@catlover1943– Lipidic means "Any of a group of organic compounds, including the fats, oils, waxes, sterols, and triglycerides, that are insoluble in water but soluble in nonpolar organic solvents, are oily to the touch, and together with carbohydrates and proteins constitute the principal structural material of living cells."
I've had 2 SBRT's. They won't do it if it's too dangerous to another organ. Do you know what type of SBRT you had? Proton, Photon? No, biopsies aren't usually done.