WO2020105224A1

WO2020105224A1 - X-ray phase imaging system

Info

Publication number: WO2020105224A1
Application number: PCT/JP2019/030293
Authority: WO
Inventors: 貴弘土岐; 木村　健士; 太郎白井; 直樹森本
Original assignee: 株式会社島津製作所
Priority date: 2018-11-20
Filing date: 2019-08-01
Publication date: 2020-05-28
Also published as: JP7074206B2; JPWO2020105224A1

Abstract

This X-ray phase imaging system (100) includes an X-ray source (1), a detector (2), a plurality of lattices, an image processing unit (6) that generates a phase contrast image, a cooling fan (7) that is disposed so as to be spaced apart from the X-ray source and cools the X-ray source by blowing air to the X-ray source, and a windshield member (8) that blocks wind (51) going toward the lattices out of wind (50) sent from the cooling fan (7).

Description

X-ray phase imaging system

The present invention relates to an X-ray phase imaging apparatus, and to an X-ray phase imaging apparatus including a cooling fan that cools an X-ray source.

Conventionally, an X-ray phase imaging apparatus equipped with a cooling fan that cools an X-ray source is known. Such an X-ray phase imaging apparatus is disclosed in, for example, Japanese Patent Laid-Open No. 2012-110395.

The X-ray imaging system disclosed in Japanese Unexamined Patent Publication No. 2012-110395 includes an X-ray source, a flat panel detector arranged in the irradiation direction of the X-ray source, and an X-ray between the X-ray source and the flat panel detector. A plurality of grids including a multi-slit provided near the source and a grid arranged between the multi-slit and the flat panel detector; and an arithmetic processing unit that arithmetically processes image data to generate a phase contrast image. It has and. The phase contrast image includes an absorption image, a phase differential image, and a dark field image. The absorption image is an image formed based on the attenuation of X-rays that occurs when the X-rays pass through the subject. The phase differential image is an image formed based on the phase shift of X-rays that occurs when the X-rays pass through the subject. Further, the dark field image is a Visibility image obtained by a change in Visibility based on small-angle scattering of an object. The dark field image is also called a small-angle scattered image. "Visibility" is definition.

Further, the X-ray source disclosed in JP 2012-110395A has an X-ray tube cooler for cooling the X-ray source. The X-ray cooler cools the X-ray source by driving a fan. The X-ray cooler described in Japanese Unexamined Patent Publication No. 2012-110395 is provided directly (in contact) with the X-ray source. Therefore, the X-ray source vibrates due to the vibration generated when the fan of the X-ray cooler is driven. When the X-ray source vibrates, the image quality of the phase contrast image deteriorates. Therefore, the X-ray imaging system disclosed in Japanese Patent Laid-Open No. 2012-110395 is configured to stop air cooling by the X-ray cooler when the X-ray source vibrates by the X-ray cooler. There is.

JP, 2012-110395, A

However, in Japanese Patent Laid-Open No. 2012-110395, since the driving of the X-ray cooler is stopped in order to suppress the vibration of the X-ray source, it is not possible to take an image while cooling the X-ray source. There is. Therefore, it is desired to be able to image while cooling the X-ray source.

The present invention has been made to solve the above problems, and is to provide an X-ray phase imaging apparatus capable of imaging while cooling the X-ray source.

In order to achieve the above object, an X-ray phase imaging apparatus according to one aspect of the present invention includes an X-ray source, a detector that detects X-rays emitted from the X-ray source, an X-ray source and a detector. Between the X-ray source and the image processing unit that generates a phase contrast image based on the intensity distribution of the X-ray detected by the detector. A cooling fan that cools the X-ray source by blowing air and a windbreak member that blocks the wind from the cooling fan that is directed toward the plurality of grids.

In the X-ray phase imaging apparatus according to one aspect of the present invention, as described above, a cooling fan that is provided separately from the X-ray source and cools the X-ray source by blowing air to the X-ray source, and a cooling fan. Among the winds from the fan, the windshield member is provided to shield the winds heading in the direction of the plurality of grids. As a result, it is possible to prevent the X-ray source from vibrating due to the cooling fan. As a result, an image can be taken while cooling the X-ray source. Here, when the cooling fan is provided apart from the X-ray source, the grid may vibrate due to the air flowing from the cooling fan toward the grid. When the grating vibrates, the quality of the obtained image deteriorates. Therefore, by configuring as described above, even when the cooling fan cools the X-ray source toward the plurality of grids, the wind from the cooling fan is shielded by the windbreak member. Therefore, it is possible to prevent the plurality of grids from vibrating due to the wind. As a result, it is possible to suppress deterioration of the image quality of the obtained image even when the X-ray source is imaged while being cooled.

According to the present invention, as described above, it is possible to provide the X-ray phase imaging apparatus capable of imaging while cooling the X-ray source.

