Varian TrueBeam

Exposure or Scan Will Not Start or Is Aborted

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Asset Type

Radiation Therapy System

Manufacturer

Varian

Model

TrueBeam

What This Guide Helps With

An imaging exposure, acquisition, scan, or related treatment workflow will not begin or stops unexpectedly after initiation.

Step-by-Step Troubleshooting

1. Protect the Patient and Stop the Clinical Workflow

If an exposure, acquisition, or treatment-related operation fails or aborts unexpectedly, do not repeatedly retry while the patient remains dependent on the system. Place the patient in a safe condition and notify the responsible Radiation Oncology team.

Expected outcome: Patient safety and treatment continuity are addressed before troubleshooting begins.

2. Determine Exactly What Failed

Identify whether the problem involves imaging acquisition, a treatment-related sequence, or another requested exposure/scan function. Record the message shown and whether the process failed before initiation or aborted after starting.

Expected outcome: The failed function and stage of failure are known.

3. Check System Readiness

Confirm that the TrueBeam has completed startup and that required imaging, positioning, workstation, and safety systems report ready.

Expected outcome: All required subsystems are available before another test is attempted.

4. Verify Room and Safety Conditions

Check accessible room interlocks, emergency-stop status, doors, and other externally observable safety conditions. Never bypass an interlock to initiate an exposure or treatment sequence.

Expected outcome: No external safety condition is inhibiting initiation.

5. Verify Patient and Equipment Positioning

Inspect the treatment couch, gantry area, imaging hardware, accessories, and immobilization devices for improper positioning or physical interference.

Expected outcome: Required components are positioned correctly and movement or acquisition paths are unobstructed.

6. Review User-Accessible Workflow Conditions

Confirm that the requested clinical workflow is properly prepared, required selections are complete, and no obvious user-accessible setting or pending acknowledgment is preventing initiation.

Do not change clinical treatment parameters simply to bypass an inhibit.

Expected outcome: The intended procedure is correctly prepared without unauthorized changes.

7. Check Supporting Hardware and Communications

Verify that required workstations, imaging components, input devices, and accessible network connections are responsive.

Expected outcome: Supporting systems required for the exposure or scan are available and communicating.

8. Repeat Only an Appropriate Controlled Test

After correcting an identified external condition, perform an approved non-patient functional verification or other facility-authorized test.

Expected outcome: The requested function starts and completes normally. If it does, troubleshooting can stop after required verification.

9. Escalate Repeated or Unexplained Aborts

Do not continue repeated exposure or treatment attempts when the system continues aborting or the reason is not clearly understood.

Expected outcome: A system with unresolved exposure or acquisition failure remains unavailable for clinical use.

If the Problem Persists

External readiness conditions, room interlocks, positioning, workflow state, supporting hardware, and accessible communications have been ruled out. Remaining causes may involve internal control systems, imaging hardware, treatment-delivery interlocks, software, safety circuits, or other service-level conditions.

The device should be:

Before return to service, the affected acquisition or treatment-related function must pass all required functional, safety, imaging, and treatment-system checks.

Knowing when to stop external troubleshooting is proper troubleshooting.

Clinical Use Tip

Repeatedly clearing an unexplained abort and retrying is not an acceptable substitute for identifying why the system prevented or stopped the requested operation.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"Radiation Oncology reported that imaging acquisition on the TrueBeam would not start and the workflow remained inhibited."

Cause

What was observed during troubleshooting.

Example:
"Clinical Engineering found that an imaging component had not reached its required external operating position."

Resolution

What action was taken.

Example:
"Clinical Engineering corrected the component position and verified successful imaging initiation and completion using an approved functional test."

Helpful Details to Include (If Known)

Final Thought

An aborted or inhibited radiation-system workflow must be treated as a safety condition until the cause is understood. Verify external interlocks, positioning, readiness, and communications first, then escalate instead of bypassing or repeatedly retrying unexplained failures.

That is successful troubleshooting.

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