JPH08322831A - Method and device for x-ray tomography - Google Patents

Abstract

PURPOSE: To provide the images of good quality at the time of recomposing the tomographic images of a testee body from X-ray transmission data obtd. by X-rays irradiation radiated inclined to a cross section desired for forming its tomographic images. CONSTITUTION: This device is provided with an X-ray irradiation means 1, an X-ray detection means 2 provided with plural detector columns arranged in the body axial direction of the testee body 200, a rotation means for relatively helically rotating an X-ray generation means 1 and the X-ray detection means 22 around the testee body 200 and a tomographic image formation means 500 for reflecting the inclination of the X-rays to the cross section desired for forming its tomographic images and forming the tomographic images of the testee body 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray tomography method and apparatus. More specifically, the present invention is effective in reconstructing a tomographic image of a subject from X-ray transmission data collected by X-rays that are irradiated while being inclined relative to a cross section to form a tomographic image. An X-ray tomography method and apparatus capable of obtaining a good image.

[0002]

2. Description of the Related Art In an X-ray tomography apparatus, a subject is irradiated with a fan-shaped X-ray beam from an X-ray source, and the transmitted X-rays are arranged in accordance with the spread of the fan-shaped X-ray beam. It is measured with a one-dimensional array of detection elements. The transmitted X-rays are measured in a plurality of view directions while rotating the X-ray source and the detector array around the subject. Such measurement of transmitted X-rays is called a scan. A tomographic image of the subject is reconstructed based on the measurement data of a plurality of views obtained by the scan.

As one form of scanning, for example, as described in Japanese Patent Publication No. 2-60332, scanning is performed a plurality of times continuously while the subject is continuously moved in the body axis direction. So-called helical scan (h
elical scan).

In the helical scan, the X-ray source makes a relative spiral motion around the subject, so that the view direction changes depending on the position of the X-ray source on the body axis of the subject. For this reason, when an attempt is made to reconstruct a tomographic image of a certain cross section on the body axis, only measurement data for one view direction is obtained for that cross section, so measurement data for all other view directions are It is created by interpolation using two measurement data whose X-ray transmission directions obtained before and after coincide with each other.

For example, as shown in FIG. 9, the measurement data is created by the interpolation. Two views V ₁ are located at the distances d ₁ and d ₂ in the body axis direction on both sides of the cross section S where the tomographic image is to be reconstructed. , if the X-ray penetration direction coincide with each other in the two measurement data P _1, P ₂ in V ₂ is obtained, the measurement data P in a cross section S, the measurement data P _1, P as shown in the following equation (1) It is obtained by multiplying ₂ by a weighting factor according to the distance from the cross section and adding.

[0006]

[Equation 1]

As another example of the X-ray tomography apparatus, as described in, for example, Japanese Patent Laid-Open No. 58-206996,
There is one in which two rows of one-dimensional arrays of detection elements are provided in the thickness direction of the fan-shaped X-ray beam and transmission X-rays for two slices are simultaneously measured.

A schematic view of the X-ray irradiation / detection system in this apparatus is shown in FIGS. 10 and 11. FIG. 10 is a perspective front view, and FIG. 11 is an AA cross section thereof. 10 and 1
In FIG. 1, 11 is an X-ray focal point, 12 is an X-ray beam, 2
Reference numerals 1 and 22 are two X-ray detectors. Each of these consists of a one-dimensional array of detection elements.

Since the X-ray detectors 21 and 22 have different positions in the thickness direction of the X-ray beam, slices connecting the X-ray focal point 11 and the X-ray detectors 21 and 22 as shown in FIG. The center planes 111 and 112 have an inclination that is not perpendicular to the body axis direction of the subject.

[0010]

Problems to be Solved by the Invention X as shown in FIG.
Assuming that a helical scan is performed using a line detector, the measurement data for two slices can be obtained at the same time, so that improvement in scan efficiency can be expected.

