Diagnostic imaging use increased significantly within fee-for-service models of care. Little is known about patterns of imaging among members of integrated health care systems. Objective:To estimate trends in imaging utilization and associated radiation exposure among members of integrated healthcare systems. Design, Setting, and Participants: Retrospective analysis of electronic records of members of six large integrated health systems from diverse regions of the country. Review of medical records allowed direct estimation of radiation exposure from selected tests. Between 1–2 million member- patients were included each year from 1996 to 2010. Main Outcome Measure: Advanced diagnostic imaging rates, and cumulative annual radiation exposure from medical imaging. Within integrated health care systems there was a large increase in the rate of advanced diagnostic imaging and associated radiation exposure between 1996 and 2010.

Diagnostic Imaging, Radiation, Healthcare Systems