[Comparison of chest and abdominal x-ray radiation dose and its image quality-a multi-center study]

While radiography provides us clinically valuable information, it increases the risk of radiation exposure. Previous studies have reported great variations in radiation doses among institutions. It is concerning that radiation doses will increase and vary greatly from institution to institution when digital radiographic modalities become more common. In the present study, we measured chest and abdominal radiation doses at 10 institutions that had X-ray digital imaging systems. Differences in radiation doses among the institutions were evaluated and compared with the previous reports. The image quality at the measured radiation doses were also evaluated. The doses were measured by the same dosimeter, and the image quality at a specific dose was evaluated using the standard deviation of the digital values and Wiener spectrum. Our results indicate that the difference in radiation among institutions was approximately five-fold at a maximum and smaller than the previous reports had indicated. The image quality was improved as the dose was increased. We considered the five-fold difference to be the result of variations in optimum image quality and associated radiation doses among institutions. In summary, evaluating the radiation dose along with the image quality is important to optimize the doses.