In that case as well, the measurement data of the view which is not in the cross section to be image-reconstructed must be generated from the measurement data of the preceding and following views.
Since it is the formula for the data obtained by measuring the transmitted X-rays of the slice plane perpendicular to the body axis direction with the single-array X-ray detector as in the apparatus described in Japanese Patent No. -60332, the slice plane of each view It is not applicable to those that are not perpendicular to the body axis direction. Even if the interpolation data is obtained by applying the equation (1), the X-ray transmission path does not match the reality, so the image reconstructed from such data is affected by partial volume artifacts, etc. Causes the image quality to deteriorate.

When the X-ray detector as shown in FIG. 10 is used, the X-ray transmission path is inclined with respect to the cross section for reconstructing a tomographic image even when a normal scan is performed. The quality of the reconstructed image is degraded.

Even when the X-ray detector array is single, the same problem occurs when the path of the X-ray beam is relatively inclined with respect to the cross section for which the tomographic image is to be reconstructed. The present invention has been made to solve the above problems,
The purpose is to obtain a high-quality image when reconstructing a tomographic image of a subject from X-ray transmission data collected by X-rays that are irradiated with being inclined relative to a cross section to form a tomographic image. X-ray tomography method and apparatus to be realized.

[0014]

A first means for solving the above-mentioned problems is to irradiate a measurement space with X-rays, and X-rays the X-rays that pass through a subject placed in the measurement space and are incident. An X-ray slice that is detected by a detector, rotates the X-ray focal point around the subject, and forms a tomographic image of the subject based on X-ray detection signals obtained at a plurality of positions on a rotation trajectory. The X-ray tomographic imaging method is characterized in that in the imaging method, the tomographic image of the subject is formed by reflecting the inclination of the X-ray with respect to the cross section for forming the tomographic image.

A second means for solving the above-mentioned problems is to irradiate the measurement space with X-rays, and the X-rays that pass through and enter the object placed in the measurement space are directed in the body axis direction of the object. A tomographic image of the subject is detected based on X-ray detection signals obtained at a plurality of positions on a rotation trajectory by detecting the focal points of the X-rays around the subject by a plurality of aligned X-ray detector rows. In the X-ray tomography method for forming a tomographic image, a tomographic image of the subject is formed by reflecting an inclination of the X-ray with respect to a cross section for forming a tomographic image. .

A third means for solving the above problems is an X-ray irradiating means for irradiating the measurement space with X-rays, and an X-ray detecting means for detecting the X-rays which are incident upon the object placed in the measurement space.
X-ray detection means, rotation means for rotating the focus of the X-rays around the object, and a tomographic image forming a tomographic image of the object based on X-ray detection signals obtained at a plurality of positions on a rotation trajectory. An X-ray tomography apparatus having an image forming means, comprising a tomographic image forming means for forming a tomographic image of the subject by reflecting an inclination of the X-ray with respect to a cross section for forming a tomographic image. It is a characteristic X-ray tomography apparatus.

A fourth means for solving the above-mentioned problems is an X-ray irradiating means for irradiating the measurement space in which the subject is placed with X-rays, and a plurality of X-ray detection arrays lined up in the body axis direction of the subject. X-ray detection means for detecting incident X-rays transmitted through the subject, rotation means for rotating the X-ray focal point of the X-ray generation means around the subject, In an X-ray tomography apparatus having a tomographic image forming means for forming a tomographic image of the subject based on X-ray detection signals obtained at a plurality of positions, the inclination of the X-ray with respect to a cross section to form a tomographic image The X-ray tomography apparatus is characterized by comprising a tomographic image forming means for forming a tomographic image of the subject by reflecting the above.

A fifth means for solving the above-mentioned problems is an X-ray irradiating means for irradiating the measurement space in which the subject is placed with X-rays, and a plurality of X-ray detection arrays lined up in the body axis direction of the subject. X-ray detection means for detecting incident X-rays transmitted through the subject, rotation means for rotating the X-ray focal point of the X-ray generation means around the subject, In an X-ray tomography apparatus having a tomographic image forming unit that forms a tomographic image of the subject based on X-ray detection signals obtained at a plurality of positions, the X-ray focal point of the X-ray generation unit is set to the subject. And a tomographic image forming unit that forms a tomographic image of the subject by reflecting the inclination of the X-ray with respect to a cross section to form a tomographic image. An X-ray tomography apparatus characterized by the above.

In the first to fifth means for solving the problems, it is preferable to form the tomographic image by back projection with weighting according to the inclination of the X-ray in order to simplify the calculation.

