How Does a Computed Tomography Scan Work?
A computed tomography (CT) scan 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. CT scans also show great bone detail, making them good for identifying fractures. When contrast dye is given, it enhances the detection of many lesions. Although there is a small amount of radiation with the scan, CT is considered a very safe exam when performed correctly and used appropriately. This procedure is often done on an outpatient basis.
How Does a Positron Emission Tomography Scan Work?
A positron emission tomography (PET) scan helps doctors distinguish between living and dead tissue or between benign (noncancerous) and malignant (cancerous) disorders. A PET scan images the entire body in a single examination and aids the doctor in detecting the primary site(s) of cancer as well as if the cancer has spread from one part of the body to another, called metastasis.
The body relies on glucose for energy. Before a positron emission tomography (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.
What is a CT/PET Scan?
CT/PET scans are often used for diagnosing and evaluating treatments for cancer and other conditions.
Why Do I Need a CT/PET Scan?
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.
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.