field-guide

Varian Clinac iX — Engineer Field Guide

Back to: Varian Clinac iX.

Therapy device — the rules are different

A linac delivers dose to patients. Downtime affects cancer schedules. Morning QA, monthly output constancy, and annual TG-142 are mandatory and signed by a qualified medical physicist. Never bypass an interlock.

The expensive failure modes

  1. Klystron end-of-life → filament current drops, system interlocks. Major parts event. Plan replacement on schedule.
  2. Waveguide vacuum leaks → catastrophic. Circulator, klystron, bend magnet can take collateral damage.
  3. MLC leaf motor failures → stuck leaves prevent treatment plans. Leaves wear asymmetrically.
  4. Cooling / chilled water faults → flow alarm = stop, now. Not optional.
  5. Thyratron degradation → scheduled consumable. Replace on interval.

Interlock culture

The iX has an extensive interlock table. When one trips, it's protecting someone — patient, operator, or the machine. Never bypass. Document, diagnose, resolve.

Accepting a refurbished Clinac iX