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Manufacturer
Model
What This Guide Helps With
Tube, generator, exposure, or high-voltage errors that prevent scan initiation or interrupt CT operation.
Step-by-Step Troubleshooting
1. Ensure Patient Safety First
Stop the scan attempt and confirm the patient is safe before troubleshooting.
Action:
- Do not continue repeated exposure attempts.
- Remove the patient from the scanner if the system cannot safely complete the exam.
- Notify CT staff that the unit should not be used until the issue is evaluated.
Expected Outcome:
Patient exposure risk is controlled and the CT scanner is not repeatedly forced into failed exposure attempts.
2. Verify the Reported Error
Confirm the exact error message, code, or system behavior.
Action:
- Ask CT staff when the error occurred: startup, warm-up, scout, axial scan, helical scan, or during exposure.
- Record the displayed error message or code.
- Note whether the system aborted exposure, inhibited exposure, shut down, or displayed a generator/tube warning.
Expected Outcome:
The reported tube or generator issue is confirmed and documented accurately.
3. Check for Active Patient or Exam Status Issues
Make sure the system is not locked in a failed or incomplete exam state.
Action:
- Confirm whether an exam is still open.
- Have CT staff properly end or close the failed exam if safe to do so.
- Return the system to a normal ready state if possible.
Expected Outcome:
If the issue was caused by an incomplete exam state or software lockout, the system may return to normal operation.
If this resolves the issue, document the finding and stop.
4. Check Emergency Stop and Room Safety Interlocks
Exposure may be inhibited if a safety circuit is active.
Action:
- Verify that the CT gantry emergency stop is not pressed.
- Check operator console emergency stop status.
- Confirm scan room doors are fully closed if connected to interlock monitoring.
- Look for any system message indicating exposure inhibit, door open, or safety interlock active.
Expected Outcome:
All safety interlocks are normal and exposure is not being blocked externally.
If this resolves the issue, document the reset or interlock correction and stop.
5. Confirm Stable Facility Power
Tube and generator faults can occur if incoming power is unstable or interrupted.
Action:
- Verify the CT system is connected to normal facility power.
- Ask if there were recent power events, generator transfers, brownouts, breaker trips, or UPS alarms.
- Check for power-related alarms at the CT power distribution area, if accessible and within Clinical Engineering responsibility.
- Do not open energized CT power cabinets unless qualified and authorized.
Expected Outcome:
No obvious external power issue is present.
If a facility power issue is found, involve Facilities or the appropriate electrical support team before further scanner troubleshooting.
6. Perform a Controlled System Restart if Appropriate
Temporary software or communication faults may clear after a proper restart.
Action:
- Coordinate with CT staff.
- Ensure no patient is in the scanner.
- Follow the site-approved shutdown and startup process for the Canon Aquilion system.
- Allow the system to fully initialize before retesting.
Expected Outcome:
The scanner boots normally and tube/generator errors clear if caused by a temporary communication or software state issue.
If this resolves the issue, document the restart and successful return to service.
7. Check Tube Warm-Up Status
Tube or generator errors may occur if warm-up is incomplete, skipped, or interrupted.
Action:
- Ask CT staff whether the tube warm-up was completed.
- Confirm whether the error occurred during warm-up or immediately after.
- Have qualified CT staff perform the normal tube warm-up procedure if the system allows it and no hard fault is active.
Expected Outcome:
Warm-up completes without fault and the system returns to ready status.
If warm-up fails again, stop repeated attempts and escalate.
8. Check for Tube Heat or Cooling-Related Warnings
The system may inhibit exposure if tube heat limits or cooling conditions are outside safe range.
Action:
- Check the console for tube heat, cooling, or waiting messages.
- Ask whether the scanner was used heavily before the fault.
- Allow the system to cool if a heat-related message is present.
- Verify room temperature and airflow are within expected clinical operating conditions.
- Check for blocked cabinet vents or abnormal room heat.
