What is the difference between a CT scan and a PET scan?
A. A CT scan uses x-rays to define the anatomic structures of the body. The PET scan uses radiolabeled glucose (sugar) that is metabolized by cells of the body and thus displays physiology rather than anatomic structures. For example, a CT scan may detect a small nodule in your lung but often offers no insight into whether the nodule is benign or malignant. The PET scan shows the metabolic activity of the nodule which is typically increased in cases of cancer and decreased or normal in benign etiologies.
