Method of mapping distribution of physical parameters of a reference used in tests employing electromagnetic radiation

Abstract

The subject of the invention comprises of a method of mapping of distribution of reference physical parameters used in tests applying electromagnetic waves, in particular in planar or spatial tests of objects imagined using a computer tomograph, wherein the entire reference (1) or its fragments of components used in its design and forming determinants of its physical parameters are imaged by high-resolution scanning, that is, at least twice, preferably five times higher than the resolution in which the reference will be used in future studies and a collection of layered images of a reference or its fragment or component is obtained, on the basis of which, by reading information out of the image of the particular cross-section, material distribution and/or absorption coefficient distribution is determined directly, with the information about the absorption coefficient, together with coordinates for every voxel, which form so called spatial distribution of the absorption coefficient for the particular reference element are stored in a three-dimensional matrix, in electronic memory, with said information being used to calculate the correction coefficient, which defines for every voxel the deviation of parameters of the particular part of element of the reference from the theoretical value resulting from manufacturing assumptions, forming so called map of manufacturing precision, individual for the particular fragment or element of the reference, and then the individual manufacturing precision map for a part of the reference or its elements is written into a common file forming the manufacturing precision definition for the entire reference.

Claims

1. Method of mapping of distribution of reference physical parameters used in tests applying electromagnetic waves, in particular in planar or spatial tests of objects imagined using a computer tomograph, characterised in that the entire reference (1) or its fragments of components used in its design and forming determinants of its physical parameters are imagined by high-resolution scanning, that is, at least twice, preferably five times higher than the resolution in which the reference will be used in future studies and a collection of layered images of a reference or its fragment or component is obtained, on the basis of which, by reading information out of the image of the particular cross-section, material distribution and/or absorption coefficient distribution is determined directly, preferably distribution, value of absorption coefficient and material grain sizes, with the information about the absorption coefficient, together with coordinates for every voxel, which form so called spatial distribution of the absorption coefficient for the particular reference element are stored in a three-dimensional matrix, in electronic memory, with said information being used to calculate the correction coefficient, which defines for every voxel the deviation of parameters of the particular part of element of the reference from the theoretical value resulting from manufacturing assumptions, forming so called map of manufacturing precision, individual for the particular fragment or element of the reference, and then the individual manufacturing precision map for a part of the reference or its elements is written into a common file forming the manufacturing precision definition for the entire reference.

2. Method according to claim 1 characterised in that the process of high-resolution scanning of the entire reference (1) or its parts or elements used in its design is performed using imagining with polychromatic radiation in laboratory scanners equipped with an X-ray lamp, or using polychromatic radiation filtered in order to cut off low-energy photons, or monochromatised radiation or electromagnetic waves, in particular optical tomography, spectroscopic methods, including layer spectroscopy, light microscopy, confocal microscopy, ultrasound methods, acoustic and microwave methods, and most preferably using a synchrotron station with high-energy X-ray radiation, monochromatic or monochromatised.

3. Method according to claim 1 characterised in that information about the absorption coefficient for every voxel is stored in a three-dimensional matrix, in a file or files, on a flash disk, SSD hard disk or HDD hard disk, in an electronic form.

4. Method according to claim 1 characterised in that correction coefficient is calculated in the following manner: $\mathrm{wsp}.\mathrm{korekcyjny}=\mathrm{Wp}-\mathrm{Wz}\left[\mathrm{jednostka}.Math..Math.\mathrm{fizyczna}\right]$ $\mathrm{wsp}.\mathrm{korekcyjny}.Math..Math.\mathrm{wzgl}.Math.\underset{‘}{e}.Math.\mathrm{dny}=\frac{\mathrm{Wp}-\mathrm{Wz}}{\mathrm{Wp}}*100.Math.\left[\%\right]$ where: W.sub.p—theoretical value assumed at the stage of reference manufacturing W.sub.z—measured value,

Description

EXAMPLE 1

[0024] Example method of mapping distribution of physical parameters of the reference used in tests applying electromagnetic waves was performed using reference 1, the main design element of which is the batten 2, in which there are three cylindrical, through opening provided, along the length of the batten and parallel to one another 3. Inside the openings, there are three bars placed tightly, having cylindrical shape and size matching the diameter of openings 3 in the batten 2, that is, of 40 mm length and 0.5 mm in diameter. Batten 2 is made of polymethacrylate resin (PMMA), which has the mineral density of bone tissue equal to 0 mgHA/ccm. Bars are made of a mixture of an epoxide resin and synthetic hydroxyapatite HA. Weight ratios of the mixture of both materials are selected in such a way that the net mineral density in each of the bars was, respectively, 50, 200, 400 mgHA/ccm.

[0025] Every bar of reference 1 was imaged by scanning at a synchrotron station using monochromatic X-ray radiation, in such a way that the obtained image resolution was defined by the voxel size of 2×2×2 μm and 20 000 cross-sections recorded in a single file were obtained, in such a manner, that the cross-section of the bar is visible in every cross-section. The measured value of mineral density have been determined on the basis of radiation absorption coefficient used in the synchrotron measurement and written into the file. Then, for every voxel of the image belonging to the bar, the value of mineral density was read from a file and compared with the theoretical value defined for the particular bar during its manufacturing, thus the correction factor was obtained, and after referring it to the theoretical value, it was obtained as relative correction coefficient. Calculations were performed according to the formulae:

[00002]$\mathrm{wsp}.\mathrm{korekcyjny}=\mathrm{Wp}-\mathrm{Wz}\left[\mathrm{jednostka}.Math..Math.\mathrm{fizyczna}\right]$$\mathrm{wsp}.\mathrm{korekcyjny}.Math..Math.\mathrm{wzgl}.Math.\underset{‘}{e}.Math.\mathrm{dny}=\frac{\mathrm{Wp}-\mathrm{Wz}}{\mathrm{Wp}}*100.Math.\left[\%\right]$

[0026] where:

[0027] W.sub.p—theoretical value assumed at the stage of reference manufacturing

[0028] W.sub.z—measured value,

and results of calculations for the selected voxel in each of the three bars are presented in Table 1.

TABLE-US-00001 TABLE 1     mineraina wsp. teoretyczna zmierzona na podstawie korekcji (    produkcy    obrazu wysokorozdzielczego mg/ mg/ccm mg/ccm ccm % 50 40 10 20 200 220 −20 −10 400 390 10 2.5 indicates data missing or illegible when filed
After the reference had been assembled, it was used in density measurements, where—using the known method—calibration curve was calculated, with values measured for bar areas in the reference before curve calculation were corrected using the determined correction factor.