JP2017009437A - Fluoroscopic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluoroscopic apparatus and a method for imaging X-ray refractive indices of a sample object and quantitatively measuring distribution of the X-ray refractive indices while limiting exposure of the sample object to X-rays.SOLUTION: A Fluoroscopic apparatus 10 comprises an X-ray source 31, a lens array 32 located between the X-ray source 31 and a sample object 33 and configured to pass X-rays emitted by the X-ray source 31, and detection means located behind the sample object 33 and including a screen 34 or a two-dimensional X-ray sensor to detect the X-rays passing through the sample object 33 as an image.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique related to a fluoroscopic apparatus. Refraction contrast method and Talbot interferometer are used as a method for imaging changes in the refractive index of a sample object when targeting biological soft tissue or resin that has little X-ray absorption and is difficult to contrast in X-ray fluoroscopy. Instead, the present invention provides a technique for enabling imaging of a change in the refractive index of a sample object at a lower exposure dose.

  X-ray fluoroscopy is widely used from medical use to industrial use. This is a projection image that reflects the absorbance of X-rays inside the sample object when X-ray is transmitted through the target sample object. This is the method obtained.

  The higher the density of heavier elements in the sample object, the higher the X-ray absorption, and the clear contrast can be obtained. When the subject is a soft tissue or a resin of a living body, there is a drawback that the image is hardly contrasted.

  As means for solving this, a refraction contrast method (FIG. 1) and a Talbot interferometer (FIG. 2) have been proposed. In either case, an image reflecting the refractive index distribution of the sample object with respect to X-rays is acquired. In general, the refractive index of a sample object with respect to X-rays is close to 1, and X-rays that have passed through a sample object having a refractive index distribution are refracted by a minute angle.

  In the refractive contrast method shown in FIG. 1, a sample object 12 is irradiated using an X-ray point light source 11, and an image projected on a screen 13 or an X-ray image sensor separated by a certain distance is obtained. This is because the X-ray refracted by a very small angle shifts the projection position compared to the case where the X-ray travels straight through a finite distance, and the position on the screen becomes darker when the X-ray travels straight. It is based on the principle that the refraction phenomenon is visualized as contrast by making the brightness brighter (see Non-Patent Document 3).

  The Talbot interferometer shown in FIG. 2 visualizes the change in the wavefront caused by the refractive index distribution as a differential phase distribution (see Patent Document 1, Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3). . Specifically, the X-ray point light source 21 is used to irradiate the sample object 22, the phase grating 23 is disposed immediately after the sample object 22, the amplitude grating 24 is disposed at an appropriate distance from the phase grating, and the amplitude The screen 25 and the X-ray image sensor are arranged immediately after the lattice. The phase grating 23 has the ability to convert the transmitted X-ray of the sample object having a phase distribution into a moire pattern depending on the differential phase, and the amplitude grating 24 converts the moire pattern into an intensity contrast. As a result, the principle is to visualize the differential phase distribution as the X-ray intensity contrast on the screen. It is also possible to directly detect the moire pattern with a two-dimensional image sensor. In that case, the distribution of the differential phase can be obtained by detecting the shape of the moire pattern, and the distribution of the X-ray absorption can also be obtained by measuring the X-ray intensity of the moire pattern.

  Compared with the refractive contrast method, the Talbot interferometer has the ability to measure the absorptivity distribution and refractive index distribution of a sample object at the same time and detect a finer refractive index distribution. However, the realistic phase grating 23 has a finite absorption with respect to the X-ray, and the X-ray transmitted through the sample object 22 is necessary because the phase grating 23 is disposed after the X-ray transmits the sample object 22. There is a problem that a part of the sample object is wasted and the X-ray exposure of the sample object is increased.

  Further, when the distance between the sample object 22 and the phase grating 23 is increased to a finite distance, there arises a problem that the effect of refraction contrast is mixed depending on the distance between the sample object 22 and the phase grating 23. If the sample object 22 and the phase grating 23 are in close contact, the Talbot interferometer can image the refraction effect as a pure differential phase and at the same time the absorptivity distribution, but the distance between the sample object 22 and the phase grating 23 is also possible. Is limited, the projection position on the screen 25 changes depending on the magnitude and distance of the change in the refractive index due to refraction at the sample object 22, and the intensity distribution of the eyelid reflecting the absorptance distribution also changes. As a result, the effect of the refractive index is mixed into the intensity distribution, and there is a problem that the position on the screen and the position of the sample object do not correspond one-to-one, making it difficult to interpret the image.

