• Discovery MR750w and SIGNA™ Architect T 3.0T System Service Methods
  • 5690002-2EN Revision 4
  • Object ID: 00000018WIA301E2A50GYZ
  • Topic ID: id_2026368 Version: 1.7
  • Date: Jan 27, 2021 9:36:35 PM

Checking the patient handling system with the laser leveling tool

The proper alignment of the entire patient handling system is important for good image quality output from the GE MR scanners.

Prerequisites

Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1-55 minutes-
Tools and test equipment
ItemQuantityPart numberManufacturer
PH Alignment and Magnet Leveling Kit15897979-
MR Patient Handling Alignment Macro Tool (Available from the Online Documentation Library)1DOC2372458-
Nonmagnetic Titanium Service Tool Kit, Small Set15113258-
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

During the PM visit, the steps in this procedure allow the FE to check the patient handling system alignment and collect data in the macro tool.

If the check fails/adjustment is required, the FE can raise a separate SR and perform the adjustment during a different visit or during the same visit if there is adequate time. The procedure for making the adjustments is Adjusting the patient handling system with the laser leveling tool.

The patient handling alignment procedure is to be completed using the patient handling and magnet leveling tool kit (5897979) and the MR Patient Handling Alignment Macro Tool (DOC2372458).

Note: Use the Excel macro tool (DOC2372458) to perform the alignment check procedure. Also, it is recommended that a print of the macro tool is used to record the measurements inside the magnet room.

Some of the tools included in the patient handling and magnet leveling tool kit (5897979) are specific to the magnet handling service procedures and will not be used during the patient handling alignment procedure. The below table lists the tools that will be used for the patient handling alignment procedure.

GE part numberQuantityPart description
58314661Laser Level PLS 180R Z
58979741Folding Ruler, 2 meters, FM-DELA.401.00
58295591Tripod, Vanguard Alta Pro 263AB 100
58297941Masking Tape, Pink, 0.94 Inch Wide
58302321Horizontal Alignment Laser Target Tool
5830232-21Horizontal Alignment Laser Target Tool - Tall
58319782Vertical Alignment Tool
58327191Table Bridge Boss Alignment Tool
53462921Brass Height Tool
Note: Make sure that all of the measuring tools do not have any slop in their assembly.

The macro tool assists the user in identifying target values for aligning the GE MR scanner. The user captures the initial state of the scanner in the macro tool. The macro tool then calculates the ideal state of the scanner. The user adjusts the scanner based on the macro tool output. The user then captures the final state of the scanner in the macro tool.

Procedure

  1. Perform the steps in the following table in the same order they are listed using the PH Alignment and Magnet Leveling Kit (5897979).
    Table 1. Patient Table Adjustments
    StepMeasurementsReference
    1Measure the longitudinal (z-dir) distance between the front bridge surface to the front surface of the end bell cover on the left and right side of the bridge. This distance should be less than ± 3 mm on each side.Checking the alignment of the bridge and rear pedestal (z-dir and x-dir)
    2Measure the gap between the bridge shoulder and body coil in the front and rear. The difference in measurement between the left and right side should be less than 2 mm.
    3Measure the distance, using the folding ruler, between the bottom of the lower bridge support assembly and floor should be >= 2 mm. This is to make sure there is no vibration "short circuit".
    4Set up the laser level and tripod such that the horizontal laser line can be seen above the LPCA in the rear of the scan room and the vertical laser line bisects the scanner. Accuracy is not important here.Setting up the laser level for measurements
    5Align the laser level and tripod such that the vertical laser line strikes the short and tall targets along the horizontal scale and is parallel to the bridge and record the values.
    6Measure the distance between the table top and bridge top. If applicable, perform this measurement on multiple tables.Checking the alignment of the patient table angle (rotation about y-axis) and offset (x-dir)
    7Measure the angle and offset of the table with the horizontal rulers.
    8Measure the height of the horizontal laser line on the bridge and rear pedestal.Measuring the bridge and rear pedestal heights
    9Use the brass height tool (5346292) to check the bridge height in the body coil at the front and rear of the bore.
    10Enter the bridge and rear pedestal data in the macro tool.
    11Boss alignment: measure the height of the boss on the dock versus the height of the boss on the table. If applicable, perform this measurement on multiple tables and record the average.Measuring the patient table height
    12Measure the height of the horizontal laser line on the vertical rulers on the table.
  2. (For DV25 and newer software versions) Record the values in the ICW tool under "Table Adjustments" if it is done during the installation. Otherwise, store the final output file on the system under the /usr/g/service/data directory.
  3. Fill in the table in the macro tool to begin the service procedure.
    Figure 1. Sample entries in the tool
    1User information, system ID, and procedure start time
    Product
    Applicable procedures
    1. Enter your first and last name, SSO, the current date (mm/dd/yyyy), system ID, and start time in the tool to begin the service procedure.
    2. Select the product the service procedure will be executed on.
    3. Select all of the patient handling procedures that apply. The macro tool has VBA code that shows and hides fields in the macro tool that are applicable to the service procedures selected.
    Note: Follow legacy procedures for products that are not currently supported in the product selection list.
Topic ID: id_2025545

