WO2008156223A1 - Tomosynthesis image acquiring method and tomosynthesis image acquiring device - Google Patents

Tomosynthesis image acquiring method and tomosynthesis image acquiring device Download PDF

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Publication number
WO2008156223A1
WO2008156223A1 PCT/JP2008/061793 JP2008061793W WO2008156223A1 WO 2008156223 A1 WO2008156223 A1 WO 2008156223A1 JP 2008061793 W JP2008061793 W JP 2008061793W WO 2008156223 A1 WO2008156223 A1 WO 2008156223A1
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subject
tomosynthesis
image
radiation
imaging
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PCT/JP2008/061793
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French (fr)
Japanese (ja)
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Masami Ando
Daisuke Shimao
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Tokyo University Of Science Educational Foundation Administrative Organization
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Publication of WO2008156223A1 publication Critical patent/WO2008156223A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/025—Tomosynthesis

Definitions

  • the present invention relates to a tomosynthesis image acquisition method and a tomosynthesis apparatus for obtaining a tomosynthesis image by radiation transmitted through a subject.
  • a tomosynthesis image is an image obtained by irradiating a subject with radiation such as X-rays from different directions, photographing a plurality of projection images, and synthesizing these projection images. Once a plurality of projection images are acquired, a plurality of tomosynthesis images at an arbitrary depth can be synthesized using these images.
  • the radiation used in the acquisition of conventional tomosynthesis images is a diverging beam that radiates from the radiation source and then expands as the distance from the radiation source increases (see, for example, Patent Document 1).
  • Patent Document 1 Japanese Patent Laid-Open No. 2005-233760
  • An object of the present invention is to provide a tomosynthesis image acquisition method and a tomosynthesis apparatus that are easy to synthesize a projected image, have a simple structure, and can obtain a clearer image.
  • the image of the subject is not enlarged, and the synthesis process for obtaining the tomosynthesis image is facilitated, and the obtained image is obtained. Becomes clearer. Further, since the subject is rotated, a tomosynthesis image can be obtained even when, for example, the radiation source cannot be rotated.
  • a collimating means for collimating incident radiation a rotating means for rotating a subject arranged on a path of the collimated radiation, and a radiation transmitted through the subject.
  • a plurality of imaging means for capturing the projected image of the subject, and rotating the subject by the rotating means so that the radiation is incident on the subject at different angles.
  • a tomosynthesis apparatus comprising: processing means for synthesizing projected images to create a tomosynthesis image.
  • the image of the subject is not enlarged, the synthesis processing for obtaining the tomosynthesis image is facilitated, and a clear projected image is obtained. Can be obtained. Furthermore, since a rotating means for rotating the subject is provided, a tomosynthesis image can be obtained even when the radiation source cannot be rotated, for example.
  • a radiation separating unit that is disposed between the subject and the imaging unit and transmits only the radiation refracted by the subject out of the radiation transmitted through the subject.
  • the processing means obtains the tomosynthesis image with respect to a plurality of fulcrum surfaces passing through the rotation center of the subject, respectively.
  • the tomosynthesis apparatus according to item. According to the invention of (13), the subject can be observed with a tomosynthesis image from a plurality of angles.
  • the projection image can be easily synthesized and a clear image can be obtained.
  • FIG. 1 is a schematic configuration diagram of a tomosynthesis apparatus according to a first embodiment of the present invention.
  • FIG. 2 is a diagram schematically showing an X-ray image when a plurality of directional forces are imaged by rotating the subject in the tomosynthesis apparatus according to the first embodiment of the present invention.
  • FIG. 3 is a schematic diagram showing an X-ray projection image when a subject is photographed with a plurality of directional forces in a conventional tomosynthesis apparatus.
  • Fig. 4 is a diagram for explaining an acupuncture image in a case where a plurality of directional forces are imaged by synchronizing the subject and the imaging surface and rotating them in the tomosynthesis apparatus of the first embodiment of the present invention.
  • FIG. 5 is a diagram showing the relationship between a fulcrum plane when generating a tomosynthesis image and an oblique plane parallel to the fulcrum plane.
  • FIG. 6 is a schematic configuration diagram of a tomosynthesis apparatus according to a second embodiment of the present invention.
  • FIG. 7 is a diagram schematically showing an X-ray image when a subject is rotated and images are taken from a plurality of directions in the tomosynthesis apparatus of the second embodiment of the present invention.
