GE Revolution CT User Manual

4 Scan Parameters
See the Section 5 for procedures on how to set the following scan parameters.
4.1 Scan Type
The Scan Type and related scan parameters are set in the
Scan Type collection.
From the
Scan Settings window, click Scan Type to display the Scan Type collection.
Illustration 13: Scan Type collection
Element
Description
Scan Type Enables one of the following scan types: Axial, Helical, Cardiac, or Cine.
Hi Res Mode Enables and disables Hi Res Mode. Hi Res Mode is compatible with Axial, Helical, and
Cardiac scan types.
Rotation Time The available rotation times depend on the scan type selected. See Section 1.6.
4.1.1 Axial
Axial scanning is the traditional “step and shoot” method of acquiring data. The X-ray tube and
Data Acquisition System (DAS) expose and rotate one 360° loop. The table and patient move a
preset distance (interval) and the process is repeated.
4.1.2 Helical
Helical or spiral scanning is a method of acquiring images in a continuous data set. The X-ray
tube and DAS expose and rotate continuously through 360° while the patient is passed through
the area of exposure at a set rate of movement depending on the rotation time and helical pitch.
The information gathered is then reconstructed into images of the prescribed slice thickness and
interval.
4.1.3 Cardiac Axial
See the Cardiac chapter for more details.
4.1.4 Cine
Cine is a method of scanning that rotates the gantry 360° continuously with no delay in between
passes while gathering input from one location over time. You may set the acquisition in groups
expanding the time to be scanned. This is especially beneficial when determining the function of
anatomy and physiology (example: hemangioma).
4.1.5 Hi Res Mode
Hi Res Mode provides the capability to acquire 2.5 more views using deflection of the X-ray
beam in both non-cardiac and cardiac acquisitions. The additional views can be used to improve
image quality to reduce aliasing, improve off-center imaging, or improve resolution. Normal
Revolution CT User Manual
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Chapter 11 Scan 265

GE Revolution CT Specifications

General

Detector Coverage	Up to 160 mm
Gantry Tilt	± 30 degrees
Spatial Resolution	Up to 0.23 mm
Scan Range	Up to 200 cm
X-ray Tube Current	Up to 800 mA
Type	Computed Tomography (CT) Scanner
Rotation Speed	0.28 seconds per rotation
Tube Voltage	80 kV to 140 kV
Number of Detector Rows	256
Power Requirements	480 VAC, 3-phase
Detector Rows	256
Coverage	160mm