JP2002136509A - Tomographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray tomographing device wherein a tomographic image of a high precision for which distortions are reduced can be instantly obtained, and the image information of a plurality of tomographic surfaces and the magnification are calculated from a detection signal which is detected by the X-ray tomography. SOLUTION: A distance from an X-ray tube R to a flat panel type X-ray detector D, a distance from the flat panel type X-ray detector D to the tomographic surface of a subject M, a distance which is detected with an equal interval from a specified tomographic surface to the front side and the rear side, and information for the quantity of imaging are set and input from an operation section 10 in advance. Then, imaging based on the set conditions is performed. The detection signal which is detected by the imaging is input in a data processing section 50. In addition, the detection signal is input in an image processing section 51, and the image information for each tomographic surface and the magnification are calculated. Then, the image information and the magnification are respectively stored in an image information storage section 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tomography apparatus used in the medical field, the industrial field, etc., and more particularly, to a high-precision tomographic image with reduced distortion, which is immediately obtained and specific image information detected. The present invention relates to a technique for calculating magnifications of a plurality of tomographic planes from the data.

[0002]

2. Description of the Related Art A conventional X-ray tomography apparatus includes an X-ray tube and an image intensifier (hereinafter referred to as "I.
[I tube] is intermittently moved to irradiate the subject with X-rays from a plurality of angles. Then, based on a plurality of detection signals obtained by imaging from each angle, image information of a specific tomographic plane and image information of tomographic planes before and after the specific tomographic plane are calculated. Hereinafter, this principle will be specifically described with reference to FIG.

In the case of a conventional X-ray tomography apparatus, an X-ray tube R and an I.D. The I-tube 70 is arranged to face. Then, when imaging a specific tomographic plane a of the subject M, the X-ray tube R is set to the I.D. While moving in the opposite direction in conjunction with the I-tube 70, any point on the specific tomographic plane a of the subject M is Intermittent imaging is performed while changing the X-ray irradiation angle θ of the X-ray tube R so that the X-ray tube R is always at the same position on the detection surface of the I-tube 70. For example, when the X-ray tube R is photographed three times while changing its position to P1, P2, and P3, an arbitrary point on the tomographic plane a (the point indicated by a triangle in FIG. 12) is always I.D. The same positions a11, a21, a on the detection surface of the I-tube 70
Since the projection image is projected onto the image 31, a clear tomographic image of the tomographic plane a can be obtained only by performing an addition operation on the detection signals such that these three projected images are superimposed. Since the height of the tomographic plane b is different from that of the tomographic plane a, I tube 70
Are moved to b11, b22, and b33 and are not constant. If the addition calculation processing of the three detection signals is performed in such a state, the output tomographic image of the tomographic plane b is totally blurred. That is, a clear tomographic image cannot be obtained. In order to obtain a clear tomographic image of the tomographic plane b, the following method is employed.

At the photographing positions P1 and P3, I.P. I tube 70
The position of an arbitrary point on the projected image b projected on the tomographic image b (the point marked with a circle in FIG. 12) is relatively relative to the position a11 of the projected image on the tomographic plane a by distances a11-b11 and a31-b33. You can see that it is off. This shift is caused by the X-ray tube R and the I.D. I tube 7
Since it depends on the angle θ between the straight line L ′ connecting 0 and the line L in the vertical downward direction of the X-ray tube R, it can be obtained by arithmetic processing. In other words, by performing an arithmetic processing such that the three detected signals are moved in parallel by the displacement of the projection position of the tomographic plane b and are all superimposed, a clear tomographic image b is obtained.
Have gained.

The conventional X-ray tomography apparatus obtains tomographic images of neighboring tomographic planes before and after a specific tomographic plane by the above-described method.

[0006]

However, the prior art having such a structure has the following problems. That is, the I.D. I tube 7
In the case of 0, the end side of the X-ray detection surface is distorted. For this reason, X-rays cannot be detected evenly on the entire detection surface, and there is a problem in that when the detected image information is output and displayed on a monitor, a tomographic image is distorted.

When X-ray photography is performed with reference to a specific tomographic plane, as shown in FIG. I
The magnification of the projection image determined by the ratio of the distance SID to the tube 70 and the distance (SID-Z) from the X-ray tube R to the specific tomographic plane a of the subject M is used as a reference. Therefore, I.I. I
When comparing the projected image of the tomographic plane a projected on the tube 70 with the projected image of the neighboring tomographic plane b separated by (+) d from the tomographic plane a, the sizes are different. As a result, the tomographic images output and displayed on the monitor are displayed as tomographic images having different magnifications. For this reason, there is a problem that comparison between the respective tomographic images, distance measurement of the region of interest, calculation of the area of the region of interest, and the like cannot be performed accurately.

The present invention has been made in view of such circumstances, and a high-precision tomographic image with reduced distortion is immediately obtained, and a tomographic plane detection signal detected in one photographing operation is used. It is another object of the present invention to provide an X-ray tomography apparatus that calculates image information and magnification of a specific tomographic plane and neighboring tomographic planes before and after the specific tomographic plane.

[0009]

The present invention has the following configuration to achieve the above object. That is, the tomographic imaging apparatus according to claim 1 includes: (a) an irradiation source that irradiates a subject with an electromagnetic wave having transparency; and (b) an irradiation source that faces the irradiation source with the subject interposed therebetween. And (c) the flat panel detector has a conversion layer that converts incident electromagnetic waves into electric charges or light, and is converted by the conversion layer. A storage element for detecting charges or light and storing the detection signal as a detection signal; and a reading element for reading out the detection signal stored in the storage element are arranged in a two-dimensional matrix. Scanning means for synchronizing and scanning at least two of the irradiation source, the subject, and the flat panel detector so as to accumulate an electromagnetic wave transmitted through an arbitrary point on the tomographic plane is provided.

