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Computed tomography scan (CT or CAT scan) is a non-invasive diagnostic imaging procedure that uses a combination of special X-ray equipment and sophisticated computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. These cross-sectional images of the area being studied can then be examined on a computer monitor or printed.
A bone scan is a specialized radiology procedure used to examine the various bones of the skeleton to identify areas of physical and chemical changes in bone. Bone scans are used primarily to detect the spread of metastatic cancer.
A magnetic resonance (REZ-oh-nans) imaging scan is usually called an MRI. An MRI does not use radiation (X-rays) and is a noninvasive medical test or examination. The MRI machine uses a large magnet and a computer to take pictures of the inside of your body. Each picture or "slice" shows only a few layers of body tissue at a time. The pictures can then be examined on a computer monitor.