JPH0326241A - Method and device for measuring quality hardening of radiation such as x rays or the like - Google Patents

Abstract

PURPOSE:To simply measure the quality hardening of X rays by varying one of equivalent substances and measuring transmission X-ray data by a body to be measured consisting of a substance in which an X-ray absorption coefficient is equivalent to a sort organization of the human body, etc., and a substance in which said coefficient is equivalent to a bone and a metal, etc. CONSTITUTION:A BEP of a body BDY to be measured is a dummy bone made of a substance having an X-ray absorption coefficient being equivalent to a bone of the human body, and made like a plate having thickness (w) of a right-angle triangle, and a WP is a cylindrical water container for containing water WT for simulating a soft organization of the human body. X rays irradiates in the direction extending from S1 to S2, and the overall length of the water container WP in this case is LWO, and the longest path length in the X-ray advance direction of the dummy bone BEP is LBO. When a path of S1 S2 is moved in the horizontal direction, path length LB of the dummy bone BEP is varied but path length LW of the water WT is constant, and a variation range of the path length LB is O-LBO. On the other hand, the path length LW of the water WT can be within a range of O-LWO by the quantity of water. By using such a body to be measured, and measuring transmission X-ray data and transmittion X-ray projection data corresponding to a pair of each of the length LW and the length LB, quality hardening of radiant rays such as X rays, etc., to the human body, etc., is derived therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention deals with the treatment of X-ray hardening (BeueH1 + duiB
) A method for measuring X-ray hardening and a filling device for eliminating the effects of this phenomenon.

(Prior art) X-ray CT is a device that performs tomography by irradiating X-rays around the entire circumference of a subject, detecting the X-rays that have passed through the subject, and processing the obtained X-ray data. It is. While it is practical to use an X-ray tube as a radiation source for XmCT,
Since the X-ray tube is a source of polychromatic energy, different phenomena occur than when using a monochromatic energy source. In other words, photons with lower energy are attenuated by substances more than photons with higher energy, so as the thickness of the object being transmitted increases and the X-rays are attenuated, the becomes larger, and the quality of the x' rays becomes harder. This is a phenomenon called linear hardening. Inside the human body, large X-ray hardening occurs particularly in highly X-ray absorbing substances such as bones and metals.

(Problem to be Solved by the Invention) By the way, when such X-rays are used, MJ shadow data is the logarithm of the amount obtained by dividing the input X-ray intensity for the same X-ray passage path by the X-rays transmitted through the subject. is not proportional to the integral value of the linear absorption coefficient of the X-ray path, and is affected by the hardening of the X-ray quality and exhibits non-linear rather than linear characteristics with respect to the transmission thickness. When image reconstruction is performed using projection data (projection data) having such nonlinear characteristics,
Unique artifacts will appear in the image.

This problem of X-ray hardening is a major technical issue in the current Y[, and an effective countermeasure is desired.

The present invention has been made in view of the above points, and its purpose is to realize a convenient 711 standard method for X-ray hardening and an apparatus for measuring the same.

(Means for Solving the Problems) The present invention solves the above problems by reducing the X-ray passage length of a substance that is made of water or an equivalent liquid or solid and has an X-ray absorption coefficient equivalent to that of soft tissue of the human body. It has a structure in which the Xll passage length of a high X-ray absorbing substance equivalent to bone or metal etc. is kept constant, and the length of the Xll passage path of a high X-ray absorption substance equivalent to bone or metal etc. is varied continuously or discretely depending on the The length of the X-ray passage path can be changed by changing the amount of the water or equivalent liquid or solid.
Length LW of material equivalent to soft tissue of the human body, etc. on the line passage path
Transmitted X-ray data corresponding to each pair of length LB and length LB of a high X-ray absorbing substance equivalent to bone, metal, etc. This method is characterized by measuring transmitted X-ray projection data and determining the radiation hardening of radiation such as X-rays in relation to the coexistence of soft tissues such as those of the human body and highly X-ray absorbing substances such as bones and metals.

