Preparation for Stereotactic Body Radiation Therapy (SBRT)

I will be undergoing SBRT shortly to deal with what is almost certainly a carcinoma in my left lung. What is there resembles what I had in my right lung, which has been surgically removed. Proceeding with SBRT means not losing any more lung tissue.

Does anyone have any experience with taking steps to prepare my body for SBRT in particular (or for radiation therapy in general)?

I'm thinking particularly of complementary or alternative modalities, but I'm open to any suggestion. For example, do you have experience with nutritional preparation that is helpful? Envisioning? Exercise?

How about follow-up after therapy? For example, do you have experience with actions that would cleanse the body of any residual radiation?

Many thanks.