FIG. 1 is a schematic diagram showing an overall configuration of an X-ray phase imaging apparatus according to an embodiment. FIG. 6 is a perspective view of a grating moving mechanism included in the X-ray phase imaging apparatus according to the embodiment. It is a perspective view for explaining the structure of the windbreak member according to one embodiment. It is a schematic diagram for demonstrating arrangement | positioning of the X-ray source, 1st grating | lattice, a cooling fan, and a windbreak member by one Embodiment. It is a schematic diagram for demonstrating the method of acquiring a moire fringe image, moving a grating in translation in a Talbot interferometer. It is a schematic diagram for demonstrating the method of generating a phase contrast image from the acquired step curve in a Talbot interferometer. FIG. 3 is a schematic diagram of an absorption image acquired by an X-ray phase imaging apparatus according to one embodiment. It is a schematic diagram of the phase differential image acquired by the X-ray phase imaging apparatus by one Embodiment. FIG. 3 is a schematic diagram of a dark field image acquired by the X-ray phase imaging apparatus according to one embodiment. FIG. 7 is a schematic diagram for explaining a phase contrast image according to a comparative example. FIG. 6 is a schematic diagram for explaining a phase contrast image according to an embodiment. It is a schematic diagram for demonstrating the structure of the windbreak member by a 1st modification. It is a schematic diagram for demonstrating the structure of the windbreak member by a 2nd modification. It is a schematic diagram for demonstrating the structure of the cooling fan by a 3rd modification. It is a schematic diagram for demonstrating arrangement | positioning of the X-ray source by a 4th modification, a 1st grating | lattice, a cooling fan, and a windbreak member. It is a schematic diagram which shows the whole structure of the X-ray phase imaging apparatus by the 5th modification. It is a schematic diagram which shows the whole structure of the X-ray phase imaging apparatus by the 6th modification.

An embodiment of the present invention will be described below with reference to the drawings.

A configuration of an X-ray phase imaging apparatus 100 according to an embodiment will be described with reference to FIGS. 1 to 11.

(Structure of X-ray phase imaging apparatus)
First, the configuration of an X-ray phase imaging apparatus 100 according to this embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the X-ray phase imaging apparatus 100 is an apparatus that images the inside of the subject 20 by utilizing the Talbot (30albot) effect. The X-ray phase imaging apparatus 100 is configured to image the subject 20 while translating any one of the plurality of gratings in the grating periodic direction (Y direction).

As shown in FIG. 1, the X-ray phase imaging apparatus 100 includes an X-ray source 1, a detector 2, a plurality of gratings, an image processing unit 6, a cooling fan 7, a windbreak member 8, and a control unit. A unit 9, a storage unit 10, and a lattice moving mechanism 11 are provided. The plurality of lattices includes a first lattice 3, a second lattice 4, and a third lattice 5. In this specification, the direction from the X-ray source 1 toward the first grating 3 is the Z2 direction, and the opposite direction is the Z1 direction. Further, a horizontal direction in a plane orthogonal to the Z direction is defined as an X direction, a direction toward the back of the paper surface of FIG. 1 is defined as an X2 direction, and a direction toward the front side of the paper surface of FIG. 1 is defined as an X1 direction. The vertical direction in the plane orthogonal to the Z direction is the Y direction, the upward direction of the paper surface of FIG. 1 is the Y1 direction, and the downward direction of the paper surface of FIG. 1 is the Y2 direction.

The X-ray source 1 is configured to generate X-rays by applying a high voltage and irradiate the generated X-rays toward the first grating 3. In the present embodiment, the X-ray source 1 includes a cathode (not shown) for generating an electron beam, an anode for generating an X-ray when the electron beam collides, and a voltage between the cathode and the anode. This is an X-ray generator including a voltage applying unit (not shown) for applying, and a cathode, an anode, and a voltage applying unit provided in a housing (not shown).

The detector 2 is configured to detect X-rays, convert the detected X-rays into an electric signal, and read the converted electric signal as an image signal. The detector 2 is, for example, an FPD (Flat Panel Detector). The detector 2 is composed of a plurality of conversion elements (not shown) and pixel electrodes (not shown) arranged on the plurality of conversion elements. The plurality of conversion elements and the pixel electrodes are arranged in an array in the X direction and the Y direction at a predetermined cycle (pixel pitch). The detector 2 is also configured to output the acquired image signal to the image processing unit 6.

The first grating 3 has a plurality of X-ray transmitting portions 3a and X-ray absorbing portions 3b arranged in the Y direction at a predetermined cycle (pitch) 30. Each X-ray transmitting portion 3a and X-ray absorbing portion 3b is formed so as to extend linearly. Further, each X-ray transmitting portion 3a and X-ray absorbing portion 3b are formed so as to extend in parallel. The first grating 3 is a so-called multi-slit.

The first grating 3 is arranged between the X-ray source 1 and the second grating 4. The 1st grating | lattice 3 is comprised so that the X-ray which passed each X-ray transmission part 3a may be used as a linear light source. When the pitch of the three gratings (the first grating 3, the second grating 4, and the third grating 5) and the distance between the gratings satisfy certain conditions, the X-rays emitted from the X-ray source 1 It is possible to increase coherence. This is called the low effect. Thereby, the interference intensity can be maintained even if the tube size of the X-ray source 1 is large.

The second grating 4 has a plurality of slits 4a arranged at a predetermined period (pitch) 31 in the Y direction, and an X-ray phase changing portion 4b. Each of the slits 4a and the X-ray phase changing portion 4b is formed so as to extend linearly. Further, each slit 4a and X-ray phase changing portion 4b are formed so as to extend in parallel. The second grating 4 is a so-called phase grating.

The second grating 4 is arranged between the X-ray source 1 and the third grating 5 and is irradiated with X-rays from the X-ray source 1. The second grating 4 is provided to form a self-image (not shown) of the second grating 4 by the Talbot effect. When the X-ray having coherence passes through the slit-formed grating, an image (self-image) of the grating is formed at a position separated from the grating by a predetermined distance (Talbot distance). This is called the Talbot effect.

