Comprehensive Gastroenterology, and Specialized Liver & Weight Care.
MacArthur Gastroenterology brings 40+ years of clinical expertise together with physician-supervised programs for fatty liver screening and medical weight management.
Full-scope Gastroenterology Care
From routine colonoscopy and endoscopy to complex GI conditions, our board-certified physicians provide diagnostic and therapeutic care across the full range of digestive health.
Upper GI Endoscopy
EGD is an outpatient procedure using a flexible video endoscope to examine the esophagus, stomach, and duodenum. Performed by Dr. Peterson, it gives a clear, direct view of the upper digestive tract.
Flexible Sigmoidoscopy
Flexible sigmoidoscopy uses a thin, flexible scope with a light and camera to examine the rectum and lower (sigmoid and descending) colon. Learn more from the National Institute of Health (NIH).
Colonoscopy
Colonoscopy uses a flexible fiber optic scope to examine the full colon, from the cecum to the descending colon. Dr. Peterson’s scoping expertise makes this exam both thorough and life-saving.
Fatty Liver Screening
A quick, non-invasive Velacur® scan detects fatty liver disease and liver stiffness in minutes, no needles, no prep required.
Weight Management
Physician-supervised programs, including GLP-1 therapy when appropriate, designed around your metabolic health and monitored by our clinical team.
Care led by Dr. Ralph Peterson
Dr. Peterson has served the Oakland community for over four decades, combining deep clinical experience with a personal, unhurried approach to every patient relationship.
From Our Health Library
Practical guidance on gastroenterology, fatty liver disease, and physician-supervised weight loss, written by our clinical team.