  • FIG. 8 is a diagram for explaining an X-ray image when a plurality of directional forces are imaged by synchronizing and rotating the subject and the imaging surface in the tomosynthesis apparatus of the second embodiment of the present invention.
  • FIG. 9 is an X-ray image actually taken with the tomosynthesis apparatus of the first embodiment type IV.
  • FIG. 10 is an X ⁇ image actually taken by the tomosynthesis apparatus of the second embodiment.
  • FIG. 11 is an X-ray image actually taken by the tomosynthesis apparatus of the second embodiment.
  • FIG. 1 is a schematic configuration diagram of the tomosynthesis apparatus 1.
  • the tomosynthesis apparatus 1 includes a monochromator 3a and a collimator 3b that make the X-rays generated from the source 2 monochromatic and parallel (collimated). Furthermore, the tomosynthesis apparatus 1 is arranged downstream of the monochromator 3a and the collimator 3b in the X direction, and a stage 5 on which the subject 4 is placed, and an X-ray projection image transmitted through the subject 4 And a processing device 7 that generates a tomosynthesis image by synthesizing projected images of X-rays photographed by the photographing device 6.
  • a synchrotron is used as the X-ray generation source 2 that generates X-rays incident on the tomosynthesis apparatus 1.
  • power using X-rays as radiation is not limited to this.
  • the X-ray generation source 2 can be any other X-ray generation source.
  • other radiation other than X-rays for example, electromagnetic waves may be used, and not only electromagnetic waves but also particle beams such as neutron beams and electron beams may be used.
  • the tomosynthesis apparatus 1 is not limited to the force described using the X-rays emitted from the X-ray generation source 2, and the tomosynthesis apparatus itself may include a small X-ray generation source. .
  • the monochromator 3a is a double crystal monochromator, which is installed in the beam line BL emitted from the ⁇ ⁇ generating source and monochromatizes the X-rays.
  • the collimator 3b is an asymmetric reflection type monochromator-collimator that further collimates and expands the monochromatic X-ray emitted from the monochromator 3a.
  • the present invention is not limited to this, and a monochromator that uses a multilayer monochromatic mirror as a parabolic mirror may be used.
  • the light beam can be condensed with a parabolic reflecting mirror or a single beam to be converted into a parallel beam, and then monochromatic with a monochromator or an asymmetric monochromator.
  • Various conventionally known means can be appropriately used.
  • the mounting table 5 is a table on which the subject 4 is placed, and a rotation mechanism 9 that rotates the subject 4 so that X-rays can be incident on the subject 4 at different angles is attached. .
  • the rotation mechanism 9 can rotate the subject 4 from the reference direction to the plus direction and the minus direction by an angle ⁇ at an interval of at least 1 ° when the direction perpendicular to the X-ray traveling direction is the reference direction. It is possible to fix at that position.
  • the imaging device 6 is a device capable of forming an X-ray image on its imaging surface 6a, and is, for example, a flat panel detector, a film camera, a CCD camera, a nuclear plate, or the like.
  • the exposure time for the X-ray of the imaging surface 6a is the X-ray image (hereinafter referred to as a normal ⁇ image) having a normal appropriate contrast in the individual X-ray images (hereinafter referred to as basic images) for obtaining a tomosynthesis image.
  • a normal ⁇ image the X-ray image
  • basic images the X-ray images
  • the exposure time of the basic image may be 1/10 of the exposure time of a normal X-ray image, and tomosynthesis by overlapping 20 basic images. To get an image, use an exposure time of 1/20.
  • the total X-ray dose when obtaining a plurality of basic images is the X-ray dose for obtaining one normal X-ray image. It is the same as the radiation dose. Furthermore, once a plurality of basic images are acquired, it is possible to synthesize a plurality of tomographic images at an arbitrary depth only with these basic images.
  • the processing device 7 is an arithmetic device such as a microcomputer that can synthesize images taken by the photographing device 6 and obtain a tomosynthesis image.
  • the tomosynthesis image generation algorithm includes (1) shift addition method (shift and attach 'tomosynthesis method), (2) Fourier technology based on Fourier oblique theorem, and (3) series of simultaneous equations. There is an algebraic method for solving the above, but in this embodiment, the shift addition method, which is the simplest algorithm, is used.
  • the subject 4 is placed on the placing table 5.
  • X-rays generated from the X-ray generation source 2 are monochromatized by the monochromator 3a, further collimated by the collimator 3b, and expanded in a direction perpendicular to the traveling direction.
