Hi A,
I hope you were able to have a good Christmas in spite of your worrying news.
I was always told by my Oncologist that once the lasting effects of my Radiotherapy left my system (about 12 months in my case) my PSA would rise as the prostate cells that weren't damaged would still naturally produce some PSA. The rate of increase would increase once my hormone treatment ended too which it did. She told me that providing the figure didn't increase by more than 2 above my lowest level then everything would be OK. At this stage, I don't think you have anything to be worried about, but at least they're doing scans to check.
Unfortunately, as you probably know, mine eventually went up to 4 and was doubling every 12 weeks so I've ended up back on hormone treatment again. You can check my profile for the details of my journey.
I hope everything is fine with the scans and you have a very Happy New Year!
Steve