In the above-mentioned body, the length of the X-ray passing path of the highly X-ray absorbing material is constant, and the length of the X-ray passing path of the material equivalent to soft tissue of the human body is variable, either continuously or discretely, depending on the X-ray passing path. A device having a structure in which the length of the X-ray passing path of the high X-ray absorption substance is changed by changing the amount of the high X-ray absorption substance can be used, and an apparatus for performing the above measurement. The above-mentioned X-ray measuring body, an integrated X-ray source and detector for measuring transmitted X-ray data transmitted through the limb measuring body, and their attached equipment are used to transmit transmitted X-rays.
A ray data measuring means, a moving means for moving the transmitted X-ray data measuring means in a required direction as necessary, and a length LW of a material equivalent to soft tissue of a human body or the like on the same X-ray passage path, bone or metal. The length LB of the highly X-ray absorbing material is equivalent to , and each projection data Pw (LW.L!1). Pa (LW,
X-ray absorption coefficient μW corresponding to each using
(LW.Le). It is characterized by comprising a calculating means for calculating μs (LW, LB).

(Function) By using the 11FJ standard, which consists of a substance whose X-ray absorption coefficient is equivalent to that of soft tissues such as the human body, and a substance equivalent to bones, metals, etc., Adjust the transmission X-ray data to be variable, and set the X-ray quality hardening to δ-1.
Set.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Figure tJ41 shows an example of the present invention. This is a schematic block diagram of the I regular holiday, and FIG. 2 is an explanatory diagram of a measurement system for measuring X-ray quality hardening based on the API regular holiday shown in FIG.

In FIG. 1, the upper part shows the i-plane view of the 1PI constant body BDY, and the lower part shows the flat-plane d view. In the figure, BEP is a simulator made of a material having an X-ray absorption coefficient equivalent to bone in order to simulate the bones of the human body, and is made in the shape of a right triangular plate with a thickness W. WP is water WT that simulates the soft tissue of the human body.
] It is an 11-cylindrical water container. X-rays are emitted in the direction from S1 to 82, and the bone path length at this time is L,
Then, the path length of water WT is L,. The total length of the water container WP is LWo+the longest path length in the X-ray traveling direction of the simulated bone BEP is L8. It is.

When the bus of S,→S2 is moved horizontally, that is, in the left-right direction of the figure, the path length L of the simulated bone BEP [I changes, but the water W
The path length LW of T is constant. Simulated l'LBEP path length L. The range of change is 0 to Lno.

On the other hand, the path length LW of the water WT can be changed in the range of 0 to LW0 by changing the amount of water.

Next, the measurement system sliding process using the object to be measured BDY is performed in the second step.
As shown in the figure. In the figure, the same parts as in the figure are given the same reference numerals. In the figure, Xs is an X-ray source that generates X-rays;
X is the focus of the X-rays. The collimator CMI is placed in front of the fish point X, sharply shapes the X-rays emitted from the fish point X, and blocks unnecessary X-rays. DET is a detector that receives X-rays emitted from the X-ray source XS and outputs a current proportional to the amount of X-rays. A collimator CM2 is placed in front of it to detect the scattered X-rays that enter the detector DET. Blocks unnecessary X-rays. Although a filter is often added to the X-ray source XS, it is omitted in the figure. In this measurement system, the X-ray source XS. While or after moving the detector DET and collimators CM1 and CM2 together in the horizontal direction, each position corresponds to the total path length of the simulated bone BEP path length L8 and the water WT path lengths t and w. Measure X-ray data. In the figure,
The focal point X of the radiation source XS moves on the straight line LL', and the detector DET moves on the straight line MM'.

FIG. 3 is a block diagram of an apparatus for measuring X-ray hardening. In the figure, parts equivalent to those in FIG. 2 are given the same reference numerals. In the figure, GA accommodates the object to be measured BDY,
The gantry that constitutes the M1 fixed system includes an X-ray source XS and a detector D.
This device has a mechanism that moves the ET and the collimators CMI and CM2 together in the left-right direction in the figure toward the water 9L. T
A is a table on which the BDY is placed on the top plate TP and moved to a predetermined position in the central space of the gantry GA. Either provide the top plate TP with a rectangular hole with a length corresponding to the above-mentioned horizontal movement distance at the measuring part of the object to be measured BDY, or use a plate made of a material with a very low X-ray absorption coefficient. The TP was designed not to affect the measured values. This top plate TP is shown in FIG.

In the figure, parts equivalent to those in FIG. 1 are given the same reference numerals. In the figure, HL is a hole provided in the top plate TP corresponding to the horizontal movement distance of the X-ray.

