X光区别于CT、B超、MRI的地方是X光可以穿透人体。被遮挡的部位，底片上不会曝光，洗片后这个部位就是白色的。X光受限于深浅组织，其影像相互重叠和隐藏，有时需要多次多角度拍摄X光片，才能看清楚。
X-ray differs from CT, B-mode ultrasound and MRI in that X-ray can penetrate the human body. The occluded part will not be exposed on the negative. After the film is developed, the part will be white. X-ray is limited to deep and shallow tissues, whose images overlap and hide each other. Sometimes it needs to take X-rays from multiple angles to see clearly.
X光产品最常见的有血管造影机、移动DR、CR、骨科C型臂、胃肠机、乳腺机、床旁机等等。
The most common X-ray products are angiograph, mobile DR, CR, orthopaedic C arm, gastrointestinal machine, breast machine, bedside machine and so on.
DR系统，即直接数字化X射线摄影系统，是由电子暗盒、扫描控制器、系统控制器、影像监示器等组成，是直接将X线光子通过电子暗盒转换为数字化图像，是一种广义上的直接数字化X线摄影。而狭义上的直接数字化摄影即DDR(DirectDigit Radiography)，通常指采用平板探测器的影像直接转换技术的数字放射摄影，是真正意义上的直接数字化X射线摄影系统。按照探测器类型主要分为非晶硅平板DR(主流)、非晶硒平板DR和CCD DR(主流);按照机架结构分为悬吊DR和立柱(UC臂)DR。
DR system, namely direct digital X-ray photography system, is composed of electronic cassette, scanning controller, system controller and image monitor. It directly converts X-ray photons into digital images through electronic cassette. It is a kind of direct digital X-ray photography in a broad sense. In the narrow sense, direct digital radiography (DDR), which usually refers to digital radiography using flat panel detector direct image conversion technology, is a real sense of direct digital X-ray photography system. According to the types of detectors, they are mainly divided into amorphous silicon flat DR (mainstream), amorphous selenium flat DR and CDDR (mainstream), and suspended DR and UC arm DR according to the frame structure.