Lynn (@lynn1961), I'm sorry to hear that, but glad they found it early. I know that likely doesn't make it any less heavy, as how it can change your life. I hope you do well on the SBRT.
Here is some information from Mayo: https://www.mayoclinic.org/tests-procedures/sbrt/pyc-20446794
And here are some links to past discussions which may be helpful:
https://connect.mayoclinic.org/discussion/sbrt/
https://connect.mayoclinic.org/comment/926427/