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What This Guide Helps With
Troubleshooting failed SPECT daily QC, uniformity, center-of-rotation, detector, phantom, or acquisition setup issues before repair escalation.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Confirm the Symbia Intevo is not being used for an active patient study.
If daily QC, uniformity, or center-of-rotation testing fails before clinical use, do not release the system for patient imaging until QC status is resolved according to site policy.
Expected outcome: Patient imaging is not performed on a system with questionable SPECT image quality.
Confirm the Exact QC Failure
Review the failed QC result and determine whether the issue involves:
- Daily SPECT QC failure
- Flood uniformity failure
- Intrinsic or extrinsic uniformity issue
- Center-of-rotation failure
- Detector head mismatch
- Unexpected count rate issue
- Energy window or photopeak issue
- Motion or gantry-related failure during acquisition
- Processing or workstation error during QC review
Expected outcome: The failure is identified before repeating tests or requesting service.
Verify the Correct QC Procedure Was Used
Confirm the technologist used the correct daily QC workflow for the Symbia system and selected the correct detector, collimator, isotope, and protocol.
Siemens provides a Symbia QC schedule job aid for recommended nuclear medicine quality control scheduling across Symbia scanners.
Expected outcome: The failure is not caused by the wrong QC test, wrong protocol, or missed required setup step.
If this resolves the issue, document the setup correction and stop.
Check Source, Phantom, and Count Setup
Verify the correct flood source, point source, or phantom was used for the specific QC test being performed.
Confirm the source activity, source placement, distance, orientation, and expiration or decay status are appropriate for the procedure.
Expected outcome: QC failure is not due to low activity, poor positioning, wrong source type, or improper phantom setup.
If this resolves the issue, repeat QC and stop.
Check Collimator Selection and Installation
Confirm the expected collimator is installed for the QC procedure.
Inspect that the collimator is fully seated, latched, and recognized by the system if applicable.
Look for obvious external damage, contamination, or incorrect collimator use.
Expected outcome: The detector is being tested with the correct and secure collimator configuration.
If this resolves the issue, repeat QC and stop.
Inspect Detector Face and External Surfaces
Visually inspect the detector face, collimator surface, and phantom/source area for contamination, fluid, adhesive residue, physical obstruction, or shielding material.
Do not disassemble the detector or access internal detector components.
Expected outcome: External contamination or obstruction is ruled out as a cause of nonuniformity or count loss.
If this resolves the issue, clean according to approved site procedure, repeat QC, and stop.
Confirm Room and System Conditions
Verify the room is clear of unexpected radioactive sources, recent spills, contaminated linen, radioactive waste, or high activity patients near the detector during QC.
Confirm the system had adequate warm-up time if required by local procedure.
Expected outcome: Background activity, contamination, or unstable operating conditions are not affecting QC results.
If this resolves the issue, repeat QC after the room condition is corrected and stop.
Review Detector and Gantry Positioning
Confirm the detector heads, table, gantry, and source/phantom are positioned correctly for the selected QC test.
For center-of-rotation testing, verify the point source or phantom is positioned according to the site’s approved procedure and is not shifted, tilted, or moving during acquisition.
Expected outcome: COR failure is not caused by mechanical setup error or incorrect source alignment.
If this resolves the issue, repeat QC and stop.
Check for Motion, Collision, or Mechanical Interruption
Ask whether the detector head, gantry, table, or source moved unexpectedly during the QC acquisition.
Check for interrupted motion, limit messages, collision warnings, emergency stop activation, or gantry/table positioning errors.
Expected outcome: The QC failure is separated from a mechanical motion or positioning problem.
If mechanical motion is abnormal, remove the system from clinical use and escalate for service evaluation.
Confirm Acquisition Completed Normally
Review whether the QC acquisition completed without aborting, freezing, or generating system errors.
Check for workstation messages, detector communication errors, acquisition software faults, or processing failures.
Expected outcome: The failure is separated into image quality failure versus acquisition or processing failure.
If the acquisition or processing workflow failed, escalate as a workstation, communication, or acquisition subsystem issue.
Repeat QC Once After Correcting External Causes
After correcting any setup, source, phantom, room, or positioning issue, repeat the failed QC test once.
Do not repeatedly rerun failed QC in an attempt to “pass” the system without identifying a cause.
Expected outcome: A corrected external issue results in a valid passing QC result.
If this resolves the issue, document the cause and final QC status.
Compare With Recent QC History
Review recent daily QC, uniformity, and center-of-rotation trends if available.
Look for gradual degradation, sudden failure after service, detector head differences, repeat failures on the same head, or failures tied to a specific collimator or protocol.
Expected outcome: The issue is recognized as either an isolated setup problem or a repeatable system performance concern.
Check CT QC Status If Hybrid Imaging Is Involved
If the complaint involves SPECT/CT alignment, hybrid workflow, or CT-related correction, verify CT daily QC/checkup status per site procedure.
EANM guidance notes that daily CT QC for SPECT / CT Systems should be performed according to manufacturer-recommended procedures.
Expected outcome: SPECT QC concerns are not confused with CT QC, attenuation correction, or hybrid alignment concerns.
If CT QC also fails, remove the system from clinical use and escalate appropriately.
If the Problem Persists
If the Symbia Intevo continues to fail SPECT daily QC, uniformity, or center-of-rotation testing after source setup, phantom positioning, room conditions, collimator status, acquisition setup, and basic system workflow have been checked, common external causes have been ruled out.
The system should be removed from service, labeled Out of Service, and sent for Siemens service evaluation or qualified nuclear medicine imaging system repair.
Possible internal or service-level causes may include detector calibration drift, detector electronics issues, crystal/PMT-related problems, gantry motion accuracy problems, center-of-rotation calibration issues, acquisition electronics faults, or workstation processing issues.
Knowing when to stop is proper troubleshooting. A SPECT / CT System that cannot pass required QC should not be released for patient imaging.
Clinical Use Tip
Do not troubleshoot daily QC, uniformity, or center-of-rotation problems during active patient imaging. If clinical imaging is needed, move the patient schedule to another approved scanner or follow the department downtime process until QC status is acceptable.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Nuclear Medicine reported that the Siemens Symbia Intevo failed SPECT daily QC with a uniformity/COR failure before patient imaging."
Cause
What was observed during troubleshooting.
Example:
"Checked QC setup, source positioning, room contamination concerns, collimator seating, detector positioning, and acquisition workflow; failure repeated after external causes were ruled out."
Resolution
What action was taken.
Example:
"Removed the Symbia Intevo from clinical use, labeled the system Out of Service, documented failed QC behavior, and escalated for Siemens service evaluation."
Helpful Details to Include (If Known)
- QC test that failed
- Detector head affected
- Intrinsic or extrinsic test
- Uniformity values or failure message
- Center-of-rotation result or error
- Source type and activity
- Phantom or point source used
- Collimator installed
- Room background or contamination check
- Whether QC was repeated
- Any gantry, table, or detector motion errors
- Any workstation or acquisition error messages
- CT QC status if hybrid imaging was involved
- Final device status
Final Thought
SPECT daily QC, uniformity, and center-of-rotation failures must be handled carefully because they directly affect image quality and diagnostic reliability. Clinical Engineering should rule out setup, source, phantom, collimator, positioning, and room-condition issues first, then stop and escalate when the system continues to fail. Clear CCR documentation helps Siemens service, Nuclear Medicine, and leadership understand the risk, the actions taken, and why the system was not released for patient use.
That is successful troubleshooting.