The third grating 5 has a plurality of X-ray transmitting portions 5a and X-ray absorbing portions 5b arranged in the Y direction at a predetermined cycle (pitch) 32. Each X-ray transmitting portion 5a and X-ray absorbing portion 5b is formed so as to extend linearly. Further, each X-ray transmitting portion 5a and X-ray absorbing portion 5b is formed so as to extend in parallel. The third grating 5 is a so-called absorption grating. The first grating 3, the second grating 4, and the third grating 5 have different roles, but the X-ray transmissive portion 3a, the slit 4a, and the X-ray transmissive portion 5a respectively transmit X-rays. .. Further, the X-ray absorbing portion 3b and the X-ray absorbing portion 5b each have a role of shielding X-rays, and the X-ray phase changing portion 4b changes the phase of the X-rays due to the difference in the refractive index with the slit 4a. Let

The third grating 5 is arranged between the second grating 4 and the detector 2 and is irradiated with the X-ray that has passed through the second grating 4. The third grating 5 is arranged at a position away from the second grating 4 by the Talbot distance. The third grating 5 interferes with the self-image of the second grating 4 to form moire fringes 16 (see FIG. 5) on the detection surface of the detector 2. As described above, the X-ray phase imaging apparatus 100 according to the present embodiment is configured by the so-called Talbot-Lau interferometer.

The image processing unit 6 is configured to generate the phase contrast image 41 (see FIG. 7) based on the image signal output from the detector 2. In the present embodiment, the image processing unit 6 generates, for example, the absorption image 42 (see FIG. 7), the phase differential image 43 (see FIG. 8) and the dark field image 44 (see FIG. 9) as the phase contrast image 41. .. The image processing unit 6 includes a processor such as a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array) configured for image processing.

The cooling fan 7 is configured to cool the X-ray source 1 by sending air to the X-ray source 1 under the control of the control unit 9. The cooling fan 7 includes a blade member (not shown), a motor (not shown), and the like. The cooling fan 7 generates wind 50 (see FIG. 4) by rotating the blade member with a motor. As shown in FIG. 1, the cooling fan 7 is provided separately from the X-ray source 1. Note that the cooling fan 7 is provided separately from the X-ray source 1 means that the cooling fan 7 and the X-ray source 1 are not directly connected (not in contact) with each other, and cooling is performed. This means that the fan 7 and the X-ray source 1 are not indirectly connected via the common fixing member. That is, the X-ray source 1 and the cooling fan 7 are individually held by a fixing member (not shown). Further, the cooling fan 7 is a fan different from a fan provided inside the housing of the X-ray source 1 for exhausting heated air. That is, the cooling fan 7 is a fan provided for cooling the focal point 1a of the X-ray from the outside of the X-ray apparatus, separately from the fan provided inside the housing of the X-ray apparatus.

The windbreak member 8 is configured to shield the wind 51 from the cooling fan 7 toward the direction of the plurality of grids 51 (see FIG. 4). As shown in FIG. 1, the windbreak member 8 and the plurality of lattices are held by separate fixing members 12, fixing members 13, fixing members 14, and fixing members 15, respectively. The fixing member 12, the fixing member 13, the fixing member 14, and the fixing member 15 are each configured to extend in the Y direction. The fixing member 12, the fixing member 13, the fixing member 14, and the fixing member 15 respectively hold the first lattice 3, the second lattice 4, the third lattice 5, and the windbreak member 8 from the Y2 direction. Is configured to. How can the fixing member 12, the fixing member 13, the fixing member 14, and the fixing member 15 hold the first lattice 3, the second lattice 4, the third lattice 5, and the windbreak member 8? It may be formed in various shapes. Note that the fixing member 15 that holds the windbreak member 8 and the fixing members 12, fixing

members

13 and 14 that hold the respective lattices generate vibrations caused by the wind 50 hitting the windbreak member 8. They are arranged at positions separated from each other so that they do not propagate to each other. The fixing member 15 that holds the windbreak member 8 is provided at a position separated from the X-ray source 1. That is, the windbreak member 8 is provided separately from the X-ray source 1 and is provided at a position separated from the X-ray source 1 (X-ray device). Further, each fixing member is fixed to a housing (not shown) of the X-ray phase imaging apparatus 100.

The control unit 9 is configured to control the cooling fan 7 to blow air to the X-ray source 1. Further, the control unit 9 is configured to control the lattice moving mechanism 11 to move the second lattice 4. The control unit 9 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory).

The storage unit 10 is configured to store the program executed by the control unit 9, the phase contrast image 41 generated by the image processing unit 6, and the like. The storage unit 10 includes, for example, an HDD (Hard Disk Drive) and a non-volatile memory.

The lattice moving mechanism 11 is configured to move the second lattice 4 under the control of the control unit 9. Further, the lattice moving mechanism 11 holds the second lattice 4 via the fixing member 13.

