Board of Directors

Dr. Thomas Greidanus, MD


Dr. Greidanus is an established Emergency Medicine physician in Pueblo, Colorado. He is board certified with extensive management experience in the military and private sector. He obtained his master’s degree in health care management and is recognized by Beta Gamma Sigma for academic excellence in business school.

Currently the Medical Director at Parkview Medical Center (Pueblo, CO) and freestanding Emergency Room Parkview Emergency Services Pueblo West, Dr. Greidanus previously served as the Chief of Staff at Parkview Medical Center.

Dr. Greidanus’ passion is driven by the bonds he builds with colleagues and community members, serving as the President of the Pueblo County Medical Society, which has a proud 136-year history in serving the Pueblo community.

President Elect

To be determined.



Dr. Marcel Junqueira, M.D.


Marcel Junqueira, M.D. attended medical school in Brazil, his native country. He earned his medical degree at Valenca Medical School in Rio de Janeiro. Afterwards, he relocated to New York City for his residency in Internal Medicine. He continued his post graduate training at Kansas University, where he specialized in Pulmonary and Critical Care Medicine and at Temple University, where he finished Sleep Medicine fellowship training.

Dr. Junqueira is ABIM Board Certified in 4 different specialties, including Internal Medicine, Pulmonary Diseases, Critical Care Medicine, and Sleep Medicine. His special interests include Sleep Medicine, Respiratory Physiology, Interstitial Lung Disease, Lung Cancer, and diagnostic work-up for lung nodules.

Dr. Robert Tonsing, MD


Dr. Bob Tonsing is Board Certified as a Psychiatrist with additional Board Certification in the subspecialty of Child and Adolescent Psychiatry.  

After completing his training in 1989, he moved to Pueblo where he worked at the Colorado Mental Health Institute Pueblo on the child and adolescent wards as the faculty liaison representative for the University of Colorado Health Sciences Center.  Since 1992, he has engaged in full time private practice.  

In addition to his private practice, he is the Medical Director for Parkview Hospital’s Child and Adolescent Psychiatry Inpatient Unit, serves on the Graduate Medical Education Committee for the Family Practice Residency Program at St. Mary Corwin Hospital, and helps proctor that Family Practice Residency’s Psychiatric Clinic.  

In 1986, he married Sara Tonsing, an OB/GYN physician in Pueblo. They have three wonderful adult-aged sons.

Dr. Alfredo Vargas, MD

Immediate Past President

Bio coming soon!


Dr. Brad Roberts, MD

Board Member & CMS Board Representative

Dr. Roberts was born and raised in Pueblo, Colorado. He graduated in the top 10 from South High School. He received his Bachelor of Science degree in Exercise Science Cum Laude from Brigham Young University and obtained his medical degree from the Medical College of Wisconsin. His residency was completed at the University of New Mexico, Department of Emergency Medicine, where he served as one of the Chief Residents.

Dr. Roberts is a passionate community volunteer and currently serves as Assistant Professor of Emergency Medicine at the University of New Mexico, and on the Board of Directors for the Colorado Medical Society, representing the Pueblo County Medical Society.

Dr. Cheryl Walker, DO

Board Member

Dr. Walker completed residency at Case Western, MetroHealth Hospital and is board certified in Anesthesiology. She has been practicing since 2009 at St. Mary-Corwin Medical Center.  

Dr. Walker received the Physician of the Year, “Golden Stethoscope Award” in 2016. She has served as the chairperson of the OR Steering Committee since it was formed in 2016. She has also served as an Associate Professor at Rocky Vista University. 

Dr. Walker is passionate about serving the Pueblo community and enjoys spending her free time in the mountains.

Dr. Kevin Weber, MD

Board Member

Dr. Weber is the medical director for most EMS agencies in southeastern Colorado along with being the Regional Medical Director for both Southeast Colorado RETAC and Southern Colorado RETAC. He has been an ED physician for about 30 years, and is board certified in EMS. He was the ED director at St Mary-Corwin Emergency Department. 

Dr. Weber recently resigned that position and took over as medical director of the ED at Spanish Peaks Regional Health Center. He loves EMS, plans to continue with EMS activity, and is very involved at the state level.

Dr. Julie Newburg, MD

Board Member

After more than a decade Dr. Newburg has joined the Southern Colorado Clinic and is located at 3937 Ivywood Lane.  Dr. Newburg performs a full range of ENT procedures on both children and adults that includes the latest techniques in Balloon Sinuplasty.

Dr. Ross Patrick, MD

Board Member

Bio coming soon.