What does "pitch" refer to in helical CT scanning?

In helical CT scanning, "pitch" specifically relates to the efficiency of the scanning process. It is defined as the ratio of the table movement per rotation of the x-ray tube to the width of the x-ray beam. Essentially, this means it measures how far the table moves during one complete rotation of the x-ray tube compared to how wide the beam is. A higher pitch indicates that the table moves a greater distance relative to the beam width, which results in less overlap between adjacent slices and faster scanning but can also affect image quality due to possible gaps in the data collected. Understanding pitch is crucial because it directly impacts both the speed of the scan and the spatial resolution of the resulting images.