Medical Staff Leadership

B. Sean Smithson, M.D. / Chief of Staff
Dr. Smithson joined the Active Medical Staff at Summit Healthcare in July, 2012. His specialty is Family Medicine. Dr. Smithson attended Medical School at the University of Arizona. He completed his Internship and Residency at Utah Valley Family Medicine. Dr. Smithson grew up in Holbrook and has always felt family physicians play an integral part in their patient’s lives. Dr. Smithson is Board Certified by the American Board of Family Medicine.

Jeffrey LeSueur, M.D. / Vice Chief of Staff
Dr. LeSueuer, Otolaryngologist, joined the Actrive Medical Staff at Summit Healthcare in July 2012. He received his medical degree from Baylor College of Medicine and completed his residency at University of Tennessee. Dr. LeSueur is Board Certified by the American Board of Otolaryngology.

Elizabeth Bierer, M.D. / Secretary / Treasurer
Dr. Bierer joined the Active Medical Staff at Summit Healthcare in August, 2011. She graduated from Blue Ridge High School and continued her education at the University of Arizona. After graduating from the U of A with a B.S. in Psychology, Dr. Bierer spent a year in South Carolina with AmeriCorp VISTA assisting Commune-i-Care, a not for profit organization, helping the medically underserved population of the state. After her year with AmeriCorp VISTA, Dr. Bierer was accepted into and began her studies at the U of A’s College of Medicine. Dr. Bierer is Board Certified by the American Board of Family Medicine.

Osaf Ahmed, M.D. / Medicine Department Chairman
Dr. Ahmed, Internal Medicine, joined the Active Medical Staff at Summit Healthcare in June of 2011. He attended medical school at King Edward Medical College in Lahore, Pakistan. He completed his Internship, Residency and Fellowship in Internal Medicine at Staten Island University Hospital. Dr. Ahmed is Board Certified by the American Board of Internal Medicine.

Philip Johnson, M.D. / Emergency Medicine Department Chairman
Dr. Johnson joined the Active Medical Staff at Summit Healthcare in February, 1991. His specialty is Emergency Medicine. Dr. Johnson attended Medical School at Northwestern University, Feinberg School of Medicine in Chicago, Illinois. He completed his Internship and his Residency at University of Arizona College of Medicine in Tucson, Arizona. Dr. Johnson is Board Certified by the American Board of Family Practice.

Charles Robertson, M.D. / Family Medicine Department Chairman
Dr. Robertson joined the Active Medical Staff at Summit Healthcare in August, 1983. His specialty is Family Medicine. Dr. Robertson attended Medical School at the University of Illinois College of Medicine in Chicago, Illinois. He completed his Internship at Cook County Hospital in Chicago and his Residency at the University of Arizona College of Medicine in Tucson, Arizona. He is Board Certified by the American Board of Family Practice.

William Waldo, M.D. / Surgery Department Chairman
Dr. Waldo joined the Active Medical Staff at Summit Healthcare in September, 1982. His specialty is General Surgery. Dr. Waldo attended Medical School at the University of Virginia School of Medicine in Charlottesville, Virginia. He completed his Internship at the University of Alabama School of Medicine, his Residency at both Emory University School of Medicine in Atlanta, Georgia and University of Colorado School of Medicine in Denver, and his Fellowship at Veterans Affairs Medical Center in Decatur, Georgia. Dr.Waldo is Board Certified by the American Board of Surgery.

Alan DeWitt, M.D. / Chief Medical Officer
Dr. DeWitt joined the Active Medical Staff at Summit Healthcare in August, 2002. His specialty is Family Medicine. Dr. DeWitt attended medical school at the University of Arizona College of Medicine in Tucson, Arizona. He completed his Internship and Residency at Good Samaritan Regional Medical Center in Phoenix, Arizona. Dr. DeWitt is Board Certified by the American Board of Family Medicine and Hospice & Palliative Medicine.

Jason Johnson, M.D. / Member at Large