How is the PET scan helpful as a diagnostic? According to the Centers for Disease Control and Prevention, cancer is the second leading cause of death in the United States. Some types of cancers, such as breast cancer, have effective screening tests, which help with early detection. However, many types of cancer (and other diseases) do not have specific screening tests and can exist undetected, until they cause symptoms. Additionally, even after they’re removed, many cancers can linger in the body and spread to other organs – a process known as metastasis.
The PET scan, an electronic imaging process, can detect cancers that might otherwise be missed. They can also monitor the cancer, during and after treatment, to determine if the cancer is still present, or has spread.
What is a PET scan?
PET stands for Positron Emission Tomography. Essentially, the PET scan uses nuclear material to take pictures of the tissues in your body to detect diseases and disorders like cancers, endocrine disorders, and neurological disorders.
How the PET scan works
The PET scan uses a radioactive dye which is injected into the patient intravenously. As the dye travels throughout the body, the tissues metabolize the dye, which makes them visible to the PET scan camera. In the case of cancers, those cells have a higher metabolic rate than the surrounding tissue and will show up brighter than the healthy tissue.
The PET scan is a large machine with an opening in the center and a table that slides into the machine. It is similar to an MRI or CT scan machine.
To undergo a PET scan, you will be asked to lay down on a table while a technician sits in a separate room and remotely controls the rate at which the table slides into the scanning machine. If you are receiving a full-body scan, the technician could slide the table all the way into the machine, while other scans may require the table to only partially slide into the scanning machine.
Because the camera is very sensitive, you need to remain still to ensure they get the best image. In some cases, you might receive a mild sedative to help you stay still.
PET Scans and Cancer
Because cancerous tissue shows up brighter on the PET scan, the radiologist can determine the location of the cancer within your body, and whether or not it has spread. For example, if you have had surgery to remove a cancerous tumor, the PET scan can indicate whether or not all of the cancerous tissue has been removed. It can also determine if the cancer has spread into the neighboring tissues, or into the lymph system.
Your medical team can then use that information to formulate a treatment strategy. If it appears that the cancer is present in the surrounding tissues, they may recommend further surgery to remove the diseased tissue; and with the PET scan they can see how much tissue they need to remove.
If it appears that the cancer has spread into the lymph system, or into other organs, your medical team could recommend surgery, additional therapies like chemotherapy, or a combination of treatments.
If it appears that the cancer is gone, your medical team could recommend observation, including follow-up scans, to monitor your status post-treatment.
PET Scans and Other Conditions
PET scans can also detect the presence of other diseases and abnormalities, such as scar tissue, benign tumors, and other issues.
PET Scan Risks
Although the PET scan uses radioactive material, the risk of over-exposure or complications is fairly low. You might feel slight pain and irritation at the injection site where they placed the IV to administer the contrast dye. Women who are pregnant or breast feeding should consult their physicians before having a PET scan.