[0010] The tomographic apparatus according to claim 2 is
2. The tomographic imaging apparatus according to claim 1, wherein (e) the scanning unit synchronizes one of the irradiation source and the flat panel detector in a first direction and moves the other of the flat panel detector in a first direction. 3. It is characterized in that it is configured to move in a straight line parallel to a second direction opposite to the first direction.

The tomographic apparatus according to claim 3 is
2. The tomographic imaging apparatus according to claim 1, wherein (f) the scanning unit rotationally moves the irradiation source in one of two parallel planes arranged in parallel to face each other across the subject. 3. In synchronization with the above, the flat panel detector is configured to be rotationally moved in a direction opposite to a rotational direction of the irradiation source in the other parallel plane.

Further, the tomographic apparatus according to claim 4 is
2. The tomography apparatus according to claim 1, wherein (g) the scanning unit fixes the irradiation source, and connects the subject and the flat panel detector to an arbitrary point on a specific tomographic plane of the subject. The interlocking movement so that it is always the same position on the detection surface of the flat panel type detector, or the flat panel type detector is fixed, the irradiation source and the subject, the specific of the subject The present invention is characterized in that an arbitrary point on a tomographic plane is interlockingly moved so as to be always at the same position on the detection plane of the flat panel detector.

[0013] The tomographic apparatus according to the fifth aspect is characterized in that:
(H) an irradiation source for irradiating the subject with an electromagnetic wave having transparency, (i) detection means arranged opposite to the irradiation source with the subject interposed therebetween and detecting the electromagnetic wave transmitted through the subject; j) scanning means for synchronously scanning the irradiation source and the detection means so that an arbitrary point on a specific tomographic plane of the subject is always at the same position on the detection surface of the detection means;
(K) Tomographic image calculation for calculating image information of a specific tomographic plane and image information of neighboring tomographic planes before and after the specific tomographic plane from a detection signal detected in association with the interlocking movement of the irradiation source and the detecting means. And (l) image display means for outputting and displaying the image information of each tomographic plane calculated by the tomographic image calculating means. (N) setting input means for setting and inputting distance information from the specific tomographic plane to a neighboring tomographic plane in advance, and (n) distance information input to the setting input means An enlargement ratio calculating means for calculating an enlargement ratio of a specific tomographic plane and a neighboring tomographic plane is provided.

The tomographic apparatus according to claim 6 is
6. The tomography apparatus according to claim 5, wherein (o) the detection means is a flat panel detector.

[0015]

The operation of the present invention is as follows. That is,
According to the first aspect of the present invention, the irradiation source irradiates the subject with an electromagnetic wave having transparency, and the flat panel detector detects the electromagnetic wave transmitted through the subject. Further, the flat panel type detector has a conversion layer for converting incident electromagnetic waves into electric charges or light, a storage element for detecting the electric charges or light converted by the conversion layer and storing it as a detection signal, A read element for reading out the detection signal stored in the element is arranged in a two-dimensional matrix. The scanning unit scans at least two of the irradiation source, the subject, and the flat panel detector in synchronization with each other so as to accumulate an electromagnetic wave transmitted through an arbitrary point on the tomographic plane of the subject. Therefore, since the entire detection surface of the flat panel detector is flat, the electromagnetic wave transmitted through the subject is uniformly detected on the entire detection surface, and the detection signal distortion due to the distortion of the detection surface does not occur. Further, since the detection signal detected and accumulated by the flat panel detector can be read out and output in real time, it is excellent in immediacy.

According to the second aspect of the present invention, the scanning means synchronously moves one of the irradiation source and the flat panel detector in the first direction in the first direction, and sets the other to the first. It is moved in a straight line parallel to a second direction opposite to the direction. Therefore, the irradiation source and the flat panel detector can be scanned in parallel and linearly across the subject, and tomography for obtaining a tomographic image of an arbitrary tomographic plane of the subject can be performed.

According to the third aspect of the present invention, the scanning means rotates the irradiation source within one of the two parallel planes arranged in parallel to face each other across the subject. In synchronization with the above, the flat panel detector is rotationally moved in the other parallel plane in a direction opposite to the rotational direction of the irradiation source. Therefore, the irradiation source and the flat panel detector are individually rotated and scanned in each of the two parallel planes sandwiching the subject, and tomography for obtaining a tomographic image of an arbitrary tomographic plane of the subject can be performed.

According to the fourth aspect of the present invention, the scanning means fixes the irradiation source, and connects the subject and the flat panel detector with each other at an arbitrary point on a specific tomographic plane of the subject. Either move them together so that they are always at the same position on the detection surface of the flat panel detector, or fix the flat panel detector, and move the irradiation source and the subject on a specific tomographic plane of the subject. An interlocking movement is made so that an arbitrary point is always at the same position on the detection surface of the flat panel type detector. Therefore, both the subject and the flat panel detector or both the irradiation source and the subject are scanned in the same direction, and tomography for obtaining a tomographic image of an arbitrary tomographic plane of the subject can be performed.

According to the fifth aspect of the present invention, before imaging a specific tomographic plane of the subject, distance information for determining the positional relationship between the irradiation source, the detecting means, and the specific tomographic plane, Distance information from the specific tomographic plane to the neighboring tomographic plane is input in advance by the setting input means. Then, while the irradiation source and the detection unit are synchronously scanned across the subject,
Intermittent imaging is performed while changing the irradiation angle of the electromagnetic wave having transparency of the irradiation source so that an arbitrary point on a specific tomographic plane is always at the same position on the detection surface of the detection means. And
Detection signals of tomographic planes corresponding to a plurality of images having different imaging angles are detected. These detection signals and the respective distance information previously input by the setting input means are input to the tomographic image calculating means. Then, image information of the specific tomographic plane and neighboring tomographic planes before and after the specific tomographic plane are calculated. However, in the image information of each tomographic plane calculated at this time, the image information of the neighboring tomographic plane has a different size (magnification ratio) from the image information of the specific tomographic plane. Then, the respective distance information input from the setting input means is input to the enlargement ratio calculating means. Then, the enlargement ratios of the specific tomographic plane and the neighboring tomographic planes before and after the specific tomographic plane are calculated.