Tools overview

The patient handling alignment procedure is to be completed using the patient handling and magnet leveling tool kit (5897979) and the MR Patient Handling Alignment Macro Tool (DOC2372458).

Note: Use the Excel macro tool (DOC2372458) to perform the alignment check procedure. Also, it is recommended that a print of the macro tool is used to record the measurements inside the magnet room.

Some of the tools included in the patient handling and magnet leveling tool kit (5897979) are specific to the magnet handling service procedures and will not be used during the patient handling alignment procedure. The below table lists the tools that will be used for the patient handling alignment procedure.

GE part numberQuantityPart description
58314661Laser Level PLS 180R Z
58979741Folding Ruler, 2 meters, FM-DELA.401.00
58295591Tripod, Vanguard Alta Pro 263AB 100
58297941Masking Tape, Pink, 0.94 Inch Wide
58302321Horizontal Alignment Laser Target Tool
5830232-21Horizontal Alignment Laser Target Tool - Tall
58319782Vertical Alignment Tool
58327191Table Bridge Boss Alignment Tool
53462921Brass Height Tool
Note: Make sure that all of the measuring tools do not have any slop in their assembly.

The macro tool assists the user in identifying target values for aligning the GE MR scanner. The user captures the initial state of the scanner in the macro tool. The macro tool then calculates the ideal state of the scanner. The user adjusts the scanner based on the macro tool output. The user then captures the final state of the scanner in the macro tool.

Topic ID: id_2026535

Checking the alignment of the bridge and rear pedestal (z-dir and x-dir)

Topic ID: task_cgj_btq_xlb

Front end bell-bridge longitudinal (z-dir) offset

Procedure

  1. Undock the table.
  2. Measure the longitudinal (z-dir) distance between the front bridge surface to the front surface of the endbell cover on the left and right side of the bridge. This distance should be less than ± 3 mm on each side. This can be done using the folding ruler (5897974).
    Note: The folding ruler has a very small amount of ferrous content. Use caution when using it near the magnet.
    Figure 2. Bridge to front surface of the endbell cover
    1± 3 mm
  3. Record these values in the macro print-out for the left and right side in mm as they will be entered in the macro tool.
    Figure 3. Sample front endbell-bridge longitudinal (z-dir) offset values in macro tool
Topic ID: task_cx1_2tq_xlb

Bridge shoulder-body coil lateral (x-dir) gap front

About this task

These steps provide instructions to measure the alignment of the bridge in the lateral (x-dir) direction (left to right of the magnet bore).

