For large AVMs that cannot meet the V12 dose constraint, how low are you willing to go in terms of single fraction dosing?

We usually use a “volume staging” approach by treating part of the AVM to 18-20 Gy in one fraction (meeting the V12 dose constraint), and return to treat the remaining nidus about 2 years later. Generally, most or all of the treated nidus has occluded by then. There will, of course, be some dose ove...

I would not go much below 18 Gy. The dose-response really falls off sharply after that for a single fraction, so the various forms of staging are likely equivalent at that point. I have reluctantly pushed V12 up to 12.5 cc in some select situations, but generally stick to 10 cc as my threshold to st...

Can this staging be done at a shorter interval (i.e., at 4-6 months instead of waiting 2 years)?