International Publication Number WO2004 / 058070

Franz Pfeiffer, Timm Weitkamp, and Christian David, “X-ray phase contrast imaging using a grating interferometer”, Europhysics News, 37, p13-15 (2006) Wataru Yashiro, Yoshihiro Takeda, Atsushi Momose, “Efficiency of capturing a phase image using cone-beam x-ray Talbot interferometry”, Journal of the Optical Society of America A | OPTICS, IMAGE SCIENCE, AND VISION, 25 (8): 2025 -39 (2008) Atsushi Momose, Wataru Yashiro, and Yoshihiro Takeda, “X-ray Phase Imaging with Talbot Interferometry”, in Biomedical Mathematics: Promising Directions in Imaging, Therapy Planning and Inverse Problems, edited by Y. Censor, M. Jiang, and G. Wang (Medical Physics Publishing, Madison, Wisconsin, USA, 2009), Ch. 14 (p281-320).

  The present invention has been made in view of such circumstances, and its purpose is to image the X-ray refractive index of the sample object while suppressing the X-ray exposure to the sample object, and to calculate the X-ray refractive index distribution. An object of the present invention is to provide an X-ray fluoroscopy device for quantitative measurement.

The present invention is grasped by the following composition.
(1) A first aspect according to the present invention is an X-ray fluoroscopy device, which is disposed between an X-ray source and the X-ray source and a sample object, and X-rays emitted from the X-ray source are A lens array that passes therethrough; and a detection unit that is arranged behind the sample object and that detects the X-ray transmitted through the sample object as an image or a two-dimensional X-ray sensor.

(2) In the configuration of (1), the X-ray source includes a point-like or linear unit X-ray source, and a plurality of point-like unit X-ray sources are 2 as the light emission shape of the X-ray source. First X-ray source arranged in a dimensional manner, second X-ray source in which a plurality of linear unit X-ray sources are arranged one-dimensionally at equal intervals or unequal intervals, a finite size A third X-ray source that effectively realizes a two-dimensional array of point-like unit X-ray sources by a diaphragm in which a plurality of small holes are two-dimensionally arranged with respect to the X-ray source having At least one of the fourth X-ray sources in which the slits are arranged one-dimensionally at equal intervals or unequal intervals to effectively realize a one-dimensional array of linear unit X-ray sources May be.

(3) In the configuration of (1), the X-ray source includes a point-like or linear unit X-ray source, and the X-ray source includes the point-shaped unit X-ray source as a light emission shape. When the plurality of point-like unit X-ray sources includes at least one of a square lattice, a triangular lattice, a hexagonal lattice, a rectangular lattice, an orthorhombic lattice, a rhomboid lattice, a strained oblique lattice, a Penrose lattice, a quasicrystalline lattice, and a random lattice. A two-dimensional shape of the entire array having a finite area shape including at least one of a triangle, a square, a hexagon, a rectangle, a circle and an ellipse, and the X-ray source is the linear unit X When including a radiation source, the plurality of linear unit X-ray sources have a finite area shape including at least one of a triangle, a square, a hexagon, a rectangle, a circle, and an ellipse as a two-dimensional shape of the entire array. It may be.

(4) In the configuration of (1), the lens array is an assembly of microlenses that converge the X-rays, and the focal point of each microlens is on the screen or the two-dimensional X-ray sensor, The focal point may have a dotted or linear shape.

(5) In the configuration of (1), the lens array is formed by superimposing a plurality of unit lens arrays and has a flat surface or a curved surface as an overall shape, and the unit lens array is made of tungsten or platinum. , Gold, Silver, Copper, Lead, Iron, Zinc, Tin, Molybdenum, Titanium, Nickel, Aluminum, Pure metals or their alloys, or Silicon, Silicon oxide, Silicon nitride, Aluminum oxide, Carbon, Carbide, Lime, Glass Alternatively, a plate made of a single material containing ceramic or a composite material thereof, the first plate formed by arranging concave depressions in an array on the plate, and glass, quartz inside the plate A spherical object formed from a material having a relatively low density, which is different from the material constituting the plate, selected from ceramics or metals A second plate in which an object, a lens-shaped object or a lens-shaped shell object is embedded, and a low-density portion or a cavity portion is formed in an array arrangement, and a diffraction lens formed from the first material is arranged in an array form. 3 plates and a fourth plate in which the concentric first materials are arranged in an array.