According to the sixth aspect of the present invention, since the flat panel detector is used, the electromagnetic wave transmitted through the subject is uniformly detected on the entire surface of the detector. That is, no distortion occurs in the tomographic image displayed on the image display means.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An X-ray tomography apparatus as an embodiment of the tomography apparatus according to the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a block diagram of an X-ray tomography apparatus according to a first embodiment of the present invention. The X-ray tomography apparatus according to this embodiment includes an operation unit 10 for inputting various information and instructions, an imaging control unit 20 for controlling X-ray imaging based on the input information and instructions, and an imaging control unit A driving unit 30 that operates the imaging unit 40 while being controlled by the imaging unit 20, an imaging unit 40 that captures a tomographic plane of the subject M,
The data processing unit 50 includes a data processing unit 50 that processes and stores the image information detected by the imaging unit 40, and a monitor 60 that outputs and displays the image information stored in the data processing unit 50.

Hereinafter, the configuration and function of each section will be described in detail. Before imaging a specific tomographic plane, a distance SFD from the X-ray tube R to the flat panel X-ray detector D shown in FIG. Specific tomographic plane M to be imaged for M
A distance Z to B, a distance d between tomograms detected at equal intervals before and after the tomographic plane MB, and information on the number of images to be acquired in one image are set and input in advance. For example, the distance d between faults
Is about 2 to 3 mm. The operation unit 10 uses an input device such as a keyboard, a mouse, and a touch panel. The X-ray tube R corresponds to the irradiation source in the present invention,
The operation unit 10 corresponds to a setting input unit in the present invention.

The photographing control unit 20 is connected with the operation unit 10, the drive unit 30 and the data processing unit 50, and based on each information set and input from the operation unit 10,
0 and the data processing unit 50 are controlled respectively. Details of the control will be described later in each section.

The driving section 30 is provided with an X-ray tube R
And the flat panel type X-ray detector D. Specifically, as shown in FIG. 2, while the X-ray tube R moves from the imaging start position P1 to the imaging end position P3, the flat panel X-ray detector D is moved from P3 to P1. . At this time, the center point of the cone-shaped X-ray radiated toward the subject M is always the center of the subject M.
Through a point on the tomographic plane MB (marked with △ in the figure)
The X-ray tube R has an inclination angle θ according to the speed and the moving distance. For example, assuming that the tilt angle θ of the X-ray R is a reference (0 °) with respect to the position P2 when the X-ray is irradiated perpendicularly to the subject M, the tilt angle θ at the imaging start position P1 and the end position P3
Is set to be the maximum (±) 20 °. Further, X-rays transmitted through one point of the tomographic plane MB of the subject M (indicated by △ in the figure) are always detected at the same position on the flat panel X-ray detector D.

The maximum inclination angle θ of the X-ray tube R is (±) 2
It is not limited to 0 °. The drive unit 30 corresponds to a scanning unit in the present invention.

The relative speed and moving distance between the X-ray tube R and the flat panel X-ray detector D, and the inclination angle θ of the X-ray tube R are information set and input from the operation unit 10. Distance SFD from R to flat panel X-ray detector D
An imaging control unit based on a distance Z from the flat panel X-ray detector D to a specific tomographic plane MB of the subject, a distance d between tomograms detected at equal intervals before and after the tomographic plane MB, and the number of images to be captured. At 20, it is automatically calculated and determined. Then, the photographing control unit 20 controls the operation of the drive unit 30 based on the photographing control conditions obtained by this arithmetic processing.

The imaging section 40 includes a top plate T on which the subject M is placed.
And an X-ray tube R for irradiating the subject M with X-rays, and a flat panel X-ray detector D for detecting X-rays transmitted through the subject M.

The X-ray tube R irradiates cone-shaped X-rays toward the subject M.

The flat panel X-ray detector D detects an X-ray fluoroscopic image of the subject M generated by X-ray irradiation by the X-ray tube R, converts the image into an electric signal as an X-ray detection signal, and outputs the electric signal. This is an X-ray detector having a configuration, and as shown in FIG. 3, a so-called two-dimensional matrix X-ray detector in which a large number of detection elements Du are arranged vertically and horizontally. The arrangement of the detection elements Du in the flat panel X-ray detector D of the embodiment is, for example, 1024 in the horizontal (X) direction and 1 in the vertical (Y) direction.
FIG. 3 shows only a matrix configuration of a total of nine matrixes in a 3 × 3 matrix configuration for convenience of description. The flat panel X-ray detector D, which has a rectangular planar shape, is different from an image intensifier in which the detection surface is limited to a circular shape, and can provide a square detection surface suitable for imaging large parts such as the chest and abdomen. This is also a useful X-ray detector.

As shown in FIG. 4, the flat panel X-ray detector D includes an X-ray conversion layer 12 for converting incident X-rays into electric charges or light, and an electric charge or light generated by the X-ray conversion layer 12. It has a laminated structure with a detection array layer 13 in which elements to be detected are arranged vertically and horizontally in a matrix. X-ray conversion layer 1 of this flat panel X-ray detector D
For example, the plane dimensions of 2 are about 30 cm in length and width.

