PREFACE

Schematics of detector elements in the arc around the patient, and detector rows perpendicular to the z axis. All CT scanners have many detector elements in the arc around the patient. However, only MDCT systems have more than one row perpendicular to the z axis.

Diagram of the detector geometry used in a MDCT from two major manufacturers. The detector array is 20 mm wide along the longitudinal (z) axis and uses eight detector rows of varying widths to allow simultaneous scanning of 4 slices up to 5 mm thick.

Diagram of the detector geometries used in 64-MDCT from four major manufacturers. The Siemens 64-MDCT uses 32 sub-mm detectors and a moving focal spot to achieve 64 overlapping slice measurements.