ABSTRACT
Image acquisition begins when timing signals, delivered to the x-ray generator under computer control, initiate the production of x-rays that are transmitted through the patient and received by the image intensier. An aperture, placed between the image intensier and the video camera, controls the amount of light delivered to the camera. e aperture is adjusted to optimize the signal-to-noise ratio (SNR) of the acquired image, as will be discussed later in this chapter. A video camera receives the light image from the image
intensier and converts it to an electronic signal that is delivered to the image processor as analog video. e image processor digitizes the image, stores it in memory, and makes it available in digital format for subtraction from other images acquired at a dierent time or at a dierent energy. e basic components of the DSA system including the x-ray tube and x-ray generator, the image intensier, and the video camera are similar to but must be of higher quality than those used in an analog uoroscopy system to ensure proper synchronization and match between analog and digital components.
