JPH10272128A - Method and apparatus for direct tomographic photographing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direct tomographic photographing apparatus capable of reducing an energy detection medium detecting photographing data and capable of shortening the photographing time. SOLUTION: A spatial coupler 45 passing X-rays from a subject 22 irradiated with X-rays from the outside to reverse the image of the subject 22 to project the same on the side opposite to the subject 22 and an accumulation type energy detection medium 46 arranged opposedly in close vicinity to the side opposite to the subject 22 across the coupler 45 to detect X-rays incident through the spatial coupler 45 to accumulate the same are provided. At least one of the subject 22 and the detection medium 46 is provided so as to be movable. The subject 22 and the detection medium 46 are relatively moved in reverse directions so that the relative position of the fault plane ready to be calculated of the subject 22 and the detection medium to the fault plane is no changed to take the image of the fault plane by the detection medium 46.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for direct tomography, which are used for industrial or medical purposes and take an image of an arbitrary layer surface of a subject using radiation.

[0002]

2. Description of the Related Art There are a CT system and a direct imaging system for performing tomography. While a CT tomography apparatus has an excellent aspect, in order to obtain imaging data of the subject from all directions, the radiation source is rotated around the subject, and in some cases, the subject is also rotated. In addition to the need to move, the hardware configuration that performs data processing according to the mathematician Radon's theorem to reproduce the tomographic image is necessary, so the device is complicated and large-scale, and There is a problem that the frequency is high, the cost is very high, and the tomographic image is incomplete due to a false image (artifact) generated in the calculation process of the data processing. In addition to the above, since the data processing is enormous, the time required for calculation, in addition to the time required for imaging, is currently required to be about 2 seconds even at the highest speed, and there is a problem of lack of real-time properties. .

On the other hand, a specific tomographic plane of a subject
A tomographic apparatus that employs a direct tomography method for performing tomography without changing the relative position of the X-ray detection medium with respect to the tomographic plane is excellent in that it does not have the above-described problems of the CT method. The principle concept of this method is as shown in FIG.

That is, in FIGS. 24A to 24C, 1 is X
An external irradiation device provided with the radiation source 2, 3 is an X-ray detection medium, 4 is a subject disposed between the external irradiation device 1 and the X-ray detection medium 3, and the external irradiation device 1 is fixed. On the other hand, the X-ray detection medium 3 and the subject 4 are both moved in the same direction. In FIGS. 24A to 24C, α is the radiation angle of the X-ray,
The maximum is 30 degrees, and for convenience, α1, α
Numeral 2 denotes a boundary line of the radiation angle α, α3 denotes a center line α of the radiation angle, and 4a denotes a tomographic plane of the subject 4 to be obtained.

FIG. 24A shows a state in which the front portion of the moving subject 4 in the moving direction intersects the boundary line α1, and the intersection of the subject 4 and the X-ray transmitted therethrough at this stage. Are representatively indicated by B, A, and E, and the images at these points are projected on the S point of the X-ray detection medium 3 while maintaining the same orientation without being inverted. FIG. 24B shows a state in which the X-ray detection medium 3 is moved together with the subject 4 and the front part in the moving direction intersects with the center line α3. The intersection with the line is typically C,
The images at these points are projected onto the point S of the X-ray detection medium 3 while maintaining the same orientation without being inverted. FIG. 24C shows the X-ray detection medium 3 together with the subject 4.
Is further moved, and the front portion in the moving direction is the boundary line α.
The intersection of the subject 4 and the X-ray passing therethrough is typically indicated by D, A, and G at this stage, and the images at these points are the same without being inverted. The image is projected onto the S point of the X-ray detection medium 3 while maintaining the orientation.

Due to such circumstances, the X-ray detection medium 3
The point A on the tomographic plane 4a is imaged at each of the positions α1 to α3, compared to detecting the image of each of the points B to F other than the point A of the subject 4 only once. The images at point A are all accumulated at point S on the X-ray detection medium 3. Therefore, as for the X-ray intensity, the image of the point A on the tomographic plane 4a stands out, and the other images BG can be regarded as the background. The image can be identified and visually recognized. Therefore, by implementing such an imaging principle for each point of the X-ray detection medium 3, the tomographic plane 4a can be imaged.

The X-ray source 2 of the direct tomography apparatus shown in FIG. 25 is used. This X-ray source 2
Electric power is applied from a cathode power supply circuit 13 to a cathode 12 accommodated in an irradiation container 11 formed of a vacuum container, and the cathode 12 is made red to emit thermoelectrons. At the same time, the cathode 12 emits light. On the other hand, since a high voltage is applied to the anode 15 accommodated in the irradiation container 11 opposite to the X-ray transmission window 14 of the irradiation container 11 by the high voltage generator 16, the negative electrode 12 has a negative potential with respect to the anode 15.
The thermoelectrons emitted from are attracted by the anode 15 according to the electric field between the cathode 12 and the anode 15 and collide with the anode 15. In this case, a focusing electrode 18 to which power is applied by a focusing electrode power supply circuit 17 is provided between the cathode 12 and the anode 15.
Is arranged, the flow of thermoelectrons from the cathode 12 to the anode 15 is concentrated at one point of the anode 15 by controlling the electric field by the electrode 18. In this way, the collision energy of the thermoelectron current to the local area of the anode 15 which is ideally close to a point is converted into X-rays and transmitted through the X-ray transmission window 14 to irradiate the subject 4. .

[0008]

In the conventional direct imaging method and apparatus, the X-ray radiated from the X-ray source 2 is processed without any processing within an angular range that diverges according to the radiation angle α. Thus, the relative position between the subject 4 and the X-ray detection medium 3 when viewed from the X-ray source 2 is the same, and the subject 4 and the X-ray detection medium 3 are both moved in parallel. Therefore, when performing tomography on the effective visual field (represented by H in FIG. 25) of the subject 4 when viewed from the X-ray source 2, the X-ray moved farthest from the X-ray source 2 As the detection medium 3, there is a problem that a medium having a detection visual field (represented by I in FIG. 25) larger than the effective visual field H must be used.

Furthermore, the amount of movement of the X-ray detection medium 3 translated in parallel with the object 4 as described above is equal to or greater than the amount of movement of the object 4 as is apparent from the comparison between the two fields of view H and I in FIG. Therefore, there is a problem that it takes a long time to perform tomographic imaging due to the time required for the movement.

Therefore, a first object of the present invention is to provide a direct tomography method and apparatus capable of reducing the size of an energy detection medium for detecting an image of a tomographic plane and shortening the imaging time. .

Moreover, conventionally, tomographic imaging requires a moving mechanism for the subject 4 and a moving mechanism for the X-ray detection medium 3 having different moving speeds from each other.
Since the structure is complicated and the subject 4 must be moved, there is a problem that when the subject 4 is a person, the person is likely to be given a considerable burden such as fear.

Therefore, a second object to be solved by the present invention is to solve the first problem by directly simplifying the structure and lessening the burden when the subject is a person. It is to obtain a tomographic apparatus.

A third problem to be solved by the present invention is to solve the first or second problem.
An object of the present invention is to provide a direct tomography apparatus capable of extracting an image of a tomographic plane in real time.

Conventionally, the X-ray detection medium 3 is
Since the tomographic imaging is performed while moving so that the relative position with respect to one tomographic plane 4a does not change, only one tomographic plane 4a can be imaged in one imaging operation. for that reason,
To perform a plurality of tomographic scans, it was necessary to repeat the scan many times, which was time-consuming and troublesome. Accompanying this, all tomographic imaging is performed when processing imaging data on a plurality of tomographic planes and converting them to tomographic images in other tomographic directions, or when obtaining a three-dimensional image by combining those images. Since it is necessary to wait until the process is completed, there is a problem that real-time performance is lacking and it takes time.

Accordingly, a fourth object of the present invention is to provide a direct tomography apparatus capable of simultaneously taking a plurality of tomographic images in one tomographic image acquisition in solving the third object.

Further, the X-ray source 2 of the conventional tomographic apparatus
In order to increase the line intensity and sharpen the tomographic image, X-rays are generated by concentrating thermoelectrons on a focus as close as possible to the point on the anode 15 (this is referred to as zero dimension). .
However, strong X-rays cannot be obtained unless the amount of thermionic electrons is increased, so that the temperature of the zero-dimensional anode rises remarkably, and damage and melting of the anode cannot be avoided. X-rays are generated at the focal point. In addition, the radiation angle α of the X-ray is obtained in proportion to the size of the thermoelectron width. However, if this width is increased, the size of the focal point is further increased.

Conventionally, since the radiation angle α of the X-ray is as small as about 30 degrees at the maximum, compared to the accumulated and emphasized image data (the point A), the background image data (the above B to B) In addition to the fact that the averaging of the (G point) is apt to be insufficient, and the focal size is large, and the image is easily blurred in the image formation on the X-ray detection medium 3, the tomographic image has a high degree of unclearness. is there.

Therefore, a fifth object of the present invention is to provide a direct tomography apparatus capable of improving the definition of a tomographic image in solving any of the first to fourth problems. is there.

Further, a sixth object of the present invention is to provide a direct tomographic apparatus capable of increasing the tomographic speed while solving the fifth object.

Further, a seventh object of the present invention is to solve the fifth or sixth problem.
An object of the present invention is to provide a direct tomography apparatus which can easily produce a radiation source having a large radiation angle.

In addition, there are organs and the like that have a strong absorption of X-rays and the like in human body tissues, and the same can be considered for other subjects. If a subject such as a human body is tomographically photographed, the image data of the portion having a strong absorption affects the image data of the surrounding portion. Such a phenomenon becomes more apparent as the radiation angle increases. Therefore, if an attempt is made to increase the radiation angle of the radiation source, an inaccurate portion may be included in the imaging data, and the reliability of the imaging data obtained by tomography may be impaired. Therefore, an eighth problem to be solved by the present invention is the fifth problem.
In order to solve the seventh to seventh problems, it is an object of the present invention to provide a direct tomography apparatus capable of improving the reliability of image data regardless of a portion where energy transmission lines are strongly absorbed.

In the tomography apparatus, when X-rays pass through the subject 4, the X-rays are scattered at a part of the subject 4, and the scattered rays (indicated by 5 in FIG. 24) are generated. There is a problem in that the tomographic image enters the S point or the like of the X-ray detection medium 3 and becomes unclear.

Accordingly, a ninth object to be solved by the present invention is to provide a direct tomography apparatus capable of preventing a reduction in the sharpness of a tomographic image based on scattered radiation.

A tenth object to be solved by the present invention is to provide a direct tomography apparatus capable of preventing an increase in the amount of exposure to a subject.

In the X-ray source 2 of the conventional tomography apparatus, X-rays generated at the anode 15 are emitted in all directions, but only a part of the X-rays is emitted to the subject 4 side. . Therefore, there is a problem that the generation efficiency of X-rays is poor, and in order to generate more X-rays, the voltage applied by the cathode power supply circuit 13 to the cathode 12 must be increased.
There is a problem that power consumption is large.

Therefore, an eleventh object to be solved by the present invention is to provide a direct tomography apparatus capable of improving the generation efficiency of energy transmission lines such as X-rays and reducing power consumption.

A twelfth object of the present invention is to provide a direct tomography apparatus which can be realized with a simple structure in solving the eleventh problem.

In the X-ray source 2 of the conventional tomography apparatus, the speed at which the X-rays generated at the anode 15 collide with the anode 15 is determined depending on the electric field strength between the cathode 12 and the anode 15. Therefore, in order to further increase the collision speed and improve the X-ray generation efficiency, there is no measure other than increasing the high voltage applied to the anode 15 by the high voltage generation circuit 16 to increase the electric field strength. There is a problem of bulging.