[0020]

According to the first means for solving the problem, a tomographic image having few artifacts is obtained by forming the tomographic image by reflecting the inclination of the X-ray with respect to the cross section to be reconstructed.

In the second means for solving the problem, the tomographic image is reflected by reflecting the relative inclination between the cross section for reconstructing the tomographic image and the X-rays incident on the plurality of X-ray detector rows. By forming it, a tomographic image with few artifacts is obtained.

In the third means for solving the problem, the tomographic image forming means forms the tomographic image by reflecting the inclination of the X-ray with respect to the cross section for which the tomographic image is to be reconstructed, and thereby the tomographic image with few artifacts is formed. To get

In a fourth means for solving the problem, the tomographic image forming means determines the relative inclination between the cross section of which the tomographic image is to be reconstructed and the X-rays incident on the plurality of X-ray detector rows. By forming a tomographic image by reflecting it, a tomographic image with few artifacts is obtained.

In a fifth means for solving the problem, a helical scan is carried out by the rotating means, and a cross section for reconstructing a tomographic image is made by the tomographic image forming means and X-rays incident on a plurality of X-ray detector rows. By forming a tomographic image by reflecting the relative inclination between the tomographic images, a tomographic image with few artifacts is obtained.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the apparatus of the embodiment of the present invention. The method of the embodiment of the present invention is shown by the operation of the apparatus of the embodiment of the present invention.

In FIG. 1, reference numeral 100 denotes a gantry having an X-ray irradiation / detection system consisting of an X-ray source 1 and an X-ray detector 2 inside, and an object insertion hole 110 forming a measurement space. Reference numeral 200 is a subject, 300 is a subject supporting device that supports the subject, and 310 is a movable top plate on which the subject is mounted.

The X-ray source 1 is an example of X-ray irradiation means in the present invention. The X-ray detector 2 is an example of X-ray detecting means in the present invention. The configuration of the X-ray irradiation / detection system is as shown in FIGS. Since this X-ray irradiation / detection system is the same as that shown in FIGS. 10 and 11, the same parts are designated by the same reference numerals and the description thereof will be omitted.

In the subject insertion hole 110 of the gantry 100, the subject 200 is placed on the top plate 310 of the subject support device 300.
Is placed and inserted. An X-ray irradiation / detection system including an X-ray source 1 and an X-ray detector 2 is driven by a driving unit (not shown) to rotate around a subject 200 for scanning.
The transmitted X-ray dose incident on each detection element of the X-ray detector 2 is measured at, for example, several hundreds of view points on a rotation orbit per one rotation. X
The drive means of the line irradiation / detection system is an example of the rotating means in the present invention.

The data collection device 400 collects the measurement signals of the X-ray detector 2, performs predetermined preprocessing and correction on the obtained data, and inputs the data to the image reconstruction device 500. The image reconstruction device 500 is a data acquisition device 400.
The tomographic image of the subject 200 is reconstructed based on the data input from the. These data collection devices 400
The image reconstruction device 500 is an example of the tomographic image forming means in the present invention. The display device 600 displays the reconstructed image as a visible image.

The control device 700 gives control signals to the gantry 100, the subject support device 300, the data acquisition device 400, the image reconstruction device 500, and the display device 600 to control their operations. Operating device 8
00 is operated by an operator and gives a command to the control device 700.

The slice center planes 111 and 112 in the X-ray irradiation / detection system have an inclination that is not perpendicular to the body axis direction. If this is generalized and shown, it will become like FIG. FIG.
, SL is the slice center plane, and is inclined at an angle ψ with respect to the xz plane. When a point in the plane of the slice center plane SL is represented by polar coordinates (r, θ) with the focal point 11 of the X-ray as the origin, the z coordinate of the point P is given by the following equation.

[0032]

[Equation 2]

However, Z ₀ is the z coordinate of the X-ray focal point 11. From equation (2), it can be seen that the z coordinate of a point within the plane of the slice center plane SL changes depending on the inclination angle ψ of the slice center plane SL, the distance r from the focal point 11 of the X-ray, and the direction θ. Where θ is the direction of the X-ray transmission path, and r
Is the distance on the path.

