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Rush Copley Administrative Team

John Diederich, MA, MBA, FACHE

President, CEO
John Diederich was named president and CEO of Rush Copley Medical Center in November 2019. He is the 8th CEO in Rush Copley’s 133-year history. An outcomes-oriented executive leader with a history of active community involvement, Diederich has risen through the ranks to become an accomplished strategic thinker, skilled administrator and affable health care leader.

Prior to his current role, Diederich served as senior vice president and Chief Operating Officer of Rush Copley since 2006, where he oversaw clinical, ancillary and support operations of the hospital including a $50 million annual capital improvement budget and all hospital construction projects. He joined the hospital’s executive team as vice president of ancillary operations in 2002, and previously held management roles in departments including IT, finance and patient registration. Diederich, who has been at Rush Copley since 1985, began his career at the medical center as a teenager working in the hospital’s kitchen.

He received his Bachelor of Business Administration, specializing in management science from the University of Iowa, where he also earned a Master of Arts degree in hospital and health administration and a Master of Business Administration degree. Diederich completed the Advanced Executive Program at the Kellogg School of Management, Northwestern University, and is a fellow of the American College of Healthcare Executives.

As a survivor of the largest mass shooting in United States' history, Diederich speaks to organizations across the country about his unique active shooter experience. He shares his story of enhancing workplace safety and training 2,500 hospital employees in active shooter response, and his personal survival story of putting this training to the test at the Route 91 Concert Shooting in Las Vegas on October 1, 2017.

Diederich, his wife Joanne, and their three sons reside in Aurora where he is the Chairman of the Board of the Community Foundation of the Fox River Valley, a past Chairman of the Board of the Aurora Regional Chamber of Commerce and an active board member of the Marmion Academy Board of Trustees. The Diederichs actively support their community and volunteer with many area non-profit organizations.

Mary Shilkaitis, MSN, MBA, RN, NEA-BC, FACHEMary Shilkaitis

Senior Vice President, Operations and Chief Operating Officer

Mary Shilkaitis was named senior vice president and Chief Operating Officer of Rush Copley Medical Center in 2019. A dynamic, team builder with a passion for excellence in patient care, Shilkaitis brings more than 25 years of progressive clinical and operational leadership with a proven record of improving quality, patient safety, clinical service revenues, productivity and business strategy.

Prior to her current role, Shilkaitis served as vice president of patient care services and Chief Nursing Officer. In that capacity she provided leadership for clinical and nursing operations across the organization, oversaw service line planning and administration, and strategic partnership development, including physician recruitment.

She joined Rush Copley in 2001 as vice president of women’s services. Previously Shilkaitis held leadership positions as director of women and children’s services at Central DuPage Hospital and director of pediatric services at Hoffman Estates Medical Center. She began her career as a neonatal and pediatric intensive care nurse.

Shilkaitis earned a baccalaureate degree from Illinois Wesleyan University and a master’s degree in nursing and business administration from Lewis University in Romeoville, Illinois, where she was honored with the Lasallian Leadership Award. She is a fellow of the American College of Health Care Executives and member of the American Organization of Nurse Executives. She holds a nurse executive advanced board certification (NEA-BC) from the American Nurses Credentialing Center.

Shilkaitis is involved in several community organizations and boards including the Nursing Advisory Council for Aurora University, Clinical Oversight Committee for Illinois Hospital Association and Board member for River West Radiation Center. She currently serves as adjunct faculty at Lewis University and as non-remunerated adjunct faculty at Rush University.

Steve B. Lowenthal, MD, MPHSteve Lowenthal, M.D.

Senior Vice President, Medical Affairs and Chief Medical Officer
As Senior Vice President, Medical Affairs and Chief Medical Officer, Dr. Lowenthal is the primary liaison between the Medical Staff and Administration of Rush Copley Medical Center.

Dr. Lowenthal's primary responsibilities include oversight of Medical Staff credentialing, privileging and bylaws, the family medicine residency program, and continuing medical education for physicians. He also is responsible for the hospital's quality and patient safety programs as well as physician relations and physician services.

Dr. Lowenthal brings a myriad of expertise to the medical center including vast experience in quality and patient safety program development, clinical informatics and its use in evidenced based clinical practice as well as Six Sigma Black Belt Training, a highly disciplined technique focusing on process improvement. He received his Doctor of Medicine degree from The Chicago Medical School, Chicago. In New York, he completed one year of General Surgery residency before moving to Los Angeles, California where he completed residency training in Urology. He also earned a Master of Public Health degree in health services administration from the Medical College of Wisconsin.