Accordingly, a thirteenth object to be solved by the present invention is to provide a direct tomography apparatus capable of improving the generation efficiency of energy transmission lines such as X-rays and reducing power consumption.

[0030]

According to a first aspect of the present invention, there is provided a method for externally irradiating an externally irradiated object to which an energy transmission line is irradiated, or radiating the energy transmission line by itself. The spontaneous emission type object and the spatial coupler that inverts the image of the object by projecting the energy propagation line from the object and projects the image on the opposite side to the object are separated from each other on the opposite side. By moving at least one of the storage-type energy detection medium that is disposed in close proximity to the space detector and detects and stores the energy propagation line, the subject and the energy detection medium are relatively moved in opposite directions. In this relative movement, the relative position between the tomographic plane to be obtained by the subject and the energy detection medium with respect to the tomographic plane is not changed. Is characterized in that the capturing the tomographic plane in said energy detection medium.

In the method according to the first aspect of the present invention, the spatial coupler converges the energy propagation line from the subject, diverges the convergence point to the base point, and enters the energy detection medium. The surface is projected onto the energy detection medium with its orientation reversed. In such a relationship, the relative position of the energy detector with respect to the tomographic plane can be kept unchanged by relatively moving the subject and the energy detection medium in the opposite directions. The tomographic plane that is stored in the energy medium and desired to be obtained can be photographed. for that reason,
By reversing the tomographic plane by the spatial coupler, the size of the energy detecting medium for detecting the image of the tomographic plane can be reduced irrespective of the distance from the subject to the energy detecting medium, and the relative position of the medium with respect to the subject can be reduced. Moving can be shortened and the shooting time can be shortened.

Similarly, in order to solve the first problem,
The invention device according to claim 2, wherein the object is transmitted by passing the energy propagation line from an external irradiation type object that is externally irradiated with the energy propagation line or a spontaneous emission type object that emits the energy propagation line by itself. A spatial coupler that inverts the image of the spatial coupler and projects it on the side opposite to the subject, and the spatial coupler disposed opposite to the spatial coupler on the side opposite to the subject with the spatial coupler as a boundary. A storage-type energy detection medium that detects and accumulates the energy propagation line incident therethrough, and at least one of the subject and the energy detection medium is provided so as to be movable; The subject and the energy detection medium are positioned relative to each other so that the relative position between the tomographic plane to be obtained and the energy detection medium with respect to the tomographic plane does not change. Is characterized in that the capturing the tomographic plane in said energy detection medium while moving in opposite directions.

As the energy propagation rays, in addition to radiations such as X-rays, gamma rays and beta rays, light rays, lines of magnetic force, electromagnetic waves and the like can be used. For the spatial coupler, a pinhole, an optical lens, a gradient magnetic field generator in a nuclear magnetic resonance tomography apparatus, or the like can be used. The storage type energy detecting medium includes a photographic film, an area type CCD image sensor,
A photostimulable imaging plate or the like can be used.

According to the second aspect of the present invention, since the first aspect of the present invention is carried out, the energy detecting medium for detecting the image of the tomographic plane can be reduced, and the photographing time can be reduced.

According to a second aspect of the present invention, in order to solve the second problem, the spatial coupler is provided for the subject arranged without being moved,
It is characterized in that a set formed by the storage type energy detection medium is moved.

The device according to the third aspect of the present invention is dependent on the invention of the second aspect, and has the following effects in addition to the ability to solve the first problem. That is, the pair formed by the spatial coupler and the energy detection medium is moved relatively to the subject, and the subject does not move. Therefore, the structure for performing the relative movement is simplified, and Even if the sample is a person, it is not moved, so that the burden on the person as the subject is small.

In order to solve the third problem, the invention according to claim 4 or claim 3, wherein the storage type energy detecting medium is an area type CCD image sensor, and The pixel row is scanned according to the relative movement direction so that the relative position between the pixel row that is scanned in the relative movement direction and accumulates electric charges and the tomographic plane to be obtained by the subject does not change. It is characterized by being performed.

The device according to claim 4 is dependent on the invention according to claim 2 or 3, and has the following effects in addition to the ability to solve the first or second problem. In other words, since an area-type CCD image sensor is used as a storage-type energy detection medium, it can be operated electronically as compared with other detection media, such as an X-ray film or a photostimulable imaging plate. Since the image of the plane can be quickly accumulated and read out, the image of the tomographic plane, in other words, the photographing data, can be taken out in real time.

In order to solve the fourth problem, the invention according to claim 5 is dependent on claim 4, wherein the spatial coupler and the storage type energy detecting medium made of an area type CCD image sensor are formed. A plurality of sets are provided side by side in the direction of the relative movement, and the scanning speeds of the pixel rows of the storage type energy detection media of each set are different from each other.

Since the invention of claim 5 is dependent on the invention of claim 4, in addition to the ability to solve the third problem, the following operation is provided. In other words, the relative moving speeds of the plurality of tomographic planes to be determined for the subject with respect to the energy detection medium are faster as closer to the spatial coupler and slower as far away from the spatial coupler. Since the relative pixel row scanning speed of each area type CCD image sensor forming a plurality of energy detection media is different according to each speed, each CCD image sensor is located at a height position where the scanning speed coincides. An image of the tomographic plane is captured. Therefore, although the visual field range of the subject viewed from each CCD image sensor is the same, tomographic planes at different heights can be simultaneously imaged by each CCD image sensor.

According to a sixth aspect of the present invention, there is provided an apparatus according to any one of the second to fifth aspects, wherein the object is irradiated with an energy propagation ray from outside thereof. An external irradiating device is provided, which has a two-dimensional or three-dimensional radiation source, generates radiation that is an energy transmission line from the entire radiation source, and irradiates the radiation to the subject. Features.

Since the invention of claim 6 is dependent on any of the inventions of claims 2 to 5, it has the following effects in addition to being able to solve any of the above first to fourth problems. That is, since the subject is irradiated with the radiation by an external irradiation device having a radiation source that emits radiation as energy propagation rays from the whole in a two-dimensional shape or a three-dimensional shape, the radiation angle with respect to the subject is set to the radiation angle. It can be large depending on the area of the source. Thereby, with respect to the image accumulated in the energy detection medium, the background formed by the other non-accumulated images is sufficiently averaged, and the difference between the accumulated image and the background is increased. Thus, the image of the tomographic plane can be improved in sharpness by making the stored image stand out.

In order to solve the sixth problem, the apparatus according to any one of the second to sixth aspects of the present invention irradiates the object with an energy propagation ray from outside thereof. An external irradiation device is provided, the device has a radiation source having a three-dimensional shape, and irradiates the subject with radiation that is an energy transmission line from the entire radiation source. Is formed by a part of a paraboloid or a spherical surface approximating the paraboloid which converges the radiation to the spatial coupler.

Since the invention of claim 7 is dependent on any of the inventions of claims 2 to 6, it has the following effect in addition to the ability to solve any of the first to fifth problems. In other words, the subject is irradiated with the radiation by an external irradiation device having a radiation source that emits radiation as energy transmission lines from the whole by forming a three-dimensional shape from a part of a paraboloid or a spherical surface similar thereto. Therefore, the radiation angle with respect to the subject can be increased according to the area of the radiation source. Thereby, with respect to the image accumulated in the energy detection medium, the background formed by the other non-accumulated images is sufficiently averaged, and the difference between the accumulated image and the background is increased. Thus, the image of the tomographic plane can be improved in sharpness by making the stored image stand out. Furthermore, according to the three-dimensional structure of the radiation source, the radiation amount directed to the focal direction of the radiation source can be increased and increased, and the radiation is converged on the spatial coupler, so that the radiation source is opposed to the vicinity thereof. The irradiation intensity incident on the energy detection medium made of the area type CCD image sensor can be increased. Thereby, the sensor can be scanned at a high speed, and the tomographic imaging speed can be further improved.

In order to solve the seventh problem, the invention according to claim 6 or claim 7, wherein the radiation source has a two-dimensional shape or a three-dimensional shape. It is a radiation source unit in which elements are continuously arranged.

Since the invention of claim 8 is dependent on the invention of claim 5 or 6, it has the following effect in addition to being able to solve the fifth or sixth problem. That is, since one radiation source is formed substantially by arranging a plurality of radiation source elements continuously, a radiation source having a large radiation angle can be easily produced.

According to a ninth aspect of the present invention, in accordance with the fourth or fifth aspect of the present invention, there is provided an apparatus according to the ninth aspect, wherein the detection is performed by the storage type energy detecting medium made of the area type CCD image sensor. The apparatus is characterized by comprising low frequency component removing means for filtering the image data of the tomographic plane and removing low frequency components in the data.

Since the invention of claim 9 is dependent on the invention of claim 4 or 5, it has the following effect in addition to the ability to solve the third or fourth problem. That is, the image data of the part where the absorption of the subject is strong contains many other low-frequency components that affect the image, and this is not sufficiently averaged as a background, and is one of the blurring factors of the tomographic image. On the other hand, when the radiation angle increases,
Since the image data of the part where the absorption of the subject is strong is also easy to detect, it easily affects the surrounding data. However, according to the ninth aspect of the present invention, since the low-frequency component is removed by the low-frequency component removing means, the reliability of the image data can be improved irrespective of the strong absorption of the energy propagation line. .

In order to solve the ninth problem, a second aspect is provided.
Claim 10 dependent on the invention of any one of claims 9 to
The invention is characterized in that the spatial coupler is made of a material having radiation blocking performance, is a pinhole having a pinhole, and covers the energy detection medium from the subject side. Things.

The tenth aspect of the present invention is dependent on any one of the second to ninth aspects.
In addition to being able to solve any of the eighth problems, the pinhole blocks scattered radiation generated in the subject and prevents scattered radiation from being incident on the energy propagation ray detection medium, thereby improving image quality.

In order to solve the tenth problem, the apparatus according to any one of claims 2 to 10 is an apparatus according to any one of claims 2 to 10, wherein an energy transmission line is provided between the radiation source and the subject. And an aligner that forms a porous structure and irradiates a part of the energy propagation line to the subject through the hole.

The eleventh aspect of the present invention is the second aspect of the present invention.
Is dependent on any one of the inventions,
In addition to being able to solve any of the issues 9 through 9,
It has the following effects: That is, the aligner having a porous structure allows the minimum amount of energy transmission lines necessary for tomography to pass through the hole to the subject side, and blocks other unnecessary energy transmission lines from acting on the object. To do. This prevents an increase in the amount of exposure to the subject.

In order to solve the above-mentioned eleventh problem, the invention according to any one of claims 6 to 11 is a device according to claim 12, wherein the external irradiating device includes a thermoelectron as the radiation source. An irradiation container having a radiation transmitting window and containing a cathode for supplying the light is provided, and the container is provided with light reflecting means for reflecting light generated simultaneously with the generation of thermionic electrons at the cathode toward the cathode. It is characterized by that.

The twelfth aspect of the present invention is the sixth aspect of the present invention.
The invention has the following effects in addition to the advantages of the above fifth to ninth aspects. That is, the light reflecting means provided in the irradiation container reflects the light generated simultaneously when the cathode emits thermoelectrons, reflects the light into the irradiation container, and applies a part of the light to the cathode to heat the cathode. In addition, the reddening of the cathode proceeds more to emit more thermoelectrons. Therefore, the generation efficiency of the energy propagation lines such as X-rays can be improved, and the power consumption can be reduced.