The flat panel type X-ray detector D includes:
The direct conversion type shown in FIG. 5A and the direct conversion type shown in FIG.
There is an indirect conversion type shown below. In the case of the former direct conversion type, the X-ray conversion layer 12 is composed of a selenium layer or a CdZnTe layer which directly converts incident X-rays into electric charges.
5, the charge is detected by the charge collection electrode group formed opposite to and the charge is stored in the capacitor Cs. One charge is detected by each charge detection element 14 and a part of the X-ray conversion layer 12 thereon. The element Du is formed. In the latter case of the indirect conversion type, the X-ray conversion layer 12 comprises a scintillator layer for converting incident X-rays into light, and the detection array layer 13
The light is detected by a photodiode group formed as a photodetecting element 16 on the surface of the device and light is stored in the capacitor Cs. Each of the photodetecting elements 16 and a part of the X-ray conversion layer 12 thereover. One detection element Du is formed.

As shown in FIG. 3, the flat panel type X-ray detector D includes an X-ray detection substrate 41 on which an X-ray conversion layer 12 and a detection array layer 13 are formed, and a carrier collection of the X-ray detection substrate 41. A capacitor Cs for storing collected carriers (collected charges) via electrodes (charge collecting electrodes);
A thin-film transistor (TFT), which is a switch element 42 for extracting charge that is normally off (cut off) for extracting the charge accumulated in s, a multiplexer 45 of a read circuit in the X and Y directions, and a gate driver 47 Have.

The flat panel X-ray detector D is
As shown in FIG. 3, the source of the thin film transistor for the switch element 42 of the detection element Du is connected to the vertical read wiring 43 arranged in the X-axis direction, and the gate is connected to the horizontal read wiring 46 arranged in the Y-axis direction. Have been. The readout wiring 43 is connected to a multiplexer 45 via a charge-voltage converter group (preamplifier group) 44,
The read wiring 46 is connected to a gate driver 47. In the charge-to-voltage converter group 44, one charge-to-voltage converter group 44 is connected to one read wiring 43, though not shown.

In the case of the flat panel X-ray detector D, a scanning signal for signal extraction is sent to the multiplexer 45 and the gate driver 47.
The identification of each detection element Du of the detection unit 10 is performed based on the addresses (for example, 0 to 1023) sequentially assigned to each detection element Du along the arrangement in the X direction and the Y direction. Are signals for specifying an X-direction address or a Y-direction address, respectively.

As a voltage for taking out is applied from the gate driver 47 to the readout wiring 46 in the Y direction in accordance with the scanning signal in the Y direction, each detection element Du is selected in a column unit. Then, by switching the multiplexer 45 according to the scanning signal in the X direction, the charge accumulated in the capacitor Cs of the detection element Du in the selected column is transferred to the charge-voltage changer group 44 and the multiplexer 45.
Will be sent out. The flat panel X-ray detector D described above corresponds to the detecting means in the present invention, the X-ray conversion layer 12 corresponds to the conversion layer in the present invention, the capacitor Cs corresponds to the storage element in the present invention, and the switch element 42 Corresponds to the read element in the present invention.

Next, the configuration and function of the data processing unit 50 will be described. The data processing unit 50 calculates image information MA, MC, and the like of a specific tomographic plane MB and tomographic planes before and after the specific tomographic plane MB based on the detected detection signal. Image information M
An image information storage unit 52 for storing A, MB, and MC is provided. Specific functions of the image processing unit 51 and the image information storage unit 52 will be described. FIG.
As shown in (1), arithmetic processing is performed to obtain a tomographic image of a specific tomographic plane MB and tomographic images of tomographic planes MA and MC separated by an equal interval (±) d from the tomographic plane MB.

Since the projected image of the tomographic plane MB is always projected on a fixed position of the flat panel X-ray detector D, as shown in FIG. 6A, the X-ray tube positions P1, P2,
When three pieces of image information photographed in P3 are vertically arranged and superimposed, all the triangle marks on the tomographic plane MB overlap. In other words, a clear tomographic image of the tomographic plane MB can be obtained by performing an addition operation using each detection signal detected by the flat panel X-ray detector D according to the X-ray tube positions P1, P2, P3. Can be

Next, as shown in FIG. 6B, a tomographic image of the tomographic plane MA is output from image information of three tomographic planes MB photographed at the X-ray tube positions P1, P2, P3. . At this time, first, a tomographic plane MB obtained at an X-ray tube position P2 in which X-rays are vertically irradiated on the subject M from the X-ray tube R.
Is used as a reference. Then, the X-ray tube positions P1 and P
3 based on each image information obtained from the detection signal detected by the flat panel X-ray detector D in accordance with each of the images 3 so that only the portions of the tomographic planes indicated by the circles which are the image information of the MA overlap each other. Shift information. That is, the image information obtained at the X-ray tube position P1 is shown on the left, and the image information obtained at the X-ray tube position P3 is shown on the right, ΔX
When they are shifted and superimposed, all of the circles on the tomographic plane MA overlap. That is, the detection signal detected at the X-ray tube position P2 and the detection signal detected at the X-ray tube positions P1 and P3, which are shifted left and right by ΔX, are subjected to an addition operation to obtain the tomographic plane MA. Is obtained.

The shift amount ΔX at this time is determined by the distance SFD from the X-ray tube R to the flat panel X-ray detector D,
Distance from the tube R to each tomographic plane (SFD- (Z ± n
d)), the angle θ between the line L ′ connecting the X-ray tube R to the flat panel X-ray detector D and the line L in the vertical downward direction of the X-ray tube R, and the specific tomographic plane MB Distance n · d
Is determined by This relationship can be expressed by the following equation (1). ΔX = SFD · n · d · tan θ / (SFD− (Z ± n · d)) (1) Note that n is an equally spaced tomographic plane that is set in order from a specific tomographic plane MB. The same applies hereinafter.

Next, the image information storage section 52 will be described. The image information storage unit 52 sequentially stores the image information MA, MB, and MC of each tomographic plane calculated by the image processing unit 51.

In this embodiment, for the sake of convenience, only three pieces of image information are acquired in one photographing operation. However, in actuality, the number of photographed images depends on the resolution of the tomographic image output and displayed on the monitor 60. To adjust.