Procedure

  1. Use the folding ruler to measure the gap between the bridge shoulder and body coil in the front and rear. The difference in measurement between the left and right side should be less than 2 mm.
    Figure 4. Body coil gaps
    1Rear left
    2Rear right
    3Front right
    4Front left
    Note: Measure from a consistent location from the filleted surface of the bridge shoulder to the body coil at the four locations.
  2. Record the values in mm in the macro print-out as they will be entered in the macro tool. The tolerance for this is left-right <= ± 2 mm for front and rear of the bridge.
    Figure 5. Sample bridge shoulder-body coil lateral (x-dir) gap values in macro tool
  3. Make sure the lower bridge support assembly is not touching the floor. Measure the distance using the folding ruler between the bottom of the lower bridge support assembly and floor should be >= 2 mm. This is to ensure that there is no vibration "short circuit".
    Figure 6. Lower bridge support assembly alignment
    1>= 2 mm
    Important: The laser measurements may not be within specifications after adjustments due to the existing magnet height and floor levelness. In such a case, try to adjust the system to as close as possible to the specifications without exceeding other specification limits.
Topic ID: id_2026536

Checking the alignment of the patient table angle (rotation about y-axis) and offset (x-dir)

Topic ID: id_l3n_cgr_xlb

Table 1 gap check

Procedure

  1. Using the folding ruler, measure the gap between the table and bridge on the left and right sides.
  2. Record the measured values in the macro tool in millimeters. The gap should be no less than 12.6 mm (0.5 inches) and no greater than 25.4 mm (1 inch).
    Figure 7. Sample table 1 gap check values in the macro tool
Topic ID: id_tcs_bgr_xlb

Table 1 angle and offset check

Procedure

  1. Place the short and tall targets at the front and rear of the table.
  2. Make sure the targets are approximately 6 cm from each of the respective ends. Make sure the target is not resting on the chamfered surface. Make sure the targets are flush against the cradle vertical wheel bearing surface.
  3. Record the values the vertical laser line strikes through on the horizontal scale on the short and tall targets. Make sure to capture if the number is positive or negative. The tolerance is ± 2 mm of the output values.
    Figure 8. Sample table 1 angle and offset check values in the macro tool
Topic ID: id_2025642

Measuring the bridge and rear pedestal heights

About this task

Note: For the remainder of the procedure, it is useful to align the laser level and tripod such that the vertical laser line bisects the scanner. Accuracy is not important in the vertical alignment. Once the laser is set, do not move the laser until all measurements are complete.
Topic ID: task_xgh_wqd_hlb

Rear pedestal

Procedure

  1. Use the vertical rulers to measure the height of the horizontal laser line above the rear leveling feet on the rear pedestal.
    Note: Do not lean on the rear pedestal while measuring as it could affect the measurement. The vertical rulers can be turned at an angle to view if required.
    Figure 9. Vertical rulers on the rear pedestal
    1Vertical ruler location above rear leveling feet
    2Rear leveling feet
  2. Record the height of the horizontal laser line on each vertical ruler in centimeters.
    Figure 10. Sample rear pedestal values in the macro tool
Topic ID: task_mqv_rbl_hlb

Bridge

Procedure

  1. Use the vertical rulers to measure the height of the horizontal laser line at the bridge side of the bridge-rear pedestal joint. Record the height of the horizontal laser line on each vertical ruler in centimeters.
    Figure 11. Vertical rulers at the rear of the bridge
    1Vertical ruler location on bridge at bridge to rear pedestal joint
    2Bridge to rear pedestal joint
  2. Place vertical rulers at the front of the bridge approximately 6 cm into the bore, measured from the end of bridge. Make sure the rulers do not rest on the chamfered surfaces.
    Figure 12. Vertical rulers at the front of the bridge
    1Vertical ruler location at front of bridge
    2Front of bridge
  3. Record the height of the horizontal laser line on each vertical ruler in centimeters.
    Figure 13. Sample bridge values in the macro tool
Topic ID: task_gwp_mhl_hlb

Bridge height in the body coil

Procedure

  1. Use the brass height tool (5346292) to check the bridge height in the body coil at the front and the rear of the bore.
    Note: The vertical laser line can be used for laterally centering the brass height tool in the body coil.
    Note: Make sure the bottom of the brass height tool rests on the bridge and not the belt.
    Figure 14. Bridge height in the body coil
    Figure 15. Brass height tool aligned with vertical laser
  2. Record the values in millimeters as they will be entered in the macro tool.
    Note: The specification for this measurement is 502-505 mm for the narrow bore and 582-585 mm for the wide bore.
    Figure 16. Sample bridge height in body coil values in macro tool
Topic ID: task_wyn_q1m_hlb

