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Manufacturer
Model
What This Guide Helps With
Detector calibration failures or image artifacts caused by setup, patient positioning, table, room, accessory, or calibration-related issues.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Confirm the patient is not actively being scanned before troubleshooting.
Action:
- Stop the scan if image quality is unsafe for diagnosis.
- Remove the patient from the scanner if repeated calibration or artifact issues occur.
- Notify clinical staff that the scanner should not be used for patient imaging until image quality is verified.
Expected outcome: Patient safety is maintained and no unreliable images are used for diagnosis.
If this resolves the immediate safety concern, continue troubleshooting with the scanner out of patient use.
Verify the Reported Artifact or Calibration Issue
Confirm exactly what is being reported.
Action:
- Ask whether the issue is a detector calibration failure, ring artifact, streak artifact, shading, banding, noisy image, or reconstruction-related artifact.
- Review the affected exam type, protocol, body part, and timing.
- Determine whether the issue occurs on every scan or only certain protocols.
Expected outcome: The issue is clearly defined before parts or internal failures are suspected.
Why it matters: Different artifact patterns can point toward patient motion, metal, calibration drift, detector issues, or reconstruction problems.
Check for Immediate Scan Setup Issues
Rule out common non-equipment causes first.
Action:
- Confirm the patient was centered properly in the gantry.
- Check that positioning aids, straps, blankets, ECG leads, oxygen tubing, or accessories were not in the scan field.
- Ask whether the patient moved during acquisition.
- Check for large metal implants, external hardware, contrast injector tubing, or arm positioning problems.
Expected outcome: Artifact is explained by positioning, motion, or external objects.
If corrected positioning or removal of external objects resolves the image artifact, return the scanner to service after confirming acceptable test images.
Inspect the Gantry Opening and Scan Field
Look for anything physically interfering with image acquisition.
Action:
- Inspect the bore, covers, table pad, head holder, positioning accessories, and scan field.
- Remove loose objects, debris, contrast tubing, ECG wires, or unused positioning devices.
- Verify that no accessory is protruding into the imaging field.
Expected outcome: The scan field is clear and free of artifact-causing objects.
Why it matters: Objects in or near the scan field can create streaking, shading, or unexpected artifact patterns.
Verify Table Positioning and Movement
Table alignment problems can mimic detector or reconstruction issues.
Action:
- Move the table through its normal travel range without a patient.
- Listen for abnormal noise or hesitation.
- Check that the table moves smoothly and returns to expected positions.
- Confirm table height and centering are appropriate.
Expected outcome: Table motion is smooth and positioning appears normal.
If table movement is abnormal, remove the scanner from service and escalate for repair evaluation before continuing clinical use.
Check Room and Environmental Conditions
Environmental problems can affect calibration stability and image quality.
Action:
- Confirm the CT room temperature is within the facility’s normal operating range.
- Check for unusual heat, humidity, water leaks, air conditioning failure, or airflow issues.
- Verify that gantry ventilation openings are not blocked.
- Look for signs of overheating, unusual smell, or warning messages.
Expected outcome: The scanner environment is stable and appropriate for CT operation.
Why it matters: Detector and electronics performance can be affected by temperature instability or poor ventilation.
Confirm System Readiness and Warm-Up Status
Detector calibration and image quality may be affected if the system has not completed normal readiness routines.
Action:
- Confirm the scanner is fully booted and ready.
- Review system messages for warm-up, calibration, detector, reconstruction, or temperature warnings.
- Confirm any required daily startup or quality check process was completed by the imaging team according to site procedure.
Expected outcome: The system is in a ready state with no active warnings preventing proper imaging.
If the system indicates required warm-up or calibration is incomplete, allow the appropriate user-level process to complete before further testing.
Run User-Level Image Quality or Phantom Check if Available
Use site-approved QA checks to confirm whether the artifact is reproducible.
Action:
- Use the facility’s approved CT QA phantom or image quality test process.
- Perform only approved user-level or Clinical Engineering-supported checks.
- Compare image appearance with expected baseline results.
- Note whether artifacts appear in the same location, same slice range, or same protocol.
Expected outcome: Image quality is either confirmed acceptable or the artifact is reproduced under controlled conditions.
Why it matters: A reproducible artifact on a phantom is stronger evidence of equipment-related failure than a single patient image.
