Since this is palliation and generally used for patients with limited longevity, there shouldn’t be a need for a CTV expansion for quad shot. You may use your typical location specific expansion, keeping in mind the particular needs of the patient - their ability to remain immobile and recreat...

GTV only with a PTV margin of 5 - 10 mm based on location and patient related factors. 

I love quad shot, and of course, reading QuadShot News. But when it comes to margins, I’ll share a story that’s worth a thousand words - and a textbook chapter that would otherwise put us to sleep. A demented patient with widely metastatic H&N ca, whose wife refused chemo, was once ...

Nothing should change based on intent, except for the omission of CTV.  ICRU fundamentals apply to curative and non-curative treatment. Contour a GTV (+/- CTV depending on intent), then add a PTV for set up error/motion. This applies to all palliation with visible tumor - doesn’t matter ...