Scientists Say: CT scan | Science News for Students

Scientists Say: CT scan

This technology gives us a peek inside the body, no cutting required
Mar 5, 2018 — 6:30 am EST
CT scan brain
These are CT scan images of the human brain.

CT scan (noun, “SEE TEE scan,” or CAT scan “CAT scan”)

The “CT” in a CT scan is an abbreviation. It’s for “computed tomography” or “computerized axial tomography” (which is abbreviated “CAT scan”). Doctors and scientists can use this technology to look inside something, without having to cut it. To make a CT scan, a person or an object is placed in a circular scanner. Inside the scanner is a machine that generates X-rays, a type of radiation. The machine uses the X-rays to take photos from every angle around the person or object. Then a computer combines the pictures. The result is a set of three-dimensional images that look like slices through the person or object. These images provide much more detail than a single X-ray. And they allow someone to look at, and through, an object from every angle. No knife required.

In a sentence

Scans of ancient pterosaur eggs using CT scans revealed babies fossilized inside. 

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CAT scan     or CT scan (see computerized axial tomography )

computerized axial tomography  (CAT or CT, for short). A special kind of X-ray scanning technology that produces cross-sectional views of the inside of a bone or body.

computerized tomography     (CT, for short). A special kind of X-ray scanning technology that produces cross-sectional views of the inside of a bone or body.

CT scan     (see computerized axial tomography )

egg     The unfertilized reproductive cell made by females.

pterosaur     Any of various extinct flying reptiles of the order Pterosauria. These animals lived 245 million years ago to 65 million years ago. Although not true dinosaurs, they lived during the reign of dinosaurs. Among members of this order were the pterodactyls of the Jurassic and Cretaceous periods, which were characterized by wings consisting of a flap of skin supported by the very long fourth digit on each forelimb.

radiation     (in physics) One of the three major ways that energy is transferred. (The other two are conduction and convection.) In radiation, electromagnetic waves carry energy from one place to another. Unlike conduction and convection, which need material to help transfer the energy, radiation can transfer energy across empty space.

scanner     A machine that runs some sort of light (which includes anything from X-rays to infrared energy) over a person or object to get a succession of images. When a computer brings these images together, they can provide a motion picture of something or can offer a three-dimensional view through the target. Such systems are often used to see inside the human body or solid objects without breaching their surface.

X-ray     A type of radiation analogous to gamma rays, but having somewhat lower energy.