Varian TrueBeam

Calibration or Quality-Control Test Fails

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Asset Type

Radiation Therapy System

Manufacturer

Varian

Model

TrueBeam

What This Guide Helps With

A required calibration or quality-control check fails, will not complete, or produces a result that cannot be accepted.

Step-by-Step Troubleshooting

1. Protect Patients by Withholding Unverified Functions

Do not use an affected treatment, imaging, positioning, or safety function clinically when a required quality-control or calibration check has failed.

Expected outcome: Clinical use is suspended when required verification is not successfully completed.

2. Identify the Exact Failed Test

Record the name of the calibration or quality-control activity, the stage at which it failed, and any displayed message. Determine whether the failure is repeatable.

Expected outcome: The failed verification activity is clearly identified.

3. Verify the Test Setup

Confirm that the correct phantom, fixture, accessory, detector position, couch position, or other approved test equipment is being used and positioned correctly.

Expected outcome: The test setup matches the approved facility or manufacturer procedure.

4. Inspect Test Equipment and Accessories

Check applicable phantoms, fixtures, cables, and accessories for damage, contamination, incorrect assembly, or obvious positioning problems.

Expected outcome: Test equipment is intact, clean, and suitable for use.

5. Confirm System Readiness

Verify that the TrueBeam and required imaging, positioning, workstation, and supporting systems have completed initialization and report normal readiness.

Expected outcome: The system is in the correct operational state for the quality-control test.

6. Check Environmental Conditions

Determine whether room temperature changes, recent power interruptions, construction, equipment relocation, or other unusual environmental conditions could have affected the test.

Do not invent or apply environmental limits unless documented by the manufacturer or facility.

Expected outcome: No obvious environmental condition is invalidating the verification.

7. Repeat the Approved Test Once the Setup Is Corrected

If a clear setup or external issue is found, correct it and repeat the test exactly as required by approved procedures.

Expected outcome: The test completes successfully. If it passes and all requirements are met, troubleshooting can stop.

8. Compare With Known-Good Test Equipment When Appropriate

Where approved and available, substitute a known-good cable, phantom, accessory, or other external test component to determine whether the failure follows the test equipment.

Expected outcome: An external test-equipment problem is either identified or ruled out.

9. Stop After a Persistent Failure

Do not repeatedly adjust calibration or configuration values merely to obtain a passing result. Persistent failures require qualified evaluation.

Expected outcome: The affected system remains unavailable until the failed quality requirement is resolved.

If the Problem Persists

Test setup, accessories, equipment condition, system readiness, and obvious environmental causes have been ruled out. Remaining causes may involve imaging calibration, geometry, detector response, positioning accuracy, treatment-delivery performance, software, or another internal service-level condition.

The device should be:

Medical Physics involvement may be required depending on the failed test and the function affected. Return to service requires successful completion of all applicable verification before patient use.

Knowing when to stop external troubleshooting is proper troubleshooting.

Clinical Use Tip

A failed quality-control result is itself meaningful information; do not adjust the system merely to make the result pass without understanding the cause.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"Radiation Oncology reported that a scheduled TrueBeam imaging quality-control test would not pass."

Cause

What was observed during troubleshooting.

Example:
"Clinical Engineering found the approved test phantom positioned incorrectly for the verification procedure."

Resolution

What action was taken.

Example:
"Clinical Engineering corrected the phantom setup and the qualified team repeated the approved quality-control procedure with an acceptable result."

Helpful Details to Include (If Known)

Final Thought

Quality-control failures should never be cleared by assumption. Verify the setup, accessories, system state, and environment first, then escalate persistent failures to qualified service and Medical Physics as appropriate before clinical use resumes.

That is successful troubleshooting.

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