SPEPIX

Flat panel radiological detectors, such as those sold by TRIXELL company, today mostly replace X-ray films (for single image imaging) and X ray Image Intensifiers (for video imaging). They offer for these applications, a large surface from 20cm x 20cm up to 43cm x 43cm, a good spatial resolution with pixels ranging from 100µm x 100µm to 200µm x 200µm, and a good temporal resolution with video rates of 100 images per second or more. Besides, the interest for distinguishing X-ray photons energy has been identified for a long while. This identification, or spectrometry, also called "color imaging", allows separating patient constituents versus their chemical composition. With a bi-energy detector, bones, which absorb both low energy and high energy X rays, can be separated from soft tissues which are mostly transparent at high energies. Any additional energy channel (three-energy, four energy,... detector) helps bringing more information. Spectrometric detector research has brought to market X ray scanner equipments for major companies (Siemens, General Electric, Philips). The goal of this project is to allow flat panel detectors to also access to the spectrometric imaging performance, thus giving them a very innovative characteristics and a key competitive advantage. This project deals with the two ends of the problem. On one end, the design of the detector will be done, specially focusing on the X ray to visible photon converting layer, and on the readout matrix. This design will be followed by the foundry and the characterization of a small surface test circuit. On the other end, large surface images will be done, but with too much costly detectors (from industrial point of view). These images will allow, with test objects or anatomical phantoms, for the evaluation of the clinical interest of spectrometric detectors. They will also help defining a more precise detector specification. To reach these goals, the project associates: TRIXELL, industrial world leader of radiological flat panel detectors; CEA-LETI, with its knowledge in innovative X-ray systems design and its facilities in design and characterization of integrated circuits; LPCML (Physical and Chemical Laboratory for Luminescent Materials); and CREATIS, linked to the Lyon-Bron Louis Pradel Cardio-vascular and Respirology Hospital, for their ability to evaluate the clinical interest of the images and to develop software improvement methods.