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What This Guide Helps With
Gantry, table, detector, or positioning motion is unavailable because of safety controls, obstruction, positioning, connections, or system readiness.
Step-by-Step Troubleshooting
1. Protect the Patient Before Investigating Motion
If a patient is on the system and normal positioning cannot be assured, stop the examination and assist the patient using approved clinical procedures. Do not troubleshoot intermittent or uncontrolled motion while a patient depends on the equipment.
Prevent staff from repeatedly commanding motion when an obstruction or mechanical problem may be present.
Expected outcome: The patient is safe and the equipment can be evaluated without creating a movement hazard.
2. Confirm Which Motion Is Affected
Determine whether the problem involves the patient table, gantry, detector positioning, vertical movement, longitudinal travel, or all system motion.
Ask whether the failure occurs from every permitted control location or only one control panel or interface. Record any displayed warning or interlock message.
Expected outcome: The affected motion and control location are clearly identified. If motion now operates normally, verify repeatability and troubleshooting can stop.
3. Inspect for Physical Obstructions
Visually inspect the table, gantry opening, detector travel path, floor area, cables, bedding, accessories, positioning devices, and nearby equipment.
Remove only external obstructions that can be safely cleared without disassembly.
Expected outcome: The full intended movement path is clear. If removing an obstruction restores smooth normal motion, complete verification and troubleshooting can stop.
4. Verify Patient Table and Accessories Are Properly Positioned
Confirm removable supports, pads, immobilization devices, table extensions, accessories, and other externally attached components are seated correctly and not interfering with travel or detection mechanisms.
Verify the patient load and positioning are appropriate for normal system operation without assuming a specific manufacturer limit.
Expected outcome: Accessories and patient-positioning components are correctly installed and do not impede motion.
5. Check Emergency-Stop and Safety Controls
Verify accessible emergency-stop controls and safety interlocks are not activated. Confirm no collision or contact condition remains present.
Reset or restore controls only through approved procedures and never bypass a safety interlock.
Expected outcome: No external safety control is intentionally inhibiting motion. If normal motion returns after proper restoration, verify all relevant axes and troubleshooting can stop.
6. Verify System Readiness
Check whether the system reports that the gantry, table, detectors, acquisition subsystem, or operator workstation is not ready.
Motion may be intentionally inhibited when another required subsystem has not completed initialization.
Expected outcome: The system reaches its normal ready state for positioning. If normal motion becomes available, verify operation and troubleshooting can stop.
7. Compare Available Control Locations
When permitted, test the affected motion using another normal system control location or interface.
If motion works from one control location but not another, document the difference and inspect the affected external control for obvious damage, contamination, or stuck buttons.
Expected outcome: Motion behavior is consistent across permitted controls, or the problem is isolated to a particular external control location.
8. Inspect Accessible Cables and Connections
Inspect exposed cables, connectors, hand controls, accessory connections, and control interfaces related to the affected positioning function.
Do not open gantry covers or access internal motion-drive components unless specifically authorized for service.
Expected outcome: Accessible external connections are secure and undamaged. If reseating an approved connection restores motion, verify repeated safe operation and troubleshooting can stop.
9. Perform Controlled Functional Verification
With no patient on the system, command the affected motions through an appropriate safe range while observing for smooth travel, abnormal noise, unexpected stopping, hesitation, or collision risk.
Verify relevant safety controls remain functional.
Expected outcome: Required motion operates smoothly, consistently, and without abnormal sound or interruption. The issue is resolved and troubleshooting can stop.
10. Escalate Persistent or Abnormal Motion
Remove the equipment from service if motion remains unavailable, intermittent, erratic, unusually noisy, or capable of unexpected movement.
Do not attempt internal motor, brake, drive, encoder, mechanical alignment, or control-board repair as part of external troubleshooting.
Expected outcome: Unsafe or unresolved positioning equipment is prevented from returning to patient use and is escalated for qualified service.
If the Problem Persists
Common external causes such as obstructions, accessories, patient positioning, safety controls, system readiness, and accessible connections have been ruled out. Remaining categories may include internal motion-control hardware, mechanical drive components, position sensing, interlocks, control electronics, or service-level configuration.
The device should be:
- Removed from service.
- Labeled Out of Service.
- Sent for repair or controlled system evaluation.
- Evaluated using appropriate GE Healthcare documentation and approved test equipment.
- Repaired or configured only by qualified personnel.
After repair, verify motion, safety interlocks, positioning accuracy as required, and overall imaging-system readiness before return to service. Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Move the patient to a safe position before investigating unreliable table, detector, or gantry motion.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Staff reported the NM/CT 870 CZT patient table would not move longitudinally during positioning."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found an external positioning accessory interfering with the table travel path."
Resolution
What action was taken.
Example:
"Clinical Engineering repositioned the accessory, verified unobstructed table movement and normal safety operation, and returned the system to service."
Helpful Details to Include (If Known)
- Exact motion unavailable
- Control location used
- Displayed warning or interlock
- Emergency-stop status
- Obstruction found
- Accessory configuration
- Abnormal sound or hesitation
- Results from alternate control location
- Results before and after correction
- Final motion and safety status
Final Thought
Protect the patient from unintended movement, eliminate physical and external causes first, verify motion under controlled conditions, and escalate whenever reliable positioning or safety cannot be demonstrated.
That is successful troubleshooting.