A radiographic contrast media is any substance introduced into the body in order to make an organ, or the surface of an organ, or materials within the lumen of an organ visible on imaging.

Digital Radiography offers improved image quality as well as provide advances in medical image management, computer-aided diagnosis and teleradiology. Image quality is intimately linked to the precise and accurate acquisition of information from the x-ray beam transmitted by the patient, i.e. to the performance of the x-ray detector. Detectors for digital radiography must meet the needs of the specific radiological procedure where they will be used. Key parameters are spatial resolution, uniformity of response, contrast sensitivity, dynamic range, acquisition speed and frame rate. Digital radiography Devices include various phosphor x-ray converters, in which light quanta are produced as an intermediate stage, as well as direct x-ray-to-charge conversion materials such as zinc cadmium telluride, amorphous selenium and crystalline silicon.