(6) In the configuration of (1), the lens array is an assembly of minute converging lenses, and the converging lens has a point-like focal point, a two-dimensional square lattice, a triangular lattice, a hexagonal lattice, a rectangular shape. Arranged on the lens array surface in an arrangement including at least one of a lattice, an orthorhombic lattice, a rhombus lattice, a strained oblique lattice, a Penrose lattice, a quasicrystal lattice, and a random arrangement, or the converging lens has a linear focus A cylindrical lens or a cylindrical lens may be arranged on the lens array surface in a one-dimensional manner at equal intervals or unequal intervals.

(7) In the configuration of (1), the lens array is composed of microlenses, and has a material and / or structure that shields the X-rays in a portion other than the lens opening of the microlenses. Also good.

(8) In the configuration of (1), a mechanism for rotating the sample object, or a mechanism for rotating the X-ray source, the lens array, and the two-dimensional X-ray sensor with respect to the sample object; And means for measuring a refractive index distribution inside the sample object.

(9) In the configuration of (1) above, when the sample object is not disposed and provided immediately before the screen or the two-dimensional X-ray sensor, the X-ray is detected by the screen or the two-dimensional X-ray sensor. A focus shielding plate that blocks a beam at a position that converges upward, and a change in the position of the X-ray convergence point due to the refraction of the X-ray at the sample object is detected on the screen or the two-dimensional X-ray sensor. Means for converting into a change in line intensity and measuring a refractive index distribution projected onto the sample object in two dimensions as a distribution of intensity contrast.

(10) In the configuration of (1), the two-dimensional shape of the sample object is further measured by measuring the position, shape, and intensity of the convergence point of the X-ray projected on the screen or the two-dimensional X-ray sensor. There may be provided means for measuring the refractive index distribution and the absorptance distribution projected onto the screen.

  According to the present invention, it is possible to provide an X-ray fluoroscopic apparatus that images the X-ray refractive index of a sample object and quantitatively measures the X-ray refractive index distribution while suppressing X-ray exposure to the sample object. .

It is a block diagram of the refractive contrast method in one prior art. It is a block diagram of the Talbot interferometer in another prior art. It is a block diagram of a lens array system according to an embodiment of the present invention (hereinafter the same). It is a block diagram of the system which converts the movement of the focus position on a screen into contrast. It is a block diagram of the system using an X-ray point source array. It is a block diagram of a system using a square square lattice X-ray point source array and a square lattice lens array. It is a block diagram of the system using a regular hexagonal regular triangular lattice X-ray point source array and a regular triangular lattice lens array. It is sectional drawing of the X-ray lens array comprised by the refractive lens, Comprising: (A) Single-sided convex type, (B) Double-sided convex type, (C) Spherical cavity type, (D) Lens cavity type. It is sectional drawing of the lens array comprised by the aggregate | assembly of a micro relief type | mold diffraction lens. FIG. 3 is a cross-sectional view of a lens array constituted by a collection of minute π phase type zone plates. It is sectional drawing of the lens array comprised by the collection | assembly of a minute amplitude type zone plate. It is a top view of the X-ray lens array comprised by the square lattice arrangement | positioning of a minute circular diffraction lens. It is a top view of the X-ray lens array comprised by the regular triangular lattice arrangement | positioning of a minute circular diffraction lens. It is a top view of the X-ray lens array comprised by the square-grid arrangement | positioning of a minute square diffraction lens. It is a top view of the X-ray lens array comprised by the regular triangular lattice arrangement | positioning of a micro regular hexagonal diffraction lens. It is a block diagram of the system of a spherical lens array of a single focal length and a spherical screen. It is a figure of the coordinate system of a lens array curved surface and a screen curved surface. It is a block diagram of the system of a single lens focal length planar lens array and a curved screen. It is a block diagram of the system of a curved lens array of a single focal length and a flat screen. CT configuration and coordinate system.

(Embodiment)
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the accompanying drawings. The same number is attached | subjected to the same element through the whole description of embodiment.

((Overall configuration of X-ray fluoroscopic apparatus 10))
As a result of investigations to solve the above-described problems, the inventor has examined the X-ray fluoroscopic apparatus 10 as shown in FIG. It has been found that it is effective to arrange a screen 34 or a two-dimensional X-ray sensor to be detected.

  The lens array 32 is composed of a large number of microlenses 35, and each of the large number of microlenses 35 is positioned so as to connect the X-ray focal point 37 on the screen 34 when the sample object 33 is not disposed. And the focal length is set. Therefore, a large number of X-ray focal points 37 are projected on the screen 34 in accordance with the positions of the microlenses 35. In the present specification, the focal point may be referred to as the X-ray convergence point.

