A CT scan is performed by placing the patient on a flat table that moves through a circular opening in the scanner's gantry. Inside the gantry, an X-ray tube rotates around the patient, emitting a narrow beam of X-rays through the body from multiple angles. On the opposite side of the body, special detectors measure the amount of X-rays absorbed by different tissues. This data is sent to a computer that creates cross-sectional images (slices) showing the details of internal structures with varying densities (bones appear white, air black, and tissues with different shades of gray). To obtain clearer images of specific structures such as blood vessels or the digestive system, a contrast agent (dye) may be injected intravenously, swallowed, or given rectally before the scan. The scan itself usually takes only a few minutes. The patient is asked to remain perfectly still and may need to hold their breath for short periods during the scan to ensure image quality.