The X-ray tube on the rotor, firing a beam through the patientThe gantry, with the bore the patient passes throughThe patient on the table, moved through the boreThe table moves the patient through the bore while the rotor turns the tube and detectors around them. Each detector reading is a projection; the computer back-projects all of them into a slice. The slice here is a simulated phantom, drawn with a parallel-beam model rather than the fan beam of a real scanner.
Detector readings

Angle 0°. Each reading is how much of the beam got through.

Sinogram

0 of 180 projections. Each row is one angle.

Reconstructed slice

Hover the slice to read a value.