Check for Protocol-Specific or Reconstruction-Specific Patterns
Determine whether the problem is linked to scanning or image processing.
Action:
- Ask CT staff whether raw acquisition completed normally.
- Compare different protocols if safe and permitted by site procedure.
- Check whether artifacts appear only after reconstruction, only on certain kernels, or only on certain image series.
- Review whether the scanner console shows reconstruction delays, failed series, or processing errors.
Expected outcome: The issue is narrowed to acquisition, detector calibration, reconstruction, or protocol behavior.
If the issue appears only with certain protocols, escalate to CT applications support or service support as appropriate.
Review Recent Changes or Service Activity
Identify changes that may have triggered the issue.
Action:
- Ask whether there was recent service, software update, calibration, power interruption, tube replacement, detector work, room temperature event, or construction near the scanner.
- Check whether the artifact began immediately after one of these events.
- Review recent work orders for related scanner issues.
Expected outcome: A recent change is identified or ruled out.
Why it matters: Detector calibration and image artifact problems often appear after service activity, environmental changes, or incomplete calibration recovery.
Power Cycle Only if Safe and Appropriate
A controlled restart may clear temporary software or reconstruction issues.
Action:
- Confirm no patient is on the table.
- Confirm with CT staff that the scanner can be taken down.
- Perform a normal shutdown and restart according to facility procedure.
- Do not interrupt power during active shutdown or scanning.
Expected outcome: Temporary software or reconstruction-related issue clears after restart.
If the artifact or calibration failure returns after restart, continue escalation.
Determine Whether the Scanner Can Safely Return to Service
Do not return the scanner to clinical use based only on the absence of an error message.
Action:
- Confirm test imaging or QA results are acceptable.
- Confirm no active detector, calibration, reconstruction, gantry, or system warnings remain.
- Confirm CT staff agree image quality appears clinically acceptable.
- Document the checks performed and final status.
Expected outcome: Scanner is either verified for use or removed from service.
If artifact remains, calibration fails, or image quality cannot be verified, stop troubleshooting and escalate.
If the Problem Persists
If detector calibration errors or image artifacts continue after external checks, positioning issues, room conditions, accessories, table motion, and user-level QA checks have been ruled out, the issue is likely internal.
The scanner should be:
- Removed from service
- Labeled Out of Service
- Sent for Philips service, CT specialist repair, or bench/system evaluation
Possible internal causes may include detector module issues, calibration data problems, data acquisition electronics, reconstruction system faults, tube output instability, gantry electronics, or software-related image processing failure.
Knowing when to stop is proper troubleshooting. CT scanner detector and reconstruction issues can directly affect diagnostic accuracy and should not be guessed through.
Clinical Use Tip
Do not troubleshoot image artifact or calibration issues on an active patient. Move the patient off the scanner, use another imaging pathway if needed, and only continue testing when the scanner is safe to operate without patient risk. Maintain therapy continuity by making sure patient care continues through an alternate imaging pathway or backup scanner when imaging is urgent.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"CT staff reported repeated detector calibration failure and ring-like image artifacts on the Philips Ingenuity CT scanner during routine scanning."
Cause
What was observed during troubleshooting.
Example:
"External scan field, table movement, patient positioning, room conditions, and accessories were checked; artifact remained during controlled image quality testing."
Resolution
What action was taken.
Example:
"Scanner was removed from service, labeled Out of Service, and escalated to Philips service for detector calibration and image acquisition evaluation."
Helpful Details to Include (If Known)
- Whether artifact occurred on patient images, phantom images, or both
- Artifact type: ring, streak, shading, banding, noise, missing data, or reconstruction failure
- Protocols or body regions affected
- Whether artifact appears in the same image location
- Whether detector calibration passed or failed
- Any gantry, detector, reconstruction, or temperature messages
- Recent service, software updates, or power events
- Room temperature or HVAC concerns
- Table movement status
- Accessories or objects found in scan field
- Power behavior, restart results, or system readiness status
- Indicator lights, warnings, or console status messages
- Final scanner status: returned to service or removed from service
Final Thought
Detector calibration and image artifact issues must be handled carefully because they affect diagnostic confidence. Start with patient safety and visible causes, verify the artifact under controlled conditions, and escalate once external causes are ruled out. Strong documentation protects the patient, the technologist, and Clinical Engineering.
That is successful troubleshooting.