(Lattice moving mechanism)
As shown in FIG. 2, the lattice moving mechanism 11 includes an X direction, a Y direction, a Z direction, a rotation direction (Rz) about an axis line in the Z direction, a rotation direction (Rx) about an axis line in the X direction, and a Y direction. The second grating 4 is configured to be movable in the rotation direction (Ry) around the axis of. Specifically, the grid moving mechanism 11 includes an X-direction direct-acting mechanism 110, a Y-direction direct-acting mechanism 111, a Z-direction direct-acting mechanism 112, a direct-acting mechanism connecting portion 113, and a stage supporting portion driving portion 114. The stage support unit 115, the stage drive unit 116, and the stage 117 are included. The X direction translation mechanism 110 is configured to be movable in the X direction. The X-direction translation mechanism 110 includes, for example, a motor. The Y-direction translation mechanism 111 is configured to be movable in the Y-direction. The Y-direction translation mechanism 111 includes, for example, a motor. The Z direction translation mechanism 112 is configured to be movable in the Z direction. The Z-direction translation mechanism 112 includes, for example, a motor.

The lattice moving mechanism 11 is configured to move the second lattice 4 in the X direction by the operation of the X-direction linear moving mechanism 110. Further, the lattice moving mechanism 11 is configured to move the second lattice 4 in the Y direction by the operation of the Y-direction linear moving mechanism 111. Further, the lattice moving mechanism 11 is configured to move the first lattice 3 in the Z direction by the operation of the Z-direction translation mechanism 112.

The stage support unit 115 supports the stage 117 from below (Y2 direction). The stage drive unit 116 is configured to reciprocate the stage 117 in the X direction. The stage 117 has a bottom portion formed in a convex curved surface shape toward the stage supporting portion 115, and is configured to reciprocate in the X direction to rotate about the Z direction axis (Rz direction). There is. In addition, the stage support driving unit 114 is configured to reciprocate the stage support 115 in the Z direction. Further, the bottom of the stage support 115 is formed in a convex curved surface shape toward the linear motion mechanism connection 113, and when it is reciprocated in the Z direction, the stage support 115 rotates about the axis in the X direction (Rx direction). Is configured. Further, the linear motion mechanism connecting portion 113 is provided in the X-direction linear motion mechanism 110 so as to be rotatable around an axis line in the Y direction (Ry direction). Therefore, the lattice moving mechanism 11 can rotate the lattice around the central axis in the Y direction.

(Structure of windbreak member)
As shown in FIG. 3, the windbreak member 8 has a plate-like shape. Further, the windbreak member 8 has an opening 80 through which X-rays emitted from the X-ray source 1 pass. In the present embodiment, the windbreak member 8 includes, for example, an X-ray absorbing member 81. The X-ray absorbing member 81 contains, for example, a heavy metal such as lead or tungsten. As shown in FIG. 3, the opening 80 is an opening formed in the X-ray absorbing member 81. That is, the windbreak member 8 is formed by providing the opening 80 in the X-ray absorbing member 81 having a plate shape. Further, the windshield member 8 is formed such that the size of the windshield member 8 in the XY plane is substantially equal to the size of the first lattice 3 in the XY plane. The size of the windshield member 8 in the XY plane is substantially equal to the size of the first grating 3 in the XY plane when the windshield member 8 and the first grating 3 are arranged side by side in the optical axis 60 direction. In addition, it means that the region formed by the XY plane of the windbreak member 8 can substantially cover the region formed by the XY plane of the first lattice 3.

(Arrangement of cooling fan and windshield member)
FIG. 4 is a schematic view of the X-ray source 1, the first grating 3, the cooling fan 7, and the windshield member 8 as viewed from the Y1 direction. As shown in FIG. 4, the cooling fan 7 includes a blower port 7a. The cooling fan 7 is arranged at a position where air is blown from a direction (X direction) intersecting the optical axis 60 of the X-ray. Specifically, the cooling fan 7 is arranged between the X-ray source 1 and the windshield member 8. In the present embodiment, the X-ray source 1 is configured to irradiate the irradiation range 63 surrounded by the straight line 61 and the straight line 62 with the X-ray, and the cooling fan 7 is outside the irradiation range 63 of the X-ray. Moreover, it is arranged between the X-ray source 1 and the first grating 3. Specifically, the cooling fan 7 is arranged between the X-ray source 1 and the first grating 3 in a direction orthogonal to the optical axis 60 so that the blower port 7a faces the X-ray focal point 1a. ing. The cooling fan 7 is configured to cool the X-ray source 1 by applying the wind 50 to the X-ray focal point 1a of the X-ray source 1. Note that in the example shown in FIG. 4, the X-ray source 1 and the cooling fan 7 are shown small for convenience. In reality, the sizes of the X-ray source 1 and the cooling fan 7 are larger than those of the windbreak member 8 and the first grid 3. Therefore, in the present embodiment, even if the cooling fan 7 is not arranged between the X-ray source 1 and the windshield member 8 in the entire housing of the cooling fan 7, the blower port 7a is connected to the X-ray source 1. If it is arranged between the windshield member 8 and the windshield member 8, it is assumed that the cooling fan 7 is arranged between the X-ray source 1 and the windshield member 8.

The windbreak member 8 is arranged between the X-ray source 1 and the plurality of grids. Specifically, the windbreak member 8 is arranged at least on the optical axis 60 of the X-ray and between the X-ray source 1 and the first grating 3. The windbreak member 8 is configured to block the wind 51 from the cooling fan 7 that is reflected by the X-ray source 1 and is directed toward the first grating 3.