  The sample object 33 is disposed between the lens array 32 and the screen 34. When the sample object 33 has a refractive index distribution, the convergent X-ray beam 36 is refracted, and the focal position on the screen provided behind the sample object 33 moves 38. The focal position shift amount increases according to the magnitude of refraction and the distance from the refraction point to the screen. By measuring this focal position shift amount as an image on the screen, the state of refraction in the sample object 33 can be measured as a two-dimensional projection image.

  The measurement sensitivity of the amount of X-ray refraction inside the sample object 33 increases as the size of the focal point 37 decreases, and increases as the distance from the sample object 33 to the screen 34 increases.

  The X-ray intensity of each focal point 37 measured as an image reflects the absorption rate of the sample object 33 on the convergent X-ray beam 36 serving as a ray, and the conventional X-ray absorption contrast can be measured simultaneously.

  The spatial resolution is determined by the size of the individual microlenses 35 constituting the lens array 32. When there is a refractive index distribution finer than the spatial resolution inside the sample, phenomena such as an increase in focal spot size, distortion, or splitting into multiple focal spots occur. Information such as the spread of the focal point can also be used as information inside the sample.

  Although the lens array 32 that can be actually created has not only the effect of converging X-rays but also the effect of absorbing it as a side effect, the X-rays are absorbed before the sample object 33 is irradiated. The amount will not increase.

  FIG. 4 shows a method of measuring an image by converting the magnitude 38 of the focal position movement 38 on the screen 34 into an intensity contrast on the screen. Although the X-ray beam collected at the focal point at the standard position when the sample is not placed is hidden by the shielding part 42, the screen 34 or the two-dimensional X-ray image sensor has a function of passing the other beams through the transmission part 43. The X-ray beam reaches the screen 44 only when the focus moves, so that the movement of the focus can be converted into an intensity contrast on the screen 34.

  This method of converting the focal shift into intensity contrast is effective when it can capture a small focal shift compared to the pixel size as an intensity change on the pixel when the pixel of the two-dimensional image sensor cannot be made small. Method. In the case of this method, the shape of the shielding portion 42 shown in black on the surface of the focus shielding plate 41 in FIG. 4 should match the position and size of the focus when there is no sample object as much as possible. The measurement sensitivity of refraction becomes higher. Further, by making the shape of the shielding portion 42 flat in the X direction or Y direction on the surface, it is possible to selectively measure only the amount of refraction of the sample in a specific direction such as the Y direction or the X direction. . The flattening of the shielding portion may have different directions and sizes for each focal point, and at the same time, the amount of refraction in each direction can be measured.

  FIG. 5 shows a configuration diagram of a system using an X-ray point source array 51 as an X-ray source. A number of X-ray point sources are two-dimensionally arranged on the X-ray point source array 51 (in this case, also referred to as “first X-ray source”). In the case of this method, the lens array 53 is composed of a large number of microlenses 54 that exist at positions that are jumped and an X-ray shielding plate 55 that fills the space between the microlenses. Each microlens has a focal length so as to project a two-dimensional image of the entire point source array 51 onto the screen 57. Further, the entire shape of the X-ray point light source array 51 and the lens array 53 are arranged so that the focus sets projected by the individual microlenses on the screen do not overlap with each other and the focus sets completely fill the screen. The arrangement of the microlenses 54 is determined. Note that, throughout this specification, an X-ray point source or point light source refers to a “point unit X-ray source”.

  FIG. 6 shows an example in which the X-ray point sources 62 are arranged in a two-dimensional square lattice as the X-ray point source array 61 and the overall shape is a square. The individual microlenses constituting the lens array project a light source image 610 onto the screen, and the projected focus distribution shape is obtained by transposing the array of the X-ray point source array vertically and horizontally. Yes. In this case, the focal points 69 can be uniformly distributed on the screen 67 by arranging the lenses of the lens array 63 in a square lattice and selecting the lattice interval appropriately.

  FIG. 7 shows an example of the light emission shape when the X-ray point sources 72 are arranged in a two-dimensional regular hexagonal lattice as the X-ray point source array 71 and the overall shape is a regular hexagon. In this case, the individual microlenses 74 constituting the lens array 73 project a light source image 710 inverted vertically and horizontally on the screen, and the lens array 73 is arranged in a triangular lattice so that the lens array 73 is arranged on the screen. The focal points 79 can be distributed evenly. 6 and 7 illustrate the case of a square lattice and a regular hexagonal lattice, but the two-dimensional array of the X-ray point sources 72 is not limited to these, but is a triangular lattice, a rectangular lattice, an oblique lattice. It may include at least one of a lattice, a rhombus lattice, a strained oblique lattice, a Penrose lattice, a quasicrystalline lattice, and a random lattice. In this case, the two-dimensional shape of the entire array may have a finite area shape including at least one of a triangle, a square, a hexagon, a rectangle, a circle, and an ellipse. Similarly, the two-dimensional shape of the entire array may have a finite area shape including at least one of a triangle, a square, a hexagon, a rectangle, a circle and an ellipse.

