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What This Guide Helps With
Gantry rotation errors, vibration, abnormal noise, or scan interruption caused by external obstruction, table contact, setup, or mechanical faults.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Stop the exam if gantry vibration, abnormal noise, rotation fault, or scan interruption occurs during patient scanning.
Action:
- Remove the patient from the scanner when safe
- Move the patient to another CT scanner if the exam is clinically urgent
- Do not attempt repeated scans if vibration or abnormal gantry noise is present
Expected outcome: Patient is safely removed from potential mechanical risk.
Verify the Reported Fault
Confirm the exact symptom before taking corrective action.
Action:
- Ask staff what occurred
- Check whether the issue happened during gantry rotation, helical scan, scout scan, or system startup
- Record any displayed error message or fault code
- Note whether the gantry stopped, vibrated, clicked, scraped, or made a grinding sound
Expected outcome: The failure pattern is clearly identified.
Check for Patient, Table, or Accessory Contact
Physical contact can cause gantry rotation faults or vibration alarms.
Action:
- Inspect the gantry opening
- Confirm the table, mattress, straps, IV lines, arm supports, positioning aids, or patient accessories are not contacting the gantry
- Check that nothing is hanging into the scan field or rotation path
Expected outcome: No obstruction or contact is present.
If contact or obstruction is found, remove it, reposition the table or accessory, and retest only when safe. If the issue clears, stop troubleshooting.
Inspect the Area Around the Gantry
External objects near the gantry can create noise, vibration, or safety concerns.
Action:
- Check for loose objects near the gantry base
- Look for dropped supplies, covers, cables, cleaning items, or debris
- Verify no panels are visibly loose or displaced
Expected outcome: The gantry area is clear and free of loose items.
Check Gantry Covers and External Panels
Loose covers may vibrate during rotation and sound like an internal failure.
Action:
- Visually inspect gantry covers and trim panels
- Look for cracked, shifted, or loose panels
- Do not remove covers unless permitted by site policy and service authorization
Expected outcome: Covers are secure with no visible damage.
If a cover is loose or damaged, remove the scanner from service and escalate for repair.
Check Table Position and Alignment
Improper table positioning can cause scan aborts, contact, or alignment-related rotation faults.
Action:
- Move the table fully out of the gantry
- Check for smooth table travel
- Confirm the tabletop is centered and not visibly skewed
- Verify the table moves without rubbing, binding, or abnormal noise
Expected outcome: Table movement is smooth and does not interfere with the gantry.
Review Recent Room or Equipment Changes
New equipment or recent service work can introduce clearance or vibration issues.
Action:
- Ask whether the room was recently cleaned, serviced, moved, or modified
- Check for new accessories, injector lines, ceiling-mounted equipment, floor mats, or positioning devices
- Confirm nothing was placed too close to the gantry or table path
Expected outcome: No recent external change explains the issue.
Perform a Controlled System Restart
A software or motion-control fault may clear after a proper restart.
Action:
- Ensure no patient is on the table
- Follow site-approved shutdown and startup procedure
- Allow the system to fully initialize
- Observe whether the fault returns during startup or standby
Expected outcome: System restarts normally with no immediate gantry fault.
If the fault clears and no abnormal noise or vibration is present, continue with caution and document the event.
Attempt Limited Non-Patient Functional Check Only If Safe
Do not test aggressively if grinding, scraping, burning smell, visible damage, or severe vibration occurred.
Action:
- With no patient present, perform only approved basic system checks
- Observe for abnormal vibration, noise, rotation hesitation, or fault recurrence
- Stop immediately if the gantry sounds abnormal or the fault returns
Expected outcome: Gantry rotation is smooth, quiet, and free of faults.
If abnormal vibration or noise returns, stop testing and remove the scanner from service.
Check Environmental and Facility Conditions
Facility issues can contribute to vibration or unstable scanner operation.
Action:
- Verify room temperature is within normal operating range
- Check for water leaks, unusual heat, or HVAC issues near the scanner
- Confirm no facility work is causing floor vibration nearby
- Check for electrical events reported by staff
Expected outcome: Environment appears stable and suitable for CT operation.
Determine Whether the Scanner Is Safe to Return to Use
Only return the CT scanner to service if no fault returns and no abnormal mechanical symptoms are present.
Action:
- Confirm no active gantry fault
- Confirm no abnormal noise, vibration, smell, or visible damage
- Confirm staff can operate the system normally
- Document all checks performed
Expected outcome: Scanner is either safely returned to service or removed from service for repair.
If the Problem Persists
If gantry rotation faults, vibration, abnormal noise, scraping, grinding, or repeated scan aborts continue after external checks, the likely cause is internal mechanical, bearing, drive, motor, encoder, slip ring, brake, or gantry control-related failure.
The CT scanner should be:
- Removed from service
- Labeled Out of Service
- Escalated to Canon service, imaging specialist, or qualified CT service provider for bench-level or system-level evaluation
Knowing when to stop is proper troubleshooting. Repeated rotation attempts can worsen mechanical damage and may create patient or staff safety risk.
Clinical Use Tip
Do not troubleshoot gantry vibration or rotation faults with a patient on the table. Remove the patient first, secure the scan room, and test only when it is safe. Any abnormal gantry noise should be treated as a potential mechanical safety issue until proven otherwise.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"CT staff reported the Canon Aquilion scanner stopped during scan setup with gantry vibration and abnormal rotation noise."
Cause
What was observed during troubleshooting.
Example:
"External inspection found no patient accessory contact, table obstruction, loose room equipment, or visible gantry cover issue; fault returned during non-patient system check."
Resolution
What action was taken.
Example:
"Scanner was removed from service, labeled Out of Service, and escalated to Canon service for gantry rotation system evaluation."
Helpful Details to Include (If Known)
- Alarm behavior
- Accessories swapped
- Power behavior
- Environmental factors
- Indicator lights
- Final device status
- Outlet or power condition checked
- Exact error message or fault code
- Whether the fault occurred during scout, helical scan, startup, or rotation test
- Description of noise or vibration
- Whether table or accessories contacted the gantry
- Gantry cover condition
- Room temperature or HVAC concerns
- Any unusual smell, heat, scraping, or grinding
- Whether the issue cleared after restart
Final Thought
Gantry rotation and vibration faults should be handled carefully because they involve moving mechanical parts around the patient area. Clinical Engineering should rule out external causes first, avoid unnecessary repeated rotation attempts, and escalate quickly when abnormal noise or vibration remains. Clear CCR documentation protects the patient, the equipment, and the service history.
That is successful troubleshooting.