• Our Doctors

    • Robert Berg, M.D.

    • Dr. Berg went to medical school at the University of Minnesota School of Medicine, graduating in 2001. He completed his radiology residency and musculoskeletal radiology fellowship at the University of Nebraska Medical Center. He was co-chief resident and won the Resident Teacher of the Year award at the University of Nebraska Medical Center in 2006. Dr. Berg joined Radiologists of North Iowa in 2007.

      Dr. Berg currently serves as Past President of Medical Staff at Mercy Medical Center - North Iowa, having served as president during 2016 and 2017. He served as Secretary of Medical Staff and Chairman of the Medical Staff Credentials Committee in 2012 and 2013 and as Vice President of the Medical Staff and Chairman of the Clinical Quality Council in 2014 and 2015. He won Family Practice Residency Teacher of the Year honors for Mercy Hospital in Mason City in 2010.

      In addition to performing general radiology and mammography, Dr. Berg's specialty area is musculoskeletal radiology. He is a member of Alpha Omega Alpha medical honor society, as well as the Society of Skeletal Radiology, [the American Medical Association, the Iowa Medical Society and the American Roentgen Ray Society. He is certified as a Clinical Densitometrist through the International Society of Clinical Densitometrists.

    • Alex Harvin, M.D.

    • Dr. Harvin, the newest member of Radiologists of North Iowa, joined in July of 2018 after finishing his Diagnostic Radiology residency and Neuroradiology fellowship, both of which were completed at the Medical University of South Carolina in Charleston, South Carolina. Dr. Harvin's academic interests are primarily centered on neuroimaging and image-guided intervention, but he has special interests in abdominal imaging, cardiac imaging, MRI, and quality improvement.

      Dr. Harvin is joined in Mason City by his wife, Dr. Molly Gentle, and has three children. His interests outside work include surfing, kiteboarding, and snowboarding. Additionally, he enjoys home repair and construction.

      Dr. Harvin is a member of the American College of Radiology, the American Board of Radiology, and the American Roentgen Ray Society.

    • Ryan Holthaus, M.D.

    • Dr. Holthaus grew up on a farm near Decorah, Iowa.  He attended the University of Northern Iowa and attended medical school at the University of Iowa College of Medicine in Iowa City, Iowa.  He completed his radiology residency training at Vanderbilt University Medical Center in Nashville, Tennessee.   He joined Radiologists of North Iowa in 2006.

      Dr. Holthaus has recieved many honors, including the Carl Gillies Award for Medical Student Excellence in Radiology,  Sophomore Medical Student Award in Pathology,  Henry J. Prentiss Award for Superior Achievement in Medical Gross Anatomy, Polyed Organic Chemistry Award, Purple and Old Gold Award in Biology, and Biology Dean’s Student Award.  He is a member of Alpha Omega Alpha medical honor society.

      As an interventional radiologist, Dr. Holthaus focuses on image-guided procedures, such as arterial and venous interventions, biopsies, drain placement, spine procedures, and hemodialysis access maintenance. He also performs general radiology, interpreting a wide variety of studies.

      Dr. Holthaus is  an endovascular diplomate of the American Board of Vascular Medicine, and belongs to the American College of Radiology and the Radiological Society of North America.  


    • Brad Janson, M.D.

    • Dr. Janson received his undergraduate degree at the University of Minnesota, graduating summa cum laude in 1981. While there, he was president of the College of Biologic Sciences student board and earned the Dean Freeman Medal and the University of Minnesota Student Leadership and Service Awards.  He attended medical school at Creighton University and completed a residency in radiology at the University of Iowa College of Medicine in 1991. He went on to complete a body imaging fellowship at the University of Iowa, gaining extra expertise in imaging of the chest, abdomen, and pelvis.  

      Dr. Janson joined Radiologists of North Iowa in 1992. In addition to general radiology and mammography, his areas of expertise are image-guided procedures, cardiac imaging, bone densitometry, and advanced body imaging. He earned the honor of being selected Family Practice Residency Teacher of the Year for Mercy Hospital in Mason City in 1999.

      Dr. Janson is a member of the American College of Radiology, the Radiologic Society of North America, the American Roentgen Ray Society, and the International Society of Clinical Densitometry. He is certified as a Clinical Densitometrist.

    • William Matthews, M.D.

    • Dr Matthews obtained his undergraduate degree at Emory University, then attended medical school at the University of South Florida College of Medicine. He completed a radiology residency at the Medical College of Georgia, then joined the United States Army. He served from 1991 until his honorable discharge in 1999. Before moving to Mason City and joining Radiologists of North Iowa, he completed a musculoskeletal radiology fellowship at Case Western Reserve. He joined Radiologists of North Iowa in 2000.

      Dr. Matthews is a member of the International Society of Clinical Densitometry and is certified as a Clinical Densitometrist. He is also a member of the Society of Skeletal Radiology. In addition to general radiology and mammography, his specialty areas are musculoskeletal radiology, breast MRI, bone densitometry, and image- guided spine procedures including vertebroplasty.

    • Bryan Navarette, M.D.

