In a CT scan, what is the pitch value when the table moves a greater distance than the width of the beam?

In a CT scan, the pitch is defined as the ratio of the distance the table moves during one complete rotation of the x-ray tube to the width of the x-ray beam or detector array. When the table moves a greater distance than the width of the beam, it indicates that the areas being scanned are further apart, which results in a pitch value greater than 1.

A pitch greater than 1 suggests that the scanner is covering more anatomical space per rotation relative to the beam width, leading to a reduced overlap between the scanned slices. This can improve scan speed and decrease patient dose, but it might result in lower image quality if the pitch is excessively high, as there can be gaps in the data collected.

In summary, when the table moves a greater distance than the width of the beam, the pitch is effectively greater than 1, allowing for more efficient scanning while understanding the trade-offs involved in terms of image resolution and reconstruction.