Health Topic

CT Scans

Doctors use CT scans (or CAT scans) to look for broken bones, cancers, blood clots, and more. Learn about the CT scan and what to expect during one.

Reviewed Reviewed by a registered pharmacistGeneral information

Also called: CAT scan

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About CT Scans

Computed tomography (CT) is a type of medical imaging test that uses special x-ray equipment to make detailed pictures of the inside of your body.

A CT scan produces cross-sectional pictures, which are like slices of the body. These images show the size and structure of organs, bones, and other tissues. CT images can also be combined to create 3-dimensional (3D) views.

Health care providers use CT scans to diagnose, treat, and monitor many health conditions.

Your provider may suggest a CT scan for many reasons, including:

  • Fractures (broken bones)
  • Cancer
  • Tumors or masses
  • Blood clots
  • Signs of heart disease
  • Spinal conditions
  • Lung disease

CT scans may also be used to find the best place to perform a biopsy or help guide certain treatments. They may also be used to check for internal bleeding or injury after trauma or to evaluate the brain for certain conditions.

You may be asked not to eat or drink for a few hours before the scan. Ask your provider if there are any special instructions to follow.

For some CT scans, you may receive a contrast material. Contrast helps certain parts of the body show up more clearly on the images. Depending on what area is being examined, contrast material might be given as:

  • A liquid to swallow
  • A shot (injection)
  • An enema (placed into the rectum)

CT scans use ionizing radiation at levels higher than a standard x-ray, but the amount is kept as low as possible. Always tell your provider if you are pregnant or think you may be pregnant.

You may be asked to change clothes and remove jewelry or other items that could interfere with the scan.

During the scan, you lie still on a table. The table slowly passes through the center of a large donut-shaped machine. The x-ray tube rotates around your body to create images.

You may hear whirring sounds during the scan. You may be asked to hold your breath for short periods. The test is painless.

The scan usually takes a few minutes, but some may last up to 30 minutes, depending on the area being scanned.

Most people can return to normal activities right away. If you were given a contrast material, drinking fluids can help your body clear it.

A specialist called a radiologist reviews the images and shares the results with your provider.

It sits within Diagnostic Tests.

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Research on CT Scans

2,374 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

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Prevention and Risk Factors

Related Issues

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Tomography, X-Ray Computed. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for CT Scans, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.