Prospective Study of the Effectiveness of Percutaneous Transhepatic Photodynamic Therapy for Advanced Bile Duct Cancer and the Role of Intraductal Ultrasonography in Response Assessment - Shim, C S; Cheon, Y K; Cha, S W; Bhandari, S; Moon, J H; Cho, Y D; Kim, Y S; Lee, L S; Lee, M S; Kim, B S (Endoscopy, 2005)