Improving image quality of synchrotron CT by scattered X-ray correction

Abstract

We developed a high-resolution CT system using synchrotron radiation. The system acquires high-quality CT images because the synchrotron CT has no beam-hardening effect that results from using monochromatic X-ray. It is said that X-ray scattering has no effects on the synchrotron CT images because a detector is set apart from a subject. However, the images have a disadvantage in non-uniformity caused by scattered X-rays owing to an area X-ray beam and a two-dimensional detector. The X-ray scattering decreased the accuracy of the CT number and increased the number of artifacts in CT images. We developed an accurate process for correcting scattered X-rays for the synchrotron CT. The correction process was applied for the synchrotron CT at 35-keV radiation. When a 10-mm-diameter 20%-hydroxyapatite homogeneous column phantom was used, the scattered X-rays led to a reduction of about 45% in the pixel values of CT images. With the correction, the pixel values were almost completely recovered.