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What This Guide Helps With
Troubleshooting detector head motion, positioning, collision avoidance, or proximity sensor faults using safe external checks before repair escalation.
Step-by-Step Troubleshooting
Ensure Patient Safety First
Confirm the patient is not in contact with the detector heads, table, gantry, or CT bore area.
If the fault occurs during an active exam, have clinical staff stop motion, keep the patient still, and follow site safety procedures before moving the system.
Expected outcome: The patient is protected from unintended detector, table, or gantry movement.
Confirm the Exact Motion or Positioning Complaint
Ask the operator what motion failed and when it occurred.
Determine whether the issue involves:
- Detector head will not move
- Detector head stops during positioning
- Detector head position is inaccurate
- Proximity or collision warning appears
- Detector head will not move close to patient
- Gantry rotation or detector orbit stops
- Table and detector alignment issue
- Intermittent fault during setup or acquisition
Expected outcome: The problem is separated into motion control, positioning accuracy, proximity sensing, or operator workflow.
Stop and Inspect for Obvious Obstructions
Look around the detector heads, patient table, gantry opening, and floor area.
Check for linens, straps, IV poles, cables, patient belongings, step stools, positioning aids, or anything blocking detector travel.
Expected outcome: No external object is interfering with detector or gantry movement.
If an obstruction is found and safely removed, retest motion only when the area is clear. If normal motion returns, document the obstruction and stop.
Verify the Patient and Accessories Are Positioned Correctly
Confirm the patient is centered and not extending unexpectedly into detector travel paths.
Check that arm boards, head holders, cushions, straps, or immobilization devices are properly secured and not triggering proximity sensors.
Expected outcome: Positioning accessories are not falsely creating a collision or proximity condition.
Check Emergency Stop and Motion Disable Conditions
Verify that all emergency stop buttons are released.
Check the console and system indicators for emergency stop, interlock, or motion-disabled messages.
Expected outcome: Motion is not being blocked by an active safety stop or interlock condition.
If an emergency stop was active, reset according to site procedure and verify the system returns to a safe ready state before testing motion.
Review the Displayed Error or Warning Message
Record the exact fault message, code, affected axis, detector head, or proximity sensor description shown at the console.
Do not clear the message before capturing useful details for service documentation.
Expected outcome: The fault information is preserved for troubleshooting and escalation.
Power Cycle Only When Safe and Appropriate
If no patient is at risk and the exam workflow allows it, perform an approved system restart or application restart according to site procedure.
Do not repeatedly reset the system to bypass a motion or collision safety fault.
Expected outcome: Temporary software or initialization issues may clear, but recurring safety faults are not ignored.
Test Detector Motion Without a Patient Present
With the room clear and the detector travel area unobstructed, have qualified staff attempt basic detector positioning or home/reference movement.
Observe whether the detector head moves smoothly, stops immediately, moves unevenly, or faults at a repeatable position.
Expected outcome: The failure pattern is identified without risking patient contact.
If motion works normally with the patient and accessories removed, the original issue may have been positioning, accessory, or proximity-related.
Check for Physical Damage or Mechanical Binding
Visually inspect the detector head area, covers, rails, cable guides, and accessible motion paths for impact damage, loose covers, abnormal gaps, or signs of collision.
Listen for unusual grinding, clicking, scraping, or motor strain during safe test movement.
Expected outcome: No obvious external damage or mechanical interference is present.
If unusual noise, binding, impact damage, or burning smell is present, stop testing and remove the system from service.
Check Proximity Sensor Areas
Inspect the detector face, proximity sensing surfaces, covers, and surrounding areas for debris, tape, cleaning residue, cracked covers, fluid contamination, or objects near the sensing zone.
Expected outcome: Proximity sensors are not being blocked, contaminated, or falsely triggered by an external condition.
Confirm Room and Table Conditions
Check whether the patient table position, table height, gantry angle, detector configuration, or scan protocol is preventing motion.
Some positioning faults may occur when the system is outside the allowed movement range or when detector motion is restricted by the selected workflow.
Expected outcome: The system is being moved within its expected safe operating range.
Attempt the Motion from Standard Operator Controls
Verify whether the fault occurs from the gantry controls, table controls, hand control, or software console.
Compare whether one control path fails while another works.
Expected outcome: The issue is narrowed to a control input, motion axis, detector head, or system-level fault.
Check Whether the Fault Is Repeatable
Determine whether the detector stops at the same position, same angle, same distance from the patient, or same point in the acquisition setup.
Expected outcome: A repeatable fault suggests a sensor, encoder, calibration, axis, or mechanical limit issue rather than random operator error.
Review Recent Events
Ask whether the system recently had:
- A detector or gantry collision
- Room cleaning or floor work
- Service activity
- Power interruption
- Failed calibration or quality control
- New accessories or positioning devices introduced
- Repeated proximity warnings on specific exam types
Expected outcome: Recent changes are identified before assuming component failure.
Run Only Approved Operator-Level Checks
If available to Clinical Engineering and allowed by site policy, review system status, error logs, and available motion/proximity diagnostics.
Do not bypass safety circuits, defeat proximity sensors, open motion assemblies, or perform internal detector adjustments without proper service authorization.
Expected outcome: External and software-visible causes are checked without compromising safety systems.
If the Problem Persists
If the detector head motion, positioning, or proximity sensor fault remains after external obstructions, patient positioning, accessories, emergency stops, room conditions, and basic controls have been checked, the issue is likely internal to the motion control, proximity sensor, encoder, calibration, drive, or gantry safety system.
The Symbia Intevo should be:
- Removed from clinical use
- Labeled Out of Service
- Escalated for Siemens service or qualified imaging service evaluation
- Kept unavailable for patient imaging until safe detector motion and collision avoidance operation are verified
Knowing when to stop is proper troubleshooting. Detector head motion and proximity systems are patient safety functions and should not be bypassed to complete an exam.
Clinical Use Tip
Do not troubleshoot detector head motion around an active patient unless the immediate goal is to safely stop motion and protect the patient. Move the patient away from the system before testing detector movement, proximity sensors, or gantry positioning.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Nuclear Medicine reported the Symbia Intevo detector head stopped during patient positioning and displayed a proximity or motion fault."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found no patient contact, obstruction, emergency stop condition, or accessory interference, and the detector fault repeated during room-clear motion testing."
Resolution
What action was taken.
Example:
"System was removed from service, labeled Out of Service, fault details were documented, and Siemens service was requested for detector motion/proximity system evaluation."
Helpful Details to Include (If Known)
- Exact detector head involved, if known
- Fault message or error code
- Whether a patient was on the table
- Whether motion stopped during setup, orbit, acquisition, or homing
- Whether the issue occurs at the same position each time
- Emergency stop status checked
- Obstructions or accessories found
- Table position and detector configuration
- Unusual sounds, vibration, heat, or smell
- Whether restart changed the symptom
- Final device status
Final Thought
Detector motion and proximity faults should always be handled with patient safety first. Rule out simple external causes such as obstructions, positioning aids, emergency stops, and accessories before assuming internal failure. If the system continues to fault, escalation is appropriate because detector motion and collision avoidance are critical safety functions. Clear CCR documentation helps service teams understand what was checked and why the system was removed from use.
That is successful troubleshooting.