A computerized tomography (CT) scan combines a series of X-ray images taken from different angles and uses computer processing to create cross-sectional images, or slices, of the bones, blood vessels and soft tissues inside your body. CT scan images provide more detailed information than plain X-rays do

Contrast media (sometimes called contrast agents or dye) are chemical substances used in medical X-ray, magnetic resonance imaging (MRI), computed tomography (CT), angiography, and occasionally ultrasound imaging.
Contrast media enhance and improve the quality of images (or pictures), so that the radiologist (a specialist doctor trained to examine the images and provide a written report to the patient’s own doctor or specialist) can more accurately report on how your body is working and whether there is any disease or abnormality present.

A single PET or PET/CT exam can provide information that once would have required several medical studies and possibly surgery. PET scans are most often used to help the physician detect cancer and monitor response to treatment. PET scans are also used to evaluate heart disease and neurological conditions.