A new system for Digital Radiography and Computed Tomography using an intensified linear array detector

A new linear array detector has been developed at the Department of Physics of the University of Bologna. The main components are an intensified digital Electron Bombarded CCD (EBCCD) camera and a coherent linear-to-rectangular fiber optics guide coupled with the photocathode of the camera. One important system element is the FO guide, consisting of seven coherent fiber optics bundles arranged in such a way as to transform an almost linear area (128.8 mm x 1.45 mm) into a rectangular one. The FO guide output is directly coupled with the EBCCD’s photocathode. A layer of gadoliniumoxysulfide (GOS) converts the X-rays into visible light on the input side of the FO guide. In this way an intensified multi-slice linear detector (5600 x 35 pixels) was obtained. The system, patented by the University of Bologna, is able to make digital radiographies using a dose equal to about 1/100 of those usually used. The detector can be arranged either in Digital Radiography mode (DR) or in Computed Tomography (CT) mode by means of a high-precision translation and rotary mechanical device. A complete characterization of the system is presented. The system’s measured spatial resolution is about 6.3 lp/mm at 5% MTF. One important feature of the system is to avoid radiation of the sensitive part of the electronics.