Gastroenterology is the study of digestive problems and disorders of the esophagus, stomach, small intestine, colon and rectum, pancreas, gallbladder, bile ducts and liver. If you or your family member is experiencing digestive issues, please call one of our physicians to schedule an appointment.
Our experienced team of board-certified gastroenterologists offer consultations and follow-ups to provide exceptional care for common GI issues such as:
- Abdominal Pain
- Acid Reflux / Heartburn (GERD)
- Blood in Stool
- Bowel Diseases
- Colonoscopy Consultations
- Colon Cancer Screening
- Crohn’s Disease
- Diarrhea
- Digestive Disorders
- Diverticulitis
- Endoscopy Consultations
- Esophageal Diseases and Cancers
- Gallbladder Diseases and Cancers
- Gallstones
- Gastroenterology Follow Up
- Gastrointestinal Disorders
- Hemorrhoid Exams
- Irritable Bowel Syndrome
- Liver Diseases and Cancers
- Pancreatic Diseases and Cancers
- Stomach Diseases and Cancers
- Ulcerative Colitis
The Richmond Health Network is proud to participate in the NYS Cancer Screening Program. Patients who meet certain criteria, please contact the Center for Cancer Care for your free FIT Kit.
Additional services and surgeries are performed at Richmond University Medical Center.
Locations and Physicians
South Shore Locations
North Shore Locations
Meet the Team
Dr. Wallen C.Y. Chan and the office staff are dedicated to providing the highest level of care to all patients. Dr. Chan earned his Medical Doctorate at the Mount Sinai School of Medicine in New York. He then completed his Internal Medicine residency training at the Mount Sinai Hospital in New York. Dr. Chan then completed his Gastroenterology fellowship at the Medical College of Pennsylvania, in Philadelphia. He is board certified by the American Board of Internal Medicine in both Internal Medicine and Gastroenterology. He has been in private practice since 1994 and sees patients in both Staten Island and Brooklyn. He is currently affiliated with Richmond University Medical Center as well as Maimonides Medical Center. Dr. Chan is a Fellow member of the American College of Gastroenterology (FACG). He also holds memberships in the American Gastroenterological Association (AGA), the American Society for Gastrointestinal Endoscopy (ASGE), and the New York Society for Gastrointestinal Endoscopy (NYSGE).
Office Locations
Dr. Vaizman has been a board certified gastroenterologist since 2011. He completed his undergraduate degree at Brooklyn College and went on to complete his medical education at St. George’s University School of Medicine in Grenada, West Indies. Dr. Vaizman completed an internal medicine residency at Maimonides Medical Center in Brooklyn and served as a clinical fellow in the department of transplant hepatology in at Mount Sinai Medical Center. Dr. Vaizman is fluent in Russian.
Dr. Xu completed his medical degree in 1986, and then became a lecturer in microbiology at the Yanbian Medical College, China. In 1991, he moved to the US and started to work as a research scientist in the virology department at the NYS Institute for Basic Research on Staten Island. In 2007, following residency and chief residency in pediatrics at the St. Vincent Medical Center, he joined a fellowship in pediatric gastroenterology, hepatology, and nutrition at SUNY Downstate Medical Center at Brooklyn, where he became full-time faculty as an assistant professor.
In 2017, he returned to RUMC and became program director of the residency program and chief of gastroenterology in the department of pediatrics. His research portfolio and interest include both basic science (molecular biology and gut immunology) and clinical gastrointestinal disorders (inflammatory bowel disease, necrotizing enterocolitis, hepatitis B, parenteral nutrition-associated liver disease and nonalcoholic fatty liver disease).
Office Locations