  • This expanded X-ray is irradiated to the subject 4.
  • the degree of transmission of X-rays that pass through the subject 4 varies depending on the density and constituent materials in the internal structure of the subject 4.
  • the X-ray transmitted through the subject 4 is imaged by the imaging device 6, and a transmission X-ray image reflecting the density in the internal structure of the subject 4 and the difference in transmittance of each constituent material is generated. .
  • FIG. 2 is a diagram schematically showing an X-ray image taken on the imaging surface 6a when the tomosynthesis apparatus 1 rotates the subject 4 and images a plurality of directional forces.
  • Black circle in the figure Indicates a part on the fulcrum plane F passing through the rotation center of the subject 4, and a white circle indicates a part on the plane H on the collimator 3b side from the fulcrum plane F by h.
  • Fig. 2 (b) shows the case where the fulcrum plane F is perpendicular to the X-ray direction
  • Fig. 2 (a) shows the case where the fulcrum surface F makes an angle of ⁇ with respect to the X-ray direction.
  • (c) is the case where the fulcrum plane F forms an angle of + ⁇ with respect to the X-ray traveling direction.
  • a plurality of basic images obtained by rotating the subject 4 so that the fulcrum plane F has different angles with respect to the traveling direction of the X-ray are obtained by the processing device 7 from the fulcrum plane F of the subject 4.
  • a tomosynthesis image is generated after the oblique transformation is performed on the parallel plane (the oblique surface), and is moved and overlapped by the shift addition method.
  • Fig. 3 shows a tomosynthesis device ⁇ that uses normal X-rays with different projected areas depending on the distance from the subject without using parallelized X-rays. In the case of Fig.
  • a is the distance between the wrinkle source 2 'and the fulcrum surface F
  • b is the distance between the imaging surface 6 and the fulcrum surface F.
  • the movement amount d is the amount that moves toward the center of the X-ray when h is positive, and moves away from the center force when h is negative.
  • the magnification M of the image in the plane H that is separated from the fulcrum plane F by the distance h is expressed by the following equation.
  • the part represented by the white circle of the subject 4 on the plane H moves the X-ray image by a distance d, Can be focused by overlapping.
  • structures outside the focal plane are blurred and blurred.
  • the enlargement ratio M of the basic image after being obliquely transformed into a plane parallel to the fulcrum plane F of the subject 4 Can be regarded as 1. This is because the X-rays are parallel and do not expand. Therefore, the movement amount d is simply given as follows, instead of the equation (1).
  • d htan ⁇ (3)
  • the movement amount d can be simply expressed in the tomosynthesis method, and the movement and superposition calculation in the shift addition method becomes very easy. For this reason, for example, the processing speed in the arithmetic processing in the processing device 7 can be increased, and an advanced processing is not required. Therefore, an inexpensive processing device can be used as the processing device 7.
  • the exposure time of the imaging apparatus is an X-ray image having a normal appropriate contrast in each basic image for obtaining a tomosynthesis image. Less exposure time required to obtain. That is, it is necessary to obtain multiple images. The total dose for obtaining tomosynthesis images does not increase with respect to the X-ray dose irradiated to obtain a normal X-ray image. In addition, since parallelized X-rays are used, the resulting image is clear.
  • the tomosynthesis apparatus ⁇ shown in FIG. 3 has a configuration in which the subject is fixed and the X-ray generation source 2 ′ and the imaging surface 6a ′ move.
  • a synchrotron device or the like is used as the X-ray generation source 2 ′
  • the mounting table 5 of the subject 4 since the mounting table 5 of the subject 4 rotates, the synchrotron device that does not need to move the X-ray generation source 2 is used as the X-ray generation source. You can. Further, since only the mounting table 5 needs to be rotated, the rotation mechanism is easy.
  • FIG. 1 As a modification of the first embodiment, as shown in FIG.
  • the object 4 (mounting table 5) and the imaging surface 6a are synchronized, and the parallel between the fulcrum surface F of the object 4 and the imaging surface 6a is achieved. It can also be rotated while maintaining the relationship. In this case, a mechanism for rotating the subject 4 and the imaging surface 6a in synchronization is required. Therefore, the rotation mechanism becomes complicated, but the processing of the obtained image becomes easier.
  • FIG. 5 is a diagram showing the relationship between the fulcrum surface F and the plurality of tomosynthesis images parallel to the fulcrum surface F when the tomosynthesis image is generated.