XR is an X-ray source XS under the control of the X-ray generation control device XGC.
This is a high voltage/X-ray generation control device that supplies high voltage to generate X-rays. DAS is the X-rays irradiated from the X-ray source XS, transmitted through the object to be measured BDY, and detected by the detection 5DET.
This is a data collection device that receives line data, converts it into a digital signal, and sends the data to a data processing device DPS. X-ray generation control device XGC, high voltage/X-ray generation control device X
R, data acquisition device DAS, etc. are the same as those used in normal X-ray CT. The data processing device DPS performs various processing on the collected data, and performs data processing of X-ray quality curing.

DS is a data storage device used as a high-speed data memory, and ADS is a low-speed but large-capacity auxiliary storage device such as a magnetic disk storage device.

TGC is a table/gantry control device that controls the horizontal movement of the gun (GA) and table TA, and SCC is a photography control device that performs unified control of each of the above-mentioned constituent devices.

Next, the operation of the apparatus configured as described above will be explained with reference to the flowchart shown in FIG.

Step 1) Place the I1 constant body BDY on the table TA, move it to a predetermined position in the gantry GA, and set the M1 constant body BDY so as to configure the measurement system shown in FIG.

At this time, m L w − L w+ of the water WT corresponding to the human soft tissue in the water container WP is appropriately set to a value of 1. In this state, the line that connects the X-ray source XS and detector DET is the object B.
It is located at the left end of DY (or may be at the right end).

Step 2 As the imaging starts, the X-ray source
While moving in the horizontal direction (sequentially from the right end to the left), at each position of the object to be measured BDY (a position having a pair of path lengths: path length LW of water WT (constant) and path length LI of simulated bone BEP) Measure and obtain X-ray transmission data. Furthermore, data corresponding to the intensity of X-rays is also measured. These processes are executed under the control of the imaging control device SCC and under the parallel operation and parallel processing of the data acquisition device DAS and the data processing device DPS.

The collected data is stored in a data storage device DS,
Offset correction of data acquisition device DAS as necessary,
After undergoing processing such as X-ray intensity correction, the auxiliary storage device ADS
is stored in

Step 3 Check whether the scheduled number of changes in the amount LW of water WT has been completed, and if so, proceed to Step 4.

If the process has not been completed, the process returns to step 1 and processes steps 1 and 2, or returns to step 2 and processes step 2. Do you need this? repeat. That is, this repeated process is performed by changing the amount LW1 of water WT (that is, changing the equivalent soft tissue path length LW), but this change is 0.
This is performed at appropriate intervals ΔLW (generally minute intervals) within the range of ≦LWl≦LWM (L song≦LWo). In this way, the pair of path lengths (LW, LR) of water WT and simulated bone BEP
Obtain transmitted X-ray data I (LW, LB) for the range O≦Lnl≦LBQ+ O≦LW,≦L■, and incident XI! corresponding to each measurement j! Strength data Io
We get (j).

1 (LW.Ln), Io(j) is data acquisition device DA
If offset processing of S is necessary, offset correction processing is performed, and the data is treated as data that has undergone offset correction processing and has undergone X-ray intensity correction. The X-ray intensity data Io(j) is
Path length of water WT 1,,-1. w, (constant), that is, 0
≦L[ll≦LI] shall be constant during the measurement of 0.

Step 4 Using the above data, perform the X-ray quality hardening calculations shown below. The X-ray absorption coefficient of water WT when passing through the path length t, w of water WT, which is an equivalent soft tissue, and the path length LB of simulated bone BEP, which is an equivalent bone tissue, is μw (LW.LFI),
Simulated bone BEPOX ray absorption coefficient μB (LW.LB)
Then, projection data P... (1) lw (LW.LB)... (2) IIs (LW.Le)... (3) Here, ΔLWI and ΔLII are the minute path lengths of water WT, The micropath length of the simulated bone BEP is shown. μ1. μ. LW
+Lllll for each data pair. Further, the following λ(LW+Le) may be obtained for each data pair of LW and L.

λ(LW, La) − 1a {LW. L! I}/
jw (LW+Ll])... (4)? Also, equation (2). μw (LW,
LB). Based on μe (LW.Le), L1
When t and w are held constant for each value of μ■(LW.
LB) as a polynomial in LB, or from μa (LW, LB) with LW constant, μB (0, O
) is approximated as a polynomial of LII, etc.
It is also possible to obtain each coefficient of the approximate polynomial. Similarly, μw (LW
．． Le) as a polynomial in t, w, or μ
It is also possible to obtain each coefficient of an equal approximation polynomial that approximates the correction formula for obtaining μw (0.0) from w (LW.LB) as a polynomial of LW.

