• Optima MR450w BASE 1.5T System Service Methods
  • 5690012-2EN Revision 3
  • Object ID: 00000018WIA30A5A650GYZ
  • Topic ID: id_2024933 Version: 2.1
  • Date: Jun 21, 2021 3:45:11 AM

Running LVShim - Gradshim for systems running DV29.1 or later

Procedure

  1. Set the universal phantom pad in the middle of the table and align the pad’s crosshairs to the closest PA crosshairs using the laser alignment lights.
  2. Put the sphere on the pad with the strap (in the groove) in the orientation shown below, making sure the laser lights are cross-centered on the sphere and phantom pad.
    Figure 1. Sphere phantom position
    Note: This image is a representative example. Actual systems may vary.
  3. Set up and align the LVShim phantom. Align the phantom so that:
    1. The strap on the phantom is aligned parallel to the table surface.
    2. The phantom is centered left to right with respect to the cradle top.
  4. Landmark on the universal phantom pad crosshairs.
    Note: The landmarking tolerances of the LVShim tool are: I/S: ± 3 mm, A/P: ± 30 mm, R/L: ± 5 mm. Ensure accuracy of the placement for landmarking.
    Note: Due to the tight landmarking tolerance, it is important to align the lasers on the crosshairs of the LVShim phantom.
  5. Press Advance to Scan.
    Note: The tool checks phantom positioning and will fail if the above landmarking specs are out of tolerance.
  6. Start the LVShim tool from the Common Service Desktop on the Calibration tab.
  7. Select the gradshim mode:
    OptionDescription
    Auto modeRunning LVShim in Auto mode
    Manual modeRunning LVShim in Manual mode