Computed Tomography, CT, is an x-ray examination using a scanner to produce a series of cross-sectional images of a selected part of the body. The CT examination involves the use of very small amounts of radiation. The images are made using a computer as well as x-rays. The examination is painless and is very helpful in evaluation of diseases of the bone, abdomen, and brain.
The CT scanner opening encircles the body during the examination. This opening contains an x-ray tube and receptors which are mounted opposite each other. These rotate around the body. With each rotation, or scan, a portion of the total image is accumulated by the receptor.
The receptor then feeds the information into a computer. The computer calculates the density of each area within the body, based on the energy absorbed as the scanner rotates, and converts it into a picture of a section of your body. The calculations that are required by each scan take the computer only a few seconds to make, but would take a mathematician years of effort.
The Procedure
For the examination, the patient may be asked to remove part or all of your clothing, and to wear a gown. After entering the examination room, the technologist will position the patient on a special table. Blankets will be provided to keep them warm.
Once you are securely in place, the patient will be moved into the scanner opening. The technologist will control the scanner and monitor the progress of the examination from an adjacent room. Patients are shown how to communicate with the technologist, if necessary.
While moved through the scanner opening, patients are asked to remain relaxed and still. The patient may be asked to hold their breath for a few seconds as each scan is made. A brief whirring sound can be heard as the x-ray equipment scans the body. After each image, or scan, is made, the table will move into position for the next scan. Once the scan sequence has begun, it is important that the patient remains still until the technologist has completed the scan.
After The Exam
The intravenous contrast medium, if used, will be eliminated through the urine and should cause no discoloration. Fluid intake should be increased after the scan to help the body eliminate the contrast. Regular food intake can resume immediately after the examination, unless otherwise determined by a doctor.