Note that the present invention is not limited to the above embodiments. Figure 6 shows the normal 3rd generation (rotate/rotate method)
FIG. 2 is a diagram of another embodiment of a measurement system using a device having a structure similar to XilCT. In the figure, the same parts as in the m3 figure are given the same reference numerals. In the figure, RA is the object to be measured BD
This is an imaging area with a center O that accommodates Y. Fan beam X-ray source X (X is actually the focus X of the X-rays) and detector group D
The detector group DET is arranged to face the detector group DET with the imaging area RA in between, and xl[x+ and the detector group DET rotate together around the center 0 of the imaging area RA. That is, the X-ray source Xt
rotates on the circumference C, and the detector group DET is arranged on the IIl arc centered on X+. The X-ray source Xl is located between X and X on the I'l circumference C in the figure. (range of angle γ;
This range includes the 8-1 constant BDY)
, or X. While rotating together with the detector group DET between A and X, generation of X-rays and measurement of transmitted X-rays are performed in each direction. In the measurement of transmitted X-rays, one transmitted X-ray data and one X-ray intensity data, which is opaque X-ray data, are measured in each direction at the same time. Direction θ shown in Figure 6
Does d−L Iinθ satisfy for? Transmitted by detector D+ Xt9! Measure data. Here, d is the distance between the perpendicular to the surface of water WT passing through Xl and the center O, and L is Xt
and the distance from the center O. θ changes between −γ/2≦θ≦γ/2.

Other measurement conditions are as described above. In FIG. 6, collimators, filters, etc. are omitted.

Transmission data of the object to be measured 1 (L
W+, Log), X-ray intensity data IO(j, i
)', the projection calculation formula is as follows. (C is a proportionality constant) P(LW.La) = P(LWI,L■)=j
Qf- 110(!,i)/l(LW+1Ln+))(
1)' {ILL, lo(i. i) - C.10(i.
l)' Fig. 7 is an embodiment of still another measuring system of the present invention. In the figure, parts equivalent to those in FIG. 2 are given the same reference numerals. CM3 is a detector D that determines the X-ray intensity by 8-1.
This is a collimator installed in front of ET2. In the measurement method shown in FIG. 2, the length of water WT is Ll#=LW+ (constant), that is, 0≦LBI≦LI1. During the measurement of Transmitted X-ray 1 (LW+.
LBt) and the X-ray intensity 1o(j, i)' are measured simultaneously, and a projection calculation is performed using equation (1)'. In this measurement system, X-ray source XS1 detector DET, DET2, collimator CM
I, CM2, and CM3 move together and measure data pairs of the X-ray intensity transmitted through the object BDY and the incident X-ray intensity at each position. During this measurement, the detector DET2 is set at such a position that the measuring body BDY does not obstruct the incident X-ray path (X-Ll).

In addition, as shown in Fig. 7, a collimator CM3, a detector D
Instead of using ET2 to directly determine the incident
X-ray tube current XC (j.i
There is also a method of measuring Io(j,i)-a-Xc (Li) and obtaining projection data using equation (1)'. In the above formula, a is a proportionality constant.

FIG. 8 is a diagram of a measurement system of another embodiment of the present invention, and FIG. 9 is a diagram of this i1? FIG. 2 is a plan view of a 11-1 constant body BDY used for positive constants. In the figure, Figure 1. Components equivalent to those in FIG. 2 are given the same reference numerals. This example shows a high-speed measurement method using fan beam XIJ9, where X is a black spot of X-rays that emit fan beam X-rays. The i1-1 constant body BDY has a front shape along the fan beam as shown in FIG. 8, and a planar shape as shown in FIG. 9 when viewed from above. The front shape of the water container WP is fan-shaped, and is filled with water WT. Therefore, the path length of every X-ray path is constant at LW. On the other hand, the path length of the simulated bone BEP is
The route of the line is different to shout. X-ray source XS (X-ray focal point
), the detector group DET remains in this relative positional relationship without moving, and by one fan beam irradiation 1・I,
X-ray transmission data and X-ray intensity data of all paths for the LW shown in the figure are measured simultaneously.

