IEC 62494-1:20 08规定了用数字X射线成像系统采集的图像的曝光指数的定义和要求。IEC 62494-1:20 08适用于一般射线照相术中使用的数字X射线成像系统，用于产生用于一般应用的投影X射线图像，例如但不限于: -基于可刺激磷光体的计算机射线照相(CR)系统； -基于平板探测器的系统； -基于电荷耦合器件(CCD)的系统。 基于图像增强器的系统和用于乳房x线照相或牙科应用的系统不包括在第一版中。IEC 62494-1:20 08仅针对单个辐照事件生成的图像定义了曝光指数。从多次照射生成的图像（例如，断层合成或双能量图像、单个CR板上的多个视图）不包括在内。

IEC 62494-1:2008 specifies definitions and requirements for the exposure index of images acquired with digital X-ray imaging systems. IEC 62494-1:2008 is applicable to digital X-ray imaging systems used in general radiography for producing projection X-ray images for general applications, such as, but not exclusively:
- computed radiography (CR) systems based on stimulable phosphors;
- flat-panel detector based systems;
- charge-coupled device (CCD) based systems.
Image intensifier based systems and systems for mammographic or dental application are not covered in this first edition. IEC 62494-1:2008 defines the exposure index only for images generated with a single irradiation event. Images generated from multiple irradiations (e.g., tomosynthetic or dual-energy images, multiple views on a single CR plate) are not covered.