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What This Guide Helps With
Image artifacts, poor reconstruction, or distorted CT images caused by setup, patient positioning, calibration, accessory, or system issues.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Confirm the patient is stable and the scan is not being repeated unnecessarily.
Action:
- Stop additional scanning until the artifact or reconstruction concern is understood.
- If imaging is clinically urgent, move the patient to another CT scanner if available.
- Notify the radiologist or CT lead if image quality may affect diagnosis.
Expected: Patient exposure is minimized and clinical care continues safely.
Verify the Reported Image Problem
Review the reported artifact or reconstruction issue with the technologist or radiologist.
Action:
- Identify whether the issue is streaking, rings, banding, motion blur, shading, missing anatomy, poor reformats, or reconstruction failure.
- Determine if the problem occurred on one patient, one protocol, one body region, or all scans.
- Confirm whether raw data, axial images, reformats, or PACS images are affected.
Expected: The issue is narrowed to acquisition, reconstruction, display, or transfer.
Why it matters: CT image problems can come from patient motion, positioning, metal, protocol selection, detector calibration, reconstruction software, or PACS transfer.
Check for Patient Motion or External Causes
Motion and external objects are common causes of poor CT image quality.
Action:
- Ask whether the patient moved, coughed, breathed, or could not follow instructions.
- Check for external metal, jewelry, leads, ECG wires, oxygen tubing, monitoring cables, or positioning aids in the scan field.
- Confirm immobilization aids were used when appropriate.
Expected: Artifact is explained by motion or external objects if only one patient or one study was affected.
If this resolves the issue, document the cause and stop troubleshooting.
Confirm Patient Positioning and Scan Centering
Incorrect positioning can cause shading, truncation, or reconstruction problems.
Action:
- Verify the patient was centered properly in the gantry.
- Confirm the anatomy of interest was fully within the scan field of view.
- Review scout/localizer images for positioning errors.
- Check that arms, shoulders, or positioning devices were not outside the intended field in a way that caused truncation artifact.
Expected: Patient and anatomy are properly centered within the selected field of view.
Why it matters: CT reconstruction depends on accurate geometry and complete projection data.
Review Protocol and Reconstruction Selection
Incorrect protocol or reconstruction settings can create images that appear abnormal even when the scanner is functioning normally.
Action:
- Confirm the correct exam protocol was selected.
- Check slice thickness, kernel/filter, reconstruction field of view, iterative reconstruction setting, and reformatted image settings.
- Compare the current protocol against a known-good protocol for the same exam type.
- Verify pediatric, low-dose, metal artifact reduction, or specialized protocols were not selected by mistake.
Expected: Protocol and reconstruction settings match the intended clinical exam.
If protocol selection caused the issue, correct the protocol use and stop troubleshooting.
Check Recent Changes or Software Behavior
Determine whether the issue began after a configuration, network, or software change.
Action:
- Ask whether there was recent service, software update, protocol editing, network change, or PACS issue.
- Check whether reconstruction jobs are delayed, stuck, failed, or producing incomplete image series.
- Restart only the workstation or reconstruction console if permitted by site policy and if no active patient scan is in progress.
- Confirm normal operation after restart using an approved test or phantom workflow.
Expected: Temporary software or reconstruction queue issues clear after safe restart or job management.
Inspect Accessories and Table-Related Causes
Objects in the imaging path can create artifacts.
Action:
- Inspect the CT table pad, positioning straps, head holder, arm boards, and immobilization devices.
- Remove damaged, wet, folded, contaminated, or incorrect accessories from the scan field.
- Check for contrast spills, foreign objects, or dense materials under the patient.
- Confirm approved CT-compatible accessories are being used.
Expected: No accessory or table item is causing attenuation or streak artifact.
Check Gantry, Bore, and Visible Obstructions
Visible contamination or obstruction can affect image quality.
Action:
- Inspect the gantry opening for obvious foreign material, loose covers, damaged panels, or debris.
- Check for fluid spills, contrast leakage, tape, packaging, or patient items near the bore.
- Listen for abnormal gantry noise during a non-patient movement check if site policy allows.
- Do not remove covers or access internal gantry components.
Expected: Gantry area is clean, intact, and free of visible obstruction.
Perform Approved Quality Control or Phantom Check
Use the site-approved CT QC process to determine whether the artifact is reproducible without a patient.
