A CT scanner is a large, tunnel-like machine with a hole in the center. During a chest CT scan, you lie on a table as it moves small distances at a time through the hole.
An x-ray beam rotates around your body as you move through the hole. A computer takes data from the x rays and creates a series of pictures, called slices, of the inside of your chest.
Different types of chest CT scans have different diagnostic uses.
High-Resolution Chest CT Scan
High-resolution CT (HRCT) scans provide more than one slice in a single rotation of the x-ray tube. Each slice is very thin and provides a lot of details about the organs and other structures in your chest.
Spiral Chest CT Scan
For this scan, the table moves continuously through the tunnel-like hole as the x-ray tube rotates around you. This allows the x-ray beam to follow a spiral path.
The machine's computer can process the many slices into a very detailed, three-dimensional (3D) picture of the lungs and other structures in the chest.