• SIGNA™ Hero 3.0T Service Methods
  • 5852800-8EN Revision 1.0
  • Object ID: 00000018WHA30DFB6GYZ
  • Topic ID: id_2001814 Version: 5.0
  • Date: Nov 3, 2021 4:07:00 PM

Checking B0 Drift

Prerequisites

Table 1. Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1Not applicable90 minutes Not applicable
Table 2. Tools and test equipment
ItemQtyPart#Manufacturer
Body TLT Loader for 3.0T12360037-
Service Foam Positioner15554839-
Table 3. Required Conditions
Condition
All other applicable calibrations must be complete.
It is required to cool down the system without any scan for 2 hours before starting B0 drift test. Refer to the Cooling the system procedure.
Table 4. Safety

Before working in any GE Healthcare MR suite or performing any GE Healthcare service procedure, you must:

  • Have read and understood all hazard conditions and safety requirements in the latest revision of the GE Healthcare MR Service Safety Manual (5452735).
  • Have successfully completed all relevant GE Healthcare Environmental Health and Safety (EHS) courses (or for non-GE employees, equivalent workplace training courses).
  • Comply with all site-specific training and workplace safety requirements.

If you have any safety concerns at any time, do not begin work or immediately stop work and move to a safe location. Immediately contact your supervisor or site safety officer for instructions on how to proceed.

About this task

Unwanted changes in the main magnetic field strength can occur when the spatially uniform field component is altered for a short term, during the process of scanning, or when the spatially uniform field component is permanently altered. This is known as short-term B0 drift.

This functional check confirms if the B0 drift values are within the system specification or not.

Procedure

  1. Cool down the system before checking B0 drift. Refer to the Cooling the system procedure.
  2. Put the TLT phantom and sphere in the foam support on the flat table.

    Position the phantom in the center of the cradle and center it on the Posterior Array (PA) coil. To achieve the best test measurement, the phantom must be located in the center (long direction) of the cradle.

    Figure 1. TLT phantom and sphere on the table
  3. Landmark on the crosshairs of the body TLT loader and press Advance to Scan.
  4. Start the B0 drift tool:
    • (For non-proprietary service tools) From the Common Service Desktop, select Calibration > B0 Drift Calibration. Click Click here to start this tool.

    Result

    The B0 Drift window appears.
  5. Select the axis that is being validated. To select a second axis, press <Shift> and click another axis.
  6. Select Check only.
    The total time required to run B0 Drift Test Mode is 63 minutes.
  7. Select Scan.
    When the test is complete, it displays the compensated drift rate for the selected axis. Values in green are passing; those in red are failing.
    If one axis fails, run B0 Drift Calibration for only the failed axis.

Finalization

Remove the service equipment and phantom.