  The above-described method using the X-ray point source array measures the X-ray refraction of the sample object 56, although there is a difference in the method of generating irradiation X-rays that converge at a large number of focal positions on the screen independently. In principle, there is no difference in the measurement principle of the method using the X-ray point source and the lens array shown in FIGS. That is, it is possible to directly use techniques such as measurement of the focal position movements 38 and 510, and measurement of focal movement as intensity contrast by installing the focal shielding plate 41 immediately before the screen.

  The technique using the X-ray point source array has an advantage that an X-ray source having a large source size with poor spatial coherence can be used for refractive index measurement. That is, an X-ray point source array 51 is formed by placing a porous aperture in which a large number of small holes for passing X-rays are arranged two-dimensionally on a plate that shields X-rays on an X-ray source having a large source size. Can be effectively constructed (in this case, also referred to as “third X-ray source”), and the amount of refraction of the sample object can be measured by using this.

  As another method, as an X-ray tube target for generating X-rays, an X-ray point source array 52 can be obtained by adopting a two-dimensional array of small heavy metal targets on the surface or inside of a light element material. Can also be configured.

  By combining this measurement technique with a computed tomography (CT) technique, it is also possible to measure the X-ray refractive index distribution inside the sample object. That is, continuous measurement of projection data while rotating the sample object by a mechanism that rotates the sample object, or continuous measurement of projection data while rotating by the mechanism that rotates the whole measuring device with respect to the sample, numerical calculation from the projection data Thus, the refractive index distribution inside the sample object can be obtained. In addition, since X-ray absorption projection data can be acquired at the same time, the absorptance distribution inside the sample can also be measured by the CT method.

  In the Talbot interferometer, since the X-ray transmitted through the sample object 22 is absorbed by the phase grating 23, there is a problem that the X-ray exposure amount of the sample object 22 increases. FIGS. 3 to 7 and claim 1 The described method solves that problem.

  In the Talbot interferometer, the sample object 22 needs to be close to the phase grating 2 in order to accurately measure the differential phase distribution. When the distance between the sample object 22 and the phase grating 23 is increased, non-local mixing of X-ray beams occurs on the screen 25 according to the distance due to the effect of refraction by the sample object 22, resulting in blurring. However, in this method, even if the distance from the lens array 32 to the sample object 33 and the distance from the sample object 33 to the screen 34 are separated, the position of the focal point 37 of each microlens 35 of the lens array 32. Only moves 38 correspondingly on the screen 34, and there is no blurring that would cause problems with the Talbot interferometer.

  Even if the sample object 33 is separated from the lens array 32 and the screen 34, there is no problem in the measurement of the refractive index and the absorptance of X-rays. This is particularly advantageous for measuring the distribution. In the CT method, since it is necessary to rotate the sample and the measuring device relatively, it is necessary to keep a certain distance between the lens array and screen of the device and the sample object, and the rotating sample object of finite size. Each internal point and each part of the apparatus have a distance that varies according to the rotation. The present method according to claim 10 is characterized in that the mixing of the effects of refractive contrast, which can be a problem at a finite distance, can be eliminated, and the CT measurement of the refractive index distribution and the absorptance distribution inside the material can be performed accurately. Yes.

  The advantages of the present technique described above are obtained by placing the sample object 33 on the downstream side of the lens array 32. Conversely, even if the sample object is placed on the upstream side of the lens array 32, the inside of the sample object is obtained. It is possible to obtain a two-dimensional image reflecting the refractive index distribution. In this case, the lens array and screen system operates as a two-dimensional wavefront sensor for X-rays that have passed through the sample and entered the lens array.

((Configuration of lens array 32))
Next, a lens array design and production method, a lens array arrangement method, and a specific calculation method for CT measurement, which are necessary for carrying out the present invention, are disclosed.

  The lens array 32 can be formed by processing a material having a refractive index with respect to X-rays. In the following, the refractive index and focal length for X-rays will be examined, and a specific design and creation method for a lens array composed of a refractive microlens and a diffractive microlens will be presented.

  The following describes a design method for a lens array composed of refractive microlenses. A sectional view of a specific lens array shape is shown in FIG.