  • FIG. 5 (a) shows one fulcrum plane F and a plurality of tomosynthesis images parallel to the fulcrum plane F.
  • a plurality of fulcrum surfaces F can be provided so as to pass through the center of rotation of the subject 4, and a plurality of tomosynthesis images corresponding to the fulcrum surfaces F can be obtained.
  • FIG. 5 (b) is a diagram showing the relationship between a plurality of fulcrum surfaces F, and FIG.
  • FIG. 5 (c) is a diagram showing the relationship of tomosynthesis images to each of those fulcrum surfaces F.
  • FIG. 5 (c) is a diagram showing the relationship of tomosynthesis images to each of those fulcrum surfaces F.
  • FIG. 5 (c) is a diagram showing the relationship of tomosynthesis images to each of those fulcrum surfaces F.
  • the subject can be observed with tomosynthesis images from a plurality of angles. Note that these tomosynthesis images can be easily obtained by simple computational processing.
  • FIG. 6 is a schematic configuration diagram of the tomosynthesis apparatus 11 of the second embodiment.
  • an angle analysis plate 20 is provided as a radiation separating means between the mounting table 15 and the imaging device 16.
  • This angle analysis plate 20 is configured so that, by adjusting the thickness, it does not transmit X-rays that travel straight, but can transmit only the third line refracted by the subject 4 (for details).
  • the subject 14 is mounted on the mounting table 15 as in the first embodiment.
  • the X-rays are generated from the X-ray generation source 12
  • the X-rays are made monochromatic by the monochromator 13a, made monochromatic by the collimator 13b, and expanded in the direction perpendicular to the traveling direction. Is done.
  • This expanded X-ray is irradiated to the subject 14.
  • the soft tissue when the subject 14 is a site having a soft tissue such as cartilage, the soft tissue is difficult to absorb X-rays and thus passes through, but the soft tissue receives a refracting action at the edge of the soft tissue. Change direction slightly.
  • the angle analyzer 20 does not transmit straight X-rays, but acts as a filter that transmits only refracted X-rays, so it is a background of straight X-rays! It is possible to obtain an X-ray image (X-ray image) having information on soft tissues such as cartilage.
  • FIG. 7 is a view similar to FIG. 2 schematically showing an X-ray image photographed on the photographing surface 16a when the subject 14 is rotated and photographed from a plurality of directions in the tomosynthesis apparatus 11. It is.
  • Fig. 7 (b) shows the case where the fulcrum plane F is perpendicular to the X-ray direction
  • Fig. 7 (a) shows the case where the fulcrum plane F makes an angle of ⁇ with respect to the X-ray direction
  • (c) is the case where the fulcrum plane F forms an angle of + ⁇ with respect to the X-ray traveling direction.
  • the plurality of images rotated so that the fulcrum plane F has a different angle with respect to the X-ray traveling direction are converted into oblique images by the processing device 17 and then moved by the shift addition method. And superimposed to generate a tomosynthesis image.
  • a plurality of tomosynthesis images can be obtained corresponding to a plurality of fulcrum planes F passing through the rotation center of the subject 14 as in the first embodiment.
  • the subject is a part having a joint such as a finger or knee or a breast
  • articular cartilage and breast cancer nests are difficult to identify clearly with a conventional transmission X-ray apparatus.
  • X-ray dark-field images eliminate articular cartilage and breasts to eliminate straight X-rays. It is possible to observe a part that slightly refracts at the edge of the cancer nest. However, it is not possible to grasp the depth information of a predetermined part of the subject from one X-ray X-ray image.
  • the eyelid image is image-processed by the tomosynthesis method, a tomographic image of the X-ray eyelid image can be obtained. Accordingly, it is possible to obtain a projection image including information in the depth direction such as a strong articular cartilage or a breast cancer nest that cannot be observed with a conventional transmission type ridge apparatus.
  • the subject 14 and the imaging surface 16a may be rotated in synchronization as shown in FIG. Even in this case, since a mechanism for rotating the subject 14 and the imaging surface 16a in synchronism is required, the rotation mechanism becomes complicated, and the processing of the obtained image becomes easier.
  • a basic image was taken using synchrotron X-rays with a vertical widerer light source at the beamline 14B at the synchrotron radiation facility of Tsukuba City, Ibaraki Prefecture, and a tomogram was synthesized by the tomosynthesis method.
  • the incident light was monochromatic to 36. OkeV by a double crystal monochromator 3a with a Si (333) diffraction plane.