According to a twelfth aspect of the present invention, in the apparatus according to the thirteenth aspect, the radiation transmitting window serves as both the radiation source and the light reflecting means. It is characterized by.

Since the invention of claim 13 is dependent on the invention of claim 12, in addition to being able to solve the eleventh problem, the radiation transmitting window of the irradiation container is provided with a radiation source to which thermoelectrons from the cathode are directed. And the light reflecting means, the structure is simple and light can be effectively reflected to the cathode.

In order to solve the thirteenth problem, the invention according to claim 14 is dependent on the invention according to claims 6 to 12,
The external irradiation device includes an irradiation container having a radiation transmission window while accommodating a cathode for supplying thermoelectrons to the radiation source. It is characterized in that a negative potential acceleration electrode facing the cathode is arranged.

The invention of claim 14 is the invention of claims 6 to 12
The invention has the following advantage in addition to the ability to solve any of the fifth to eleventh problems. That is, since the accelerating electrode has the same negative potential as the cathode, an electric field that repels thermoelectrons is formed between these two electrodes. By this electric field, thermoelectrons emitted from the cathode toward the accelerating electrode bounce back to the radiation source side, and the thermoelectrons emitted toward the radiation source side can be accelerated. In this way, a large amount of thermoelectrons can be made to collide with the radiation source at a higher speed to generate energy propagation rays such as X-rays. Therefore, the efficiency of generating energy propagation rays such as X-rays can be improved and power consumption can be reduced. Can be reduced.

[0059]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

The first embodiment is an example realized as a medical tomography apparatus. In FIG. 1, reference numeral 21 denotes a bed on which a human body 22 as a subject is placed in a posture such as a supine position. I will The couch 21 is formed of a material through which energy transmission lines described below can pass. The human body 22 is arranged on the bed 21 without moving in the first embodiment.

As described above, to hold the human body 22 as a subject so as not to move in the tomography, the tension applied to the human body 22 with the imaging operation as in the case where the human body 22 is moved in the tomography described later. It is excellent in that it can reduce the burden of feeling and fear.

Since the human body 22 does not itself emit energy propagation rays, it is recognized in this embodiment as an external irradiation type subject. However, when the gradient magnetic field generator described below is used as a storage type energy detection medium described later, the human body 22 itself receives changes in the human body and propagates changes in the human body to the outside with the assistance of external energy. In this case, the subject itself can be recognized as a spontaneous subject that emits an energy propagation line by itself.

In FIG. 1, reference numeral 23 denotes an external irradiation device which is disposed above the bed 11 so as not to move, for example, by being supported by a fixed structure (not shown). Is what you do. X-rays, gamma rays, beta rays, and other radiation,
Although a light beam, an electromagnetic wave, a line of magnetic force, or the like can be used, in the first embodiment, radiation, particularly X-rays, is used, so that the external irradiation device 23 can be called an X-ray irradiation device or an X-ray tube. .

The external irradiation device 23 is composed of an assembly in which a plurality of irradiation device elements 23a are arranged in the body axis direction of the subject 21 and connected to each other. Each irradiation device element 23a includes an irradiation container 24, a cathode 25, a radiation source 26 as an anode, and an accelerating electrode 27 as shown in FIG.

The irradiation container 24 is a vacuum container formed with a pressure difference of about 1 atm between the inside and the outside. In the first embodiment, the irradiation container 24 is formed of a transparent material such as light-transmitting glass. It may be formed of a light-impermeable material.
The irradiation container 24 has a radiation transmitting window on one surface, for example, a lower wall. In the first embodiment, the radiation source 26 is also used as a radiation transmitting window by arranging the radiation source 26 while closing the window. Such dual-purpose adoption
This is advantageous in that the number of parts can be reduced and the structure and assembly of the irradiation device element 23a and thus the external irradiation device 23 can be simplified.

In the irradiation container 24, light reflecting means 28, 29 for reflecting light (including visible light, ultraviolet light, and infrared light) generated simultaneously with generation of thermoelectrons in the cathode 25 toward the cathode 25. Is provided. Each of these means is formed of a light reflecting material. That is, the one light reflecting means 28 is provided so as to cover the outer surface of the irradiation container 24 except for the bottom wall. As the light reflecting material constituting the light reflecting means 28, a material having a high light reflectance, having less deterioration such as oxidation, chipping, and rust, and having a small decrease in the reflectance, for example, aluminum can be used. The light reflecting material can be applied by forming a dense film on the outer surface of the irradiation container 24 by a method such as plating, vapor deposition, or thermal spraying. In the first embodiment, an aluminum vapor-deposited film is provided as the light reflecting means 28, and this employment is advantageous in that light in a wavelength range from visible light to infrared light can be reflected.

When the irradiation container 24 is light-impermeable, a light reflecting means such as an aluminum vapor-deposited film may be provided on the inner surface of the container 24. Also, the light reflecting means 28
May be provided only on the upper wall located on the back side surface (the upper side in FIG. 3) of the cathode 25, or may be provided only on the other part, but almost entirely as in the first embodiment. In the case where it is provided, it is excellent in that light can be incident on the cathode 25 as a result of light reflection a plurality of times.

A protective layer 30 is provided on the surface of the light reflecting means 28. This protective layer 30 is provided in order to further reduce a decrease in the reflectance of the light reflecting means 28 due to aging such as oxidation or deterioration of the irradiation container 24 from the outside.
It can be formed by coating a protective material such as silicon dioxide by vapor deposition or the like. As the protective material, magnesium fluoride or the like can be used in addition to silicon dioxide.

The other light reflecting means 29 is provided on the surface of the radiation source 26 which also serves as the anode and the radiation transmitting window, facing the cathode 25. This means 29 is the one light reflecting means 2
8 has the same structure as that of FIG. 8, and is formed of an aluminum vapor-deposited film or the like, and a protective layer 31 made of a silicon dioxide vapor-deposited film or the like is adhered on the surface thereof. The protective layer 31 is effective for preventing deterioration of the aluminum vapor-deposited film due to surface roughness and the like caused by the collision of the thermoelectron stream with the aluminum vapor-deposited film constituting the light reflecting means 29, and maintaining reflection characteristics. . Of course, the light reflecting means 29 and the protective layer 3
1 may be formed of another material described for the one light reflecting means 28 and the protective layer 30 and may be provided by the forming method already described.

The cathode 25 is disposed substantially at the center of the irradiation container 23 in the thickness direction, and power is supplied to the cathode 25 from the cathode power supply circuit 32. As a result, the cathode 25 glows red, and simultaneously emits thermoelectrons and light to its surroundings.

A radiation source 26 which also functions as an anode and a radiation transmitting window.
Is a metal whose source number is as large as 0 or more because it is necessary to generate radiation, for example, X-rays, has high heat resistance, high mechanical strength in a thin plate, and has good workability, for example, a thin plate of molybdenum or tantalum. (20 microns or less). An inner surface of the radiation source 26 on the inner side of the irradiation container 24 is formed as a light reflecting surface 26a.

As the light reflecting surface 26a, an electropolished surface obtained by subjecting the surface 26a to electropolishing can be used.
A mirror surface of a plated film or a deposited film formed by performing silver plating, gold plating, rhodium plating, aluminum deposition, multilayer film deposition, or the like can be employed. When the electropolished surface is adopted, the reflectance can be improved by 10 to 20% as compared with the untreated case where the electropolishing surface is not used. When the boundary surface is adopted, the reflectance is at least 20% or more than the untreated case. Can be improved. In the first embodiment, the light reflection surface 26a is a metal mirror surface formed of a gold or rhodium plating film or a vapor deposition film. According to this embodiment, the light reflection surface 26a is chemically stable and hardly deteriorates.
In addition, they are excellent in that they have good heat resistance. This surface 26
The light reflecting means 29 is adhered to the surface of a.

A high voltage is applied to the radiation source 26 from a high voltage generating circuit, and a potential difference V1 necessary for accelerating thermoelectrons is provided between the radiation source 26 and the cathode 25. This potential V1
The thermoelectrons emitted from the cathode 25 in the direction of the radiation source 26 by the electric field formed between the radiation source 26 and the cathode 25 by the
And is collided with the radiation source 26 (accelerated). The outer surface of the radiation source 26 which is in contact with the outside is covered with an outer protective layer 26b for preventing aging of the surface due to rust or the like. This layer 26b is thin enough to not prevent transmission of X-rays as radiation generated in the radiation source 26, has a thickness of about 2 microns, and is preferably formed of a gold or rhodium plating film or a vapor deposition film.

The accelerating electrode 27 is disposed in the radiation container 24 with the cathode 25 interposed therebetween, opposite to the radiation source 26 and opposed to the cathode 25. The surface of the cathode 25 on the cathode 25 side has a light reflectance. It has a good metal mirror surface. That is, as the acceleration electrode 27, a stainless plate or the like formed by applying an aluminum film to the surface on the cathode 25 side by plating or vapor deposition can be used.

The acceleration electrode 27 has a power supply circuit 34 for the acceleration electrode.
, And a potential difference V2 necessary for accelerating the thermoelectrons from behind is provided between the cathode and the cathode 25. The electrode 27 is maintained at the same negative potential as the negative potential of the cathode 26 and at a lower negative potential than the cathode to form a repulsive electric field between the electrodes 25 and 27. I have.

Accordingly, the thermoelectrons emitted from the cathode 25 toward the acceleration electrode 27 can be reflected and bounced back to the radiation source 26 side, and the bounced thermoelectrons can be accelerated by the repulsive electric field. That is, thermoelectrons can be accelerated by the total voltage of the potential differences V1 and V2. Thereby, a large number of thermoelectrons can be made to collide with the radiation source 26 at a higher speed.

Since the power consumption of the cathode power supply circuit 32 in the irradiation device element 23a is constant, the power consumption of the high voltage generation circuit 33 is the product of the current I flowing through the circuit 33 and the potential difference V1, Further, since the voltage for accelerating the thermoelectrons is equal, the potential difference V1 is equal to V2, and the accelerating electrode 27 has a more negative potential than the cathode 25, so that almost no current flows through this electrode 27. . Therefore, it can be considered that the power consumption of the acceleration electrode power supply circuit 34 is almost nil. Therefore, the acceleration electrode 2
7, the potential difference V1 is smaller than the potential difference between the high-voltage generation circuit and the cathode 25 necessary for accelerating thermoelectrons as in the first embodiment. Low power consumption.

According to the configuration of the irradiation device element 23a,
By the light reflecting means 28 and 29 provided in the irradiation container 24,
The light generated from the cathode 25 is retained in the reflection container 24,
Since a part of the cathode 25 is applied to the cathode to reheat the cathode 25, the cathode can be further heated to red and the amount of thermoelectrons emitted from the cathode 25 can be increased. Therefore, the generation efficiency of energy transmission lines such as X-rays to be described later can be improved, and a large amount of power is not required for realizing it. it can. In addition, the provision of the accelerating electrode 27 accelerates the flow of thermionic electrons toward the radiation source 26 and increases the collision energy with the radiation source 26. In this respect, the efficiency of generation of energy propagation lines such as X-rays also increases. Can be improved. Therefore, power consumption can be reduced if the generation efficiency is the same.

