Helical multi-slice: pitch

• Pitch can be defined relative to total x-ray collimation (x), or individual detector width (d)

• Pitchd = Pitchx x number of slices

• In practice, pitchx is useful when looking at dose, pitchd for image quality

• Pitchx is IEC definition

• Pitchx = table travel

• x-ray beam width (x)

• Pitchd = table travel

• detector width (d)