As shown in FIG. 4, the windbreak member 8 and the X-ray source 1 are arranged on the optical axis 60 of the X-ray and between the X-ray source 1 and the first grating 3. The distance 33 between them is smaller than the distance 34 between the windshield member 8 and the first grid 3.

(Generation of phase contrast image)

Next, a configuration in which the image processing unit 6 generates the phase contrast image 41 will be described with reference to FIGS.

In the present embodiment, the X-ray phase imaging apparatus 100 acquires the moire fringe image 40 at each step as shown in FIG. 5 by translating the second grating 4 by the grating moving mechanism 11. The image processing unit 6 acquires the step curve 46 as shown in FIG. 6 based on the pixel value of the same pixel 17 in the moire fringe image 40 at each step. 6 shows an example of the step curve 47 acquired without arranging the subject 20 and an example of the step curve 48 acquired with the subject 20 arranged as the step curve 46. The example of the step curve 46 shown in FIG. 6 is a graph showing the relationship between each step and the intensity of the pixel value. Plots indicated by circles in FIG. 6 represent values obtained when the subject 20 is photographed without being placed. In addition, the plots shown by square marks in FIG. 6 show values when the subject 20 is arranged and photographed.

As shown in FIG. 6, the image processing unit 6 measures the average intensity (Cs) of X-rays when the subject 20 is placed and imaged, and the average intensity (Xs) of the X-rays when the subject 20 is not placed ( The absorption image 42 is generated by the ratio with Cr). Further, the image processing unit 6 sets a predetermined phase difference (Δφ) between the step curve 47 acquired by capturing the subject 20 without arranging it and the step curve 48 acquired by arranging the subject 20 and capturing the image. The phase differential image 43 is generated by multiplying the number obtained by the calculation of In addition, the image processing unit 6 generates the dark-field image 44 based on the ratio of the Visibility (Vr) when the subject 20 is imaged without being arranged and the Visibility (Vs) when the subject 20 is arranged and imaged. .. Vr can be obtained by the ratio of the amplitude (Ar) of the step curve 47 and the average intensity (Cr). Further, Vs can be obtained by the ratio of the amplitude (As) of the step curve 48 and the average intensity (Cs).

7 to 9 are schematic diagrams of the phase contrast image 41. As described above, the image processing unit 6 uses the acquired step curve 47 and step curve 48 to obtain the absorption image 42 shown in FIG. 7, the phase differential image 43 shown in FIG. 8, and the dark field image shown in FIG. 44 and.

(Comparative example)
FIG. 10 is a schematic diagram of a phase contrast image 45 according to a comparative example when the image is captured without disposing the windshield member 8. The example illustrated in FIG. 10 is an example in which the subject 20 including the rectangular internal structure 22 (the internal structure 23, the internal structure 24, and the internal structure 25) is imaged. In the comparative example, since the image is captured without disposing the windshield member 8, the wind 51 reflected by the X-ray source 1 reaches the first grating 3. In this case, the first grating 3 vibrates. When the first grating 3 vibrates, the image quality of the phase contrast image 45 deteriorates. Specifically, when the first grating 3 vibrates, the shape of the step curve 46 collapses, so that in the phase contrast image 45 according to the comparative example, the contour 21 of the subject 20 is blurred or the internal structure 22 is unclear. .. In the example shown in FIG. 10, the outline 21 of the subject 20 is illustrated by a double line to represent the blur of the outline 21 of the subject 20. In addition, in the example shown in FIG. 10, the internal structure 23, the internal structure 24, and the internal structure 25 are illustrated by double lines, and the corners of the rectangular shape are illustrated by circles to represent the blurring of the internal structure 22. ing. Further, the wind 51 reflected by the X-ray source 1 is the wind that is rebounded by the X-ray source 1 toward the first grating 3 and the wind that is redirected by the X-ray source 1 toward the first grating 3. including.

FIG. 11 is a schematic diagram of the phase contrast image 41 captured by this embodiment. In the present embodiment, since the windshield member 8 is arranged, it is possible to prevent the wind 51 reflected by the X-ray source 1 from reaching the first grating 3. Therefore, it is possible to suppress the vibration of the first grid 3 caused by the wind 51 flowing from the cooling fan 7 toward the grid. Therefore, like the phase contrast image 41 shown in FIG. 11, it is possible to acquire an image in which each internal structure 22 is clearly depicted and the contour 21 of the subject 20 is clearly depicted.

(Effect of this embodiment)
In this embodiment, the following effects can be obtained.

In the present embodiment, as described above, the X-ray phase imaging apparatus 100 includes the X-ray source 1, the detector 2 that detects the X-rays emitted from the X-ray source 1, the X-ray source 1, and the detector 2. Based on the plurality of gratings (the first grating 3, the second grating 4, and the third grating 5) arranged between and the X-ray intensity distribution detected by the detector 2, the phase contrast image 41 And an image processing unit 6 for generating X, and a cooling fan 7 provided separately from the X-ray source 1 for cooling the X-ray source 1 by blowing air to the X-ray source 1, and a wind 50 from the cooling fan 7. Among them, the windshield member 8 for shielding the wind 51 heading in the direction of the plurality of lattices (the first lattice 3, the second lattice 4, and the third lattice 5) is provided. As a result, the cooling fan 7 can prevent the X-ray source 1 from vibrating. As a result, an image can be taken while cooling the X-ray source 1. Further, even when the wind 50 when cooling the X-ray source 1 by the cooling fan 7 is directed toward the plurality of grids (the first grid 3, the second grid 4, and the third grid 5), the cooling fan 7 Since the wind 50 and the wind 51 from the wind are shielded by the windbreak member 8, the plurality of grids (the first grid 3, the second grid 4, and the third grid 5) vibrate by the wind 50 and the wind 51. Can be suppressed. As a result, even when the X-ray source 1 is imaged while being cooled, it is possible to suppress deterioration of the image quality of the obtained phase contrast image 41.

