Nakamae Mitsuhiro, Miyajima Yusuke, Nakano Tomomi, Kitanaka Yasutomo, Okura Yasuhiko
Central Division of Radiology, Nara Medical University Hospital.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2014 Nov;70(11):1250-7. doi: 10.6009/jjrt.2014_jsrt_70.11.1250.
With the digitization of general radiography, there are some concerns about an increase in radiation exposure doses. Therefore, the exposure index (EI) as a new dose index was proposed in 2008 by IEC. However, the settings for the interest region and the interest value in the clinical image do not show concrete prescribed values. Therefore, we inspected the distribution of EI by changing the interest region and the interest value for a standing-position chest radiograph image in students' medical examinations. EI50f, which is generally used, fluctuated between 41 and 136. In addition, as the area of the interest region became smaller, EI increased and the variation index increased. For the interest value, 50% (EI50h) was smaller than 85% (EI85h), and the variation index was also smaller. EI was not the absolute value in the clinical image, and immediate display of the deviation index (DI) with target exposure index (EIT) was effective of the adequacy of the radiography condition.
随着普通放射成像的数字化，人们对辐射暴露剂量增加存在一些担忧。因此，国际电工委员会（IEC）于2008年提出了曝光指数（EI）作为一种新的剂量指数。然而，临床图像中兴趣区域和兴趣值的设置并没有具体规定的值。因此，我们通过改变学生体检中站立位胸部X光片图像的兴趣区域和兴趣值来检查EI的分布。通常使用的EI50f在41至136之间波动。此外，随着兴趣区域面积变小，EI增加且变异指数增加。对于兴趣值，50%（EI50h）小于85%（EI85h），且变异指数也较小。EI在临床图像中不是绝对值，即时显示与目标曝光指数（EIT）的偏差指数（DI）对判断放射成像条件是否合适有效。
