A computerized tomography (CT) scan combines a series of X-ray images taken from different angles around your body and uses computer processing to create cross-sectional images (slices) of the bones, blood vessels, and soft tissues inside your body. CT scan images provide more detailed information than plain X-rays do. A CT scan has many uses, but it's particularly well-suited to quickly examine people who may have internal injuries from car accidents or other types of trauma. A CT scan can be used to visualize nearly all parts of the body and is used to diagnose disease or injury as well as to plan medical, surgical, or radiation treatment. Radiation exposure
During a CT scan, you're briefly exposed to ionizing radiation. The amount of radiation is greater than you would get during a plain X-ray because the CT scan gathers more detailed information. The low doses of radiation used in CT scans have not been shown to cause long-term harm, although, at much higher doses, there may be a small increase in your potential risk of cancer. CT scans have many benefits that outweigh any small potential risk. Doctors use the lowest dose of radiation possible to obtain the needed medical information. Also, newer, faster machines and techniques require less radiation than was previously used. Talk with your doctor about the benefits and risks of your CT scan. Tell your doctor if you're pregnant. Although the radiation from a CT scan is unlikely to injure your baby, your doctor may recommend another type of exam, such as ultrasound or MRI, to avoid exposing your baby to radiation. At the low doses of radiation used in CT imaging, no negative effects have been observed in humans. In certain cases, your doctor may recommend that you receive a special dye called contrast material. This can be something that you are asked to drink before your CT scan or something that is given through a vein in your arm or inserted into your rectum. Although rare, the contrast material can cause medical problems or allergic reactions. Most reactions are mild and result in a rash or itchiness. In rare instances, an allergic reaction can be serious, even life-threatening. Tell your doctor if you've ever reacted to contrast material. They use a narrow X-ray beam that circles one part of your body. This provides a series of images from many different angles. A computer uses this information to create a cross-sectional picture. Like one piece in a loaf of bread, this two-dimensional (2D) scan shows a “slice” of the inside of your body.
This process is repeated to produce several slices. The computer stacks these scans one on top of the other to create a detailed image of your organs, bones, or blood vessels. For example, a surgeon may use this type of scan to look at all sides of a tumor to prepare for an operation. In a CT scan, dense substances like bones are easy to see. But soft tissues don’t show up as well. They may look faint in the image. To help them appear clearly, you may need a special dye called a contrast material. They block the X-rays and appear white on the scan, highlighting blood vessels, organs, or other structures. Contrast materials are usually made of iodine or barium sulfate. You might receive these drugs in one or more of three ways:
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Injection: The drugs are injected directly into a vein. This is done to help your blood vessels, urinary tract, liver, or gallbladder stand out in the image.
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Orally: Drinking a liquid with the contrast material can enhance scans of your digestive tract, the pathway of food through your body.
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Enema: If your intestines are being scanned, the contrast material can be inserted in your rectum.
After the CT scan, you’ll need to drink plenty of fluids to help your kidneys remove the contrast material from your body.
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