Dr. Petelin is a board certified surgeon who has recently retired from private practice in Phoenix. He received his medical degree from Creighton University School of Medicine in Omaha, Nebraska, and has a bachelor's degree in chemistry from Gonzaga University in Spokane, Washington. Dr. Petelin completed his internship and residency at St. Joseph's Hospital and Maricopa Medical Center in Phoenix.

From 1984 to 1988 and again from 2000 to 2004, he was Chief of Surgery at St. Joseph's Hospital. He is in his second term as governor of the State of Arizona American College of Surgeons. Dr. Petelin is a member of the Board of Directors of the Phoenix Surgical Society, and is a past president of that organization. He also serves on the Board of Directors of the Arizona Medical Association. His other professional society memberships include: Maricopa County Medical Society, Phoenix Society of Gastroenterology, Creighton University Surgical Society, Society of Breast Surgeons, American Hernia Society, American Society of General Surgeons, and American College of Surgeons.

“Phoenix Magazine” has named Dr. Petelin one of its “Top Docs” fives times since 1995, including the present year. He was also selected as one of America's Top Surgeons in 2004-2005.

Dr. Petelin has been a leader in community and civic efforts as well. He has been a member of the Fiesta Bowl Committee since 1979. He is the chairman of Physicians Against Drug Abuse, and a member of Physicians for the Phoenix Symphony. In the past, he has served on the St. Joseph's Hospital Philanthropic Board and has been a member of the Arizona State University Sun Angel Foundation, the Catholic Community Foundation, and Phi Chi Medical Fraternity.