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Adjustments/Calibrations
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Calibrating High Order Shim (HOS)
This procedure creates High Order Shim (HOS) reference maps characterizing the fields created by the HOS windings. These maps are used by the HOS feature.

Adjustments/Calibrations
- System
  - B0 Drift Calibration
  - Doing DQA calibration
    The DQA tool determines proper gradient polarity and proper gradient wiring by scanning a series of axial and coronal images of the DQA III phantom.
  - Troubleshooting the Daily Quality Assurance (DQA) II tool
    If problems are encountered while using the Daily Quality Assurance (DQA) calibration procedure, refer to the following guidelines for troubleshooting.
  - Dual drive quadrature tool
  - Doing the Echo Planar Test
  - Deionization procedure
  - HIS/RIS Setup and Troubleshooting
  - Calibrating High Order Shim (HOS)
    This procedure creates High Order Shim (HOS) reference maps characterizing the fields created by the HOS windings. These maps are used by the HOS feature.
    - HOShim Reference Map Creation and Verification for DV26.0 or earlier
    - Configuring for systems running DV29.1 and later
    - Running High Order Shim (HOS) calibration
    - Doing a check scan
      A check scan is done at the conclusion of many procedures. This functional check assures the unit is in good clinical working order.
  - ICN On/Off procedure for Sun 4100, 4170, and Dell R620
  - LVShim Procedures
  - Running LVShim
    The objective of the LVShim tool is to fine-tune magnet homogeneity.
  - Running LVShim - Gradshim
  - Running LVShim in Auto mode
  - Running LVShim in Manual mode
  - System gain calibration
    Head and body system gain calibration.
- Gradient
- Radio Frequency (RF)
- Magnet Enclosure
- Patient Table
- Global Operator Console (GOC)
- Spectroscopy

Discovery MR750 3.0T System Service Methods
5690009-2EN Revision 4
Object ID: 00000018WIA307FE010GYZ
Topic ID: id_2003262 Version: 2.38
Date: Mar 3, 2021 6:21:08 PM

Calibrating High Order Shim (HOS)

Prerequisites


Personnel Requirements
Required persons	Preliminary requirements	Procedure	Finalization
1	-	60 minutes	-


Tools and test equipment
Item	Quantity	Part number	Manufacturer
LVShim Phantom Inner Sphere	1	2274476	-
Universal Phantom Pad	1	46-328383P1	-

Note: For LVShim procedures, continue to use side lobes.


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.

Please choose from the following:


HOShim Reference Map Creation and Verification for DV26.0 or earlier
Configuring for systems running DV29.1 and later