The radiation source 26 generates X-rays as energy transmission lines from the entire radiation source 26, and has a shape other than the zero-dimensional shape, that is, a one-dimensional shape (FIG. 4A). In addition, it refers to a linear shape having a certain thickness instead of a line having no geometric thickness.), A two-dimensional (planar) shape as shown in FIG.
A three-dimensional shape, particularly a curved shape as shown in (C) is used. The first embodiment shows a case where a two-dimensional radiation source 26 is employed. The thermoelectrons are accelerated and collide with the entire inner surface of the radiation source 26 located inside the irradiation container 24, and X-rays are generated from the entire two-dimensional radiation source 26 by the collision energy of the thermoelectrons. The radiation passes through the radiation source 26 itself and the outer protective layer 26b and is emitted to the outside of the irradiation container 24.

The radiation source 26 intersects at right angles with the body axis of the human body 22 and extends in the front and back directions on the drawing of FIG. The radiation sources 26 of the adjacent irradiation device elements 23a are arranged in the body axis direction close to each other as if they are continuous, forming a single plate-shaped radiation source assembly. The boundary portion between the adjacent radiation sources 26 in this assembly does not emit X-rays, but even so, it can be practically ignored in tomography by combination with a storage type energy detection element described later. By the above-mentioned aggregate, a radiation angle from the whole can be secured large enough to obtain the sharpness required for the tomographic image, and the total radiation angle may be 50 degrees or more in order to obtain a clear tomographic image.

In FIG. 1, reference numeral 41 denotes a moving device, which comprises an XY table 42 and a frame 43 supported thereon. The XY table 42 includes an X table that reciprocates the frame 43 in the body axis direction of the human body 22 and a width direction that intersects the frame 43 at right angles to the body axis (the front and back sides of the drawing of FIG. 1). A reciprocating Y table. At least one of these tables is used. In the first embodiment, an example is shown in which only the X table is used.
May be capable of reciprocating in any direction without the table.

A flat plate-like holder plate 44 protruding from, for example, the lower surface of the bed 21 is attached to the frame 43. A spatial coupler 45 and a storage-type energy detecting medium 46 disposed in close proximity to the spatial coupler 45 are fixed to the holder plate 44, respectively. It is sufficient that at least one pair is formed by the spatial coupler 45 and the energy detection medium 46. In the first embodiment, a plurality of pairs, for example, three pairs are arranged in the body axis direction. Are also arranged in the width direction.

The spatial coupler 45 is a pinhole, an optical lens through which X-rays can be transmitted, a gradient magnetic field generator in each magnetic resonance tomography apparatus, and the like. In the first embodiment, a plate having a pinhole hole is used. The pinhole is adopted.
The portion other than the pinhole is made of a material having a property of not transmitting X-rays, and covers the energy detection medium 46 from the subject 22 side. Thereby, it is possible to prevent the scattered radiation generated due to the transmission of radiation to the human body 22 from being incident on the energy detection medium 46, to prevent the blurred difference of the tomographic image caused by the scattered radiation, and to improve the image quality. ing.

The spatial coupler 45 inverts the direction of the image by 180 degrees between the coordinate points on the specific tomographic plane to be obtained by the human body 22 and the corresponding coordinate points on the detection medium 46, and makes a one-to-one correspondence.
Is an object corresponding to. In other words, X-rays that pass through the human body 22 and enter are converged at the pinhole, and diverge toward the detection medium 46 from the pinhole as a base point. The angle of convergence / divergence is set to 50 degrees or more depending on the relationship with the total radiation angle of the external irradiation device 23.

According to the configuration in which the pinhole is employed for the spatial coupler 45, the structure is extremely simple, lightweight, small, and easy to produce. Further, the spatial resolution of the spatial coupler 46 affects the sharpness of the tomographic image, and the resolution of the spatial coupler 46 can be proportionately improved as the pinhole hole diameter is reduced. Since it is easy to reduce the diameter of the pinhole to about 0.1 mm to 0.001 mm by an etching technique or the like, the use of the pinhole is also excellent in this regard. For comparison, the conventional zero-dimensional anode dimension equivalent to a spatial coupler is currently limited to a minimum of about 0.5 mm at present.

The storage type energy detecting medium 46 does not passively erase or actively transfer the trace of the energy transmitting line, which propagates in a space in a substantially linear shape, acting on the medium 46. Traces are added as long as the traces are accumulated. The medium in which traces are added and accumulated here may be the medium itself,
It may be a semiconductor IC or a computer linked to this medium. The medium 46 is disposed on the opposite side of the human body 22 so as to be opposed to the human body 22 with a pinhole-made spatial coupler 45 paired therewith. This installation is performed by the external irradiation device 23.
The distance may be less than or equal to the vertical distance between the space coupler 45 and desirably less than half of the distance. However, the closer the medium 46 is placed to the space coupler 45, the smaller the shape of the medium 46 becomes. It is excellent in that it can be used.

As the energy detection medium 46, an X-ray film, an area type CCD image sensor, a photostimulable type imaging plate, or the like can be used. In the first embodiment, an area type CCD image sensor is employed. According to this employment, the sensor 46 itself does not need to be physically moved only by apparently moving the pixel column electronically in order to accumulate the X-ray which is the energy propagation line, and is extremely small in size. Since the scanning speed for moving the pixel array is high, it is excellent in that tomographic imaging can be processed in real time.

FIG. 5 shows an area type CCD image sensor 46.
1 schematically shows the structure of the photosensitive section. As shown in this figure, the pixels of the photosensitive portion are arranged vertically and horizontally and arranged in a grid, and the M column in FIG. 5 has a total number of pixels of about 800 pixels and the N column of about 500 pixels. Thus, each pixel generates an electric charge proportional to the incident intensity of an energy transmission line such as an X-ray incident thereon. The sensor 46 is supplied with power from a sensor power supply circuit 47 as shown in FIG.
The electric charges generated in the pixels are electronically moved without being physically moved by the sensor 46, and are stored and read out.

FIG. 5 (A) to FIG.
This will be described with reference to (C). In FIG. 5A, M row is 3
Assuming that X-rays are incident on a pixel at an address having three rows and three N columns, and charges E1 (indicated by black circles) are generated in proportion to the incident intensity, scanning of the sensor drive circuit 48 causes M rows to become three.
The electric charge E1 is transferred to an address having four rows and N columns, and an electric charge E2 proportional to the incident intensity of the X-ray incident on this address is accumulated. That is, the charge E at the transfer address
3 is the sum of E1 and E2. Next, the charge E3 is transferred to an address where M rows are 3 rows and N columns are 5 columns by scanning of the sensor drive circuit 48, and charges E4 proportional to the incident intensity of the X-rays incident on this address are accumulated. You. That is, the charge E5 at the transfer address is the sum of E3 and E4. Thereafter, similarly, the sensor 46 is scanned, and the electric charges are electronically moved to the last N columns, and are sequentially read therefrom. Thus, the storage type and area type CCD
The sensor 46 is capable of accumulating charge and moving.
In this movement, the movement of the pixel column storing the electric charge is performed by the scanning operation of the sensor driving circuit 48 so that the relative position with respect to the tomographic plane of the human body is not changed.

In the three sets of the spatial coupler 45 and the energy detecting medium 46 arranged in the width direction orthogonal to the body axis of the human body 22, each area type CCD constituting each medium 46
The scanning speed of each pixel row of the image sensor is different. Incidentally, the sensor 46 in the middle in FIG.
The scanning speed of the sensor 46 on the right side is faster than the scanning speed of, and the scanning speed of the sensor 46 on the left side is the slowest.

By the way, the tomographic plane 49 to be obtained in the human body 22 corresponds to the first to third lines indicated by dotted lines in FIG.
, The relative moving speed of these tomographic planes 49a to 49c with respect to each CCD image sensor 46 is the same as that of the tomographic planes 49a to 49c about the spatial coupler 45. If you look at
As shown in FIG. 2B, the viewing angle β1 with respect to the first tomographic plane 49a at the lowest position is the largest,
Next, the viewing angle β2 with respect to the second tomographic plane 49b at the intermediate height position is the next largest, and the viewing angle β3 with respect to the third tomographic plane 49c at the highest height position is the smallest. In other words, the required pixel area of the CCD image sensor 46 corresponding to each of the viewing areas is the viewing angle β.
1, smaller in the order of β2 and β3. According to this pixel area, the scanning speed of the right sensor 46 is faster than the scanning speed of the middle sensor 46 in FIG. 2A, and the scanning speed of the left sensor 46 in FIG. It's the slowest.

Thus, the apparent moving speed of the first tomographic surface 49a and the scanning speed of the sensor 46 on the right side in FIG.
The first tomographic plane 49a is photographed by the scanning of the sensor 46. Similarly, the apparent moving speed of the second tomographic surface 49b and the scanning speed of the sensor 46 in the middle of FIG. The second tomographic plane 49b is photographed, and the apparent moving speed of the third tomographic plane 49c and the scanning speed of the sensor 46 on the left side in FIG. The third tomographic plane 49c is photographed by the scanning of the sensor 46.

That is, the spatial coupler 45 and the area type C
Storage type energy detection medium 46 made of CD image sensor
By providing a plurality of sets in parallel with each other in the direction of relative movement between the set and the human body 22, and making the scanning speed of the pixel row of the storage type energy detection medium 46 of each set different, A plurality of tomographic images can be taken simultaneously in a single tomographic image. The structure and method of such tomography are based on the spatial couplers 4 arranged in the body axis direction of the human body 22.
5 and a plurality of sets formed by the storage type energy detection medium 46 made of an area type CCD image sensor.

The output of each storage type energy detecting medium 46 made of the area type CCD image sensor is supplied to a tomographic image memory 50 shown in FIG. 1 and is temporarily stored therein. Data on the plurality of tomographic images (tomographic images of the respective tomographic planes 49a to 49c) stored in the memory 50 is supplied to the tomographic image conversion circuit 51, where the tomographic angles differ from the plurality of tomographic images. Generate a converted tomographic image. The different tomographic angles are other than the above because the plurality of tomographic images are parallel to the body axis, and other than that, the vertical angle in the thickness direction of the human body 22 that intersects the body axis at right angles, or is oblique to the body axis. Is the angle of intersection.

The image will be described with reference to FIG. FIG. 10A shows three tomographic images 52 to 5 for the respective tomographic planes 49 a to 49 c stored in the tomographic image memory 50.
4 is an image.

FIG. 10B shows images of converted tomographic images 55a to 55f generated by converting the tomographic images 52 to 54 into tomographic images in a direction perpendicular to the body axis by the tomographic image conversion circuit 51. These converted tomographic images 55a to 55f are
From image data (indicated by... In FIG. 10) forming three tomographic images 52 to 54, at a certain position in the body axis direction,
After the image data in the direction perpendicular to this position is extracted by the first image data extraction unit of the tomographic image conversion circuit 51, the extracted image data is rearranged by the first image reproduction unit of the tomographic image conversion circuit 51. And get it.

FIG. 10C shows images of the converted tomographic images 56a to 56e generated by converting the tomographic images 52 to 54 into tomographic images obliquely intersecting the body axis by the tomographic image conversion circuit 51. I have. These converted tomographic images 56a-
Reference numeral 56e denotes a second part of the tomographic image conversion circuit 51 which converts image data in a direction obliquely intersecting the position at a certain position in the body axis direction from the image data forming the three tomographic images 52 to 54 at the second position. After the image data is extracted by the image data extraction unit, the extracted image data is rearranged by the second image reproduction unit of the tomographic image conversion circuit 51 to obtain the image data.

As described above, since a plurality of tomographic planes parallel to the body axis direction of the human body 22 can be simultaneously imaged, the imaged data can be processed by the tomographic image conversion circuit 51 to obtain images of different tomographic planes. Therefore, the human body 22 does not have to be exposed to X-ray irradiation until all of these tomographic scans are performed, and the tomographic image conversion process for rearranging the image data is processed by an electronic circuit. The processing time until completion is short, and the time until obtaining the converted tomographic image can be reduced.

