PIXSCAN: Pixel detector CT-scanner for small animal imaging

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 571; no. 1; pp. 425 - 428
• Main Authors: Delpierre, P., Debarbieux, F., Basolo, S., Berar, J.F., Bonissent, A., Boudet, N., Breugnon, P., Caillot, B., Cassol Brunner, F., Chantepie, B., Clemens, J.C., Dinkespiler, B., Khouri, R., Koudobine, I., Mararazzo, V., Meessen, C., Menouni, M., Morel, C., Mouget, C., Pangaud, P., Peyrin, F., Rougon, G., Sappey-Marinier, D., Valton, S., Vigeolas, E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2007; Elsevier
• Subjects: Acoustics; Bioengineering; Computer Science; CT-scanner; Engineering Sciences; Hybrid pixels; Image Processing; Imaging; Life Sciences; Mechanics; Medical Imaging; Medical Physics; Neurons and Cognition; Nuclear medicine; Photon counting; Photon detector; Physics; Signal and Image Processing; Photon detector; 42.50.Ar; Photon counting; 85.40.Bh; CT-scanner; 87.59.−e; Hybrid pixels
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2006.10.126

The PIXSCAN is a small animal CT-scanner based on hybrid pixel detectors. These detectors provide very large dynamic range of photons counting at very low detector noise. They also provide high counting rates with fast image readout. Detection efficiency can be optimized by selecting the sensor medium according to the working energy range. Indeed, the use of CdTe allows a detection efficiency of 100% up to 50
keV. Altogether these characteristics are expected to improve the contrast of the CT-scanner, especially for soft tissues, and to reduce both the scan duration and the absorbed dose. A proof of principle has been performed by assembling into a PIXSCAN-XPAD2 prototype the photon counting pixel detector initially built for detection of X-ray synchrotron radiations. Despite the relatively large pixel size of this detector (330×330
μm
2), we can present three-dimensional tomographic reconstruction of mice at good contrast and spatial resolution. A new photon counting chip (XPAD3) is designed in sub-micronique technology to achieve 130×130
μm
2 pixels. This improved circuit has been equipped with an energy selection circuit to act as a band-pass emission filter. Furthermore, the PIXSCAN-XPAD3 hybrid pixel detectors will be combined with the Lausanne ClearPET scanner demonstrator. CT image reconstruction in this non-conventional geometry is under study for this purpose.