    • Originally from Laredo, Texas, Dr. Navarette obtained his undergraduate degree in biology at Baylor University and a Masters of Public Health in International Health at Tulane University. He attended medical school at the Universtiy of Texas Southwestern Medical School.  After completing his internship at the Marshfield Clinic in Marshfield, Wisconsin, he proceeded to a residency in diagnostic radiology at Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire. He then completed a fellowship in vascular and interventional radiology at the University of Minnesota.  He joined Radiologists of North Iowa in 2012. 

      As an interventional radiologist, his specialty focuses on image-guided procedures such as arterial and venous therapies, tumor embolization, biopsies, radiofrequency ablation, drain placement, spine procedures, and hemodialysis access maintenance. He also performs general radiology, interpreting a wide variety of studies.


    • Joe Ocel, M.D.

    • Dr. Ocel completed his undergraduate education at the University of Minnesota's Twin Cities campus, then attended Mayo Medical School in Rochester Minnesota. He completed a Transitional Year Residency at Gundersen-Lutheran Hospital in LaCrosse Wisconsin, then returned to the Mayo School of Graduate Medical Education for his residency in Diagnostic Radiology. He stayed at Mayo for his fellowship in Neuroradiology, finishing in 2009.

      In addition to neuroradiology, Dr. Ocel covers general radiology, basic procedures involving the spine, joints, and breast, women's imaging, and nuclear imaging. He is a member of the American College of Radiology, the American Roentgen Ray Society, the American Society of Neuroradiology, and the American Medical Association. He is certified by the American Board of Radiology.

    • Jeana Petree, M.D.

    • Dr. Petree trained at the University of Nebraska Medical Center, where she attended  medical school, performed one year of internal medicine residency, and completed her radiology residency.  

      Dr. Petree joined Radiologists of North Iowa in 2006.  In addition to the performance of general radiology and mammography, her focus areas include ultrasound and cross-sectional imaging of the body, including the chest, abdomen, and pelvis.

      Dr. Petree is a member of Alpha Omega Alpha medical honor society, the American Roentgen Ray Society, the Radiologic Society of North America, the American Association for Women in Radiology, and the American College of Radiology.

    • Travis Petree, M.D.

    • Dr. Petree trained at the University of Nebraska Medical Center, where he attended  medical school, performed one year of internal medicine residency, completed his radiology residency, and performed a fellowship in magnetic resonance imaging (MRI). 

      Dr. Petree joined Radiologists of North Iowa in 2006. In addition to performing general radiology and mammography, his specialty areas are complex cross-sectional imaging including MRI and cardiac imaging. He also specializes in many image-guided  procedures.

      Dr. Petree is a member of the American College of Radiologists, the American Board of Radiology, and the American Roentgen Ray Society.


    • Santosh Shah, M.D.

    • Dr. Shah grew up in Oklahoma City and attended University of Oklahoma for both undergraduate studies and medical school.

      After an internship in pediatrics, he completed a radiology residency at the University of Texas in Houston and a two year neuroradiology fellowship at Massachusetts General Hospital in Boston. 

      Dr. Shah joined the Radiologists of North Iowa in 2017.  In addition to general radiology, Dr. Shah specializes in neuroradiology, which involves imaging of the brain, head/neck, and spine.

      Dr. Shah is a member of the Alpha Omega Alpha medical honor society, American College of Radiology, RSNA, American Society of Neuroradiology. 

    • Ryan Smith, M.D.

    • Dr. Smith attended medical school at the University of Iowa. He completed a one year transitional residency at Gundersen-Lutheran Hospital in Wisconsin, then completed his residency in radiology at the Mayo School of Graduate Education in Rochester, Minnesota. During this time, he served one year as chief resident in the radiology department.

      Dr. Smith joined Radiologists of North Iowa in 2008. In addition to general radiology, his practice concentrates on breast imaging, including as mammography, ultrasound, and breast MRI.

      Dr. Smith is a member of Alpha Omega Alpha medical honor society. He is currently the President of Radiologists of North Iowa.

    • Gary Swenson, M.D.

    • Dr. Swenson attended medical school at the Uniformed Services University of Health Sciences F. Edward Ebert School of Medicine in Bethesda, Maryland.  He completed his radiology residency at Tripler Army Medical Center in Honolulu, Hawaii. He served 16 years in the United States Army, moving to Mason City and joining Radiologists of North Iowa in 2002 after being honorably discharged.

      Dr. Swenson's specialty areas are breast imaging and biopsy, and he regularly teaches seminars to other radiologists on the topic at the Radiologic Society of North America's annual conference. He is a member of the Radiologic Society of North America, the Society of Breast Imaging, the American Roentgen Ray Society, and the American College of Radiology. He is also a Clinical Densitometrist, certified through the International Society of Clinical Densitometry.

  • Lorem ipsum dolor interdum

  • Ut vel nisl tristique justo ornare iaculis. Suspendisse suscipit, orci ac interdum viverra, nulla orci facilisis mi, a ultrices mi lectus vitae felis. Morbi suscipit adipiscing orci et blandit. Morbi a nulla ut tellus blandit placerat a quis eros.

  • Magna phasellus etiam ultrices

  • Ut vel nisl tristique justo ornare iaculis. Suspendisse suscipit, orci ac interdum viverra, nulla orci facilisis mi, a ultrices mi lectus vitae felis. Morbi suscipit adipiscing orci et blandit. Morbi a nulla ut tellus blandit placerat a quis eros.