GE Discovery LS - Section 3.4 Electrical Requirements

GE HEALTHCARE
DIRECTION 2307224-100, REVISION 6DISCOVERY LS SYSTEM SERVICE MANUAL
Page 82 Chapter 3 - DLS System Functional Description
3.3.3 Detector Ring
The Detector Ring consists of 56 detector modules. A movable collimator is used to limit stray and
scattered radiation. A segmented, lead ring also attenuates stray radiation, reducing the stray
gamma rays impinging on the detector modules from unwanted angles. The modules detect the
gamma rays, which are a by-product of positron annihilation.
Each module consists of four Photo Multiplier Tubes with 36 Bismuth Germinate (BGO) crystals.
The signal from the detector is amplified by the detector electronics, which also digitizes the location
and energy of the event. The PMTs are vacuum tubes and require high voltage (HV) to function.
3.3.4 PCU
The Gantry Power Control Unit (PCU) takes power from the PDU in the electronics cabinet and
supplies power for motors for motion control and internal power supplies.
3.3.5 Power Switch Box
There is a Power Switch box mounted on the Gantry, which allows the Detector HV, service outlets
and PCU to be turned on and off independently.
3.3.6 Gantry Motion Control Board Rack
The Gantry Motion Control Board Rack holds the motion controller for the Gantry tilt, collimator
motor and source loader robotics. The radioactive sources are used for calibration and attenuation
correction.
3.4 Electrical Requirements
The Discovery LS combined CT-PET system has separate electrical requirements for the CT and
PET. These requirements are exactly the same requirements for the Advance PET and the
LightSpeed CT systems.
The Advance PET general power requirements are 220/240 VAC (+/-10%) single-phase, 10 kVA
maximum. Further details can be found in the Site Preparation Manual, Direction 46-322503,
Chapter 5.
The LightSpeed CT general power requirements are 380/480 VAC (+/-8%) three-phase, 90 kVA
maximum @ selected technique 140 Kv, 380 mA. Further details can be found in Chapter 7 of the
following manuals:
• LightSpeed 2.X Pre-Installation Manual, Direction 2243311-100 (for 4-slice SDAS Systems)
• LightSpeed 3.X Pre-Installation Manual, Direction 2296438-100 (for 4 or 8-slice MDAS
Systems)
• LightSpeed 4.X Pre-Installation Manual, Direction 2341956-100 (for 16-slice MDAS
Systems)
The A1 Main Power Disconnect Box is a customer-supplied unit that should provide over current
protection and safety electrical disconnection control from the hospital main voltage supply line. The
customer-supplied emergency off buttons are recommended to be mounted in the Gantry room and
near the console.