  As described above, a large number of spherical or lens-shaped concave depressions 82 are provided on the surface of a metal or silicon material plate, or a large number of spherical cavities 84 or convex lens-shaped cavities 85 are provided inside the material. The material plate can be processed into a lens array by a method such as. As a specific method for forming the concave portion, machining by an NC processing machine, pressing by a convex array die, pressing a large number of spherical glass balls or ceramic spheres onto a metal plate, and the like are possible. Here, a plate formed by arranging concave dents in an array is selected from glass, quartz, ceramic or metal in the first plate and the plate, and is different from the material constituting the plate. Spherical object, spherical shell object, lens-shaped object or lens-shaped shell object formed from a low-density material is embedded in an array-like arrangement with a low-density part or cavity part formed from the second plate or material. A plate in which the formed diffractive lenses are arranged in an array is called a third plate, and a plate in which concentric materials are arranged in an array is called a fourth plate. The material plate is composed of at least one of the first plate, the second plate, the third plate, and the fourth plate.

  The arrangement of the microlenses in the lens array is preferably an arrangement such as a square lattice or a triangular lattice, but may be a random arrangement. In the case of random arrangement, X-rays are emitted without arranging the sample in advance, the focal position appearing randomly on the screen is measured, and by comparing the focal position with the case where the sample is arranged, The amount and direction of refraction inside the sample object are measured. In the case of adopting a creation method in which a spherical or convex lens-shaped material is embedded inside the material, the position of the material to be embedded may not be accurately controlled. However, the above method can be used. The two-dimensional arrangement of the microlenses is at least one of a hexagonal lattice, a rectangular lattice, an orthorhombic lattice, a rhomboid lattice, a strained oblique lattice, a Penrose lattice, and a quasicrystalline lattice, in addition to a square lattice, a triangular lattice, and a random lattice. May be included.

  The lens array can also be formed as an array in which a diffractive lens including a zone plate or the like is used as a constituent minute lens. The diffractive lens or Fresnel zone plate that is a component of the lens array is roughly divided into two types: phase type that modulates the phase depending on the location, and amplitude type that distributes the absorptance. It can be adopted.

  In the following, a relief type diffractive lens (or a continuous phase type Fresnel zone plate or multi-value phase type Fresnel zone plate as an equivalent designation) with high beam utilization efficiency and low unnecessary scattering is used for the lens array. The design method in the case of using as a component is presented. A sectional view of this shape is shown in FIG. 9, and plan views of this shape are shown in FIGS.

  As described above, a method using a continuous phase Fresnel zone plate as a relief type diffractive lens as a design method of a lens array has been presented. A π phase shift binary phase Fresnel having a cross-sectional shape as shown in FIG. -You may create as a lens array which has a zone plate as a component. Compared to the continuous phase type, the binary phase type has a simpler structure and can be produced more easily. However, the continuous phase type is more preferable because it has a disadvantage of increasing unnecessary scattering. Further, the lens array can be formed not as a phase type but as an aggregate of amplitude type (or absorption type) Fresnel zone plates as shown in FIG. In this case, the annular zone is formed using a material that easily absorbs X-rays. FIG. 11 shows a method of forming a zone plate ring body 111 made of a heavy element that makes X-rays more spherical on a substrate 112 made of a light element that hardly absorbs X-rays. The amplitude type has a drawback that the absorption of X-rays increases compared to the phase type, and the phase type is more desirable.

  The two-dimensional arrangement of the minute diffractive lenses on the lens array can be any arrangement such as the arrangement of a square lattice shown in FIG. 12 or the arrangement of a regular triangular lattice shown in FIG. The shape of the minute diffraction lens is not limited to the circular shape shown in FIGS. 12 and 13, but the basic region of the lattice such as a square in the square lattice shown in FIG. 14 and a regular hexagon in the regular triangular lattice in FIG. 15 is maximized. The form to use is also possible. As the shape of the micro diffractive lens, the shape that uses the basic region to the maximum as compared with the circular shape has the effect of maximizing the utilization efficiency of X-rays and reducing unnecessary X-ray irradiation to the sample.

  The method of aligning the focal lengths of the lenses constituting the lens array to a constant value and making the lens array flat has the advantage of simplifying the manufacturing of the lens array. In this case, each focus of the lens array can be adjusted on the screen by making the screen shape into a specific rotating curved surface shape with respect to the beam axis. This curved surface shape is obtained as follows.