Dr. Lowenthal resides in St. Charles and has four adult children, two of whom are now fourth generation physicians.

Brenda Van Wyhe, MBA, CPABrenda Van Wyhe

Senior Vice President, Finance and Chief Financial Officer
Strong financial skills and technical project expertise, combined with a strong sense of fiscal responsibility are what make Brenda Van Wyhe a highly effective finance administrator. Her responsibilities include financial reporting, accounts receivable management, managed care contracting and reimbursement, materials management and medical records.

Brenda received her Bachelor of Science degree from Clarion University of Pennsylvania and her Master of Business Administration degree from DePaul University. She is a CPA and has served as an adjunct instructor for Aurora University.

Active in the community, Brenda is treasurer for the Oswego Chamber of Commerce, Vice Chair of the Oswego Economic Development Commission and serves on the Oswego YMCA Board, the Sugar Grove Chamber of Commerce, and is a committee member for Mutual Ground. She is past treasurer for the Oswego Economic Development Corporation and the Oswego Rotary Club and has participated on various other committees including Kendall County CASA, Women's Topic, Finance Committee and Advisory Committees for District 308. Brenda resides in Sugar Grove.

Ryan Asmus

Vice President, Legal Affairs and General Counsel
As Vice President and General Counsel, Ryan is responsible for the overall legal affairs at Rush Copley and its affiliated operations. Ryan has extensive experience in hospital and health law, as well as the management of medical professional liability matters. During his decade of service at the Illinois Hospital Association (IHA), Ryan held several positions, including Director for the Illinois Provider Trust and Illinois Risk Management Services, where he managed litigation and liability matters for large health systems. Prior to joining the IHA, Ryan was an attorney with a large, national professional liability insurance company located in Chicago. Ryan began his legal career in 1993 at a Chicago law firm where he concentrated his litigation practice on aviation-related matters.

Originally from the East Coast, Ryan received his Bachelor of Arts degree from the State University of New York at Albany and his law degree from the University of Akron School of Law. Ryan is multi-engine rated commercial pilot who enjoys flying his two sons around the Midwest.

Ryan is a member of the Illinois Association of Healthcare Attorneys (IAHA), and an elected member of the Gower District 62 school board.

Ryan lives in Burr Ridge with his wife and two sons.

Alexander F. Pope, CFREAlex Pope

Vice President, Foundation and Chief Development Officer
Alexander (Alex) Pope serves as Chief Development Officer. His career spans 25 years of professional experience in institutional advancement. He has particular expertise in identifying opportunities for and implementing fundraising best practices (including action and outcome-based performance metrics) which create efficient and very effective development programs. His career path has allowed him to gain a fairly equitable balance between major gift work (individual and corporate) and other foundation/fundraising operations, including volunteer board management, direct marketing, workforce giving, special events, planned giving and advancement services.

He has a strong track record of success not only as a fundraiser, but also as a manager and leader. The majority of this experience/success is within regional and national “hub-and-spoke” organizations including Advocate Health Care, the American Association of Oral and Maxillofacial Surgeons, the American Society of Plastic Surgeons, and the American Academy of Pediatrics.

Alex has served on the Association of Fundraising Professionals, Chicago Chapter, Board of Directors since 2007 to 2014, including as president in 2010. In 2013 Alex was awarded the Chapter’s prestigious Presidents Award recognizing his leadership and service to the industry. Additionally, Alex is a member of the Aurora Noon Rotary Club and Chairman of the Aurora Regional Chamber of Commerce Board of Directors.

Alex is a graduate of Northern Illinois University and resides in Naperville, Illinois, with his wife and four children.

Marcee BrummelMarcee A. Brummel

Vice President, Rush Copley Medical Group
As Vice President of Rush Copley Medical Group, Marcee is responsible for the overall operations of Rush Copley’s multispecialty medical group. With more than 20 years of healthcare experience, she has been instrumental in bringing excellence in primary and specialty healthcare services to the community. Under her leadership, the medical group has grown to more than 100 providers offering healthcare services in Aurora, Naperville, Oswego, Sugar Grove, and Yorkville, including Rush Convenient Care locations throughout the area.