Projection calculation is performed using equation (1)'. Different lI of LW
For P1 constant, the water container WP of the object to be measured BDY is replaced with a different one and the measurement is repeated. Although this method allows measurements of different Ln to be performed at the same time in one fan beam measurement, L. There is an inconvenience that it is necessary to exchange the object to be measured BDY for different measurements. Path length L of water WT
Figure 10 shows an example of a structure that changes W to Urabe. 1st
There is one shown in Figure 1. FIG. 10 is a front view of the object to be measured BDY of this embodiment, and FIG. 11 is a side view of the object to be measured BDY. In the figure, parts having the same functions as those in FIG. 1 are given the same reference numerals. In the figure, S is the slice thickness, and the width of each step of the stepped structure is made approximately equal to the slice thickness S. The X-rays are directed in the direction of XDI-XD2 (or the opposite direction may be used), and as shown in FIG. In FIG. 11, the shaded area is selected for the water WT. For each different path length of water WT, the path length of the simulated bone BEP can vary from 0 to LIlo.

In Figure 10, one fan beam illumination 1.1 simulates the total path length of water with path length LW by 1° IBE.
Although xl transmission data and X-ray intensity data for P can be obtained simultaneously, when changing the path length of the water WT, it is moved in a direction perpendicular to the plane of the drawing.

It is also possible to further modify the measurement system as follows.

(1) FIG. 12 is a diagram of the object to be measured BDY shown in FIG. 1, which has legs attached to it and is used by standing vertically on a table TA. In the figure, parts equivalent to those in FIG. 1 are given the same reference numerals. In the diagram, FT is ? There are three wooden legs attached to one fixed body BDY.

The legs are arranged as shown in the ten-sided diagram.

(I1) Instead of measuring the object BDY by placing it on the table TA, a structure may be adopted in which the 11111 constant body BDY is supported by two arms in the water shell direction. In this case, table TA is not necessary.

(il+) By using various metals instead of using the simulated bone BEP as a substance equivalent to bone, X-ray hardening can be measured in the coexistence of metals and soft tissues. Further, the liquid injected into the water container WP is not limited to water, and various solutions that simulate the soft tissues of the human body can be used. Furthermore, the water container WP can be made of a solid material having an X-ray absorption coefficient equivalent to that of soft tissue, instead of being a container containing a liquid.

(Iv) The structure of the object to be measured BDY is the opposite of that in Figure 1, with the water container WP (water WT) being triangular and the simulated bone BEP being at a constant height to reduce the absorption of X-rays by the bone. It is also possible to keep it constant and change the absorption of X-rays by water WT, which is equivalent to soft tissue.

In this case, the change in the height of the simulated bone BEP is
This is done by changing the amount of bone-like material that is attached to the bone.

In the above explanation, the radiation is X-rays, but it goes without saying that the present i1P1 method and the present ilP1 constant method can be applied to other radiations such as γ-rays.

(Effects of the Invention) As described above in detail, according to the present invention, the following effects can be expected, and the practical effects are great.

(1) Regarding the problem of X-ray hardening, which remains a major technical issue in the -1 constant method and its 11113 constant device can be realized.

(11) X due to presence of bone γF and mixture of bone and soft tissue 71:
In addition to the measurement of X-ray hardening, it has wide applicability, such as the δ-1 constant of X-ray hardening due to the presence of metal and mixed depressions of metal and soft tissue, and is a highly flexible measuring method and δt1. A fixed device can be realized.

(III) Structure of the arytenoid. The structure of the ilPI system is simple and very convenient. High-speed and accurate measurement of X-ray hardening becomes possible.

4. Figure 1 is a structural diagram of the 111 regular holiday according to an embodiment of the present invention, and Figure 2 is an illustration of the structure of the M1 constant in Figure 1. Diagram of I definite system,
Figure 3 is a configuration diagram of the measuring device, Figure 4 is a diagram of the table top, and Figure 5 is a flowchart 1 of the operation of the measuring device in Figure 3.
・, FIG. 6 shows f using a measuring body of another embodiment of the present invention.
FIG. 7 is an explanatory diagram of measurement according to another embodiment of the present invention, and FIGS. 8 and 9 are explanatory diagrams of the object to be measured according to other embodiments of the present invention. 9 is a front view thereof, FIG. 9 is a plan view thereof, FIGS.
1 is a side view thereof, and FIG. 12 is a diagram of a measuring body according to still another embodiment of the present invention.

BDY...Object to be measured BEP...Simulated bone commercial
I, CM2, CM3... Collimator DAS... Data acquisition device DET, DET2... Detector DPS... Data processing device DS... Data storage device GA... Gantry SC
C...Photography control device TA...Table TGC/
...Table gantry control device TP...Top plate
WP...Water container WT...Water X
...Focus XGC...X-ray generation control device XR...High pressure/X-ray generation control device XS...X-ray source 1st figure Front view 2nd figure xS Xli! ! 5th Cocoon 7 Fig.

