How does CT scanning work?

A thin beam of x-rays passes through the body in the axial plane chosen for study as the x-ray tube moves in a continuous arc around the patient. Electronic detectors placed opposite the x-ray tube on the other side of the body convert the exiting beam into electrical pulses whose intensity depends on the amount of the x-ray beam that was not absorbed by the intervening tissues. This information is conveyed to a computer, which calculates the x-ray absorption for each voxel and creates the final CT image.