The monitor 60 outputs and displays predetermined image information stored in the image information storage unit 52. The monitor 60 corresponds to an image display unit according to the present invention.

Next, the operation of the embodiment device having the above-described configuration will be described. First, the operator sets the distance SFD from the X-ray tube R to the flat panel X-ray detector D before taking an image, and the distance Z from the flat panel X-ray detector D to a specific tomographic plane MB of the subject M. From the operation unit 10, information on the distance d between tomograms detected at equal intervals before and after the tomographic plane MB and information on the number of shots acquired in one shot is input.

The photographing control unit 20 calculates photographing control conditions for the driving unit 30 based on the input information of the operation unit 10. The imaging control unit 20 controls the driving unit 30 based on the imaging control conditions. In other words, the driving unit 30 moves the X
The tube R and the flat panel X-ray detector D are moved in conjunction with each other, and an arbitrary point on a specific tomographic plane MB is always located at the same position on the flat panel X-ray detector D.
Intermittent imaging is performed while changing the X-ray irradiation angle θ of the X-ray tube R. The detection signals detected by the flat panel X-ray detector D are sequentially output to the data processing unit 50 in real time.

The data processing section 50 calculates the images of the tomographic planes MA to MC based on the input detection signals. That is, the image processing unit 51 calculates image information of the tomographic plane MB and the tomographic plane separated by the distance d at equal intervals before and after the tomographic plane MB. The calculated image information of each of the tomographic planes MA to MC is stored in the image information storage unit 52.

Each image information stored in the image information storage section 52 is arbitrarily displayed on the monitor 60 by an operation of the operator. For example, the image information of the tomographic plane arbitrarily selected by the operator is read and displayed on the monitor 60.

As described above, in the above-described embodiment, the flat panel X-ray detector D that detects the X-rays emitted from the X-ray tube R and transmitted through the subject M converts the incident X-rays into electric charges or light. A capacitor Cs having an X-ray conversion layer 12 for detecting the converted charge or light and storing the detected charge or light as a detection signal;
The switch elements 42 for reading out the stored detection signals are
Since the electromagnetic wave transmitted through the subject M can be uniformly detected on the entire flat detection surface of the flat panel type X-ray detector D because of being arranged in a dimensional matrix, the distortion caused by the detection surface distortion In addition, since the detected signal distortion does not occur, and the detected signal detected and accumulated by the flat panel X-ray detector D can be read out and output in real time, the instantaneousness is excellent.

The driving section 30 synchronizes with moving one of the X-ray tube R and the flat panel X-ray detector D in the first direction and sets the other in a direction opposite to the first direction. 2
The X-ray tube R and the flat panel X-ray detector D are moved parallel to each other across the subject M by moving the X-ray tube R and the flat panel X-ray detector D. Tomography for obtaining a tomographic image of an arbitrary tomographic plane of the subject M can be performed by performing a parallel linear scan across the subject M.

In the first embodiment, as shown in FIG.
Although the line tube R and the flat panel X-ray detector D are scanned in parallel and linearly, as shown in FIG. In synchronization with the rotational movement of the X-ray tube R about the rotation axis B in one of the parallel planes, the X-ray tube R is flattened about the rotation axis B in the opposite direction to the rotation direction of the X-ray tube R in the other parallel plane. The panel type X-ray detector D may be driven by the driving unit 30 so as to rotate, so-called circular rotation scanning may be performed. In this case, the X-ray tube R and the flat panel X-ray detector D are individually rotationally scanned in each of two parallel planes sandwiching the subject M, and a tomographic image of an arbitrary tomographic plane of the subject M is provided. Tomography can be performed to obtain

As shown in FIG. 7 (b), the center of the sector having a central angle smaller than 180 ° is located toward the subject M, and the X-ray tube R is moved in one direction of the arc of the sector. Synchronously with this, the flat panel X-ray detector D is driven by the drive unit 30 so as to linearly move in a direction substantially opposite to the moving direction of the X-ray tube R, so-called arc-linear scanning is performed. You may do it. The flat panel X-ray detector D may be moved in an arc, and the X-ray tube R may be moved in a straight line.

As shown in FIG. 7 (c), two sectors each having a central angle smaller than 180 ° are defined by the center of the object M
And place it so as to sandwich the subject M,
In synchronization with moving the X-ray tube R in the arc direction of one sector, the flat panel X-ray detector D is moved in the arc direction of the other sector to detect the X-ray tube R and the flat panel X-ray. In other words, so-called arc-arc scanning may be performed by driving the driving unit 30 so that the directions of movement with the container D are moved in opposite directions.

As shown in FIG. 8, a large flat-panel X-ray detector D capable of performing tomography for obtaining a tomographic image of an arbitrary tomographic plane of the subject M is provided. The detector D and the subject M are fixed, and only the X-ray tube R is driven by the driving unit 30 so as to rotate in a plane parallel to the flat-panel X-ray detector D in a circular manner, thereby forming a cone beam. The effective detection area A, which is a part of the flat panel X-ray detector D to which the X-ray is irradiated, is such that the X-ray tube R moves sequentially as shown in FIG. However, so-called electronic scanning, in which the images of the tomographic planes MA to MC are calculated by the image processing unit 51 based on the transmitted X-rays detected in each of the effective detection areas A, may be performed. . Further, instead of rotating the X-ray tube R in a circular shape, the flat panel X-ray detector D
The X-ray tube R may be fixed, and only the subject M may be rotated. Therefore, "the X-ray tube R, the subject M, and at least two of the flat panel X-ray detector D are synchronized so as to accumulate the X-rays transmitted through an arbitrary point on the tomographic plane of the subject M. The meaning of “scan” is not only the meaning that at least two of the X-ray tube R, the subject M, and the flat panel X-ray detector D are synchronized and mechanically scanned, but also the above-mentioned. Electronic scanning is also included.

