Can photodynamic therapy (pdt) reduce the looks of acne scars and pigmentation?

Under clinical trial: Photodynamic therapy (pdt) is currently under clinical trials for treatment of severe acne. While initial clinical trials indicate that it may well be an effective treatment for severe acne, the question remains as to whether or not it is actually better than current standard acne treatment regimens. Treatments can spur redness and burning. The concept of pdt altering pigmentation is ancient.