  • the asymmetry factor was 0.025 under these conditions, and the collimator 3b expanded the lateral dimension of the incident X-ray beam by about 40 times.
  • Subject 4 has a dedicated power.
  • Proximal interphalangeal joint (PIP J) in an interrupted state that has been cut and soaked in formalin (without slicing or stripping the main part) was used.
  • FIG. 9 (c) is a normal X-ray projection image with an exposure time of 55 seconds for comparison. Compared to Fig. 9 (a), there is less information in the depth direction. Thus, according to the tomosynthesis image, information in the depth direction can be obtained.
  • an angle analysis plate was placed between the mounting table of the first example and the imaging surface, and X-ray images were taken in other states.
  • the angle analysis plate is obtained by identifying, cutting, and mirror-polishing a silicon (220) surface using X-ray diffraction.
  • the thickness of the angle analysis plate was 1070 / z m. It was tilted so that the effective thickness through which X-rays pass was 1107 ⁇ . As a result, all X-rays traveling straight were diffracted and set at the Bragg angle position where they did not travel forward. Other conditions were the same as in the first example, and a cocoon image was taken.
  • FIGS. 10 (a), (b) and (c) correspond to FIGS. 9 (a), (b) and (c), respectively.
  • the tomosynthesis method to the X-ray acupuncture field method, it was possible to observe the articular cartilage portion that cannot be seen by conventional X-ray photographs, including information in the depth direction.
  • the subject 4 was cut off in the contact state and immersed in formalin, which was close to the intact state (the state in which the slicing process and the main part bare process were not performed).
  • the interphalangeal joint (PIPJ) was used.
  • a CCD camera X-FDI manufactured by Photonic Science was used as an image detector for photographing.
  • the exposure time was 7 seconds (when the ring current was 250 mA) in the basic image. This is equivalent to the imaging dose in the first and second embodiments.
  • Arbitrary tomosynthesis images parallel to the basic image at intervals are obtained in a radial fashion.

Abstract

It is an object to provide a tomosynthesis image acquiring method in which synthesis processing of projecting images can be easily performed and a clear image can be obtained. In the tomosynthesis image acquiring method, X-rays generated from an X-ray generating source (2) are made to be monochromatic and paralleled through a monochromator (3a) and a collimator (3b), and the monochromatic and paralleled X-rays are irradiated onto an examinee (4). X-rays transmitted through the examinee (4) is detected and an image picking-up device (6) picks up a projecting image of the examinee (4). In the image acquiring method, this image picking-up is carried out a plurality of times by rotating the examinee (4) so that radiation rays are made to be incident onto the examinee at different angles. A processing device (7) synthesizes a plurality of projecting images of the examinee (4) obtained by picking-up images a plurality of times to make out a tomosynthesis image.

Description

明 細 書  Specification
トモシンセシス画像取得方法及びトモシンセシス装置  Tomosynthesis image acquisition method and tomosynthesis apparatus
技術分野  Technical field
[0001] 本発明は、被検体を透過した放射線によるトモシンセシス画像を得るためのトモシ ンセシス画像取得方法及びトモシンセシス装置に関する。  The present invention relates to a tomosynthesis image acquisition method and a tomosynthesis apparatus for obtaining a tomosynthesis image by radiation transmitted through a subject.
背景技術  Background art
[0002] トモシンセシス (tomosynthesis)画像は、例えば X線等の放射線を被検体に対し て異なる方向から照射し、複数の投影画像を撮影し、これらの投影画像を合成した 画像である。一度、複数の投影画像を取得してしまえば、これらを用いて複数枚の任 意の深さでのトモシンセシス画像を合成することができる。従来のトモシンセシス画像 の取得において使用される放射線は、放射線発生源から放射された後、放射線発生 源力 離れるほど照射面積が広がる発散ビームである (例えば、特許文献 1参照）。 特許文献 1 :特開 2005— 233760号公報  [0002] A tomosynthesis image is an image obtained by irradiating a subject with radiation such as X-rays from different directions, photographing a plurality of projection images, and synthesizing these projection images. Once a plurality of projection images are acquired, a plurality of tomosynthesis images at an arbitrary depth can be synthesized using these images. The radiation used in the acquisition of conventional tomosynthesis images is a diverging beam that radiates from the radiation source and then expands as the distance from the radiation source increases (see, for example, Patent Document 1). Patent Document 1: Japanese Patent Laid-Open No. 2005-233760
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0003] しかし、発散ビームを用いた場合、被検体の投影画像の大きさが、放射線発生源、 被検体及び撮影面の位置関係により異なり、複数の画像を合成してトモシンセシス画 像を得る場合、その合成処理が複雑になる。また、発散ビームを用いると、ビームの 拡大により画像が不鮮明になるという問題もある。 [0003] However, when a divergent beam is used, the size of the projected image of the subject varies depending on the positional relationship between the radiation source, the subject, and the imaging surface, and a tomosynthesis image is obtained by combining a plurality of images. , The synthesis process becomes complicated. In addition, when a divergent beam is used, there is a problem that the image becomes unclear due to the expansion of the beam.
