When completing radiation treatment planning on a 4D scan do you prefer the average or free breathing scan for dose calculation?

We always plan on the average. If we are treating while the patient is free breathing, we plan on the average of all phases. If we are treating with gating, we plan on the average of the phases we are treating on (30-70 is our most common).

I am not aware of any prospective data on this, but we do not use average scan for planning when treating free breathing or gated. We just use the free-breathing scan for calculation.

At my previous institution there was a period of time we used MIP(on which we contoured ITV) for calculation of lun...

Since this question was posted in 2019, is anyone aware of strong data for utilizing avg for planning vs the free breathing scan? How do you approach situations where patients cannot breathe regularly despite coaching/anxiolytic medications etc, and the 4D scan has extensive artifacts?