  When a linear light source is used as the X-ray light source, a lens array in which cylindrical lenses or cylindrical lenses in a direction parallel to the shape of the light source are arranged one-dimensionally at equal intervals or unequal intervals is used. Used (in this case, also referred to as "second X-ray source"). Further, linear slits may be arranged one-dimensionally at equal intervals or unequal intervals to effectively realize a one-dimensional arrangement (in this case, also referred to as “fourth X-ray source”). If the lens array and the screen are arranged in a concentric cylindrical shape centered on the line light source, the individual lens focal lengths of the lens array can be made constant. When the focal length of the lens array is set to a constant value, a combination of a flat lens array and a curved screen, and a combination of a curved lens array and a flat screen can be selected. Note that, throughout this specification, an X-ray linear light source or a linear light source refers to a “linear unit X-ray source”.

  When measuring the refractive index distribution inside the sample, continuous shooting while rotating the sample with respect to the device, or continuous shooting while rotating the device consisting of the X-ray source, lens array and screen while the sample is stationary. For example, a computed tomography (CT) method for obtaining the refractive index distribution inside the sample by numerical calculation from the obtained projection information can be used. The specific method is disclosed below.

  INDUSTRIAL APPLICABILITY The present invention is used as an X-ray diagnostic imaging apparatus including X-ray CT for medical / medical / biological and veterinary medicine, and an industrial X-ray inspection apparatus.

DESCRIPTION OF SYMBOLS 10 ... X-ray fluoroscope, 11 ... X-ray point source, 12 ... Sample object, 13 ... Screen, 21 ... X-ray point source, 22 ... Sample object, 23 ... Phase grating, 24 ... Amplitude grating, 25 ... Screen, 31 ... X-ray point source, 32 ... Lens array, 33 ... Sample object, 34 ... Screen, 35 ... Micro lens, 36 ... Focus X-ray beam, 37 ... X-ray focus, 38 ... Focal position shift, 41 ... Focus shield Plate, 42 ... shielding part, 43 ... transmission part, 44 ... beam reaching the screen, 51 ... X-ray point source array, 52 ... X-ray point source, 53 ... lens array, 54 ... micro lens, 55 ... shielding plate, 56 ... Sample object, 57 ... Screen, 58 ... Converging X-ray beam, 59 ... X-ray focal point, 510 ... Focus position shift, 61 ... X-ray point source array, 62 ... X-ray point source, 63 ... Lens array, 64 ... micro lens, 65 ... shielding plate, 6 ... object of specimen, 67 ... screen, 68 ... focused X-ray beam, 69 ... focus of X-ray, 610 ... image of light source, 71 ... X-ray point source array, 72 ... X-ray point source, 73 ... lens array, 74 ... Micro lens, 75 ... shielding plate, 76 ... sample object, 77 ... screen, 78 ... focused X-ray beam, 79 ... focus of X-ray, 710 ... image of light source, 81 ... material, 82 ... concave (micro lens), 83 ... Both sides concave (micro lens), 84 ... spherical cavity (micro lens), 85 ... lens cavity (micro lens), 91 ... material, 92 ... micro relief diffractive lens, 93 ... lens center, 94 ... sawtooth Ring zone, 101 ... material, 102 ... minute π phase zone plate, 103 ... zone plate center, 104 ... phase zone, 111 ... ring zone of X-ray absorbing material, 112 ... light element substrate, 113 ... minute amplitude zone ·plate, 114: Zone plate center, 161 ... X-ray point source, 162 ... Spherical lens array, 163 ... Sample object, 164 ... Spherical screen, 171 ... X-ray point source, 172 ... Lens array curved surface, 173 ... Sample object, 175 ... X-ray ray, 181 ... X-ray point source, 182 ... plane lens array, 183 ... sample object, 184 ... curved screen, 191 ... X-ray point source, 192 ... curved lens array, 193 ... sample object, 194 ... flat screen DESCRIPTION OF SYMBOLS 195 ... Solution curve, 196 ... Curved lens array, 197 ... Sample object, 201 ... X-ray parallel beam incidence, 202 ... Lens array, 203 ... Sample object, 204 ... Screen plane, 205 ... Center of rotation

Claims (10)

