| X-ray radiation from medical diagnostic examinations is the largest source of exposure to manmade ionizing radiation in the US. The purpose of this study was to estimate variation in X-ray examinations and define the source of variation. The Los Angeles County Radiation Management data set was used. Results indicated that the entrance skin exposure (ESE) varies substantially depending not only on the x-ray machine and the type of examinations, but also the type of medical facilities and calendar year. Even after accounting for these measured sources of variation, there remains substantial residual variation in ESE. |