Further, in the present embodiment, as described above, the windbreak member 8 and the plurality of lattices (the first lattice 3, the second lattice 4, and the third lattice 5) are separate fixing members (fixing members). 12, fixed member 13, fixed member 14 and fixed member 15). Accordingly, unlike the configuration in which the windshield member 8 and the plurality of lattices (the first lattice 3, the second lattice 4, and the third lattice 5) are held by the same fixing member, the windshield member 8 It is possible to suppress the vibration from propagating to the lattices (the first lattice 3, the second lattice 4, and the third lattice 5) via the same fixing member. As a result, the

winds

50 and 51 from the cooling fan 7 directly hit the plurality of grids (the first grid 3, the second grid 4, and the third grid 5), so that the grids (the first grid 3, the second grid 5). 4 and the third lattice 5) can be suppressed from vibrating, and the lattice (the first lattice 3) by the vibration of the windshield member 8 generated by the wind 50 and the wind 51 from the cooling fan 7. , The second grating 4 and the third grating 5) can be suppressed from vibrating, so that the grating (the first grating 3, the second grating 4 and the third grating 5) vibrates. This can be suppressed more.

Further, in the present embodiment, as described above, the cooling fan 7 is arranged at a position where the air is blown from the direction (X direction) intersecting the optical axis 60 of the X-ray, and the windshield member 8 is the X-ray. It is arranged between the source 1 and the plurality of gratings (first grating 3, second grating 4 and third grating 5). As a result, even when the wind 50 from the cooling fan 7 is reflected by the X-ray source 1 and heads in the direction of the lattices (the first lattice 3, the second lattice 4, and the third lattice 5), the windshield member. 8 can block the wind 51 heading in the direction of the plurality of grids (the first grid 3, the second grid 4, and the third grid 5). As a result, it is possible to suppress the wind 51 from hitting the plurality of lattices (the first lattice 3, the second lattice 4, and the third lattice 5).

Further, in the present embodiment, as described above, the cooling fan 7 is arranged between the X-ray source 1 and the windshield member 8. Thereby, it is possible to shield the wind 51 that is reflected by the X-ray source 1 and travels in the direction of the lattices (the first lattice 3, the second lattice 4, and the third lattice 5), and at the same time, the cooling fan 7 is provided. It is possible to shield the wind 50 from the direction of the lattice (the first lattice 3, the second lattice 4, and the third lattice 5). As a result, it is possible to further prevent the

winds

50 and 51 from hitting the lattices (the first lattice 3, the second lattice 4, and the third lattice 5).

Further, in the present embodiment, as described above, the plurality of gratings (the first grating 3, the second grating 4, and the third grating 5) reduce the coherence of X-rays emitted from the X-ray source 1. The cooling fan 7 includes a first grating 3 for enhancing and a second grating 4 for forming a self-image, and the cooling fan 7 is outside the X-ray irradiation range 63 and between the X-ray source 1 and the first grating 3. The windshield member 8 is arranged at least on the X-ray optical axis 60 and between the X-ray source 1 and the first grating 3. Here, the first grating 3 is arranged at a position closest to the X-ray source 1 among the plurality of gratings (the first grating 3, the second grating 4, and the third grating 5), and the period of the grating is 30 is smaller than the cycles of the other gratings (the cycle 31 of the second grating 4 and the cycle 32 of the third grating 5). Therefore, even if the vibration generated in the first grating 3 is small, the influence on the image quality of the phase contrast image 41 is larger than that of the other gratings (the second grating 4 and the third grating 5). Therefore, with the configuration as described above, it is possible to prevent the wind 50 from the cooling fan 7 from hitting the first grid 3. As a result, it is possible to prevent the first grating 3 from vibrating due to the wind 50 from the cooling fan 7, and thus it is possible to suppress deterioration of the image quality of the phase contrast image 41.

Further, in the present embodiment, as described above, the windbreak member 8 has a plate-like shape, and the wind 50 from the cooling fan 7 is reflected by the X-ray source 1 to be the first windshield 50. It is configured so as to shield the wind 51 heading in the direction of the grid 3. Thereby, the windshield member 8 can prevent the wind 50 from the cooling fan 7 and the wind 51 reflected by the X-ray source 1 from hitting the first grating 3. As a result, it is possible to further suppress the occurrence of vibration in the first grating 3, and it is possible to further suppress deterioration of the image quality of the phase contrast image 41.

Further, in the present embodiment, as described above, the windshield member 8 is provided on the optical axis 60 of the X-rays and between the X-ray source 1 and the first grating 3. The distance 33 between the X-ray source 1 and the X-ray source 1 is arranged at a position smaller than the distance 34 between the windshield member 8 and the first grating 3. As a result, the windshield member 8 can be arranged in the vicinity of the X-ray source 1, so that the wind 51 reflected by the X-ray source 1 can be shielded before being diffused. As a result, the size of the windshield member 8 can be reduced as compared with the configuration in which the windshield member 8 is arranged near the first lattice 3.

