What is an acceptable SBRT dose for a central lung cancer encasing a coronary artery bypass graft?

As a Minnesotan, my immediate reply to your problem is "uff da, that's a tough one eh?". An image of the tumor location would really help here, but I'm going to presume it's maybe off the subclavian artery (longer course and may have more lung surrounding)? Either way, your patient is in a tough spo...