CT scanners produce cross-sectional images of the body by using X-rays from different angles to reconstruct tomographic slices. CT scanners rotate an X-ray tube and detector array around the patient, measuring attenuation profiles along rays. These projection data are reconstructed using filtered back projection to produce images with improved contrast compared to radiography but some artifacts. Advances like spiral CT allow faster full-volume imaging but increase patient dose. CT provides anatomical detail but cannot replace modalities like MRI for all clinical needs.