[0004] 本発明は、投影画像の合成処理が容易で且つ構成が簡単で、さらにより鮮明画像 を得ることのできるトモシンセシス画像取得方法及びトモシンセシス装置を提供するこ とを目的とする。 [0004] An object of the present invention is to provide a tomosynthesis image acquisition method and a tomosynthesis apparatus that are easy to synthesize a projected image, have a simple structure, and can obtain a clearer image.
課題を解決するための手段  Means for solving the problem
[0005] 本発明者らは、上記目的を達成するために鋭意研究を重ねた結果、平行な放射線 を使用することで投影画像の合成処理が容易になり、且つ鮮明な投影画像を得るこ とができることを見出し、以下の発明をした。 [0005] As a result of intensive studies to achieve the above object, the present inventors have made it easy to synthesize projected images and obtain clear projected images by using parallel radiation. The following invention was found.
[0006] (1)平行放射線を被検体に照射し、前記被検体を透過した放射線を検出して行う 前記被検体の投影画像の撮影を、前記被検体を回転させることにより前記放射線を 異なる角度で前記被検体に入射させて複数回行い、該複数回の撮影により得られた 前記被検体の複数の投影画像を合成してトモシンセシス画像を作成するトモシンセ シス画像取得方法。 [0006] (1) Performing by irradiating a subject with parallel radiation and detecting the radiation transmitted through the subject The projection image of the subject is photographed a plurality of times by rotating the subject so that the radiation is incident on the subject at different angles, and the plurality of the subjects obtained by the plurality of times of photographing are obtained. A tomosynthesis image acquisition method that creates a tomosynthesis image by combining projected images.
[0007] (1)の発明によると、平行な放射線を被検体に照射するので、被検体の画像が拡 大せずに、トモシンセシス画像を得るための合成処理が容易となり、また得られる画 像も鮮明になる。さらに被検体を回転させるので、例えば放射線源が回転できないよ うな場合においても、トモシンセシス画像を得ることができる。  [0007] According to the invention of (1), since the subject is irradiated with parallel radiation, the image of the subject is not enlarged, and the synthesis process for obtaining the tomosynthesis image is facilitated, and the obtained image is obtained. Becomes clearer. Further, since the subject is rotated, a tomosynthesis image can be obtained even when, for example, the radiation source cannot be rotated.
[0008] (2)前記被検体を透過した前記放射線のうちの前記被検体により屈折された放射 線のみを検出してトモシンセシス画像を作成することを特徴とする（1)に記載のトモシ ンセシス画像取得方法。（2)の発明によると、被検体により屈折された放射線のみを 透過させるので、バックグラウンドのなレ、屈折した放射線のみの画像を得ることができ る。  [0008] (2) The tomosynthesis image according to (1), wherein only the radiation refracted by the subject out of the radiation transmitted through the subject is detected to create a tomosynthesis image. Acquisition method. According to the invention of (2), since only the radiation refracted by the subject is transmitted, an image of only the refracted radiation without background can be obtained.
[0009] (3)前記投影画像が、前記複数回の撮影において不動の位置で撮影されることを 特徴とする（1)又は（2)に記載のトモシンセシス画像取得方法。（3)の発明によると、 撮影面は固定されているので回転機構が簡単である。  [0009] (3) The tomosynthesis image acquisition method according to (1) or (2), wherein the projection image is captured at a fixed position in the plurality of capturing operations. According to the invention of (3), since the imaging surface is fixed, the rotation mechanism is simple.