The driving section 30 fixes the X-ray tube R, and connects the subject M and the flat panel X-ray detector D to each other at an arbitrary point on the specific tomographic plane of the subject M. The X-ray detector D is interlocked and moved so as to be always at the same position on the detection surface, or the flat panel X-ray detector D is fixed, and the X-ray tube R and the subject M are connected to the subject M. May be moved so that an arbitrary point on the specific tomographic plane is always at the same position on the detection plane of the flat panel X-ray detector D. In this case, the subject M and the flat panel X-ray detector D or the X-ray tube R and the subject M are scanned in parallel and linearly in the same direction to obtain a tomographic image of an arbitrary tomographic plane of the subject M. Shooting can be performed.

Second Embodiment Next, an X-ray tomography apparatus according to a second embodiment of the present invention will be described. The X-ray tomography apparatus according to the second embodiment is the same as the first embodiment except that the configuration and functions of the data processing unit 50 are different as described below. The configuration and functions of 50 will be described in detail.

The data processing unit 50 calculates an image information of the specific tomographic plane MB and the tomographic planes before and after the specific tomographic plane MB and an enlargement ratio of each tomographic plane based on the detected detection signal. An image information storage unit 52 stores both the calculated image information and the enlargement ratio. Note that the image processing unit 51 corresponds to the tomographic image calculation unit and the enlargement ratio calculation unit of the present invention.

Hereinafter, specific functions of the image processing section 51 and the image information storage section 52 which are characteristic parts of the second embodiment will be described. As described with reference to FIG. 2 and FIG. 6 in the first embodiment, the image processing unit 51 generates a tomographic image of a specific tomographic plane MB and a tomographic image separated from the tomographic plane MB by an equal interval (±) d. Calculation processing for obtaining the tomographic images of the planes MA and MC is performed.

Next, a specific calculation process for determining the magnification of the image information of each tomographic plane will be described with reference to FIG.
X-rays emitted from the X-ray tube R toward the subject M pass through the subject M and are detected by the flat panel X-ray detector D. At this time, the projected images of the plurality of tomographic planes projected on the flat panel X-ray detector D include the distance SFD from the X-ray tube R to the flat panel X-ray detector D, and the subject from the X-ray tube R. M to each fault plane (SFD- (Z ± n
d)) appears as an enlargement factor Y determined by the ratio. The relationship between the enlargement factors can be expressed by the following equation (2). Y = SFD / (SFD− (Z ± n · d)) (2) As described above, the image processing unit 51 uses the equations (1) and (2).
Is used to calculate the image information and the magnification of each tomographic plane.

Next, the image information storage section 52 will be described. The image information storage unit 52 sequentially stores the image information of each tomographic plane calculated by the image processing unit 51 and one of the enlargement ratios as one file in association with each other. That is, FIG.
As shown in (1), the enlargement ratio Yb and image information of the tomographic plane MB serving as a reference are stored as one file. Similarly, the enlargement factor Ya of the tomographic plane MA at a distance (+) d away from the tomographic plane MB
The image information is stored as one file each of the enlargement ratio Yc and the image information of the tomographic plane MC separated by a distance (-) d from the tomographic plane MB.

In this embodiment, for the sake of convenience, only three pieces of image information are acquired in one photographing operation. However, in actuality, the number of photographed images depends on the resolution of the tomographic image output and displayed on the monitor 60. To adjust.

The monitor 60 outputs and displays predetermined image information stored in the image information storage unit 52. The monitor 60 corresponds to an image display unit according to the present invention.

Next, the operation of the apparatus having the above-described configuration will be described with reference to the flowchart of FIG. Step S1: The operator sets the distance SFD from the X-ray tube R to the flat panel X-ray detector D before imaging,
The distance Z from the flat panel X-ray detector D to a specific tomographic plane MB of the subject M, the distance d between tomograms detected at equal intervals before and after the tomographic plane MB based on the tomographic plane MB, and acquired by one imaging Information on the number of shots is input from the operation unit 10.

Step S2: The photographing control unit 20 calculates photographing control conditions of the drive unit 30 based on the input information of the operation unit 10.

Step S3: The photographing control section 20 controls the driving section 30 based on the photographing control conditions. That is, the drive unit 30 moves the X-ray tube R and the flat panel X-ray detector D in conjunction with each other with the subject M interposed therebetween, and moves any point on the specific tomographic plane MB to the flat panel X-ray detector D. Intermittent imaging is performed while changing the X-ray irradiation angle θ of the X-ray tube R so as to always be at the same position on the surface. Then, the detection signal detected by the flat panel X-ray detector D is sequentially output to the data processing unit 50.

Steps S4 and S5: The detected detection signal is input to the data processing unit 50. Then, the image processing unit 5
In step 1, image information of a tomographic plane MB and a tomographic plane separated by a distance d at equal intervals before and after the tomographic plane MB are calculated. And the fault plane M
The enlargement ratio of each tomographic plane before and after B and the tomographic plane MB is calculated.

Step S6: The calculated image information and magnification of each tomographic plane are stored in the image information storage unit 52 as one file.

Step S7: Each of the stored image information is
The image is arbitrarily displayed on the monitor 60 by the operation of the operator. For example, the image information and the enlargement ratio are read from the file of the tomographic plane arbitrarily selected by the operator, and the image information adjusted to the same scale as the tomographic plane MB can be displayed on the monitor 60.

In this embodiment, the image information and the enlargement ratio are obtained for the tomographic planes at equal intervals before and after the specific tomographic plane.
The determination may be made for each tomographic plane having an unspecified interval.