Expected Outcome:
If the fault was heat-related, the system may recover after cooling and returning to normal operating temperature.
If the same error returns after cooldown, remove the scanner from service and escalate.
9. Inspect External Gantry and Cabinet Conditions
Look for obvious signs of overheating, electrical odor, or abnormal operation.
Action:
- Visually inspect around the gantry, generator cabinet, and system electronics cabinets.
- Check for unusual sounds, burnt smell, excessive heat, visible fluid intrusion, or tripped external indicators.
- Do not remove covers or access high-voltage areas during basic troubleshooting.
Expected Outcome:
No obvious external hazard is present.
If unusual heat, smell, smoke, or electrical noise is present, stop immediately, remove the scanner from service, and escalate urgently.
10. Check Operator Console Communication
Some generator or tube messages may be triggered by communication loss between the console, gantry, and generator subsystem.
Action:
- Confirm the operator console is responsive.
- Check whether gantry controls, table controls, and system status screens respond normally.
- Note whether the error appeared after a network, software, or console freeze.
- Restart only if safe and site procedure allows.
Expected Outcome:
The console and scanner subsystems communicate normally.
If communication errors continue with tube/generator faults, escalate for service evaluation.
11. Attempt Only One Controlled Functional Retest
After external checks and a proper restart, perform a limited retest only if the system appears safe.
Action:
- Ensure no patient is in the scanner.
- Have authorized CT staff perform the appropriate system readiness check or phantom/non-patient test if allowed by site policy.
- Observe whether the same tube/generator error returns.
Expected Outcome:
System completes readiness testing without exposure faults.
If the error returns, stop troubleshooting and remove the scanner from service.
If the Problem Persists
If tube or generator errors continue after checking safety interlocks, power, system state, warm-up status, cooling conditions, and controlled restart, common external causes have been ruled out.
The issue is likely related to an internal tube, high-voltage generator, inverter, cable, cooling, control, or communication fault.
The device should be removed from service, labeled Out of Service, and escalated for Canon service, vendor repair, or qualified CT bench/system evaluation.
Knowing when to stop is proper troubleshooting. CT tube and generator systems involve high voltage, radiation exposure control, and critical safety circuits. Do not continue repeated exposure attempts or perform internal repair without proper training and authorization.
Clinical Use Tip
Do not troubleshoot tube or generator errors with a patient on the table unless the troubleshooting is limited to safe observation and immediate removal from service. Move the patient to another scanner or reschedule the exam before performing restart, warm-up, or retest steps so therapy continuity and patient care are maintained.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"CT staff reported that the Canon Aquilion scanner displayed a tube/generator error during scan initiation and would not complete exposure."
Cause
What was observed during troubleshooting.
Example:
"Verified recurring exposure inhibit after checking emergency stops, room interlocks, system status, cooling condition, and facility power with no external cause identified."
Resolution
What action was taken.
Example:
"Removed CT scanner from service, labeled unit Out of Service, documented error behavior, and escalated to Canon service for tube/generator system evaluation."
Helpful Details to Include (If Known)
- Exact error message or code displayed
- When the error occurred: startup, warm-up, scout, axial, helical, or exposure
- Whether the exam was interrupted or exposure was inhibited
- Emergency stop and door interlock status
- Facility power condition or recent power events
- Tube warm-up result
- Tube heat or cooling messages
- Room temperature or ventilation concerns
- Any unusual sounds, odor, heat, or visible cabinet indicators
- Whether restart was performed
- Whether the error returned after retest
- Final device status
Final Thought
Tube and generator errors on a Canon Aquilion CT scanner should be handled carefully because they involve radiation control, high voltage, and patient safety. Clinical Engineering should rule out external causes first, avoid repeated failed exposure attempts, and escalate once the issue points to the internal tube or generator system. Clear CCR documentation helps the vendor or imaging specialist continue troubleshooting efficiently.
That is successful troubleshooting.