Characterization of a flat-panel amorphous silicon detector for X-ray computed tomography

Article type: Research Article

Authors: Lee, H.-R. | Ellingson, W.

Affiliations: Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 USA

Abstract: The characteristics of an amorphous silicon detector for use in an X-ray imaging system have been evaluated. The primary use of the detector is in a three-dimensional (3-D) computed tomography (CT) system. The detector is a two- dimensional (2-d) flat panel array consisting of a 1024 \times 1024 matrix of photodiodes placed on a 100-\mum center. Combined with a Lanex(tm) scintillator, the detector-sensor presents an ideal solution for high-resolution industrial X-ray imaging applications. Modulation transfer function (MTF), determined from a 2-D projection image of a line-pair phantom, shows that the detector can achieve a resolution of 140 \mum at 50% contrast, and a resolution of approximately one pixel (100 \mum) at 20% of maximum image contrast. Further, examination of monolithic ceramic material with projection data from this detector demonstrates that such a flat-panel detector has promise for use in a CT system to provide highly resolved information. The reconstructed CT image of a ceramic hole-phantom demonstrates that the smallest holes (with a diameter of 300 \mum) can be detected with a spatial resolution of \sim 150 \mum at 50% contrast.

Journal: Journal of X-Ray Science and Technology, vol. 9, no. 1, pp. 43-53, 2001