* Corresponding author. Tel.: #33-1-4552-7459; fax: #33- 1-4552-7450. E-mail address: guy.prevot@ires.in2p3.fr (P. Fessler) Nuclear Instruments and Methods in Physics Research A 442 (2000) 38} 44 New quantum detection system for very low dose X-ray radiology B. Hilt, P. Fessler*, G. Prevot GRPHE, Universite & de Haute Alsace, 61 rue Albert Camus, F-68093 Mulhouse Cedex, France 11 rue Rabelais, F92170 Vanves, France IReS, IN2P3CNRS/ULP, BP28, F67037 Strasbourg, France Abstract A new X-ray radiology system has been devised that signi"cantly reduces the dose of radiation administered to patients in spinal X-ray examinations. The apparatus scans the patient, using a high-e$ciency linear solid-state detector and highly sensitive electronics, operating in counting mode. Two speci"c integrated circuits were developed, one of which contains an automatic o!set correction. The detection system characterization data will be brie#y presented. Data is acquired in real time by a high-speed computer-controlled VME system. The scan parameters and image "ltering are also computer-controlled. The "rst images recorded using this new apparatus are given, along with the preliminary comparative dosimetric analysis.  2000 Elsevier Science B.V. All rights reserved. Keywords: X-ray radiology; Low dose; Microstrip silicon detector 1. Introduction X-rays, discovered by Roentgen at the end of 1895, are largely responsible for the takeo! of medi- cine in the course of this century. Many medical specialties make generous use of them } in radiol- ogy, of course, but also tomography, osteodensime- try, scintigraphy, and elsewhere. They are quite often a unique and irreplaceable means of non-invasive investigation. Silver-based radiographic "lms, which were the very origin of Ro K ntgen's discovery, are still in use today in nearly all radiological systems. They have a certain number of advantages, of course, such as the fact that their manufacture is perfectly control- led, and they exhibit excellent intrinsic spatial resolution. But they have other less favorable characteristics, among which we may mention lim- ited e$ciency and sensitivity, poor linearity, and a restricted dynamic. These de"ciencies seem to be incompatible with the criteria of the future radiology. What are these criteria? The "rst part of this article attempts to answer this question. Once these criteria are identi"ed, they should be translated into technological options. What type of particle should be used? What is the best-suited mode of patient exposure? How should the detec- tion system be de"ned? The sometimes original answers to these questions are presented in Section 2. From these remarks and motivations, a new type of radiological device has been constructed. The 0168-9002/00/$ - see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 9 0 0 2 ( 9 9 ) 0 1 1 9 7 - 3