 The major theoretic risk to the patient with this procedure is the development of acute pancreatitis. If acute pancreatitis were to develop, it should become clinically evident by day 3 following HIFU ablation. Therefore, the initial phase of this pilot study is designed to allow a sufficient interval between HIFU treatments to identify whether this theoretic risk will manifest clinically. Previous clinical experience in China suggests that HIFU of pancreatic tumors is safe without risk of developing severe acute pancreatitis. 