As described above, in the above-described second embodiment, when performing X-ray imaging of a specific tomographic plane MB, the distance from the X-ray tube R input from the operation unit 10 to the flat panel X-ray detector D in advance. SFD and flat panel X-ray detector D
From the object to the tomographic plane MB to be imaged by the subject M
And a distance d between tomograms detected at equal intervals in the front-rear direction from the tomographic plane MB, information on the number of images of the tomographic plane MB, and a detection signal detected from the flat panel X-ray detector D, Image information of a tomographic plane at equal intervals before and after the plane and a specific tomographic plane is obtained. In addition, magnification rates of a plurality of tomographic planes having different magnification rates are obtained from the respective distance information input from the operation unit 10. The image information and the enlargement ratio are stored in the image information storage unit 52 in association with each other. The operator arbitrarily selects a plurality of tomographic plane files stored in the image information storage unit 52, reads out the image information and the enlargement ratio stored in the file,
For example, image information adjusted to the same scale as the specific tomographic plane MB can be displayed on the monitor 60. As a result, it is possible to easily compare the tomographic images.

<Third Embodiment> The features of the third embodiment are as follows.
As shown in FIG. 11, a mouse 11 is provided separately from the console 10. That is, the image information of the tomographic plane is displayed on the monitor 60, and an arbitrary distance, area, and the like can be obtained.

That is, the operator operates the image information storage 5
2 is arbitrarily selected and displayed on the monitor 60. Then, by operating the mouse 11 and moving the cursor on the tomographic image displayed on the monitor 60 to designate any two points, the distance between the two points is calculated by the arithmetic processing.

Similarly, by moving the cursor on the tomographic image displayed on the monitor 60 to set an area, an arbitrary area can be obtained by arithmetic processing.

When comparing the distances and areas of the tomographic planes calculated and calculated as described above, the scales of the tomographic planes can be made the same by adjusting the ratio of the enlargement ratio for each tomographic plane to be compared. In addition, local comparison on a tomographic plane can be easily performed. The other configuration is the same as that of the first embodiment, and the description is omitted here.

The present invention is not limited to the above embodiment, but can be modified as follows.

(1) In the above-described second embodiment, after calculating the image information and the enlargement ratio of each tomographic plane in the image information storage unit 52, each of the image information and the enlargement ratio is set to 1 for each tomographic plane. Although the files are stored as one file, the image information of each tomographic plane and the input information set and input in advance may be sequentially stored. That is, the image information of the specific tomographic plane, the image information of each of the tomographic planes separated at equal intervals before and after the specific tomographic plane, the distance SFD between the X-ray tube R and the flat panel X-ray detector D, The distance Z from the flat panel X-ray detector D to a specific tomographic plane and the distance d between tomograms detected at equal intervals before and after the specific tomographic plane are stored as associated files. Then, when the operator selects a file of the tomographic plane to be output and displayed on the monitor 60 from the stored files, the information of the selected file is re-input to the image processing unit 51 to perform the calculation processing of the enlargement ratio. Then, the tomographic image of the selected tomographic plane may be adjusted to the same scale as the specific tomographic plane and output and displayed on the monitor 60.

(2) In each of the embodiments described above, the subject M is irradiated with the X-rays by the X-ray tube R.
The same effect is obtained even when electromagnetic waves such as gamma rays and light having transparency to the subject M are used. Therefore, the tomographic apparatus according to the present invention is not limited to the X-ray tomographic apparatus, but may be applied to a tomographic apparatus that performs tomographic imaging using electromagnetic waves that are transparent to the subject M other than X-rays. Applicable.

[0076]

As is clear from the above description, according to the tomography apparatus of the first aspect, the flat panel detector for detecting the electromagnetic wave emitted from the irradiation source and transmitted through the subject is provided. A two-dimensional matrix comprising a storage element having a conversion layer for converting incident electromagnetic waves into electric charges or light, detecting the converted electric charges or light, and accumulating it as a detection signal, and a reading element for reading out the stored detection signal. The electromagnetic wave transmitted through the subject can be uniformly detected on the entire flat detection surface of the flat panel detector, and the detection signal distortion due to the distortion of the detection surface does not occur. Further, since the detection signal detected and accumulated by the flat panel type detector can be read out and output in real time, it is excellent in immediacy.

According to the tomographic imaging apparatus of the second aspect, the scanning means synchronously moves one of the irradiation source and the flat panel type detector in the first direction, and sets the other one in parallel. Since the irradiation source and the flat panel detector are moved in parallel and linearly in a second direction opposite to the first direction, the irradiation source and the flat panel detector are scanned in parallel and straight lines with the object interposed therebetween, and a tomographic image of an arbitrary tomographic plane of the object is obtained. Tomography to obtain it.

Further, according to the tomography apparatus according to the third aspect, the scanning means rotates the irradiation source in one of the two parallel planes arranged in parallel to face each other across the subject. In synchronization with the movement, the flat panel detector is rotationally moved in the other parallel plane in the direction opposite to the rotation direction of the irradiation source, so that the irradiation source and the flat panel detector are individually moved to the subject. It is possible to perform tomography for obtaining a tomographic image of an arbitrary tomographic plane of the subject by rotating and scanning in each of the two parallel planes sandwiched therebetween.

Further, according to the tomography apparatus of the fourth aspect, the scanning means fixes the irradiation source, and connects the subject and the flat panel detector to an arbitrary portion on a specific tomographic plane of the subject. Move the points so that the points are always at the same position on the detection surface of the flat panel type detector, or fix the flat panel type detector, and connect the irradiation source and the subject to a specific tomographic plane of the subject. Since the above arbitrary point is moved in conjunction so as to be always at the same position on the detection surface of the flat panel detector, the subject and the flat panel detector or the irradiation source and the subject are scanned in the same direction, Tomography for obtaining a tomographic image of an arbitrary tomographic plane of the subject can be performed.

According to the tomography apparatus of the fifth aspect, image information of a specific tomographic plane and a neighboring tomographic plane is obtained from each input information input to the setting input means and a detection signal detected by the detecting means. Is required. Further, it is possible to obtain the respective enlargement ratios of the specific tomographic plane and the neighboring tomographic plane from each distance information input to the setting input means.