Further, in the present embodiment, as described above, the windbreak member 8 is located on the optical axis 60 of the X-rays and with the X-ray source 1 and the plurality of gratings (first grating 3, second grating 4, and , And the third grating 5), and has an opening 80 through which the X-rays emitted from the X-ray source 1 pass. Thus, unlike the configuration in which the windshield member 8 does not have the opening 80, it is possible to suppress the attenuation of X-rays due to the windshield member 8. As a result, it is possible to prevent the X-ray dose detected by the detector 2 from being reduced by the windshield member 8, and thus it is possible to prevent the contrast of the phase contrast image 41 from being reduced. ..

Further, in the present embodiment, as described above, the windbreak member 8 includes the X-ray absorbing member 81, and the opening 80 is an opening formed in the X-ray absorbing member 81. As a result, of the X-rays emitted from the X-ray source 1, the X-rays that are emitted to the areas other than the opening 80 are absorbed by the X-ray absorbing member 81. Therefore, it is possible to prevent X-rays from being transmitted from other than the opening 80. Therefore, it is possible to use the X-ray source 1 having the focus size such that the irradiation range 63 of the X-rays emitted from the X-ray source 1 is larger than the opening 80. As a result, the degree of freedom in selecting the X-ray source 1 can be improved.

(Modification)
In addition, it should be thought that the description of the embodiment, the operation, and the effect disclosed this time is an exemplification in all respects and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and further includes meanings equivalent to the scope of the claims and all modifications (modifications) within the scope.

For example, in the above-described embodiment, an example in which the windbreak member 8 is configured by providing the opening 80 in the X-ray absorbing member 81 having a plate shape is shown, but the present invention is not limited to this. For example, instead of the windbreak member 8 of FIG. 1, a windbreak member 8a as shown in FIG. 12 may be provided. The windbreak member 8a may include an X-ray absorbing member 81 and an X-ray transmitting member 82. Specifically, the windshield member 8a may be formed by an X-ray absorbing member 81 having an opening 80 and an X-ray transmitting member 82 provided so as to surround the X-ray absorbing member 81. The X-ray transmission member 82 includes, for example, resin or glass.

Further, in the above embodiment, an example of the configuration in which the windbreak member 8 has the opening 80 has been shown, but the present invention is not limited to this. For example, instead of the windbreak member 8 shown in FIG. 1, a windbreak member 8b as shown in FIG. 13 may be provided. The windbreak member 8b may not have the opening 80. When the windshield member 8b does not have the opening 80, the windshield member 8b is preferably formed by the X-ray transmitting member 82. Even when the windshield member 8b is formed by the X-ray transmission member 82, the X-rays are slightly attenuated by the windshield member 8b, so that the configuration in which the opening 80 is provided is preferable. Further, in the case where the windshield member 8b is formed by the X-ray transmitting member 82 and has the opening 80, the X-rays are diffracted due to the difference in the refractive index between the opening 80 and the windshield member 8b. In order to suppress the above, it is preferable to adjust the X-ray irradiation range 63 so that only the X-rays that have passed through the opening 80 are detected by the detector 2.

In the above embodiment, the example in which the cooling fan 7 blows the air 50 directly toward the focal point 1a of the X-ray source 1 has been shown, but the present invention is not limited to this. For example, instead of the cooling fan 7 shown in FIG. 1, a cooling fan 70 may be provided as shown in FIG. The cooling fan 70 may be provided with a duct 71 for adjusting the direction of the wind 52 diffused from the cooling fan 70 and blowing the air in a predetermined direction. By providing the duct 71 in the cooling fan 70, the air 52 from the cooling fan 70 can be collected and sent to the focal point 1a of the X-ray source 1, so that the cooling efficiency of the X-ray source 1 is improved. be able to. The duct 71 is provided in the cooling fan 70 in a state of being in contact with the periphery of the blower port 70a of the cooling fan 70.

Further, in the above embodiment, an example of the configuration in which the cooling fan 7 is arranged between the X-ray source 1 and the windbreak member 8 has been shown, but the present invention is not limited to this. For example, as shown in FIG. 15, the cooling fan 7 may be arranged between the windshield member 8 and the first grid 3. When the cooling fan 7 is arranged between the windshield member 8 and the first grid 3, the air 53 directed from the cooling fan 7 directly to the first grid 3 is shielded and the air 54 from the cooling fan 7 is provided. It is preferable to further provide a second windshield member 8c in order to suppress the reflection of the windshield member 8 by the windshield member 8 toward the first lattice 3.

In addition, in the above-described embodiment, the plurality of lattices (the first lattice 3, the second lattice 4, and the third lattice 5) are held in the Y2 direction by the fixing member 12, the fixing member 13, and the fixing member 14. However, the present invention is not limited to this. For example, instead of the fixing member 12, the fixing member 13, and the fixing member 14 shown in FIG. 1, as shown in FIG. 16, the X-ray phase imaging apparatus 100 includes a fixing member 120, a fixing member 130, and a fixing member 140. A beam portion 18 that holds the fixing member and the lattice moving mechanism 11 from the Y1 direction is provided, and is configured to hold the plurality of lattices (the first lattice 3, the second lattice 4, and the third lattice 5) from the Y1 direction. May be. That is, a configuration may be adopted in which a plurality of lattices (the first lattice 3, the second lattice 4, and the third lattice 5) are suspended and held. In this case, the windbreak member 8 may be held by the fixing member 15 fixed to the bottom surface of the X-ray phase imaging apparatus 100 or the like.

