By Adam Brochert, MD
Many people have heard of PET scans to detect the presence and location of cancer. This test typically uses a type of radioactive sugar injected into a vein, which can then be detected by a machine that creates images of the person’s body while he or she lies still on a table. A new type of radioactive tracer has been developed for prostate cancer called Axumin (generic name: fluciclovine F-18).
Axumin is a radioactively tagged synthetic amino acid (amino acids are the building blocks for protein) that is injected into the body via a vein. Where the tracer goes in the body can be detected by a PET scan machine – usually at the same time a CT scan is obtained, known as a PET-CT scan. The radioactive physiology images are laid on top of or fused with the CT scan anatomy images to create a whole body exam that looks for prostate cancer.
The left picture is an Axumin metabolism PET image with an abnormal area of activity (highlighted by arrow). The right picture is the metabolism image fused with a CT scan image showing that prostate cancer has recurred in this patient within a pelvic bone (images courtesy of Blue Earth Diagnostics, Ltd.).
Axumin is officially approved by the U.S. FDA to look for prostate cancer relapse/recurrence after initial treatment. Typically, men with prostate cancer are followed with the prostate specific antigen (called PSA for short) blood test. After successful prostate cancer treatment, the PSA level usually goes to zero or close to it. If the PSA level later rises, this raises concern that the prostate cancer has come back. Where the cancer comes back is important to help determine what the next treatment step should be, such as watchful waiting, radiation or drug treatment.
Traditional tests like plain CT scans and PET scans using radioactive sugar are not very good at detecting early prostate cancer recurrence, but Axumin is turning out to be a powerful advanced imaging tool for patients where this is of concern. Because prostate cancer is the most commonly diagnosed type of cancer in men, this concern is unfortunately a common situation. The test is painless other than the initial needle injection to get the Axumin into the body via an arm vein (similar to the needle stick when getting blood drawn). After that, the person simply lies still on a table while the pictures are created by a large donut-shaped camera that surrounds the body. The test takes around 30-60 minutes to complete. There is a small amount of radiation exposure from the test, just like with X-rays and CT scans.
After the test, the tracer simply dissolves/decays and is excreted mostly through the urine. People who have this test can go back to their normal routine later the same day. The images are processed and usually available for physician review the day of the exam. If you or someone you know has concern regarding prostate cancer recurrence, an Axumin PET-CT scan just may be the test you need to achieve peace of mind or figure out what the next step is in your battle against the not-so-friendly “C” word.
Adam Brochert, MD, is board certified in radiology with specific expertise in oncology/cancer imaging. He can be reached at (760) 694.9559 or at www.desertmedicalimaging.com. He is also a member of Desert Doctors. For more information visit DesertDoctors.org or call (760) 232.4646.