The converted tomographic image obtained by the tomographic image conversion circuit 51 is supplied to a display 57 for image display, and is also supplied to an image storage device 58 for filing and stored. The first to third tomographic images 52 to 54 as original images stored in the tomographic image memory 50 are also supplied to the display 57 to be displayed as images, and are also supplied to the image storage device 58 for filing and stored. You.

Further, data on a plurality of tomographic images (tomographic images for the respective tomographic planes 49a to 49c) stored in the memory 50 are supplied to a high-pass filter circuit 59 as low frequency component removing means. Here, the imaging data of each tomographic plane is filtered, and low frequency components in the data are removed. The tomographic image from which the low-frequency components have been removed in this way is supplied to the display 57 to be displayed as an image, and is also supplied to the image storage device 58 for filing and stored.

In FIG. 11, X-rays transmitted through the human body 2 are represented by X
1 to X5. To explain with X1 as a representative,
The X-ray of X1 causes the human body 22 to move to E1, E2, E3,.
.., G4, G3, G2, and G1, pass through the human body while being absorbed by these portions. Where F
Is a part that absorbs X-rays very strongly, the influence of the absorption greatly affects adjacent E4 and the like. This is due to the fact that the total radiation angle exists over 50 degrees, and the portion largely absorbed in this way is used as an image signal taken out of the CCD image sensor 46 as a signal h1 in the signal waveform H in FIG. Shown in parts. This low-frequency component is a portion that is not sufficiently averaged as a background of the tomographic image, and if it exists, the tomographic image becomes unclear.

Therefore, in the first embodiment, the high-pass filter circuit 59 is provided, and processing is performed through the photographing data of the tomographic image. Therefore, the low-frequency component h1 in the signal waveform H is removed by this circuit 59 to remove the low-frequency component h1. In addition, since a high-frequency component or the like can be passed, the signal waveform I in FIG. 11 is obtained, whereby the influence of the portion F having a high absorption can be reduced and the tomographic image can be sharpened. it can.

The high-pass filter circuit 59 is constituted by an electronic circuit. In this circuit, a characteristic adjusting section may be provided so that the frequency characteristic can be adjusted by an external input thereto. In such a case, for example, regarding the tomographic image of the lesion of the human body 22, the tomographic image of the tomographic plane near the specific tomographic plane can be included in the tomographic image of the specific tomographic plane, so that the visibility of the tomographic image is improved. it can.

To explain this point, regarding the visibility of the tomographic image, compared to the tomographic image of only the specific tomographic plane, the images of the tomographic planes before and after in the depth direction can be clearly seen in a range where the visibility is not impaired. In some cases, the visual recognition of a tomographic image of a lesion of a human body may be appealed to the viewer's intuition. This is because, when the tomographic image is visually recognized, if the image in the depth direction is slightly included, a three-dimensional effect can be given to the tomographic image. Therefore, the configuration in which the frequency characteristic of the high-pass filter circuit 59 can be adjusted by the characteristic adjustment unit can provide the viewer with a three-dimensional vision, particularly for a tomographic image for medical use, by adjusting the characteristic as needed. This is excellent in that the visibility of the tomographic image can be improved.

The inputs of the three systems to the display 57 and the image storage device 58 are arbitrarily selected and switched by an operation on an operation panel (not shown).

The frame 43 is provided with a shield 60 having a function of blocking energy propagation rays. The shield 60 is disposed between the external irradiation device 23 and the human body 22 so that X-rays unnecessary for the human body 22 are not provided. It is provided to shield unnecessary radiation such as. An aligner 61 is attached to the center of the shield 60, and the human body 22 is irradiated with X-rays or the like through the aligner 61.

The aligner 61 has a porous structure, and irradiates the human body 22 with a part of radiation such as X-rays incident on the aligner 61 through the hole, and blocks other unnecessary radiation. As a result, unnecessary radiation exposure of the human body 22 is reduced.

More specifically, as shown in FIG. 6, the aligner 61 includes two aligner plates 62 arranged in parallel with each other.
63 is formed. The upper and lower aligner plates 62, 63 made of a material for blocking radiation of energy, such as radiation, have a number of holes 62a or 63a arranged in rows and columns at equal pitches P1 or P2, respectively, as shown in FIGS. The hole 62 a of the upper aligner plate 62 is larger than the hole 63 a of the lower aligner plate 63. The two upper and lower aligner plates 62 and 63 have a proportional relationship between the center coordinates of the hole 62a and the center coordinates of the hole 63a when viewed from the pinhole hole of the spatial coupler 45, that is, a relationship of proportional enlargement or proportional reduction. It is arranged as follows. Thereby, radiation such as X-rays incident from the radiation source 26 converges at one point of the pinhole of the spatial coupler 45 as shown by an arrow in FIG. 6 or FIG.

This point of convergence will be described with reference to FIG. That is,
FIG. 9 is a schematic view of a part of FIG. In FIG. 9, assuming that an intersection point between the radiation that goes straight through the holes 62 a and 63 a at the positions A and B and the radiation that goes straight through the holes 62 a and 63 a at the positions D and E is C, Hole 62a,
It proves that the radiation going straight through 63a passes through intersection C. In other words, as described above, the upper aligner plate 62 having the holes 62a at the A, D, and F positions, and the B, E, and G
The lower aligner plate 63 having the holes 63a at the positions is parallel, the hole pitch P1 between the positions A and D and the positions D and F is equal, and the hole pitch P2 between the positions B and E and the positions E and G is equal. Under this condition, assuming that a point at which a straight line connecting the points F and C intersects the lower aligner plate 63 is g, it is proved that the point g coincides with the point at the position G.

In FIG. 9, the triangle CDF is the triangle CEg.
And the triangle CAD is similar to the triangle CBE. Then, the pitch between the points AD and the point DF
Since the pitch between the points BE is equal to the pitch between the points Eg
Equal to the pitch between. Further, as described above, the pitch between the points BE and the pitch between the points EG are also equal. Therefore, the pitch between the points EG, the pitch between the points BE, and the pitch between the points Eg are all equal. Therefore, it can be seen that the point G and the point g match.

As described above, the upper and lower aligner plates 62, 63
Of convergence of a radiation flux such as an X-ray passing through a plurality of spatial couplers 45
Are also distributed in large numbers on the same plane. )
As shown in FIG. 8, the pinholes of the spatial coupler 45 are arranged, and the energy detecting medium 46 is arranged in close proximity to these holes, so that the human body 22 can be exposed to unnecessary radiation without being exposed to unnecessary radiation. Tomography can be performed only by exposing to radiation.

The aligner 61 is provided with a number of holes 62.
The configuration made of two parallel flat plate aligner plates 62 and 63 having a and 63a is excellent in that the production is easy. That is, both aligner plates 62, 62
Can be performed individually, and since the aligner plates 62 and 63 are thin plates,
The hole 62a or 63a may be formed perpendicularly to the plate, and it is not necessary to make a hole diagonally. In the case where holes for passing radiation are formed on one thick aligner plate so as to converge to one point of the pinhole holes as described above, the holes at each position of the aligner plate become oblique and the angle becomes However, the diagonal processing requires a lot of trouble, the production is troublesome, and the cost is high. However, such a point can be solved in the first embodiment. The hole shape of the large number of holes 62a and 63a provided in both aligner plates 62 and 63 is not limited to a circular shape, and a square hole shape such as a square or a hexagon or any other hole shape can be selected. Also, since both aligner plates 62 and 63 are thin plates, they are excellent in that they can be easily processed.

The operation of the direct tomography apparatus having the above configuration will be described. After placing the human body 22 on the bed 21 in a predetermined posture, the external irradiating device 23 starts the irradiating operation, and the aligner together with the detecting means and the shield 60 formed by the space coupler 45 and the energy detecting medium 46 by the driving device 41. 61 is reciprocated at high speed. Power is supplied to the energy detection medium 46 by a sensor power supply circuit 47, and the medium 46 is driven by a sensor drive circuit 48. The movement of the frame 43 by the driving device 41 is, for example, X
-At least one reciprocation is performed by the Y table 42 along the body axis direction, along the width direction of the human body 22, or a combination of both.

Then, X-rays are radiated from the entire large radiation source 26 having a two-dimensional shape of the external irradiation device 23 toward the human body 22 at a radiation angle of 50 degrees or more, and a necessary amount of a part of the radiation is emitted. Is irradiated on the human body 22 through the aligner 61, passes through the human body, and further enters the energy detection medium 46 through the spatial coupler 45.
The tomographic imaging of the tomographic plane to be obtained by the human body 22 is performed twice in one reciprocation of the frame 43.

In this tomography, since the X-rays transmitted through the human body 22 pass through the pinhole of the spatial coupler 45, the X-rays converge in this hole and have the same angle of incidence as the incident angle on the spatial coupler 45 after being converged in this hole. Diverging towards 46. Therefore, the tomographic planes 49a to 49c of the human body 22 to be obtained are projected on the corresponding energy detecting media 46 in the opposite directions, and the scanning direction of the media 46, in other words, the electronic moving direction is , The direction of movement of the human body 22 relative to the energy detection medium 46 is opposite. In this case, the relative moving speed of the tomographic plane of the human body 22 to be determined with respect to the energy detecting medium 46 and the moving speed of the energy detecting medium 46 (in this case, the scanning speed for moving the pixel array) are spatially coupled. Is inversely proportional to the distance to the pinhole hole of the container 45.

Therefore, the product of the relative moving speed T1 of the tomographic plane 49a to be obtained in FIG. 2, the distance S1 between the tomographic plane 49a and the pinhole hole, and the relative The product of the moving speed R1 and the distance S2 between the medium 46 and the pinhole is equal. Similarly, the relative moving speed T2 of the tomographic plane 49b,
The product of the distance S3 between the tomographic plane 49b and the pinhole hole and the relative moving speed R2 of the energy detection medium 46
Is equal to the product of the distance S2 between the medium 46 and the pinhole. Similarly, the relative moving speed T3 of the tomographic plane 49c, the product of the distance S4 between the tomographic plane 49c and the pinhole hole, the relative moving speed R3 of the energy detection medium 46, and Distance S between pinhole hole
It is equal to the product of two. In FIG. 2, T2 · S3 = R2 · S
2, T3 · S4 = R3 · S2. Here, the relation between the relative moving speeds T1, T2, and T3 of the tomographic planes 49a to 49c with respect to the energy detection medium 46 is T1> T2.
> T3, and the tomographic plane 49a of the energy detection medium 46
The relative movement speeds R1, R2, and R3 with respect to .about.49c are R1>R2> R3.

In the tomography, in the first embodiment, three sets of the detecting means are provided in the body axis direction.
Are provided in the width direction of the frame 43, so that each time the frame 43 is reciprocated once by the moving device 41, 3 × 3 × 2 =
Eighteen tomographic images can be taken, and their imaging capabilities are high. Therefore, when the high-speed reciprocation of the frame 43 is set to 10 reciprocations per second, a 180-layer tomographic image can be obtained per second.

In addition, the 3 arranged in the width direction of the human body 22
As described above, since the scanning speeds of the storage type CCD image sensors, which are the respective energy detection media 46, are different from each other, the detection means of the set have three tomographic planes at different positions in the thickness direction of the human body 22. You can shoot at the same time.

