Computed tomography/positron emission tomography (CT/PET) scans are often used for diagnosing and evaluating treatments for cancer and other conditions.
Why Do I Need a CT/PET Scan?
A PET scan helps doctors distinguish between living and dead tissue or between benign (noncancerous) and malignant (cancerous) disorders. PET imaging provides additional information about cellular activity such as determining a questionable abnormality as malignant or benign.
Combined, a CT/PET scan can show the extent of disease. If you’ve been newly diagnosed with cancer, it’s important to determine if the cancer has spread to other parts of the body. A PET scan images the entire body in a single examination and aids the doctor in detecting the primary site(s), as well as any metastases (the spread of cancer from one part of the body to another).
How Do CT/PET Scans Help with Treatment?
A CT/PET scan can help doctors monitor the treatment of disease. For example, chemotherapy leads to changes in cellular activity that are observable by CT/PET long before structural changes can be measured. This gives doctors an alternative technique to evaluate treatments earlier. Plus, it can lead to modifications in treatment, before an evaluation would normally be made using other imaging technologies.
After treatment is complete, we perform a CT/PET scan to investigate suspected recurrence of cancer. This reveals tumors that might otherwise be obscured by scar tissue resulting from surgery and radiation therapy.
With a PET/CT scan, time is on your side. The earlier the diagnosis and the more accurate the assessment of the extent of disease, the better the chance for successful treatment.
How Does CT Work?
CT is an imaging test in which a part of the body is X-rayed from different angles. These images are combined by a computer to produce complete pictures of internal organs. This procedure is often done on an outpatient basis.
How Does PET Work?
The body relies on glucose for energy. Before a PET scan, a patient is injected with a harmless radioactive glucose/water solution called a “tracer.” Once the tracer is inside the body, the patient is positioned into the PET scanner.
As the body processes the tracer, positrons begin to collide with electrons, causing gamma rays to be emitted. A PET scanner detects and measures these gamma rays. A computer uses the measurements to create pictures of the various organs at work within the body. The images give physicians the ability to tell healthy tissue from unhealthy tissue.
The PET scanner itself does not produce any radiation. It merely picks up signals from the tracers already in your body.