[1] Harvard Massachusetts Inst Technol, Hlth Sci & Technol, Cambridge, MA 02139 USA
[2] Massachusetts Gen Hosp, Wellman Ctr Photomed, Thier Res Bldg,MGH,55 Blossom St, Boston, MA 02114 USA
[3] Harvard Med Sch, Massachusetts Gen Hosp, Div Gastrointestinal & Oncol Surg, Boston, MA USA
[4] Harvard Med Sch, Boston, MA USA
[5] Massachusetts Gen Hosp, Liver Ctr, Div Gastroenterol, Boston, MA USA
[6] Harvard Med Sch, Dept Dermatol, Boston, MA USA