After the imaging data (imaging signal) obtained by the tomographic imaging is supplied to the tomographic original image memory 50 and temporarily stored therein, if the tomographic angle conversion processing is unnecessary,
Without passing through the tomographic original image conversion circuit 51, through the bypass filter circuit 59, or without passing through both the circuit 59 and the tomographic original image conversion circuit 51, the image data is supplied to the image storage device 58, filed, and stored. At the same time, an image is formed on the display 57 and displayed. If the tomographic angle conversion processing is required, the tomographic angle conversion processing is performed via the tomographic original image conversion circuit 51, and the processed tomographic angle conversion image is stored in the image storage device 5.
In addition to being supplied to the filing unit 8 for filing and recording and storage, an image is formed on the display 57 and displayed.

In the tomographic angle conversion processing, the angle and the angle are calculated simply by rearranging and interpolating the imaged data forming a plurality of tomographic planes, with almost no complicated and enormous calculation processing as in the CT method. However, different tomographic data can be obtained at high speed. That is, a tomographic image at an arbitrary angle different from the original tomographic image can be obtained in real time. This also enables continuous tomography even if the subject is not a human body 22 but a continuous object. The accuracy or resolution of tomographic planes at different angles obtained by tomographic angle conversion can be easily improved by increasing the number of the detection means and increasing the number of tomographic original images.

FIGS. 12 to 14 show a second embodiment of the present invention. This embodiment has basically the same configuration as that of the first embodiment. Therefore, the same components are denoted by the same reference numerals as those of the first embodiment, and the configuration and operation will be described. Are omitted, and different portions will be described below. This embodiment differs from the first embodiment in that an irradiation container 24 of an external irradiation device 23 and a cathode 2
5 and a radiation source 26 and the like.

That is, in the second embodiment, the external irradiation device 23 is integrally connected to the frame 43 by a connection structure (not shown) and is moved together with the frame 43. Therefore, in this embodiment, the relative speed between the external irradiation device 23 and the detection means is the same, and the relative position between the tomographic plane of the human body 22 to be obtained and the energy detection medium 46 with respect to this tomographic plane is not changed. Then, the tomographic plane can be photographed. In this case, what moves relatively is the charge due to the electronic scanning of the pixel array of the storage type CCD image sensor forming the energy detection medium 46. In the second embodiment, as shown in FIG. 13, the radiation transmitting window of the irradiation container 24 is formed by an aligner 61 fixed to the wall surface of the container 24.

Further, the cathode disposed in the irradiation container 24 does not become reddish due to resistance heating, but a cathode heater 25a made of a heating coil which generates heat by resistance heating, and a cathode body 25b arranged close to the cathode heater 25a. The cathode heater 25a emits red heat and emits thermoelectrons and the like by the heating action of the cathode heater 25a.

The radiation source 26 as an anode disposed in the irradiation container 24 is formed by a radiation source unit in which a plurality of radiation source elements 26a each having a two-dimensional shape or a three-dimensional shape are continuously arranged. This radiation source 26 emits X-rays from the entire radiation source 26 obtained by thermionic electrons from the cathode 25 colliding with the radiation source 26, and the radiation angle is set to 50 degrees or more. As described above, it can be easily made by assembling a plurality of radiation source elements 26a.

It is practically difficult to increase the size of one radiation source element, not a plurality of aggregates, to produce only a single radiation source element, and to obtain a radiation angle of 50 degrees or more that can eliminate blurring of a tomographic image. . Specifically, the radiation source 26 is housed in the vacuum irradiation container 24. If one radiation source 26 has a radiation angle of 50 degrees or more, it is not only difficult to manufacture the radiation source itself but also to perform irradiation. The pressure difference between the inside and the outside of the container 24 must be able to withstand 1 atm.
4 has to be considerably thicker. This is due to the fact that the thickness of the vacuum vessel needs to be increased in proportion to the first to fourth powers of the size, and therefore, it is difficult to manufacture.

However, if formed as an aggregate as in the second embodiment, manufacture is easy, and a radiation angle of an arbitrary size can be created by the number of aggregates.
Further, the irradiation container 24 can be manufactured without having to be so thick. Since the radiation source elements 26a are gathered, X-rays cannot be generated from the joint, but this joint is a small part as a whole, and
As described above, the detection medium 46 for detecting a line is an accumulation type CC.
Since the image sensor is a D image sensor, the effect of the small portion can be eliminated by the charge accumulation action, and the small portion does not cause any practical problem.

Moreover, in the second embodiment, since the radiation source element 26a has a three-dimensional shape having a curved surface structure, the radiation source 26 has a parabolic surface or a part of a spherical surface approximating the parabola. Of the face. In addition, since the processing of the paraboloid is generally difficult and the processing cost is high, forming the radiation source 26 on a part of the spherical surface approximating the paraboloid is excellent in that the processing is easy and the manufacturing can be performed at low cost. ing.

The cathode 2 covers the entire curved inner surface of the radiation source 26.
Since the thermoelectrons emitted in parallel from 5 collide, the radiation source 26 generates X-rays from the whole and emits them toward the aligner 61. Then, as shown in FIG. 13 and the like, the pinhole hole of the spatial coupler 45 is arranged at the focal position of the paraboloid of the radiation source 26 or a part of the spherical surface approximated thereto. Radiation such as X-rays generated by the collision of thermoelectrons has the highest radiant energy in the direction of specular reflection, unlike the case where light is specularly reflected by a mirror surface, but it is at an angle around the point of collision of thermoelectrons. Emitted in all directions over the area. Therefore, the radiation to each of these directions is transmitted through the human body 22 and then converged on the pinholes of the spatial couplers 45 to be incident on the storage type CCD image sensors 46 individually arranged close to the couplers 45. In this way, it is possible to perform tomography on the tomographic plane of the human body 22 to be obtained. The configuration other than the points described above is the same as that of the first embodiment, including the points not shown.

The tomographic imaging apparatus according to the second embodiment has
The tomography can be performed by the same operation as the first embodiment, and the first to sixth objects, ninth to first objects of the present invention can be performed.
All three problems can be solved. In addition, since the X-rays generated by the radiation source 26 can be collected and converged by the curved surface structure of the radiation source 26 as described above, the energy of the storage type CCD image sensor 46 is higher than that of the first embodiment. X-rays can be applied. Therefore, CC
Since the value of the electric charge generated in the pixel of the D image sensor 46 can be increased, the sensor 46 can be driven (scanned) at a higher speed, so that the tomographic imaging can be performed in a shorter time and the captured tomographic image can be obtained. It is excellent in that the image can be sharpened.

Note that in the second embodiment, the first
The external irradiation device 23 may be fixed similarly to the embodiment. In this case, the radiation transmitting window of the irradiation container 24 is formed of an aluminum thin plate, and the aligner 61 is attached to the shield 60 of the frame 43 so that the radiation source 26 and the human body 2
2 may be arranged.

FIG. 15 shows a third embodiment of the present invention. This embodiment has basically the same configuration as that of the first embodiment. Therefore, the same components are denoted by the same reference numerals as those of the first embodiment, and the configuration and operation will be described. Are omitted, and different portions will be described below.
The difference between this embodiment and the first embodiment is the arrangement of the irradiation container 24 of the external irradiation device 23 and the detection means.

That is, in the third embodiment, the external irradiation device 23 is attached to the holder plate 44, and the human body 22 positioned above the holder plate 44 is X-positioned from below.
It is provided to irradiate an energy propagation line such as a line. A human body 22 and an external irradiation device 23
The shield 60 having the aligner 61 is disposed.

The upper part of the frame 43 is the human body 2 on the bed 21.
2, and a detecting means is provided at an arbitrary angle in that portion. The detection means, needless to say,
A spatial coupler 45 such as a pinhole and a storage-type energy detection medium 56 such as a storage-type CCD image sensor disposed close to and opposed to the space coupler 45 are provided.
6 is installed in a posture perpendicular to the body axis. Configurations other than those described above are the same as those of the first embodiment, including a configuration not shown.

The tomography apparatus according to the third embodiment has
The tomography can be performed by the same operation as the first embodiment, and the first to sixth objects, ninth to first objects of the present invention can be performed.
All three problems can be solved. Moreover, with the arrangement of the storage type energy detection medium 56 as described above, it is possible to simultaneously image a plurality of tomographic planes in a direction perpendicular to, but not parallel to, the body axis. In this case, a conventional helical scan X-ray C
As in T, it is not necessary to continuously rotate the radiation source 26 around the human body, and tomography can be performed on a plurality of tomographic planes in a stationary state, so that imaging time is short and high-speed tomography is possible. It is excellent in that. In the second embodiment, the original tomographic image conversion circuit 51 converts a tomographic image parallel or oblique to the body axis from a plurality of tomographic images perpendicular to the body axis. .

In the second embodiment, FIG.
5, the storage-type energy detecting medium and the spatial coupler that forms a pair with the storage-type energy detecting medium as shown by a two-dot chain line are parallel or oblique with respect to the body axis, or in an oblique posture in a direction opposite to the oblique posture. The support may be supported by 43 so that tomographic imaging of a multi-layer tomographic plane can be performed along a direction parallel or oblique to the body axis. Thereby, it is possible to configure a tomographic apparatus in which the posture of the detection means is changed and arranged in an appropriate direction according to an organ or the like to be diagnosed.

Further, in order to improve the image quality of the tomographic image, the first external irradiation device 2 disposed above the human body 22
3 and a first detecting means having a storage type energy detecting medium which is disposed under the human body 22 in a pair with the oblique or perpendicular posture with respect to the body axis, and the human body 2
And a second external irradiating device 23 disposed below the second external irradiating device 23 and a storage type energy detecting medium disposed above the human body 22 in a pair with the second external irradiating device 23 and having a posture oblique or perpendicular to the body axis. And the imaging signals obtained by these two systems of tomographic imaging units are synthesized, and therefore, equivalently, the effective convergence and divergence angles of the spatial coupler 45 are compared with those of one system of tomographic imaging systems. In this case, the image quality may be substantially doubled to further improve the image quality.

Further, the present invention is not limited to the above embodiments. The technology described below can be applied to each of the above embodiments, and can also be applied to the following embodiments.

For example, the relative relationship among the subject 22, the radiation source 26, the spatial coupler 45, and the storage-type energy detecting medium 46 includes the embodiment already described, but FIG. A) to (C).

FIG. 16A shows that only the subject 22 is physically moving and the rest is stationary, but the pixel row of the area type CCD image sensor forming the storage type energy detecting medium 46 is Scanning is performed so as to move in the opposite direction to the subject 22.

FIG. 16B shows that the subject 22 is stationary and the rest is physically moving, and the pixel row of the area type CCD image sensor forming the storage type energy detecting medium 46 is the subject 22. Are scanned so as to move in the opposite direction relative to.

FIG. 16C shows that only the spatial coupler 45 is physically moving, and the rest is all stationary, but the area type CC forming the storage type energy detecting medium 46 is shown.
The pixel row of the D image sensor is scanned so as to move in a direction opposite to the subject 22. In this case, the scanning speed (moving speed) of the pixel row and the moving speed of the spatial coupler 45 are made equal. In other words, when the subject 22 and the sensor 46 stand still and the spatial coupler 45 moves, the spatial coupler 4
5 and the moving speed of the pixel array (charge) of the sensor 46 are set to zero, and the relative speed difference is eliminated.

