Scanner User Manual

22
Scan and Reconstruction
Pitch
In single slice CT:
Pitch = table movement per rotation/slice collimation
E.g.,: slice collimation = 5 mm,
table moves 5 mm per rotation, then pitch = 1.
With the Siemens Multislice CT, we differentiate
between:
Feed/Rotation, the table movement per rotation
Volume Pitch, table movement per rotation/single
slice collimation.
Pitch Factor, table movement per rotation/complete
slice collimation.
E.g., slice collimation = 2 x 5 mm,
table moves 10 mm per rotation,
then Volume Pitch = 2, Pitch Factor = 1.
With the SOMATOM Spirit, the pitch, slice, collimation,
rotation time, and scan range can be adjusted. The
pitch factor can be selected from 0.5-2.
Pitch Models
Pitch 1
Pitch 1.5
Pitch 2
C2-025.630.01.01.02_APPLICATIONGUIDE_SPIRIT.book Page 22 Friday, April 8, 2005 9:55 AM