[0010] (4)前記投影画像が、前記複数回の撮影において前記被検体の回転と同期して 回転した位置で撮影されることを特徴とする（1)又は（2)に記載のトモシンセシス画 像取得方法。（4)の発明によると、撮影面が被検体と同期して回転するので、トモシ ンセシス画像を得る際の合成処理が容易となる。 [0010] (4) The tomosynthesis image according to (1) or (2), wherein the projection image is imaged at a position rotated in synchronization with rotation of the subject in the plurality of imaging operations. Image acquisition method. According to the invention of (4), since the imaging surface rotates in synchronization with the subject, the composition processing when obtaining the tomosynthesis image becomes easy.
[0011] (5)前記放射線が X線又は中性子線であることを特徴とする（1)〜（4)のレ、ずれか に記載のトモシンセシス画像取得方法。 [0011] (5) The tomosynthesis image acquisition method according to any one of (1) to (4), wherein the radiation is an X-ray or a neutron beam.
[0012] (6)前記トモシンセシス画像を、前記被検体の回転中心を通る複数の支点面に対 してそれぞれ求めることを特徴とする（1)〜（5)のレ、ずれかに記載のトモシンセシス 画像取得方法。（6)の発明によると、被検体を、複数の角度からトモシンセシス画像 で観察すること力 Sできる。 (6) The tomosynthesis image according to (1) to (5), wherein the tomosynthesis image is obtained for each of a plurality of fulcrum surfaces passing through the rotation center of the subject. Image acquisition method. According to the invention of (6), the force S can be observed with a tomosynthesis image from a plurality of angles.
[0013] (7)入射する放射線を平行にする平行化手段と、前記平行にされた放射線の進路 上に配置される被検体を回転させる回転手段と、前記被検体を透過した放射線を検 出して前記被検体の投影画像を撮影する撮影手段と、前記回転手段により前記被 検体を回転させることにより前記放射線を異なる角度で前記被検体に入射させて撮 影された前記被検体の複数の投影画像を合成してトモシンセシス画像を作成する処 理手段と、を備えるトモシンセシス装置。 [0013] (7) A collimating means for collimating incident radiation, a rotating means for rotating a subject arranged on a path of the collimated radiation, and a radiation transmitted through the subject. A plurality of imaging means for capturing the projected image of the subject, and rotating the subject by the rotating means so that the radiation is incident on the subject at different angles. A tomosynthesis apparatus comprising: processing means for synthesizing projected images to create a tomosynthesis image.
[0014] (7)の発明によると、平行な放射線を被検体に照射するので、被検体の画像が拡 大せずに、トモシンセシス画像を得るための合成処理が容易となり、また鮮明な投影 画像を得ることができる。さらに被検体を回転させる回転手段を備えるので、例えば 放射線源が回転できないような場合においても、トモシンセシス画像を得ることができ る。 [0014] According to the invention of (7), since the subject is irradiated with parallel radiation, the image of the subject is not enlarged, the synthesis processing for obtaining the tomosynthesis image is facilitated, and a clear projected image is obtained. Can be obtained. Furthermore, since a rotating means for rotating the subject is provided, a tomosynthesis image can be obtained even when the radiation source cannot be rotated, for example.
[0015] (8)前記平行化手段に入射する放射線を発生する放射線発生源をさらに備えるこ とを特徴とする（7)に記載のトモシンセシス装置。  [0015] (8) The tomosynthesis apparatus according to (7), further comprising a radiation generation source that generates radiation incident on the collimating means.
[0016] (9)前記被検体と前記撮影手段との間に配置されるとともに、前記被検体を透過し た前記放射線のうちの前記被検体により屈折された放射線のみを透過させる放射線 分離手段をさらに備えることを特徴とする（7)又は（8)に記載のトモシンセシス装置。 (9)の発明によると、被検体により屈折された放射線のみを透過させる放射線分離手 段を備えるので、ノくックグラウンドのなレ、屈折した放射線のみで形成される画像を得 ることができる。  [0016] (9) A radiation separating unit that is disposed between the subject and the imaging unit and transmits only the radiation refracted by the subject out of the radiation transmitted through the subject. The tomosynthesis apparatus according to (7) or (8), further comprising: According to the invention of (9), since the radiation separating means for transmitting only the radiation refracted by the subject is provided, it is possible to obtain an image formed only by the refracted radiation without knocking.
[0017] (10)前記撮影手段の撮影面が、前記複数の撮影において不動であることを特徴と する（7)〜（9)のいずれ力 1項に記載のトモシンセシス装置。（10)の発明によると、 被検体は回転するが、撮影面は固定されているので回転機構が簡単である。  [0017] (10) The tomosynthesis apparatus according to any one of (7) to (9), wherein a photographing surface of the photographing unit is stationary in the plurality of photographings. According to the invention of (10), the subject rotates, but since the imaging surface is fixed, the rotation mechanism is simple.
