Method of determination of physical parameters of an object imaged using computer tomograph and equipment for implementation of said method

摘要

The core of the invention lies in a method of determination of physical parameters of the object (3) imaged using computer tomograph, in particular determination of absolute parameters of physical density and/or X-ray absorption coefficient, wherein the reference (2) of the determined physical parameters is installed between the X-ray source (4) and the detector (1) or, advantageously, directly on the detector (1), outside the rotating tomograph platform where the scanned object (3) is placed, followed by object scanning, during which the images of tomographic projections record simultaneously the two-dimensional image of the studied object and the two-dimensional image of the reference, where for at least one projection for at least one reference area the value of image greyscale intensity is performed in relative units by readout of pixel value from the projection image, which reflects the X-ray radiation intensity in greyscale after passing through the scanner chamber and the reference, and the obtained results are used as a basis for calculations of coefficients of calibration function, preferably using linear regression, then the calibration function is substituted with a variable, namely the value determined from the pixel value from the projection image, which reflects the intensity of X-rays in greyscale after passing through the scanner chamber and the scanned object and the value of calibration function is calculated, reflecting the value of the physical parameter and it is stored, preferably in the same pixel in the projection, then on the basis of thus determined projection a computer image reconstruction takes place, the result of which represents in the absolute scale values of the determined physical parameter. The core of the invention is also contained in the equipment for using this method.

主权项

1. The method of determination of physical parameters of the object imaged using computer tomograph, in particular determination of absolute parameters of physical density and/or X-ray absorption coefficient, characterised in that the reference (2) of the determined physical parameters is installed between the X-ray source (4) and the detector (1) or, advantageously, directly on the detector (1), outside the rotating tomograph platform where the scanned object (3) is placed, followed by object scanning, during which the images of tomographic projections record simultaneously the two-dimensional image of the studied object and the two-dimensional image of the reference, where for at least one projection for at least one reference area the value of image greyscale intensity is performed in relative units by readout of pixel value from the projection image, which reflects the X-ray radiation intensity in greyscale after passing through the scanner chamber and the reference, and the obtained results are used as a basis for calculations of coefficients of calibration function, preferably using linear regression, then the calibration function is substituted with a variable, namely the value determined from the pixel value from the projection image, which reflects the intensity of X-rays in greyscale after passing through the scanner chamber and the scanned object and the value of calibration function is calculated, reflecting the value of the physical parameter and it is stored, preferably in the same pixel in the projection, them of thus determined projection a computer image reconstruction takes place, the result of which represents in the absolute scale values of the determined physical parameter.