How should the V10 or V12 be defined when evaluating intracranial SRS plans?

Milano et al., as part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy investigating normal tissue complication probability (HyTEC), published a review of 51 studies in 2020 and evaluated the risk of symptomatic radiation necrosis based on a defi...

I consider V10 and V12 for brain-GTV as this is the way it was done in a report by Minniti et al (Radiat Oncol. 2011 May 15;6:48). However, some of the other studies did use (brain + GTV). In the same report, I believe they looked at statistics per lesion treated.

When I collected the data for the paper I authored on 12 Gy volume for GKS I included the brain and GTV as the target receiving 12 Gy, so the GTV was not subtracted out. I also did the analysis on a per lesion basis.

I have always used this number as a predictor for the patient and myself of how like...