Andy,
radiotherapy has advanced enormously in recent years and maybe the biggest improvement is accuracy and the ability to target small areas, with minimal radiation spread outside the target zone. LINAC machines are now quite common and they do a sort of orbit around your body sending beams in from different positions on the 360 run. This gives them a very good "view" of the target cancer and the ability to attack it from different directions. There's an extra benefit in that because they're so narrow beam, the level of radiation used can be higher [without spread] and thus more effective.
I don't know how blanket the blanket RT would be as it's always been a goal not to spray radiation in places where it would serve no purpose but as to your question, I'd say if you've got a choice to go somewhere that uses the latest LINAC type RT, take it.
Jules