TG-142
AAPM Task Group 142 — the consensus standard for linear-accelerator quality assurance. Defines daily, monthly, and annual test schedules. Signed by a Qualified Medical Physicist.
Why it matters to buyers: Physicist-signed. A linac that fails TG-142 is not clinical-use-ready. Refurb purchases must include TG-142 baseline survey before patient #1.
Why it matters to engineers: Daily output constancy is the most-frequent test; annual is comprehensive (beam data, MLC end-to-end, imaging chain, dose rate, mechanical accuracy).