• Optima MR450w BASE 1.5T System Service Methods
  • 5690012-2EN Revision 3
  • Object ID: 00000018WHA30AE62GYZ
  • Topic ID: id_2001480 Version: 8.0
  • Date: Feb 24, 2021 1:52:29 AM

Calibrating grafidy

Grafidy adjusts and compensates short, long, and very long time constant eddy currents for both linear and B0 terms. Use the Grafidy procedure to do eddy current compensation.

Prerequisites

Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1-2 hours5 minutes
Tools and test equipment
ItemQuantityPart numberManufacturer
1.5T Grafidy Kit1-5135527-7
Service Filler Panel1-5344577-
Service Foam Positioner1-5554839-
Replacement parts
ItemQuantityPart numberManufacturer
RF coil assembly15135514-
Required conditions
DQA (Grad Cal/IsoVector2) tool within specification. See DQA calibration.
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

Grafidy adjusts and compensates short, long, and very long time constant eddy currents for both linear and B0 terms. Use the Grafidy procedure to perform eddy current compensation. Grafidy should be run in auto mode first. If auto mode fails to bring any of the terms into specification, manual mode can be used.

Grafidy uses a dedicated pulse sequence, six-channel fixture, and Grafidy software. The Grafidy P-port connector plugs into the port for transmit/receive. No additional fixtures or cables are needed.

This tool simplifies setting up the calibration and collects data from all six coils simultaneously.

Table 1.
Auto mode - The Grafidy tool is initially run in auto mode.
Manual mode - When doing this procedure, if auto mode does not bring all the terms into specification (still red in the Result/Area table).
Note: If VLONG, LONG or SHORT terms are failing, manual mode should be run to bring the VLONG mode into specification.