本研究的目的是利用放射師一級品保作業（以下稱爲一級QA）及放射師二級品保作業（以下稱爲二級QA）兩種作業程序，來比較兩種QA對影像不良率的影響。方法自94年1月到94年8月總共收集14762 views並將每月不良的影像記錄下來，並利用描述性統計來比較只有一級QA與二級QA相對於數位醫療影像不良率的影響，結果我們發現如果二級QA達成率72%以上，影像不良率一級QA將是二級QA的5倍。

The objection of this study is to evaluate the poor ratio of digital image in x-ray by quality assurance of single check and double check. The method is that from 94/1 to 94/9 we have collected total 14762 views and record e poor quality images every months and use described statistics to compare the influence of poor ratio of digital image between single check and double check. The result is the if the double check is achieved more than 72%, image poor ratio of single check is 5 times than that of double check.