Next, the operation of the apparatus of the present invention will be described. An operation explanatory diagram is shown in FIGS. Control device 700
Under the control of, the top plate 310 is continuously fed in one direction, and the X-ray irradiation / detection system including the X-ray source 1 and the X-ray detector 2 is continuously rotated a plurality of times to scan the subject 200. To do.

Normally, the relationship between the feeding of the top plate 310 and the rotation of the X-ray irradiation / detection system is determined so that the top plate 310 moves by half the slice thickness while the X-ray irradiation / detection system makes one rotation. . That is, for example, assuming that the slice thickness of one row of the X-ray detector 2 is 20 mm, the slice thickness of the two rows is 20 mm.
sent in mm.

This is twice the feed amount of the conventional example having only one row of X-ray detectors, and the helical scan can be performed with twice the efficiency of the conventional example. Therefore, for example, when breathing is stopped and the entire liver is scanned, the time to stop breathing can be shortened to half.

When viewed from the subject 200, the X-ray irradiation / detection system performs a spiral motion about the z axis (body axis) as shown in FIG. 5, for example. That is, the continuous feeding means of the top plate 310 and the rotation driving means of the X-ray irradiation / detection system are examples of the rotating means for rotating in a spiral shape in the present invention.

The sector in FIG. 5 is the X in each view.
3A and 3B respectively show the center planes of slices of the line irradiation / detection system. Since the slice center plane of the X-ray irradiation / detection system has two different tilts, they can be treated as independent views. As a result, the number of views or slices per spiral motion is the same as in Japanese Patent Publication No. 2-6033.
It is twice as large as that described in Japanese Patent No. However, Figure 5
In order to avoid complication, only one fan shape is drawn at each position.

In each of these views, transmitted X-rays are measured by the respective detecting elements of the X-ray detector 2, the measurement data is collected by the data collecting device 400, and the image reconstructing device 500 is based on the collected data. , Filtered back projection (filtered
back-projection method and convolution (convolutio
Image reconstruction is performed by the n) method.

The cross section for reconstructing the image is set by the operator through the operation device 800. Now, assuming that a tomographic image at the cross section S is reconstructed, measurement data at other slice positions must be used for a view that is not at the position of the cross section S.

As such data, for example, measurement data P ₁ obtained in view V ₁ before section S and section S
Measurement data P ₂ obtained in view V ₂ after more is used as a pair. These pair of measurement data P ₁ , P
₂ , for example, as shown in FIG. 6, when the views V ₁ and V ₂ are viewed in an overlapping manner in the body axis direction, the X-ray paths that pass through the subject 200 overlap each other.

The path of these X-rays is the view V₁At
From the X-ray focal point 11 to θ₁Route R in the direction of₁And
View V₂At the focus from the X-ray focus 11 to θ₂The direction of
Road R ₂Is. Route R₁And route R₂Then the X-ray traveling direction
Are opposite to each other. 1 obtained by such a relationship path
The paired measurement data is referred to as opposed view data.

In FIG. 6, the route R ₁ and the route R ₂ should be overlapped with each other, but they are drawn so as to be easy to see.
The x axis and the y axis are orthogonal coordinate axes in a plane perpendicular to the z axis.

These two X-ray paths R ₁ and R ₂ are inclined with respect to the cross section S from which a tomographic image is to be reconstructed, and their positions are different in the z-axis direction. If you show the situation, for example,
become that way.

The pair of measurement data P ₁ and P ₂ contributes to the formation of X-ray transmission data in the direction of θ ₁ in the virtual view corresponding to the view V ₁ at the position of the cross section S (or of the cross section S 1). This contributes to the formation of X-ray transmission data in the direction of θ ₂ in a virtual view corresponding to the view V ₂ at the position).

A pair of such measurement data is extracted from the measured data for all X-ray transmission directions in the virtual view corresponding to the view V ₁ (or V ₂ ) at the position of the cross section S, and , Similar measurement data pairs are similarly extracted for virtual views corresponding to all the other views that are not at the position of the section S.

The pair of measurement data can be formed not only by the opposite view data but also by those having the same X-ray traveling direction. Such data pairs are obtained from adjacent rows of X-ray detectors and also as measured data after 360 ° (and an integral multiple thereof) rotation of the same detector.