Entering the initial bridge and rear pedestal data in the macro tool

Procedure

  1. Record the following measurements in the macro tool:
    • Rear pedestal
    • Bridge
    • Body coil size
    • Bridge height in body coil
    Note: The macro tool will calculate and output target values for alignment. The output is targeted towards leveling the bridge and rear pedestal to the ground while remaining within the upper (505 or 585 mm) and lower (502 or 582 mm) limits of the bridge height in the body coil specification (crucial for maintaining image integrity).
  2. Record the output values of the macro tool on the print-out to be used for adjustments.
Topic ID: id_2026539

Checking the patient table height

Topic ID: id_oyc_f1s_xlb

Multiple table configuration

Procedure

Select a response from the Multiple tables? drop-down menu in the macro tool. Select yes if the scanner has multiple tables and no if the scanner only has one table.
Figure 17. Multiple table selection
Topic ID: task_j1q_f1s_xlb

Boss 1 height

Procedure

  1. Remove the front table covers and use the boss height gauge to check the height difference between the table and dock bosses. Make sure to slide the boss height gauge in from the side and that the gauge covers both bosses.
    Note: A missing front table cover, as shown in the illustration, may result in 16-channel systems reporting a 32-channel connector is not attached. When the adjustment is complete, replace the front cover to prevent this error.
    Note: The specification for the height difference between the table and dock bosses is less 1 mm. If the boss height gauge does not slide over both bosses from the side, the bosses are outside of the specification.
    Figure 18. Boss height alignment check
    1Dock boss
    2Table boss
    3Boss height gauge
  2. If the boss height alignment is within specifications, select Pass from the drop-down menu in the macro tool. If the alignment is outside of specifications, select Fail from the drop-down in the macro tool.
    Figure 19. Boss height alignment pass/fail drop-down
Topic ID: id_l3r_jcs_xlb

Table 1 check

Procedure

  1. Place the vertical rulers at each of the four corners of the table approximately 6 cm in from the ends. Make sure the rulers do not rest on the chamfered surfaces.
  2. Record the final table values in the macro tool in centimeters. The tolerance is ± 2 mm of the output values.
    Figure 20. Sample table 1 check values in macro tool
Topic ID: id_rbl_ycs_xlb

Casters 1 check

Procedure

  1. At each of the four caster wheel assemblies, measure the height from the floor to the bottom edge of the aluminum support casting.
    Figure 21. Caster measurement
  2. Record the values for each caster in the macro tool in millimeters. The tolerance is 207 ± 10 mm.
    Note: If the table casters are not within specifications (207 ± 10 mm), lower or raise the casters until they are at the minimum or maximum depending on the situation.
    Figure 22. Sample caster 1 check values in macro tool
Topic ID: id_2025743

Doing the pass/fail check

Procedure

Check the macro tool for any alignment failures shown in the Pass/fail check.
Figure 23. Sample pass/fail table values in the macro tool
Topic ID: id_2025745

Uploading data

Topic ID: task_ctc_31c_jlb

Table adjustment ICW input

Procedure

If required to input values into the Installation Calibration Wizard (ICW), enter the values specified by the table in the macro tool.
Note: These values are derived from the inputs entered in the macro tool during the alignment procedure.
Figure 24. Sample table adjustment ICW input values in the macro tool
Topic ID: task_tjp_xbc_jlb

Save/upload data

Procedure

  1. Select the Save Session button in the macro tool to save the results from the alignment.
    Note: Selecting the Save Session button will export a .csv record of the values from the service procedure executed into the same directory of the excel workbook. This is the file that will be uploaded.
    Figure 25. Save session
  2. Copy the *.csv record file to the USB drive and save this file on the host computer under /usr/g/service/data directory.
  3. When the patient handling alignment is complete, place the laser level in locked mode before shipping.
    Figure 26. Laser level in locked mode