Dr. Rosenquist practices diagnosis and treatment of gastrointestinal and biliary ductal system disorders, including gastrointestinal barium evaluations and biliary contrast examinations. He was honored with a UC Davis Medical Staff Award for Outstanding Service in 1996. Dr. Rosenquist consults in radiology for the Veterans Administration Medical Center in Martinez and reviews Mayo Clinic Proceedings and several other publications. He recently influenced revised American Cancer Society recommendations for annual mammograms beginning at age 40 by determining that yearly screenings from age 40 to 49 could triple breast cancer mortality reduction rates. He has analyzed the cost effectiveness of colon cancer screenings and how litigation affects breast cancer screenings. His research also includes the radiology of retained objects following surgery, the contrast agents used in radiology imaging, and the effectiveness of digital radiology for swallowing studies.