Jeff,
I hope you'll take Swim's advise and consider a second opinion. Radiation soft tissue necrosis is one of the possible side effects and it's definetly one of uglier ones to endure and treat.
Research your options, be pro-active in your health care program and THEN decide with your doctor which option(s) might be available to you. If it turns out radiation IS the right choice, then at least you'll KNOW it, can make an informed, educated decision and won't be left feeling "What if...If I'd only...would've, should've, could've".
A little "doctor" story for ya.. Once upon a time, I was caring for a young horse (5 yrs old) that was exhibiting symptoms of Cushing's Disease. Cushing's in horses is considered to be a more common condition in the "geriatric" horse - not unlike the PC problem in older men attitude, "Most of them will eventually get it"
Anyway, I had the vet come out, told him what I knew and requested he draw blood to confirm my dx. (no, I'm not a vet). He argued all the points - horse too young, never see Cushings @ this age, might be this, might be that.... "Humor me, will you doc? Just pull a couple vials and sent them off to Cornell, ok?"
When the blood work came back positive for insulin resistance, you better believe that vet was absolutely floored! But to his credit, he sucked in the "Dr." ego and said "Thank you! Sometimes I get "tunnel vision" and set on a certain path, not seeing or LISTENING to the caregivers who know my patients so well". He then proceeded to prescribe pergolide mesylate, a common treatment option for the condition. Already having done my research, my immediate reaction was to wait. I told him, "No, I 'm going to change his feed program - strict diet of beet pulp, (no grains) orchard grass/timothy hay (no alphalfa allowed), no carrots, cookies, treats of any kind. Let's re-test in 6-8 weeks and see if his glucose/cortisol levels come down". They did (but you knew that!) and 2 years later this horse is thriving and leading a wonderful life as a police mount!
The moral of the story; be a skeptic, get informed, weigh your options and then make your choice - in the end that's what it is...your choice.
Stay strong!