GE HEALTHCARE
DIRECTION 2307224-100, REVISION 6DISCOVERY LS SYSTEM SERVICE MANUAL
Chapter 7 - Gantry Page 225
7.1.2.2 Gantry-Table Cable Routing
Cable routing inside the system was changed. The cables from the gantry to the table are routed
under the CT static gantry. Refer to Figure 7-2. Since the entire table slides from its CT to its PET
position on the secondary base, the cables are flexible (robotics grade) and routed inside three
retractors that nest one inside the other and slide on the floor. The retractors are required to enable
Gantry service while keeping the cables in operating condition for the service life of the system.
Figure 7-2: Table Retractors
7.1.2.3 Gantry Covers
New covers were designed for the entire system. The covers enclose the CT and the PET Gantries,
and provide a uniform look of both gantries as one system. The covers are designed to allow quick
installation and removal.
7.1.2.4 Moving the PET Gantry to Service Position
To enable movement of the PET gantry into its service position, some of the covers require removal
to allow access to the driving mechanism and the gantry holding bracket. Disassembly of covers is
detailed in Section 7.6.1, and activation of the driving mechanism to move the PET Gantry to its
service position is detailed in Section 7.6.2.
7.1.2.5 System Calibration
One of the major concerns in connecting two different systems, such as the LightSpeed CT and the
PET Advance, is with the need for registration between the images.
Discovery LS uses a combination of software and mechanical registration techniques. Image
registration is initially based on a mechanical registration of both gantries, such that the isocenter
of both gantries is located along the same line. This initial mechanical calibration ensures that the
images are inherently registered.
Precise registration of the images is achieved by the use of mechanical alignment mechanisms that
enable adjustment of the PET Gantry. Six different degrees of freedom are calibrated, using four
adjusters in the PET, four in the CT, and four in the secondary base until both systems are aligned
within specified requirements.
Table Retractors
Table Secondary Base
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