Digital Radiology With A Slit Scan Detector

Linear solid state X-ray detectors are used to produce digital images. The detectors produce the X-ray image line by line as the patient is scanned with a narrow X-ray beam. One of the decisive advantages of this principle of imaging is that it rejects scattered radiation. This translates to an increase in image contrast. The main functions of a solid state X-ray detector are : image detection ; signal multiplexing ; DC offset and gain calibration. The output signal is a digital signal coded on 8 bits or 12 bits. The dynamic range is 4000:1. The avantages of solid state linear detectors are : large field of view (for example 18") ; high contrast ; direct digital output ; high dynamic range. Multilinear detectors will be described. They integrate a TDI function (time delay and integration) in synchronism with the scanning.