a. Before being sedated and having endoscopic ultrasound, all patients are informed about the risks of the procedure, alternatives, and what will be done. The patients who decide to undergo endoscopic ultrasound will sign a consent form. Our goal is to enroll 30 patients (This number is limited by both the amount of contrast received from Lantheus and the number of patients typically seen in a year. Ideally we will enroll as many as possible for the purposes of power).