Claims (6)

[Claims] (1) The X-ray passage length of a substance composed of water or an equivalent liquid or solid that has an X-ray absorption coefficient equivalent to that of soft tissues such as the human body is fixed, and a high X-ray absorption material that is equivalent to bones, metals, etc. has a structure in which the length of the X-ray passage path is varied continuously or discretely depending on the X-ray path, and the length of the X-ray passage of the substance equivalent to the soft tissue of the human body can be changed by using the water or equivalent liquid or By changing the amount of solid material, the length L_W of a material equivalent to soft tissue such as a human body and the height X equivalent to bone, metal, etc. on the same X-ray passage path
The transmitted X-ray data and transmitted X-ray projection data corresponding to each pair of the length L_B of the radiation absorbing material are measured, and from this, the A method for measuring radiation hardening of radiation such as X-rays, characterized by determining radiation hardening of radiation such as X-rays. (2) The length of the X-ray passage through a substance with high X-ray absorption equivalent to bone or metal is constant, and the length of the X-ray passage through a substance equivalent to soft tissue of the human body is continuous or discrete, depending on the X-ray passage. The length of the X-ray passing path of the high X-ray absorbing material is changed by changing the amount of the high X-ray absorbing material. Measure the transmitted X-ray data and transmitted X-ray projection data corresponding to each pair of the length L_W of a material equivalent to soft tissue of the human body, etc., and the length L_B of a high X-ray absorption material equivalent to bones, metals, etc. death,
A method for measuring radiation hardening of radiation such as X-rays, which is characterized in that the hardening of radiation such as X-rays is determined for the coexistence of soft tissues such as human bodies and high X-ray absorption substances such as bones and metals. (3) Let L_W be the length of a material equivalent to soft tissue of a human body, etc. on the same X-ray passage path, and L_B be the length of a highly X-ray absorbing material equivalent to bones, metals, etc., and calculate each projection data as P_W(L_
W, L_B), P_B(L_W, L_B),
The X-ray absorption coefficient μW (L_W, L_B) of materials equivalent to soft tissue of the human body, which corresponds to X-ray hardening, and the X-ray absorption coefficient μB (L_W, L_
B) respectively as {P_W(L_W+ΔL_W,L_B)−P
_W(L_W, L_B)}/ΔL_W, {P_B(L_
W, L_B+ΔL_B)-P_B(L_W, L_B)}
3. The method for measuring radiation hardening of radiation such as X-rays according to claim 1 or 2, characterized in that it is determined as /ΔL_B or various quantities derived therefrom. (4) A material composed of water or an equivalent liquid or solid that has an X-ray absorption coefficient equivalent to soft tissue of the human body, etc. and a high X-ray absorption material equivalent to bone, metal, etc. are arranged on the X-ray passage path. an object to be measured having a structure of A moving means for moving the X-ray data measurement means in a required direction as needed, a length L_W of a material equivalent to soft tissue such as a human body on the same X-ray passage path, and a high X-ray equivalent to bone, metal, etc. Length L_B of absorbing material, each projection data P_W(
L_W, L_B) and P_B(L_W, L_B), the corresponding X-ray absorption coefficient μw(L_W, L_B
), μB(L_W, L_B), and calculating means for determining the radiation quality hardening of radiation such as X-rays. (5) The object to be measured is a substance composed of water or an equivalent liquid or solid that has an X-ray absorption coefficient equivalent to that of soft tissues such as the human body, and has a constant X-ray passage length. X
It has a structure in which the X-ray passing path length of the radiation absorbing substance is varied continuously or discretely and continuously depending on the X-ray path, and the changing of the X-ray passing path length of the substance equivalent to the soft tissue of the human body etc. is done by using the water or equivalent material. 5. The radiation hardening measurement device for radiation such as X-rays according to claim 4, characterized in that it has a structure achieved by changing the amount of liquid or solid. (6) For the object to be measured, the length of the X-ray passage through a substance with high X-ray absorption equivalent to bone or metal is constant, and the length of the X-ray passage through a substance equivalent to soft tissue such as the human body is continuous by the X-ray passage. It has a structure in which the X-ray passing path length of the high X-ray absorption material is changed by changing the amount of the high X-ray absorption material. The radiation hardening measuring device for radiation such as X-rays according to claim 4.