In FIG. 5, since the number of views per spiral is twice that of the conventional example, the top plate 310 per spiral is
When the feed amount of is the same as that of the conventional method, a pair of measurement data can be obtained as those having a shorter distance from the cross section S. Obtaining a measurement data pair closer to the cross section S in this way is advantageous in that a tomographic image with high fidelity to the actual tomographic image of the subject is reconstructed.

The image reconstruction is performed by the filtered back projection method or the convolution method using the measured data pair. Filtered back projection is a method of processing the measured data with a predetermined filter function in the frequency space to recover the blur of the image, and then returns it to the real space data by the inverse Fourier transform. This is a process of integrating (backprojecting) on a path in the corresponding reconstruction space.

In the convolution method, the measurement data is subjected to a convolution process with a predetermined filter function in the real space for image blur restoration, and then the reconstructed space in the reconstruction space corresponding to the path of the transmitted X-ray that has brought the measurement data is obtained. This is a process of integrating (backprojecting) on the route.

Although there is a difference between these two methods in that the blur restoration filter processing is performed in the frequency space or in the real space, there is essentially no difference in backprojecting the filtered measurement data. Hereinafter, both are collectively referred to as back projection.

[0052] Speaking by applying the backprojection in FIGS. 6 and 7, the measurement data P ₁ obtained by X-ray path R ₁ views V ₁ was after filtering, integrating on X-ray path R _1,
The measurement data P ₂ obtained by X-ray path R ₂ views V ₂ after filtering, is to accumulated on the X-ray path R _2.

Therefore, the result of the back projection is X in FIG.
The backprojection data of the measurement data P ₁ exists on the line path R ₁ , and the backprojection data of the measurement data P ₂ exists on the X-ray path R ₂ .

In order to reconstruct a tomographic image of the section S, backprojection data on the virtual X-ray path corresponding to the X-ray path R ₁ and the X-ray path R ₂ in the section S is required. From the geometrical relationship between the cross-section S and the X-ray path R ₁ and the X-ray path R ₂ , such backprojection data are the backprojection data on the X-ray path R ₁ and the backprojection data on the X-ray path R _2. Can be obtained by interpolation.

[0055] That is, the reverse projection data a point on the cross section S is backprojected data and a ₂ points on the X-ray path R ₂ of a ₁ point on the X-ray path R ₁ located nearest the z-axis direction Can be obtained by weighted addition with the back projection data of. Further, the backprojection data of the point b on the cross section S is obtained by weighted addition of the backprojection data of the point b ₁ on the X-ray path R ₁ and the backprojection data of the point b ₂ on the X-ray path R _2. You can Backprojection data at other positions on the cross section S can be similarly obtained.

On the basis of such a relationship, in reality, the filtered measurement data P ₁ and P ₂ are imaginary X-ray paths (both of which are equivalent to the X-ray paths R ₁ and R ₂ on the cross section S). Will be the same). When backprojecting onto, weighting is performed according to the position on those paths.
Such backprojection by weighting is preferable in that the calculation is simplified.

That is, for point a, measured data P
₁ of backprojection is performed at a weight of _{d 2 / (d 1 + d} 2), backprojection of measured data P ₂ is carried out under the weight of _{d 1 / (d 1 + d} 2). As a result, weighted addition, that is, interpolated backprojection data is obtained at the point a. Regarding point b,
The back projection of the measurement data P ₁ is performed with the weight of D ₂ / (D ₁ + D ₂ ), and the back projection of the measurement data P ₂ is D ₁ / (D ₁ +
D ₂ ) weight. Back projection is also performed for other points in accordance with this. As a result, backprojection data formed by interpolation is obtained on the virtual X-ray path corresponding to the X-ray path R ₁ (or R ₂ ) on the cross section S.

Since the z-axis coordinates of each point on the X-ray paths R ₁ and R ₂ are given by the above equation (2), the distances d ₁ and d ₂ from the coordinates to the cross section S can be obtained. The weight of points can be calculated.

Weighted backprojection is similarly performed for the measurement data pairs of all other views. As a result, image reconstruction that reflects the inclination of the X-ray path with respect to the cross section S is performed, so that a tomographic image with few artifacts and good image quality can be obtained.

