Hi,
I've got trouble answering you on this one: you don't say how old you are, or if there is any sign of recurrent prostate cancer......other than your scans.
In my opinion, I don't think it should be that high.....ie. PSA, but if your Dr's don't seem concerned thats good. There are a couple of other guys that contribute to this site that are far more knowledgeable that me: perhaps they will respond.
Good Luck.............Stan.