Catching Errors: Why Independent QA Matters

1
A single monitor chamber was the source of fluctuating linac outputs. Daily QATM 3 caught it, protecting patients.1
~10%
A patient's spinal cord was overdosed by ~10%. The precise reason why was caught by SunCHECKTM Patient.2
52
A year of weekly trajectory log file measurements on 2 linacs found no errors. Concurrent EPID-based data caught many.3
>1 mm
“It has been clinically observed the log-file derived leaf positions can differ from their actual position by >1 mm.”4

1 T. McCaw, et al., When a Good Monitor Chamber Goes Bad: Diagnosing Atmospheric Communication of a Sealed Monitor Chamber, AAPM 2018
2 Sun Nuclear SunCHECK user internal testing
3 A. Agnew et al., Monitoring daily MLC positional errors using trajectory log files and EPID measurements for IMRT and VMAT Deliveries, Phys. Med. Biol. 59, (2014)
4 B. Neal, et al., A clinically observed discrepancy between image-based and log-based MLC positions, Med Phys. 43, 2933 (2016)