As the measurement data pair, the one closest to the section S in the z-axis direction is used. Therefore, for example, suppose that measurement data P ₁ , P ₂ , P ₃ are respectively obtained by _three X-ray paths R ₁ , R ₂ , R _{3 in} the vicinity of the cross section S as shown in FIG. R ₁ , R ₂ , and R ₃ all overlap when viewed in the z-axis direction.) Which two of these three measurement data should be adopted depends on which X-ray path from the cross section S is selected. It is decided as follows according to the distance.

If the distances from the cross section S to the X-ray paths R ₁ , R ₂ and R _{3 in} the z-axis direction are d ₁ , d ₂ and d ₃ , respectively, these values are d ₁₀ , d ₂₀ and d ₃₀ , respectively. At point C where (= d ₁₀ ),

[0062]

(Equation 3)

Therefore, in the area above the point C in the figure,

[0064]

[Equation 4]

In the area below point C,

[0066]

(Equation 5)

It becomes Based on this distance relationship,
In the area above the point C, the measurement data P ₁ and P ₂ are adopted as the measurement data pair, and in the area below the point C, the measurement data P ₂ and P ₃ are adopted as the measurement data pair. Then, weighted backprojection according to the distance from the cross section S is performed using the pair of measurement data.

Next, the modifications which belong to the scope of the present invention are listed below. In the above-mentioned embodiment, the X-ray detector having two rows of detector arrays is used, but the number of rows is not limited to two and may be any number of rows of three or more.

Although the X-ray detector rotates around the subject together with the X-ray source, the X-ray detector may be fixed. The X-ray source is fixed in itself like the electron beam scanning type X-ray source in the so-called fifth generation tomography apparatus, and the X-ray focal point is rotated around the subject by scanning the electron beam. May be.

Not only in the helical scan, even when the present invention is applied to the case where the subject is stopped and a normal scan is performed by using a plurality of X-ray detector rows, the X-ray for the cross section for which the tomographic image is to be reconstructed is used. Since image reconstruction that reflects the inclination of can be performed, it is possible to obtain a high-quality tomographic image with few artifacts.

The inclination of the X-ray with respect to the cross section for which the tomographic image is to be reconstructed is not limited to the case where a plurality of X-ray detector rows are used, but the inclination of the slice plane is obtained not only when a single X-ray detector row is used. Since it also occurs when scanning is performed, the present invention can be applied to such a case.

For example, in a so-called fifth-generation tomography apparatus using an electron beam scanning X-ray source, the X-ray detector is also fixedly arranged around the subject, but the X-ray irradiated to the subject In order not to block the rays, the X-ray source and the X-ray source are displaced from each other in the body axis direction. Therefore, the slice plane is not perpendicular to the body axis and is inclined with respect to the cross section perpendicular to the body axis from which the tomographic image is to be reconstructed. In such a case, the image quality can be improved by applying the present invention. It is possible to obtain a tomographic image that is perpendicular to the body axis with good accuracy.

The inclination of the X-ray path with respect to the cross section for reconstructing the tomographic image is relative. Therefore, X
The present invention can also be applied to the case where the line path is perpendicular to the body axis and the cross section for reconstructing the tomographic image is inclined with respect to the body axis.

As such an example, for example, a single X-ray detector array is used to perform a helical scan in a slice perpendicular to the body axis, and the measured data is used to cross a section inclined with respect to the body axis, for example. In some cases, a tomographic image is reconstructed for a cross section along a line connecting the eye and the ear of the subject.

The formation of such an image of an arbitrary cross section is usually carried out by the reformation from the reconstructed image data of a plurality of cross sections, but according to the present invention, it is not the indirect method but the measurement data. Can be done directly by reconstructing the image, and a much better image quality can be obtained.

[0076]

As described in detail above, the present invention provides
Since the tomographic image of the subject is formed by reflecting the inclination of the X-ray with respect to the cross section for forming the tomographic image, the irradiation is performed with an inclination relative to the cross section for forming the tomographic image. When reconstructing a tomographic image of a subject from X-ray transmission data collected by X-rays, an X-ray tomography method and apparatus capable of obtaining a high-quality image can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of an X-ray irradiation / detection system in the apparatus of the embodiment of the present invention.