Marcee received her Bachelor’s degree in Business and Communications from Northern Illinois University. She is an active member of The Medical Group Management Association and serves on the board of Invest Aurora Illinois. Marcee resides in Sheridan with her family.

David Petasnick

Vice President, Ancillary Services
An effective leader, David Petasnick brings over 20 years of clinical and operational experience to Rush Copley’s administrative team.

As Vice President, Ancillary Services, David oversees multiple clinical areas including Imaging Services, Laboratory, Pharmacy, Emergency Services, Heart and Vascular Services, GI & Pain Center and the Castle Surgicenter. In addition, he manages Facilities and Hospitality Services at Rush Copley.

David received his bachelor’s degree in political science and a master’s degree in Hospital and Health Administration from the University of Iowa. David, his wife, and their three children reside in Oswego.

Brenda Fann, M.D.Brenda K. Fann, MD, MBA, FAAFP

Assistant Vice President, Medical Affairs
As the Assistant Vice President, Medical Affairs, Dr. Fann has both administrative and clinical roles at Rush Copley. Dr. Fann is the administrative support for Medical Staff Credentialing and Privileging and the Professional Practice Committee, our centralized physician peer review committee, and reports to our Chief Medical Officer, Dr. Lowenthal. Additionally, Dr. Fann is responsible for the Medical Staff Bylaws, continuing medical education for physicians, and the Medical Staff Office.

Prior to her current role, Dr. Fann served as the Chair of the Credentials Committee since its inception in 2007. In this role, she developed and implemented a solid and consistent credentialing and privileging process within the organization. For her work on this committee, she was selected by her peers for the Medical Staff Leadership Award in 2009. Additionally, she has been a long-standing member of the Medical Executive and Bylaws Committees.

Dr. Fann, a board-certified family physician, was the Program Director of the Rush Copley Family Medicine Residency Program and Clinic Director for their Family Medicine Center. She is still clinically active as senior faculty within the residency program. Dr. Fann has been on the medical staff at Rush Copley Medical Center and an Assistant Professor at Rush Medical College since 2001.

Dr. Fann received a Bachelor of Science degree with high honors in biology from Elmhurst College. She graduated from the University of Illinois, College of Medicine with Alpha Omega Alpha Honors and completed her training at the Kaiser Permanente Family Medicine Residency Program in Riverside, California.

Terese RaabeTerese Raabe

Assistant Vice President, Strategy
As Assistant Vice President of Strategy at Rush Copley, Terese Raabe is responsible for evaluating new business opportunities and strategic initiatives, service line development, planning-related regulatory functions, analytics oversight and knowledge management, development and implementation of the hospital’s Community Health Needs Assessment and Improvement Plan, and executive oversight of the Rush Copley Healthplex Fitness Center. With more than 20 years of experience in health care, she spearheads strategy for Rush Copley with her extensive experience in planning, strategy, analytics.

Terese holds an MBA and BS in administration from Benedictine University. She is a professional member of American College of Healthcare Executives and the Society for Healthcare Strategy & Market Development. Terese is an active member of the community and currently serves on the Board of the Fox Valley United Way, the Kendall County Health Advisory Board and is an executive member of the Kane Health Counts Committee. She resides in Oswego with her husband and two children.

Don KalishDon Kalish

Assistant Vice President, Finance and Controller
As Assistant Vice President of Finance and Controller of Rush Copley Medical Center, Don Kalish is responsible for financial reporting, accounts payable, taxes, payroll, decision support and revenue integrity. Don has served as Controller since 2010 and was named Assistant Vice President in January 2020.

A CPA, he has more than 40 years of financial and accounting expertise in executive positions. In addition to his CPA, he has a Bachelor of Arts degree from City College of New York with majors in psychology and pre-law.

Don and his wife, Roberta, reside in Naperville and raised four sons and now have seven grandchildren. For more than 20 years, he was actively involved in coaching and running youth sport organizations and held positions on the boards of Naperville Little League Baseball and the Naperville Youth Basketball Association. He was awarded the Distinguished Service Award for Youth & Family by the Naperville Jaycees in 2001.

He currently serves as president of the Path to Recovery Foundation, a not-for-profit foundation that helps families dealing with substance use disorders. He also held positions as the treasurer of the Montgomery Economic Development Corporation and on the board of A Man in Recovery Foundation.