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A computed tomography (CT) scan uses thin beams of X-rays to produce a series of images focused on a certain area of the body, such as the liver or chest. A CT scan can detect many conditions that may not show up on a standard X-ray, and the results can help the physician make an accurate diagnosis and determine the best course of treatment.
To prepare for the CT scan, the patient will be asked to lie on a table and the part of the body that is to be scanned is positioned in the middle of a large, doughnut-shaped CT scanner ring. Once the preparations are completed and the patient is in the appropriate position, the actual exam time (time the patient is on the table) can vary from 3 to 7 minutes, while the time that the X-rays are being used will typically be less than one minute, and often just a few seconds. During the exam time, the patient needs to lie very still. The patient may feel the table move and may hear clicking or buzzing sounds as the scanner moves around the body. Some patients may be given a contrast medium (commonly called "dye") by mouth or injection, and this can produce a feeling of warmth or flushing.
Because a CT scan uses X-ray beams, the patient will be exposed to radiation as the CT scan is performed. The exact amount of radiation depends on many factors. Patients should discuss this with the radiologist and their healthcare team for more details.
A female patient must notify her physician, the radiologist and the radiology technologist if she is pregnant or if there is a possibility she is pregnant or if she is breastfeeding before undergoing a CT scan. In addition, patients should let their healthcare team know if they are allergic to any foods or drugs before receiving contrast material.
For more details, visit Your CT Exam.