FIG. 3 is a schematic diagram of an X-ray irradiation / detection system in the apparatus of the embodiment of the present invention.

FIG. 4 is a geometrical diagram of an X-ray irradiation / detection system in the apparatus of the embodiment of the present invention.

FIG. 5 is an operation explanatory diagram of the apparatus according to the embodiment of the present invention.

FIG. 6 is an operation explanatory diagram of the apparatus according to the embodiment of the present invention.

FIG. 7 is an operation explanatory diagram of the apparatus according to the embodiment of the present invention.

FIG. 8 is an operation explanatory diagram of the apparatus according to the embodiment of the present invention.

FIG. 9 is an operation explanatory diagram of a conventional example.

FIG. 10 is a schematic diagram of a conventional example.

FIG. 11 is a schematic diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray source 11 Focus 2, 21, 22 X-ray detector 100 Gantry 200 Subject 300 Subject support device 400 Data acquisition device 500 Image reconstruction device 600 Display device 700 Control device 800 Operating device

Claims (5)

[Claims] 1. An X-ray is radiated into a measurement space, an X-ray that passes through a subject arranged in the measurement space and is incident is detected by an X-ray detector, and the focus of the X-ray is detected by the subject. In an X-ray tomography method of rotating around and forming a tomographic image of the subject based on X-ray detection signals obtained at a plurality of positions on a rotation orbit, the X-ray for a cross section to form a tomographic image X-ray tomography method, characterized in that the tomographic image of the subject is formed by reflecting the tilt of the object. 2. The measurement space is irradiated with X-rays, and the X-rays transmitted through and incident on the subject arranged in the measurement space are detected by a plurality of X-ray detector rows arranged in the body axis direction of the subject. Then, in the X-ray tomography method, the focus of the X-ray is rotated around the subject, and a tomographic image of the subject is formed based on X-ray detection signals obtained at a plurality of positions on a rotation orbit, An X-ray tomographic imaging method, wherein a tomographic image of the subject is formed by reflecting an inclination of the X-ray with respect to a cross section for forming a tomographic image. 3. An X-ray irradiating means for irradiating the measurement space with X-rays, an X-ray detecting means for detecting an X-ray transmitted through an object arranged in the measurement space, and a focus of the X-ray. X-ray tomography having rotating means for rotating the subject around the subject, and tomographic image forming means for forming tomographic images of the subject based on X-ray detection signals obtained at a plurality of positions on a rotation trajectory. An X-ray tomography apparatus, comprising: a tomographic image forming means for forming a tomographic image of the subject by reflecting an inclination of the X-ray with respect to a cross section for forming a tomographic image. 4. An X-ray irradiating means for irradiating a measurement space in which a subject is placed with X-rays, and a plurality of X-ray detection rows lined up in the body axis direction of the subject and transmitting the subject. Incident X
X-ray detection means for detecting X-rays, rotation means for rotating the X-ray focal point of the X-ray generation means around the subject, and X-ray detection signals obtained at a plurality of positions on the rotation trajectory. In an X-ray tomography apparatus having a tomographic image forming unit that forms a tomographic image of the subject, a tomographic image of the subject is formed by reflecting an inclination of the X-ray with respect to a cross section where a tomographic image is to be formed. An X-ray tomography apparatus comprising a tomographic image forming means. 5. An X-ray irradiating means for irradiating a measurement space in which a subject is placed with X-rays, and a plurality of X-ray detection rows lined up in the body axis direction of the subject and transmitting the subject. Incident X
X-ray detection means for detecting X-rays, rotation means for rotating the X-ray focal point of the X-ray generation means around the subject, and X-ray detection signals obtained at a plurality of positions on the rotation trajectory. In an X-ray tomography apparatus having a tomographic image forming means for forming a tomographic image of the subject, an X-ray of the X-ray generating means is provided.
Rotating means for rotating the focal point of the line relatively spirally around the subject, and a slice for forming the tomographic image of the subject by reflecting the inclination of the X-ray with respect to the cross section for forming the tomographic image. X comprising an image forming means
Line tomography device.