I had 28 sessions of IMRT radiation treatments for the prostate. The RO said it was very accurate in targeting the cancer before I started. The side effects I have now 9 months later are frequent urination/burning and bowel movements 3+ times a day. If I could do it again I would get a proton radiation treatment. Both of the ones you mentioned are photon radiation. After everything I have read I would find a proton facility as they are harder to find but it would be worth the drive in my opinion if it is farther away. Everything I have read says photon radiation treatment regardless of the delivery, ie IMRT, SRS or SBRT, will leave you with side effects. When I was going thru my treatment I had to meet with the Doctor once a week and when the side effects started he acted like that was a normal outcome for pretty much everyone. They say they should go away in weeks or a couple months but 9 months later I am still having them non stop. My RO also had me get the "gold seeds" inserted for a more accurate treatment as they are a better target but the RO I had during treatment said that was redundant the machine is as accurate and in the end didn't help anyway as the radiation obviously hit the bowels and the bladder & urethra to give me these side effects. I just hope incontinence is not in the future as I have read that in some years later that happens as well. Anyway, my 2 cents. Good Luck.