That is, when a specific tomographic plane is used as a reference, by adjusting the ratio of the magnification of the specific tomographic plane to the neighboring tomographic planes before and after the specific tomographic plane, the same scale as that of the specific tomographic plane is obtained. The adjusted tomographic image can be displayed on the image display means. That is, it is possible to easily compare the tomographic planes.

According to the tomography apparatus of the sixth aspect, since the flat panel detector is used, the electromagnetic wave transmitted through the subject can be uniformly detected on the entire surface of the detector, and the image display can be performed. The distortion can be removed from the tomographic image displayed on the means.

[Brief description of the drawings]

FIG. 1 is a block diagram of an X-ray tomography apparatus according to a first embodiment of the present invention.

FIG. 2 is a view showing a mode of imaging according to the X-ray tomography apparatus of the present invention.

FIG. 3 is a configuration diagram of a flat panel X-ray detector.

FIG. 4 is a perspective view showing a schematic configuration of a flat panel X-ray detector.

FIGS. 5A and 5B are cross-sectional views showing a layer structure of a flat panel X-ray detector.

FIGS. 6A and 6B are stylized views showing the principle for calculating each tomographic plane.

FIGS. 7A to 7C are schematic diagrams illustrating a state in which an X-ray tube and a flat panel X-ray detector are moved and scanned.

FIG. 8 is a schematic diagram showing a state in which an object and a flat panel X-ray detector are fixed and scanning is performed by moving only an X-ray tube.

FIG. 9 is a diagram showing a magnification and a filing format of image information.

FIG. 10 is a flowchart illustrating an imaging procedure of the X-ray tomography apparatus according to the second embodiment.

FIG. 11 is a block diagram of an X-ray tomography apparatus according to a third embodiment.

FIG. 12 is a diagram showing a style of imaging according to a conventional X-ray tomography apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Operation part 12 ... X-ray conversion layer 20 ... Imaging | photography control part 30 ... Drive part 40 ... Imaging part 42 ... Switch element 50 ... Data processing part 51 ... Image processing part 52 ... Image information storage part 60 ... Monitor Cs ... Capacitor D … Flat panel X-ray detector M… Subject R… X-ray tube

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Eiichi Morita 1-term, Kuwaharacho, Nishinokyo, Nakagyo-ku, Kyoto F-term in Shimadzu Corporation (reference) 2G001 AA01 BA11 CA01 DA01 DA09 GA13 HA12 HA13 HA14 JA01 JA06 JA08 JA09 JA20 KA03 LA01 4C093 AA11 CA05 EA02 EB12 EB17 EC26 EC28 FG04

Claims (6)

[Claims] 1. An irradiation source for irradiating an electromagnetic wave having transparency to an object, and (b) an electromagnetic wave transmitted through the object while being disposed opposite to the irradiation source with the object interposed therebetween. (C) the flat panel detector has a conversion layer for converting incident electromagnetic waves into electric charges or light, and detects and detects the electric charges or light converted by the conversion layer. A storage element for storing as a signal,
And a read-out element for reading out the detection signal stored in the storage element are arranged in a two-dimensional matrix, and (d) the read-out element is configured to store the electromagnetic wave transmitted through an arbitrary point on the tomographic plane of the subject. A tomographic apparatus comprising: a scanning unit configured to synchronize and scan at least two of an irradiation source, a subject, and the flat panel detector. 2. The tomography apparatus according to claim 1, wherein (e) the scanning unit is synchronized with linearly moving one of the irradiation source and the flat panel detector in a first direction. A tomographic apparatus configured to move the other side in a straight line parallel to a second direction opposite to the first direction. 3. The tomographic imaging apparatus according to claim 1, wherein (f) the scanning means irradiates the irradiation within one of two parallel planes which are arranged in parallel to face each other across the subject. A tomographic structure configured to rotate the flat panel detector in a direction parallel to the rotational direction of the irradiation source in the other parallel plane in synchronization with the rotational movement of the source. Shooting equipment. 4. The tomography apparatus according to claim 1, wherein (g) the scanning unit fixes the irradiation source, and connects the subject and the flat panel detector to a specific tomographic plane of the subject. An arbitrary point above is interlocked and moved so that it is always at the same position on the detection surface of the flat panel detector, or the flat panel detector is fixed,
The irradiation source and the subject are configured to be linked and moved so that an arbitrary point on a specific tomographic plane of the subject is always at the same position on the detection surface of the flat panel detector. A tomographic apparatus characterized by the above-mentioned. 5. An irradiation source for irradiating an electromagnetic wave having transparency to a subject, and (i) an electromagnetic wave transmitted through the subject while being disposed opposite to the irradiation source with the subject interposed therebetween. (J) scanning for synchronously scanning the irradiation source and the detection means so that an arbitrary point on a specific tomographic plane of the subject is always at the same position on the detection surface of the detection means; And (k) calculating image information of a specific tomographic plane and image information of neighboring tomographic planes before and after the specific tomographic plane from a detection signal detected with the interlocking movement of the irradiation source and the detecting means. A tomographic apparatus comprising: a tomographic image calculating unit; and (l) an image display unit configured to output and display image information of each tomographic plane calculated by the tomographic image calculating unit.
(M) setting input means for presetting and inputting distance information for determining a positional relationship between the irradiation source, the detecting means, and a specific tomographic plane, and distance information from the specific tomographic plane to a neighboring tomographic plane; A tomography apparatus comprising: an enlargement ratio calculating unit that calculates an enlargement ratio of a specific tomographic plane and a nearby tomographic plane from each distance information input to the setting input unit. 6. The tomographic apparatus according to claim 5, wherein (o) the detecting means is a flat panel detector.