Action:
- Run the appropriate daily QC, air calibration, water phantom, or image quality check according to local procedure.
- Review whether the artifact appears on phantom images.
- Note any failed calibration, detector, tube, gantry, or reconstruction-related warnings.
- Compare results to prior QC records if available.
Expected: QC passes and images are free of artifacts.
If QC fails or the artifact appears on phantom images, remove the scanner from clinical use and escalate.
Check Reconstruction Console and Storage Status
Reconstruction issues may occur if the system cannot process or store image data correctly.
Action:
- Verify the reconstruction console is powered on and responsive.
- Check for full storage, frozen applications, failed reconstruction jobs, or excessive backlog.
- Confirm image series are being generated completely before transfer to PACS.
- Check whether the issue is local to the CT console or only appears after network/PACS transfer.
Expected: Reconstruction completes normally and images are available locally before transfer.
Why it matters: A PACS or network issue can look like a reconstruction issue if images are missing, delayed, or incomplete.
Verify Network and PACS Transfer Separately
If reconstructed images look correct locally but wrong or incomplete in PACS, troubleshoot the image transfer path.
Action:
- Confirm local CT images are complete and usable.
- Check whether all expected series were sent to PACS.
- Resend the affected series if appropriate.
- Verify network connectivity and DICOM destination status.
- Contact PACS or IT support if local images are normal but PACS images are missing, incomplete, or displayed incorrectly.
Expected: The scanner reconstruction is confirmed separate from PACS transfer or display issues.
Review System Messages and Error Logs at the Operator Level
Check for visible system messages without performing internal service procedures.
Action:
- Review current system alerts, reconstruction errors, calibration messages, or detector-related warnings.
- Record exact error text, time, scan protocol, and affected exam.
- Avoid clearing service messages before documentation unless required for safe workflow.
- Do not perform service-level calibration or internal diagnostics unless authorized.
Expected: Any system fault information is captured for service evaluation.
If the Problem Persists
If image artifacts or reconstruction issues continue after patient motion, positioning, accessories, protocol selection, QC, reconstruction console status, and PACS transfer have been checked, the likely cause is internal or service-level.
Possible internal causes may include detector calibration failure, data acquisition fault, reconstruction hardware/software failure, tube or generator instability, gantry alignment issue, or system storage failure.
The device should be removed from service if image quality may affect diagnosis, labeled Out of Service, escalated to Philips service, imaging service, or qualified CT repair support, and held from patient use until image quality and reconstruction performance are verified.
Knowing when to stop is proper troubleshooting. CT image quality issues can affect diagnosis and patient dose, so continued clinical use should not be allowed when image integrity is uncertain.
Clinical Use Tip
Do not troubleshoot image artifact problems by repeatedly scanning patients. Use phantom testing, approved QC workflows, prior images, and local image review whenever possible to reduce unnecessary radiation exposure.
Do not troubleshoot on an active patient. Move the patient to a backup scanner first when imaging must continue, and protect therapy or care continuity by coordinating with CT staff and the radiologist.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"CT staff reported streak artifacts and incomplete reconstructed image series on a Philips Brilliance CT scan."
Cause
What was observed during troubleshooting.
Example:
"Patient motion and external objects were ruled out, protocol settings were verified, and phantom QC reproduced image artifacts."
Resolution
What action was taken.
Example:
"Scanner was removed from service, labeled Out of Service, and escalated to Philips service for detector/reconstruction system evaluation."
Helpful Details to Include (If Known)
- Exact artifact type observed
- Body region and protocol used
- Whether one patient or multiple patients were affected
- Whether artifact appears on scout, axial, reformatted, or PACS images
- Patient motion or metal present
- Positioning and centering verified
- Accessories removed or inspected
- Power behavior or restart behavior of the reconstruction console
- Environmental factors such as temperature, humidity, recent room work, or contrast spill
- QC or phantom results
- Reconstruction job status
- Local console image status
- PACS transfer status
- Indicator lights or visible system alerts
- Exact system messages or error codes
- Date and time of occurrence
- Final scanner status
Final Thought
CT image artifacts and reconstruction problems should be approached logically and safely. Rule out patient motion, positioning, protocol selection, accessories, and PACS transfer before assuming scanner failure. If QC fails or image integrity is uncertain, remove the system from service and document the findings clearly.
That is successful troubleshooting.