If the pinhole of the spatial coupler 45 is made smaller, the spatial resolution can be improved. However, X-rays which enter the storage type and area type CCD image sensor 46 through this hole can be improved. However, the amount of energy propagation lines decreases, which is a factor that impairs high-speed imaging. To solve this problem, the configuration shown in FIG. 17A or 17B can be adopted. In FIG. 17A, a radiation converter 61 such as a fluorescent plate that converts radiation into light, a photoelectric converter 62 that is bonded to the back surface and converts light into electricity, A photomultiplier tube (image intensifier) 63 and an optical lens 6 provided opposite the output end.
4 is provided. The radiation converter 61 is disposed on the side of the spatial coupler so as to receive the radiation incident through the pinhole,
Further, an optical lens 64 capable of transmitting radiation is provided to face the sensor 46.

In this way, even if the radiation passing through the spatial coupler 45 is weak, the visible light is amplified by the photomultiplier 63 and the sensor 4 is amplified.
6, the light having a high intensity is finally incident on the sensor 46 to stabilize the imaging signal and make the tomographic image clear. Further, by adopting such an incident system, since there is no direct incidence of radiation on the CCD image sensor 46, deterioration of the sensor 46 due to radiation can be reduced, and it is weaker by the amplification factor of the photomultiplier 63. Since a necessary and sufficient tomographic image can be obtained with the radiation intensity, the radiation exposure amount of the human body 22 can be reduced and the safety can be increased. The optical system may be provided for one set of detecting means in correspondence with each other, or one optical system may be provided in common for all the optical systems.

In this optical system, optical distortion is generated in the radiation conversion tube 61 as shown by reference numeral a in the figure, but by using an optical lens 64 having a characteristic b to correct the optical distortion, Is corrected so as to be very small (refer to the reference numeral c in the figure), and the light can be made to enter above the tomographic plane of the sensor 46, and an appropriate tomographic image can be obtained.

FIG. 17 (B) shows a radiation converter 61 such as a fluorescent plate for converting radiation incident through the pinhole into light, and a photoelectric converter adhered to the back surface and converting light into electricity. A converter 62 and a photomultiplier tube (image intensifier) provided continuously on the back surface of the converter 62
63, an electro-optical converter 65 provided at the output end for converting electrons into light, and an optical fiber bundle 66 connecting the converter 65 and the sensor 64 are provided.

Even in this case, even if the radiation passing through the spatial coupler 45 is weak due to the visible light amplifying action of the photomultiplier 63, it is amplified and the sensor 4
6, the light having a high intensity is finally incident on the sensor 46 to stabilize the imaging signal and make the tomographic image clear. Further, by adopting such an incident system, since there is no direct incidence of radiation on the CCD image sensor 46, deterioration of the sensor 46 due to radiation can be reduced, and it is weaker by the amplification factor of the photomultiplier 63. Since a necessary and sufficient tomographic image can be obtained with the radiation intensity, the radiation exposure amount of the human body 22 can be reduced and the safety can be increased. The optical system may be provided for one set of detecting means in correspondence with each other, or one optical system may be provided in common for all the optical systems.

In the present invention, as shown in FIG. 17C, a radiation converter 61 such as a fluorescent plate for converting radiation incident through the pinhole into light, Optical fiber bundle 6 for connecting to the sensor 64
6 to eliminate direct incidence of radiation on the CCD image sensor 46 by this optical system.
May be reduced by radiation. Also in this case, the optical system may be provided so as to correspond to one set of detection means, or may be provided in common for all the optical systems.

When simultaneously photographing a plurality of tomographic planes having different height positions, the tomographic planes to be photographed may not be parallel to each other. That is, the CCD image sensor 4
By scanning with the sensor drive circuit 48 so that the scanning speed of the sample No. 6 is not constant and there is a speed difference, one of the sensors 46 as shown in FIG. The oblique tomographic plane 22E connecting the points A2 and B1 of the subject 22 is straightened by another sensor 46 adjacent to the sensor 46.
F may be photographed.

Further, as shown in FIGS. 19A and 19B, the relationship between the cathode 25 and the accelerating electrode 27 in the external irradiation device is shown in FIG. While having a curved surface structure such as a cylindrical shape,
The cathode 25 may be arranged at the focal position. In this case, the light emitted to the accelerating electrode 27 side can be converged on the cathode and reflected as indicated by the arrow in FIG. 2B, so that the cathode can be further heated to red light. It is excellent in that it can be done.

FIGS. 20 to 22 show a fourth embodiment of the present invention. This embodiment is basically similar to the first embodiment.
Since the configuration is the same as that of the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description of the configuration and operation will be omitted, and different portions will be described below.

The specimen 22 in this embodiment is a steel slab in a high temperature and red hot state produced by a continuous casting machine (typically a thickness of about 150 mm, a width of about 1 to 3 m, and a total length of about several hundred m. In order to detect a defect of the slab 22, for example, a crack near the surface layer or a foreign substance 22p mixed therein, the tomographic apparatus according to the fourth embodiment is used. Is used.

In this imaging apparatus, since the subject is a glowing object that emits energy propagation rays by itself, the external irradiating device 23 does not need to be particularly used. However, when it is used as in this embodiment, The following measures may be taken for thermal protection from the steel slab 22. In other words, on the front surface of the irradiation container 24 on the steel slab 22 side, a heat-insulating plate 71 having a heat resistance and made of a material that can transmit X-rays as energy transmission lines is provided as a radiation transmission window. A cooling water passage 72 is provided in the irradiation container 23, and the cooling water is forcibly circulated through the cooling water conduits 73 and 74 through a cooling water forced circulation pump (not shown) in the water passage 72, so that the external irradiation device 2
3 is suppressed.

Further, as shown in FIG. 20, the set of the detecting means formed by the accumulation type area type CCD image sensor 46 and the spatial coupler 45 having the pinhole is at least in the moving direction of the steel slab 22. Three sets are provided for tomography of the upper, middle and lower layers of the steel slab 22, and several sets to several tens of sets (five sets in the representative of FIG. 21) are arranged in the width direction of the steel slab 22. And implement it.

Further, a tomographic image abnormality inspection circuit 75 is connected to the tomographic original pixel memory 50 to which the output of the detection means is supplied, and the high-pass filter circuit 59 interposed therebetween may be omitted. The inspection circuit 75 is a comparator, and a threshold value set as a reference thereof (FIG. 22)
Is compared with an input output signal from the sensor 46 to judge pass / fail. That is, if there is a defect such as a crack in the steel slab 22, the X-ray transmittance of that portion is improved, and the output signal 77 from the sensor 46 for that portion increases as shown in FIG. And this output signal 77
Is greater than the threshold value 76, the inspection circuit 75
Outputs an abnormality detection signal.

When an abnormality is detected by the inspection circuit 75, the image data of the tomographic image is transferred to the abnormal part image memory 77, temporarily stored, displayed on the display 57, and visually recognized by the operator. Is done. Each time the abnormality is detected, the signal is supplied to an alarm device 78 to perform an alarm operation, and is also supplied to a recording device 79, so that a tomographic image of a tomographic plane including each abnormality is obtained. Be recorded.

In this embodiment, both the external irradiation device 23 and the inspection means are fixed, and the aligner and the moving device are omitted. The configuration other than the above is the same as or similar to the first embodiment, including the parts not shown. Therefore, the tomography apparatus according to the fourth embodiment can perform tomography by the same operation as that of the first embodiment, and can solve any of the problems of the present invention. In the fourth embodiment, if the number of the detecting means used is increased, the number of inspection layers can be further increased to increase the inspection accuracy, and the tomographic apparatus shown in FIGS. 20 and 21 can be used. By disposing a plurality of steel slabs 22 in the moving direction of the steel slab 22, the number of inspection layers may be increased to increase the inspection accuracy.

FIGS. 23 and 24 show a fifth embodiment of the present invention. This embodiment has basically the same configuration as that of the first embodiment. Therefore, the same components are denoted by the same reference numerals as those of the first embodiment, and the configuration and operation of the first embodiment are omitted. The description will be omitted, and different portions will be described below.

The subject 22 in this embodiment is a die-cast casting, which is an industrial product, which is molded in the same mold, has the same dimensions and shape, and is used for inspection at regular intervals after the molding. And the like. The tomographic apparatus according to the fifth embodiment is used to detect a defect of the casting 22 such as a chip or an inside.

At the exit side of the conveyor line 81, there is provided a gate 83 which is opened and closed via a gate driving device 82 based on the inspection result by the tomography apparatus. While the gate 83 is closed, the casting 22 determined to be non-defective passes through, and when the gate 83 is opened, the casting 22 determined to be defective is conveyed from the opened position. It is discharged from the line 81.

A tomographic apparatus is provided so as to sandwich the conveyor line 81 from above and below. In this device, the external irradiation device 23 and the inspection means are both fixed,
Also, the aligner and the moving device are omitted. In this embodiment, for example, two storage-type and area-type CCD image sensors 46 are used in accordance with the number of tomographic planes that need to be inspected.

The output of the first sensor 46 is supplied to a first tomographic image memory 84 and a reference image file 85. Similarly, the output of the second sensor 46 is supplied to the second tomographic image memory 8
6 and the file 85. The two tomographic image memories 84 and 86 temporarily store captured images of different tomographic planes. In the reference image file 85, a tomographic image of a predetermined tomographic surface of the casting product 22 as a non-defective product is recorded in advance as a reference image. This recording is performed by capturing the tomographic image displayed on the display 57 as a reference image in accordance with a capturing operation by the operator when the operator determines that the tomographic image is non-defective.

The first and second reference image memories 87 and 88 are connected to the reference image file 85, and the reference images recorded in the reference image file are read and recorded in these memories. Then, a first tomographic image memory 84 and a first reference image memory 87 provided corresponding to the one sensor 46 are provided.
Means the second tomographic image memory 8 connected to the first image comparing circuit 89 and similarly provided for the other sensor 46.
6 and the second reference image memory 88 are connected to the image comparison circuit 90.

The comparison circuits 89 and 90 compare the tomographic image (inspection image) supplied from the first or second tomographic image memory 84 or 86 with the reference image taken in by a method such as pattern matching. And a match / mismatch is detected. If the comparison results match, it is determined to be a non-defective product having no abnormality, and if the comparison results do not match, it is determined to be a defective product having abnormality.

When an abnormality is determined in these comparison circuits 89 and 90, the tomographic image concerned is displayed as an image on the display 57. At the same time, an abnormal signal is supplied to the alarm device 91 to operate it. The alarm device 91 operates the gate drive device 82 in response to the input of the abnormal signal to open the gate 83 held in the closed position for a certain period of time. The configuration other than the above is the same as or similar to that of the first embodiment, including portions not shown.

Therefore, the tomography apparatus of the fifth embodiment can perform tomography by the same operation as that of the first embodiment, and can solve all the problems of the present invention.

[0166]

The present invention is embodied in the form described above and has the following effects.

According to the method and apparatus according to the first and second aspects of the present invention, the energy detection medium for detecting the image of the tomographic plane can be reduced, and the photographing time can be reduced.

According to the third aspect of the invention, which is dependent on the second aspect, in addition to the effect of the second aspect, the structure can be simplified and a burden is imposed when the subject is a human. Can be reduced.

A fourth aspect of the present invention is dependent on the second or third aspect of the invention.
According to the invention device described in (1), in addition to the effect of the invention according to claim 2 or 3, the photographing data can be extracted in real time.

According to the fifth aspect of the invention, which is dependent on the fourth aspect of the invention, in addition to the effect of the fourth aspect of the invention,
A plurality of tomographic images can be taken simultaneously in a single tomographic image.

A sixth aspect of the present invention is dependent on the fourth or fifth aspect of the present invention.
According to the invention device described in (1), in addition to the effect of the invention of claim 4 or 5, the definition of a tomographic image can be improved.

According to the seventh aspect of the present invention, which is dependent on any one of the second to sixth aspects,
In addition to the effect of any one of the inventions, the tomographic imaging speed can be further increased.