Further, in the above embodiment, an example of the configuration including the first lattice 3, the second lattice 4, and the third lattice 5 as the plurality of lattices is shown, but the present invention is not limited to this. For example, if the pixel pitch of the detector is smaller than the period of the self-image, the self-image can be directly resolved by the detector. Therefore, when the detector 2 shown in FIG. 1 is provided with a detector 2 having a pixel pitch smaller than the cycle of the self-image, a plurality of detectors 2 are provided as in the X-ray phase imaging apparatus 100 shown in FIG. The grating may include the first grating 3 and the second grating 4.

In the above embodiment, the size of the windshield member 8 in the XY plane is approximately equal to the size of the first grating 3 in the XY plane, but the present invention is not limited to this. When the wind 51 reflected by the X-ray source 1 hits only a part of the first grating 3, the size of the windshield member 8 in the XY plane is larger than the size of the first grating 3 in the XY plane. It may be small. The size of the windbreak member 8 may be any size as long as it can shield the wind 51 hitting the first grid 3.

Further, in the above embodiment, an example of the configuration in which the windshield member 8 is arranged on the optical axis 60 of X-rays and between the X-ray source 1 and the first grating 3 has been shown. The invention is not limited to this. For example, when the subject 20 is imaged while applying the wind 50, the windshield member 8 may be disposed between the subject 20 and the lattice.

Further, in the above embodiment, an example of the configuration in which the wind shield member 8 is provided to shield the wind 50 from the cooling fan 7 and the wind 51 reflected by the X-ray source 1 has been shown, but the present invention is not limited to this. Not limited. For example, in addition to the windshield member 8, a windshield member for shielding the wind from the air conditioner or the like may be further provided.

Further, in the above-described embodiment, the windshield member 8 has a plate-like shape and is arranged between the X-ray source 1 and the first grating 3. However, the present invention is not limited to this. Not limited. For example, the windbreak member 8 may have a curved shape. Further, for example, the windbreak member 8 has a box shape, and is configured to block the wind 50 (wind 51) from the cooling fan 7 by disposing the first lattice 3 inside. It may have been done. The windshield member 8 may have any shape as long as it can shield the wind 50 (wind 51) from the cooling fan 7.

1 X-ray source 2 Detector 3 First grating (plural gratings)
4 Second grid (plural grids)
5 3rd lattice (plural lattices)
6 image processing unit 7

cooling fan

8, 8a, 8b,

8c windshield member

12, 13, 14, 15 fixing member 20 subject 33 distance between windshield member and X-ray source 34 windshield member and first Distance between 1 grid 41 Phase contrast image 50 Wind (Wind from cooling fan)
51 Wind that is reflected by the X-ray source and heads in the direction of the first grating 60 Optical axis of X-ray 63 Irradiation range of X-ray 80 Opening 81 X-ray absorbing member 100 X-ray phase imaging device

Claims

X-ray source,
A detector for detecting X-rays emitted from the X-ray source,
A plurality of gratings arranged between the X-ray source and the detector;
An image processing unit that generates a phase contrast image based on the intensity distribution of the X-ray detected by the detector;
A cooling fan which is provided apart from the X-ray source and cools the X-ray source by blowing air to the X-ray source;
An X-ray phase imaging apparatus, comprising: a windbreak member that shields the wind from the cooling fan that is directed toward the plurality of grids.
The X-ray phase imaging apparatus according to claim 1, wherein the windshield member and the plurality of gratings are held by separate fixing members.
The cooling fan is arranged at a position to blow air from a direction intersecting with the X-ray optical axis,
The X-ray phase imaging apparatus according to claim 1, wherein the windbreak member is disposed between the X-ray source and the plurality of gratings.
The X-ray phase imaging apparatus according to claim 3, wherein the cooling fan is arranged between the X-ray source and the windbreak member.
The plurality of gratings include a first grating that enhances coherence of X-rays emitted from the X-ray source, and a second grating that forms a self-image,
The cooling fan is arranged outside the X-ray irradiation range and between the X-ray source and the first grating,
The X-ray phase imaging apparatus according to claim 1, wherein the windbreak member is disposed at least on the optical axis of X-rays and between the X-ray source and the first grating.
The windbreak member has a plate shape, and is configured to shield the wind from the cooling fan that is directed toward the first lattice by being reflected by the X-ray source. The X-ray phase imaging apparatus according to claim 5, which is provided.
The windshield member is on the optical axis of X-rays, and between the X-ray source and the first grating, the distance between the windshield member and the X-ray source is the windshield. The X-ray phase imaging apparatus according to claim 5, wherein the X-ray phase imaging apparatus is arranged at a position smaller than a distance between the shelter member and the first grating.
The windshield member is arranged on the optical axis of X-rays and between the X-ray source and the plurality of gratings, and an opening through which X-rays emitted from the X-ray source pass. The X-ray phase imaging apparatus according to claim 1, further comprising:
The windbreak member includes an X-ray absorbing member,
The X-ray phase imaging apparatus according to claim 8, wherein the opening is an opening formed in the X-ray absorbing member.