Dose Information
For spiral scan protocols, the indicated mAs is the effective mAs per image. The correlation between tube current mA and effective mAs of spiral scans on a Mul- tislice CT scanner is given by the following formula:
Effective mAs = mA x RotTime/Pitch Factor
Pitch Factor =
Feed/Rot
nrow x Slice collimation
mA = effective mAs x Pitch Factor RotTime
where Slice collimation refers to the collimation of one detector row, and nrow is the number of used detector rows.
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