Important to the committee’s task and many times reiterated is the need for a source of information on medical diagnostic procedures that use radiation, especially those that use high doses such as CT scans. The main data source for aggregate counts on medical diagnostic procedures that involve radiation by body part is IMV19 IMV is a market research and database provider founded in 1977 which, using a variety of survey methods, tracks diagnostic medical procedures. While IMV surveys have high participation rates and cover a large number of imaging facilities (IMV data were the main source for the NCRP Report 160 [NCRP, 2009]), they do not have a detailed categorization of procedures and therefore are unable to capture the variation in radiation doses and protocols. Detailed data on counts of procedures for large populations are also available from administrative claims such as Medicare. However, information is restricted to those that are age 65 or over and use this social insurance program. Neither IMV nor Medicare data are directly applicable for the present task, as they do not contain information about medical diagnostic imaging at the census-tract level.
This chapter provides the committee’s assessment of methodological approaches for carrying out a cancer epidemiology study. Based on this assessment, the committee finds that: