Should density overrides for VMAT lung SBRT planning be utilized for small mobile tumors?

I don't think it's a huge issue to change it, but I/we don't usually do that. VMAT plans are very robust to density changes so I bet if you looked between the plans it would be a very subtle difference....like less than 5% if I had to guess. We don't do it that way because it's a bit of a cheat (or,...

The following reference offers a word of caution: Zou et al, Dynamic simulation of motion effects in IMAT lung SBRT., Radiat Oncol, 2014 9:225.

This study calculated the magnitude of dose deviation which can be attributed to the "interplay effect" for both the target and organs at risk in a series ...

The paper referred to by @Dr. First Last is Xiao et ao, IJROBP, 2009, 73(4): 1235-1242

It actually showed that with heterogeneity correction applied, the percent of PTV receiving 60 Gy was reduced, largely due to the physical issue of not having so much depth of high density tissue in the ITV to rea...