
Robert J. Ponec, M.D., F.A.C.P., F.A.C.G., F.A.S.G.E., A.G.A.F

Makkalearn Em, M.D.

Katherine Hoda, M.D.

Nabil Choueiri, M.D.

Falguny Bhavan, M.D.

Charles Du, M.D.

Eric Tatro, M.D.
Physician Assistants

Chandler Boyd, PA-C
BIO
Chandler Boyd, PA-C joins us from Illinois. He attended Southern Illinois University for his Master of Science in Physician Assistant Studies. He earned a Bachelor of Science degree in Exercise Science at Utah Valley University, College of Science and Health. Chandler has worked in the medical field since 2017 in various roles.

Daniel C. Butler, PA-C, M.S., M.P.A.S.
BIO
Daniel C. Butler PA-C is a graduate of University of Iowa College of Medicine Physician Assistant Program, where he completed both his physician assistant certification and a Master of Physician Assistant Studies degree. Prior to admission to the Physician Assistant program, Mr. Butler received a Master of Science degree from Colorado State University in Human Anatomy and Physiology. Mr. Butler had seven years’ experience in primary care medicine prior to joining SGC.

Amy Ditzel, PA-C
BIO
Amy Ditzel, PA-C, is a board-certified physician assistant specializing in gastroenterology. She brings more than 20 years of clinical experience and a warm, patient-centered approach to digestive care. Amy is passionate about helping patients feel comfortable discussing their symptoms and confident in managing their health. She earned her Master of Science in Physician Assistant Studies from Seton Hall University and her Bachelor of Science in Biology from Pennsylvania State University. Before joining Salem Gastroenterology in 2017, Amy practiced in primary care for 15 years. Originally from New Jersey, she enjoys exploring Oregon with her husband, three children, and their dog.

Michael Slabaugh, PA-C
BIO
Michael Slabaugh, PA-C, is a board-certified physician assistant specializing in gastroenterology. He brings over a decade of experience in digestive health and a calm, patient-centered approach to care. Michael earned his Master of Physician Assistant Studies from Rosalind Franklin University of Medicine and Science and his Bachelor of Arts in Art History from Indiana University. Before joining Salem Gastroenterology in 2015, he practiced at Mid-Valley Gastroenterology in Corvallis. Outside of the clinic, Michael enjoys spending time with his wife and children, biking, hiking, skiing, traveling, and exploring art and architecture.

Thomas Nasr, PA-C
BIO
Thomas Nasr, PA-C, is a board-certified physician assistant specializing in gastroenterology and internal medicine. He brings a patient-centered, education-focused approach to digestive health and is a valued member of the Salem Gastro care team. Thomas is passionate about helping patients regain control over their GI health. He emphasizes listening closely to patient concerns and ensuring they feel heard. His care philosophy is rooted in education—he believes patients make the best health decisions when they fully understand their condition and treatment options. Thomas earned his Master of Physician Assistant Practice from Ohio University and holds a Bachelor of Science in Microbiology from the University of California, Davis. He also completed a hospital internal medicine fellowship at the Mayo Clinic, where he rotated through hepatology, neurology, hematology, palliative care, critical care, and more. Outside of the clinic, Thomas enjoys playing and writing music, spending time with his wife and their dog, and exploring the outdoors.
