Brain scan for ADHD child?

Our almost 7 year old son has been on meds for ADHD and an "undiagnosable" related condition (aggression and anger/depression) for about one year.  He is doing better, but I'm not sure that we have a complete and fully accurate diagnosis and appropriate treatment.  He is still having a hard time controlling his impulses and continues to be very mean at times, hurt people, take far too many risks w/o thinking, etc.  I have read Dr. Amen's books and heard him speak and wonder if anyone has had any personal dealings with him or his clinics?  He uses the Spect brain scan as a diagnosis tool for treatment.  I feel in my gut that we are missing part of the picture here.  I'm very worried about him being labeled as a "bad" kid and being left out.  A few parents have already made comments about him and/or told their children to not play with him at school.  I'm also worried about his relationship with his twin brother since he is so mean and does hurt him a lot.  I would appreciate any comments and especially like to hear if anyone has had any experience with the Amen clinics.  Thanks.