First Time User? Enroll now.
As the COVID-19 situation has evolved, our visitor policy is evolving as well. Get full details.
For the most current information, please visit our Coronavirus resource pages.
Home > Health Library > Computed Tomography (CT) scan
A computed tomography (CT) scan uses X-rays to make detailed pictures of structures inside of the body.
During the test, you lie on a table that is attached to the CT scanner, which is a large doughnut-shaped machine. The CT scanner sends X-ray pulses through the body. Each pulse lasts less than a second and takes a picture of a thin slice of the organ or area being studied. One part of the scanning machine can tilt to take pictures from different positions. The pictures are saved on a computer.
A CT scan can be used to study any body organ, such as the liver, pancreas, intestines, kidneys, adrenal glands, lungs, and heart. It also can study blood vessels, bones, and the spinal cord.
An iodine dye (contrast material) is often used to make structures and organs easier to see on the CT pictures. The dye may be used to check blood flow, find tumors, and look for other problems. Dye can be put in a vein (IV) in your arm. Or, for some tests, you may drink the dye. CT pictures may be taken before and after the dye is used.
A special CT scanner called a spiral (helical) CT can provide a scan of the lungs in half the time of a standard CT scan. Spiral CT gets its name from the circular movement of the scanner around your body.
Current as of: June 17, 2021
Author: Healthwise Staff
Medical Review:Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Howard Schaff MD - Diagnostic Radiology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2021 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.
Get started learning more about your health!
Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups, and pregnancy.