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-
\mu
m 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
\mu
m at 50% contrast, and a resolution of
approximately one pixel (100
\mu
m) 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
\mu
m) can be detected with a
spatial resolution of
\sim 150
\mu
m at
50% contrast.
