Elekta MLC

Stephen Amadon

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Jul 7, 2025, 7:40:08 PMJul 7

to Pylinac

Not necessarily a Pylinac question, BUT Just wondering if anyone uses Pylinac for MLC QA with VersaHD? I'm trying to set up MLC QA for a Versa HD and since I'm used to Varian Linacs I'm finding it weird to get the typical DRGS and MLCspeed tests done.

Thanks,

Steve

Dan Kirby

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Jul 11, 2025, 6:51:16 AMJul 11

to Pylinac

Hi Stephen,

Welcome to the world of Elekta! Where you aren't given any MLC QA tools out of the box... it might be that AQUA users have some tests provided, but I wouldn't know.

Elekta have a VMAT-CAT dynamic picket fence analysis tool, but it's a MATLAB based, a bit clunky and I didn't like the analysis method where positions are all relative so it might not pick up systematic MLC offsets to a whole leafbank. I have written (long ago) my own customised MLC picket fence that first finds the radation isocentre and all picket positions are set relative to that. However it's a step and shoot test, so we are currently looking into implementing the VMAT accuracy test described in IPEM81 (Bedford et al), to test gantry rotation, dose rate and MLC synchronisation, although it's far from straight forward, and I don't know any other centres that do it! Otherwise, we rely mostly on standard VMAT plans being delivered monthly to our PSQA device and checking for consistency against a baseline measurement.

Best wishes,

Dan

Dan Kirby

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Jul 11, 2025, 6:55:23 AMJul 11

to Pylinac

I should add, if there's a way to get the PyLinac tests working with an Agility MLC then that would be very useful! I've not looked at it recently but in the past I assumed it would only work on Varian MLC images... and I don't know what the beam prescriptions would need to be.