○
The Hi Res Modes supported include the following:
■
Axial – 40, 80, 120, 140, 160 mm detector coverage
■
Helical
0.516:1 pitch 40 mm detector coverage
0.984:1 pitch 40 mm detector coverage
0.992:1 pitch 80 mm detector coverage
■
Cardiac Axial – 40, 80, 120, 140, 160 mm detector coverage
4. Click a
Rotation Time
.
○
Axial – 0.28 s, 0.35 s, 0.5 s, 1.0 s
○
Cine – 0.28 s, 0.35 s, 0.5 s, 1.0 s
○
Helical – 0.28 s, 0.35 s, 0.5 s, 1.0 s
○
Cardiac Axial – 0.28 s, 0.35 s
5. Click [Save].
4.5.2 Set the Coverage Speed options
Use this procedure to set the coverage speed options for detector coverage, image slice
thickness, pitch, table speed, and rotation speed.
1.
From the
Scan Settings
window, click
Coverage Speed
.
2.
Choose the
Detector Coverage
.
3. For a Helical scan type, choose the
Pitch
.
NOTE: Total Exposure Time is updated automatically when a pitch is selected.
○
The pitch is the table travel in millimeters per rotation divided by the detector coverage.
■
4 Row Interleaved provides a 40% mAs reduction, is 1.5 to 3 times faster than single
slice helical and has minimal helical artifacts, but interleaved pitch 0.5:1 provides
only one third of the coverage compared to interspaced mode.
■
4 Row Interspaced provides data acquisition 2 to 6 times faster than single slice
helical, but requires more interpolation, has more helical artifacts, and only a 20%
mAs reduction.
○
Helical pitches include: 0.516:1, 0.984:1, 0.992:1 and 1.375:1.
4. For Axial, Cine and Cardiac scan types, the detector coverage and slice thickness
determine the images per rotation.
Revolution CT User Manual
Direction 5480385-1EN, Revision 1
280 4 Scan Parameters
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