Hi Dr Thrall,
Welcome to the site. I believe that Dr Kahalel is running a PDT trial at Mass General I think. I was in contact with someone from the site a while ago and I'm sure that they said that their mum was going to be doing that at Mass General I think.
I'm sure that if you contact Dr Kahalel he would be able to provide more info for you.
My best wishes to you and your Mum,
Any advice or comments I give are based on personal experiences and knowledge and are my opinions only, they are not to be substituted for professional medical advice. Please seek professional advice from a qualified doctor or medical professional.