Computed tomography, also called CT or CT scan, is a process that uses X-
rays and computer technology to make cross-sectional images of the body. A
series of X-ray pictures, each a thin slice, are put together in a computer to
form a three-dimensional view of the inside of your body. If an X-ray is like looking at a photo of a heart,
a CT scan is like looking at a model that you can pick up and examine from any angle.
In a CT scan, X-rays pass through the body and are analyzed by a computer.
The computer builds an image based on the amount of X-rays passing
through tissues of different thickness. For example, bone appears white on a
CT scan, and gas bubbles in the stomach and intestines appear black.
You can have a CT scan in an outpatient facility or in a hospital. The
procedure is painless, and takes about 20 minutes, but can be longer or
shorter depending on the area of the body being scanned.
What It's Used For CT can reveal abnormal masses that may be cancerous
tumors. CT scans show the size and shape of the tumor, its precise location
in the body, and whether the tumor is solid or hollow. Sometimes, a CT scan
can tell the difference between a noncancerous and cancerous tumor,
although a biopsy or other test is needed to make the final diagnosis. In a
biopsy, a small piece of tissue is removed to be examined in a laboratory.
During a CT-guided biopsy, the physician will use the CT scan as a guide as
he or she inserts the needle into the right location to remove a sample of the
tumor.
In addition to detecting cancer, CT scans have many other uses. They can
show abscesses and other infections, strokes, head injuries and bleeding
inside the skull, as well as a variety of other medical conditions.
For obese patients, CT scanning may be a more useful diagnostic tool than
ultrasound, because large amounts of body fat can interfere with ultrasound
waves, producing poor images.
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