Me? Gray (Gy) is the radiation dosage amount. Actually, I read another abstract that says it's above 45Gy. Your radiation oncologist knows where and how much you were radiated, but if its SCC, squamous cell carcinoma, the minimum is usually over 50Gy to kill SCC, and it also depends on how far out you are from your radiation. You many have to get clearance from the radiation oncologist. Hope this answers your question.
Good luck.