Not sure why the two surgeons and the one radiation oncologist would say no to the markers.

I have had SRT to the prostate bed and radiation to the pelvic lymph nodes. In both cases my radiation oncologist and her team had markers which served to align me on the table in the same exact location each time. They also had a mold made of my lower body to assist in my laying in the exact same position each time.

The precision required to deliver the exact radiation beam, the location, depth of the beam, angle in which it is delivered, duration of the beam, intensity…all require it.

Even then they take an image of the radiation target area before they start and then make any adjustments to the plan for that session.

Your radiation oncologist should show you the plan, mine did, it’s a complex 3D model.