X-ray CT device and method for correcting scattered X-rays

摘要

It is an object to prevent a poor X-ray CT image due to scattered X-rays. An X-ray CT scanner (100) uses an X-ray detector (4), etc., to scan (F1) an object (3) to obtain X-ray transmission image data, and estimate (F3) an X-ray absorption coefficient distribution inside the object (3) based on the scanned X-ray transmission image data. Next, the X-ray CT scanner (100) performs a Monte Carlo simulation on a simulated object (3) having the X-ray absorption coefficient distribution estimated, and estimates (F4 and F7) a point spread function or scattered X-ray distribution derived from the object. Then, the X-ray CT scanner (100) corrects (F5 and F8), based on the point spread function or scattered X-ray distribution estimated, the X-ray transmission image data, and finally creates (F6 and F9) an image of the X-ray absorption coefficient distribution of the object (3).

主权项

1. An X-ray CT scanner comprising:
a scanning section that scans an object to obtain X-ray transmission image data of the object from a plurality of projection directions, the scanning section comprising an X-ray source generating X-rays from an X-ray focus and an X-ray detector having X-ray detection elements in a two-dimensional array so as to detect the X-rays, wherein the X-ray source and the X-ray detector rotate around the object while facing each other and the object is interposed therebetween; an internal-distribution-estimating section that estimates an X-ray absorption coefficient distribution inside the object, based on the X-ray transmission image data scanned by the scanning section; a point-spread-function-estimating section that estimates a point spread function of a scatter derived from the object by performing a Monte Carlo simulation to simulate a physical interaction of the X-rays in a simulated object having the X-ray absorption coefficient distribution estimated by the internal-distribution-estimating section; a correction section that corrects the X-ray transmission image data by processing the point spread function estimated by the point-spread-function-estimating section and the X-ray transmission image date according to a deconvolution integral method; and an image-creating section that creates an image of the X-ray absorption coefficient distribution of the object by using the X-ray transmission image data corrected by the correction section.