Claim 8 dependent on the invention of claim 6 or 7
According to the invention device described in (1), in addition to the effect of the invention of claim 6 or 7, a radiation source that obtains a large radiation angle can be easily produced.

A ninth aspect of the present invention is dependent on the fourth or fifth aspect of the present invention.
According to the invention device described in the above, in addition to the effect of the invention of the fourth or fifth aspect, even if a part of the subject is located in a part where the energy propagation ray is strongly absorbed, the reliability of the imaging data is irrespective of that. Can be improved.

According to the tenth aspect of the present invention, which is dependent on any one of the second to ninth aspects, in addition to the effects of the one of the second to ninth aspects, the scattered radiation The image quality can be improved by preventing a decrease in the sharpness of the tomographic image based on the image.

According to the eleventh aspect of the present invention, the second aspect is dependent on any one of the second to tenth aspects.
In addition to the effect of any one of the inventions described above, an increase in the amount of exposure to the subject can be prevented.

According to the twelfth aspect of the present invention, the twelfth aspect of the present invention is dependent on any one of the sixth to eleventh aspects.
In addition to the effect of any one of the inventions, it is possible to improve the efficiency of generating energy transmission lines such as X-rays and to reduce power consumption.

According to the thirteenth aspect of the present invention, the effect of the twelfth aspect can be realized with a simple structure.

According to the invention of claim 14, which is dependent on any one of claims 6 to 12, claim 6 to claim 1
In addition to the effects of any one of the inventions described above, the generation efficiency of energy transmission lines such as X-rays can be improved and the power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a medical tomography apparatus according to a first embodiment of the present invention.

FIG. 2A is a cross-sectional view illustrating a relationship between a radiation source, a detection unit, and a subject of the medical tomography apparatus according to the first embodiment. FIG. 2B is a diagram for explaining the relative relationship between the movement of the plurality of tomographic planes of the subject and the movement of the CCD image sensor in FIG.

FIG. 3 is a cross-sectional view illustrating a configuration of an external irradiation device provided in the medical tomography apparatus according to the first embodiment.

FIG. 4A is a diagram showing a one-dimensional radiation source that can be used for an external irradiation device of the medical tomography apparatus according to the first embodiment. FIG. 3B is a diagram illustrating a two-dimensional radiation source that can be used for an external irradiation device of the medical tomography apparatus according to the first embodiment. FIG. 3C is a diagram showing a three-dimensional radiation source that can be used for an external irradiation device of the medical tomography apparatus according to the first embodiment.

FIGS. 5A, 5B, and 5C are diagrams sequentially illustrating a charge accumulation operation in a photosensitive section of a CCD image sensor of the medical tomography apparatus according to the first embodiment.

FIG. 6 is a cross-sectional view showing the relationship between the aligner and the detection means of the medical tomography apparatus according to the first embodiment.

FIG. 7A is a plan view showing a configuration of an upper aligner plate of the aligner shown in FIG. 6; FIG. 7B is a plan view illustrating a configuration of a lower aligner plate of the aligner illustrated in FIG. 6.

FIG. 8 is a diagram showing a relationship between an aligner and a detection unit of the medical tomography apparatus according to the first embodiment.

FIG. 9 is a view for explaining the relationship between the aligner shown in FIG. 8 and a detecting means;

FIG. 10A is a diagram showing images of a plurality of tomographic images parallel to the body axis of the subject obtained by the medical tomography apparatus according to the first embodiment. 10B is a diagram showing an image of a converted tomographic image obtained by converting the tomographic image of FIG. 10A in a direction perpendicular to the body axis. 10C is a diagram showing an image of a converted tomographic image obtained by converting the tomographic image of FIG. 10A obliquely with respect to the body axis.

FIG. 11 shows directions of X-rays acting on an X-ray absorbing unit when an X-ray-absorbing subject is imaged by the medical tomography apparatus according to the first embodiment, and an image signal accompanying the imaging. When,
The figure which shows the relationship with the image signal which processed it.

FIG. 12 is a diagram showing a configuration of a medical tomography apparatus according to a second embodiment of the present invention.

FIG. 13 is a schematic cross-sectional view showing a configuration of a medical tomography apparatus according to a second embodiment along a direction perpendicular to a body axis of a subject.

FIG. 14A is a cross-sectional view illustrating a relationship between a radiation source unit and a detection unit included in an external irradiation device of the medical tomography apparatus according to the second embodiment. (B) is an enlarged sectional view showing a configuration of a part of the radiation source unit provided in the external irradiation device of the medical tomography apparatus according to the second embodiment.

FIG. 15 is a diagram showing a configuration of a medical tomography apparatus according to a third embodiment of the present invention.

16 (A), (B) and (C) are cross-sectional views showing different relative movement relationships established between the radiation source, the subject, and the detection means in the present invention.

FIG. 17 (A) is a diagram illustrating a configuration in which a spatial coupler is connected to a CC according to the present invention.
The figure which shows the improvement example added to the radiation incident system to D image sensor with the distortion relationship of the image in each part. (B) is a figure which shows the other improvement added to the radiation incidence system from a spatial coupler to a CCD image sensor in this invention.
(C) is a diagram showing still another improved example added to the radiation incident system from the spatial coupler to the CCD image sensor in the present invention.

FIG. 18 is a cross-sectional view showing the relationship between the detection means and different tomographic planes of the subject imaged by the detection means in the present invention.

FIG. 19A is a perspective view showing a cathode reheating structure of an external irradiation device improved in the present invention. FIG. 20B is a sectional view of the cathode reheating structure shown in FIG.

FIG. 20 is a diagram showing a configuration of an industrial tomography apparatus according to a fourth embodiment of the present invention.

FIG. 21 is a cross-sectional view illustrating a relationship between a radiation source, a detection unit, and a subject of the industrial tomography apparatus according to the fourth embodiment.

FIG. 22 is a waveform chart for explaining a comparison process performed by the industrial tomography apparatus according to the fourth embodiment.

FIG. 23 is a diagram showing a configuration of an industrial tomography apparatus according to a fifth embodiment of the present invention.

FIGS. 24A, 24B, and 24C are views for explaining a procedure of tomography performed in a conventional direct tomography apparatus.

FIG. 25 is a cross-sectional view showing a configuration of an external irradiation device provided in a conventional direct tomography apparatus.

[Explanation of symbols]

Reference numeral 22: human body (subject), 22: red-hot slab (subject), 22: die-cast casting (subject), 23: external irradiation device, 24: irradiation container, 25: cathode, 26: radiation source, anode, Radiation transmission window 26a: radiation source element, 26A: radiation source unit, 27: acceleration electrode, 28: light reflection means, 29: light reflection means, 45: pinhole (spatial coupler), 46: area type CCD image sensor ( 49, 49a to 49c: tomographic plane, 59: high-pass filter circuit (low frequency component removing means), 61: aligner, 62: upper aligner plate, 63: lower aligner plate, 62a, 62b: hole .

Claims (14)

[Claims] 1. An externally illuminated type subject to which an energy transmission line is irradiated from the outside or a spontaneous emission type subject which emits an energy transmission line by itself, and said object by passing said energy transmission line from said subject. A storage type in which an image of a specimen is inverted and projected on the opposite side to the spatial coupler on the opposite side with respect to the spatial coupler for projecting to the opposite side of the subject and detecting and storing the energy propagation line. By moving at least one of the energy detection medium and the object, the object and the energy detection medium are relatively moved in opposite directions. Direct imaging, wherein the tomographic plane is photographed with the energy detection medium while keeping the relative position with respect to the energy detection medium unchanged. Layer shooting method. 2. An image of the object is inverted by passing the energy propagation line from an externally irradiating type object to which the energy transmission line is irradiated from the outside or a spontaneous emission type object which radiates the energy transmission line by itself. A spatial coupler for projecting to the opposite side of the subject and projecting on the opposite side of the subject on the opposite side of the subject from the spatial detector with the spatial coupler as a boundary, and entering through the spatial coupler. And a storage-type energy detection medium that detects and accumulates the energy propagation line, and at least one of the test object and the energy detection medium is provided so as to be movable, and it is intended to obtain the test object. The subject and the energy detection medium are moved in opposite directions so that the relative position between the tomographic plane and the energy detection medium with respect to the tomographic plane does not change. Direct tomography apparatus characterized by photographing the tomographic plane in said energy detection medium while. 3. The apparatus according to claim 1, wherein a pair formed by the spatial coupler and the storage-type energy detection medium is moved with respect to the object arranged without being moved. 3. The direct tomography apparatus according to 2. 4. The storage-type energy detection medium is an area-type CCD image sensor, and a pixel row that is scanned in the relative movement direction of the sensor to store charges.
The method according to claim 2, wherein the pixel row is scanned in accordance with the relative movement direction so that a relative position of the subject with respect to a tomographic plane to be obtained does not change. Direct tomography equipment. 5. A plurality of sets of said spatial coupler and said storage type energy detecting medium made of an area type CCD image sensor are provided side by side in the direction of said relative movement. 5. The direct tomography apparatus according to claim 4, wherein scanning speeds of the pixel rows of the energy detection medium are different from each other. 6. An external irradiation device for irradiating the object with energy propagation rays from the outside thereof,
6. A radiation source having a two-dimensional shape or a three-dimensional shape, wherein radiation as an energy transmission line is generated from the entire radiation source and irradiated to the subject. The direct tomography apparatus according to any one of the above. 7. An external irradiation device for irradiating the object with energy propagation rays from outside thereof, wherein the device comprises:
A radiation source having a three-dimensional shape, the radiation source being a source of radiation that is an energy transmission line, and irradiating the radiation to the subject; and the three-dimensional shape converges the radiation to the spatial coupler. The direct tomography apparatus according to any one of claims 2 to 6, wherein a part of a paraboloid to be formed or a spherical surface similar thereto is formed. 8. The direct tomography according to claim 6, wherein the radiation source is a radiation source unit in which a plurality of radiation source elements having a two-dimensional shape or a three-dimensional shape are continuously arranged. Shooting equipment. 9. A low frequency component removing means for filtering imaging data of said tomographic plane detected by said storage type energy detecting medium made of said area type CCD image sensor and removing low frequency components in said data. The direct tomography apparatus according to claim 4 or 5, wherein: 10. The spatial coupler is made of a material having radiation blocking performance, is a pinhole having a pinhole, and covers the energy detection medium from the subject side. A direct tomography apparatus according to any one of claims 2 to 9. 11. The radiation source and the subject have a function of blocking energy transmission lines, form a porous structure, and irradiate a part of the energy transmission lines to the subject through the holes. The direct tomography apparatus according to any one of claims 2 to 10, wherein an aligner for causing the direct tomography is arranged. 12. The external irradiation device includes an irradiation container containing a cathode for supplying thermoelectrons to the radiation source and having a radiation transmission window, wherein the irradiation container is provided with a cathode which is generated simultaneously with the generation of the thermoelectrons at the cathode. The direct tomography apparatus according to any one of claims 6 to 11, further comprising a light reflection unit configured to reflect light toward the cathode. 13. A direct tomography apparatus according to claim 12, wherein said radiation transmitting window serves as said radiation source and said light reflecting means. 14. An external irradiation device comprising an irradiation container accommodating a cathode for supplying thermoelectrons to said radiation source and having a radiation transmission window, said radiation transmission window having said cathode interposed therebetween. A negative electrode accelerating electrode facing the cathode is disposed on the side opposite to the negative electrode.
The direct tomography apparatus according to any one of the three items.