An X-ray source;
A lens array disposed between the X-ray source and the sample object, through which X-rays emitted from the X-ray source pass;
Detection means including a screen or a two-dimensional X-ray sensor which is disposed behind the sample object and detects the X-ray transmitted through the sample object as an image;
An X-ray fluoroscopic apparatus comprising: The X-ray source includes a point-like or linear unit X-ray source, and as the light emission shape of the X-ray source,
A first X-ray source in which a plurality of point-like unit X-ray sources are two-dimensionally arranged;
A second X-ray source in which a plurality of linear unit X-ray sources are arranged one-dimensionally at equal intervals or unequal intervals;
A third X-ray that effectively realizes a two-dimensional array of point-like unit X-ray sources by a diaphragm in which a plurality of small holes are two-dimensionally arranged with respect to an X-ray source having a finite size. A fourth X-ray source effectively arranging a linear slit unit X-ray source by linearly arranging linear slits at equal intervals or unequal intervals;
The X-ray fluoroscopic apparatus according to claim 1, comprising at least one of the following. The X-ray source includes a point-like or linear unit X-ray source, and as its light emission shape,
When the X-ray source includes the point-like unit X-ray source, the plurality of point-like unit X-ray sources are a square lattice, a triangular lattice, a hexagonal lattice, a rectangular lattice, an oblique lattice, a rhomboid lattice, a strained oblique lattice, a Penrose. A two-dimensional array including at least one of a lattice, a quasicrystal lattice, and a random lattice, and having a finite area including at least one of a triangle, a square, a hexagon, a rectangle, a circle, and an ellipse as a two-dimensional shape of the entire array Having a shape,
When the X-ray source includes the linear unit X-ray source, the plurality of linear unit X-ray sources is at least a triangle, a square, a hexagon, a rectangle, a circle, and an ellipse as a two-dimensional shape of the entire array. The X-ray fluoroscopic apparatus according to claim 1, having a shape of a finite area including one.   The lens array is an aggregate of microlenses that converge the X-rays, and the focal point of each microlens is present on the screen or the two-dimensional X-ray sensor, and the focal point has a dot-like or linear shape. The X-ray fluoroscopic apparatus according to claim 1, comprising: The lens array is composed by superimposing a plurality of unit lens arrays, and has a flat surface or a curved surface as an overall shape,
The unit lens array is
Pure metals or their alloys including tungsten, platinum, gold, silver, copper, lead, iron, zinc, tin, molybdenum, titanium, nickel or aluminum, or silicon, silicon oxide, silicon nitride, aluminum oxide, carbon, carbide, A plate made of a single material containing lime, glass or ceramic or a composite material thereof,
A first plate formed by arranging concave depressions in an array on the plate;
A spherical object, a spherical shell object, a lens-shaped object, or a lens formed of a material having a relatively low density different from the material constituting the plate, which is selected from glass, quartz, ceramic, or metal in the plate. A second plate in which a shell object is embedded and a low-density part or a cavity part is formed in an array arrangement;
A third plate in which diffractive lenses formed from the material are arranged in an array, and a fourth plate in which the concentric materials are arranged in an array,
The X-ray fluoroscopic apparatus according to claim 1, comprising at least one of the following. The lens array is a collection of minute convergent lenses,
The convergent lens has a point-like focus, and has at least one of a two-dimensional square lattice, a triangular lattice, a hexagonal lattice, a rectangular lattice, an orthorhombic lattice, a rhomboid lattice, a strained oblique lattice, a Penrose lattice, a quasicrystalline lattice, and a random arrangement. Arranged on the lens array surface in an arrangement comprising, or
2. The converging lens is a cylindrical lens or a cylindrical lens having a linear focal point, and is arranged on the lens array surface in a one-dimensional manner at equal intervals or unequal intervals. X-ray fluoroscopy device.   The X-ray fluoroscopic apparatus according to claim 1, wherein the lens array includes a minute lens, and has a material and a structure that shields the X-ray in a portion other than the lens opening of the minute lens.   Further, a mechanism for rotating the sample object, or a mechanism for rotating the X-ray source, the lens array, and the two-dimensional X-ray sensor with respect to the sample object, and measuring a refractive index distribution inside the sample object. The X-ray fluoroscopic apparatus according to claim 1, further comprising: Further, provided immediately before the screen or the two-dimensional X-ray sensor, when the sample object is not disposed, the X-ray blocks a beam at a position where it converges on the screen or the two-dimensional X-ray sensor. A focus shielding plate;
A change in the position of the convergence point of the X-ray due to the refraction of the X-ray on the sample object is converted into a change in the intensity of the X-ray on the screen or the two-dimensional X-ray sensor and projected onto the two-dimensional of the sample object Means for measuring the measured refractive index distribution as an intensity contrast distribution;
The X-ray fluoroscopic apparatus according to claim 1, comprising:   Furthermore, the refractive index distribution and the absorptance distribution projected onto the sample object in two dimensions by measuring the position, shape and intensity of the convergence point of the X-ray projected onto the screen or the two-dimensional X-ray sensor. The X-ray fluoroscopic apparatus according to claim 1, further comprising a unit that measures