What is a PET/CT Scan or a Fusion Scan? A PET/CT scan combines PET and CT into one image. PET (Positron Emission Tomography) utilizes a low-level radiopharmaceutical or a “glucose tracer” to visualize processes within the body. The glucose tracer emits positrons, or positive electrons. As the positrons encounter electrons within the body, a reaction occurs which produces gamma rays. These gamma rays are then detected by the PET scanner. Therefore, the image produced by PET contains information about metabolic activity taking place in the body. Malignant or cancerous tumors are metabolically active so with that being said, PET is very good at determining whether or not a tumor is malignant through its metabolic activity. CT stands for Computed Tomography. This technique uses x-rays to make cross-sectional images (called slices) of your body. The structure of body organs is more clearly visualized than with conventional x-rays. “Fusion” means that the anatomical information obtained from CT is combined with the biological PET information to form an image that records living tissues and life processes with great precision and detail.		What is the Benefit of having a PET/CT Scan Performed? The PET/CT scan is a powerful tool used by doctors when evaluating patients who may or may not have cancer. It allows them to effectively diagnose and evaluate the cancer and whether or not it has spread to other areas of the body. It is often used to measure the response of a tumor to therapy, which ultimately guides therapeutic decisions. PET/CT is also used to direct or guide biopsies and surgeries as well as focusing radiation treatments. This scan essentially can be thought of as a tool that helps doctors see the whole picture because it gives them a better, more complete picture of his or her patient.