[0018] (11)前記撮影手段の撮影面が、前記複数の撮影において前記被検体の回転と同 期して回転することを特徴とする（7)〜（9)のいずれ力 4項に記載のトモシンセシス装 置。（11)の発明によると、撮影面も被検体と同期して回転するので、トモシンセシス 画像を得る際の合成処理が容易となる。  [0018] (11) The force described in any one of (7) to (9), wherein the imaging surface of the imaging unit rotates in synchronization with the rotation of the subject in the plurality of imaging. Tomosynthesis device. According to the invention of (11), since the imaging surface also rotates in synchronization with the subject, the composition processing when obtaining a tomosynthesis image is facilitated.
[0019] (12)前記放射線が X線又は中性子線であることを特徴とする（7)〜（11)のいずれ 力 1項に記載のトモシンセシス装置。  [0019] (12) The tomosynthesis apparatus according to any one of (7) to (11), wherein the radiation is an X-ray or a neutron beam.
[0020] (13)前記処理手段が、前記トモシンセシス画像を、前記被検体の回転中心を通る 複数の支点面に対してそれぞれ求めることを特徴とする請求項 7〜： 12のいずれか 1 項に記載のトモシンセシス装置。（13)の発明によると、被検体を、複数の角度からト モシンセシス画像で観察することができる。 [0020] (13) The processing means obtains the tomosynthesis image with respect to a plurality of fulcrum surfaces passing through the rotation center of the subject, respectively. The tomosynthesis apparatus according to item. According to the invention of (13), the subject can be observed with a tomosynthesis image from a plurality of angles.
発明の効果  The invention's effect
[0021] 本発明によれば、平行な放射線を使用することで、投影画像の合成処理が容易に なるとともに鮮明な画像を得ることができる。  [0021] According to the present invention, by using parallel radiation, the projection image can be easily synthesized and a clear image can be obtained.
図面の簡単な説明  Brief Description of Drawings
[0022] [図 1]本発明の第 1実施形態のトモシンセシス装置の概略構成図である。  FIG. 1 is a schematic configuration diagram of a tomosynthesis apparatus according to a first embodiment of the present invention.
[図 2]本発明の第 1実施形態のトモシンセシス装置において、被検体を回転させて複 数の方向力 撮影した場合の、 X線画像を模式的に示した図である。  FIG. 2 is a diagram schematically showing an X-ray image when a plurality of directional forces are imaged by rotating the subject in the tomosynthesis apparatus according to the first embodiment of the present invention.
[図 3]従来のトモシンセシス装置において被検体を複数の方向力 撮影した場合の、 X線投影画像を示した模式図である。  FIG. 3 is a schematic diagram showing an X-ray projection image when a subject is photographed with a plurality of directional forces in a conventional tomosynthesis apparatus.
[図 4]本発明の第 1実施形態のトモシンセシス装置において、被検体及び撮影面を同 期させて回転させそ複数の方向力 撮影した場合の、 锒画像を説明する図である。  [Fig. 4] Fig. 4 is a diagram for explaining an acupuncture image in a case where a plurality of directional forces are imaged by synchronizing the subject and the imaging surface and rotating them in the tomosynthesis apparatus of the first embodiment of the present invention.
[図 5]トモシンセシス画像を生成する際の支点面と、その支点面と平行な斜影面との 関係をした図である。  FIG. 5 is a diagram showing the relationship between a fulcrum plane when generating a tomosynthesis image and an oblique plane parallel to the fulcrum plane.
[図 6]本発明の第 2実施形態のトモシンセシス装置の概略構成図である。  FIG. 6 is a schematic configuration diagram of a tomosynthesis apparatus according to a second embodiment of the present invention.
[図 7]本発明の第 2実施形態のトモシンセシス装置において、被検体を回転させて複 数の方向から撮影した場合の、 X線画像を模式的に示した図である。  FIG. 7 is a diagram schematically showing an X-ray image when a subject is rotated and images are taken from a plurality of directions in the tomosynthesis apparatus of the second embodiment of the present invention.
[図 8]本発明の第 2実施形態のトモシンセシス装置において、被検体及び撮影面を同 期させて回転させて複数の方向力 撮影した場合の、 X線画像を説明する図である。  FIG. 8 is a diagram for explaining an X-ray image when a plurality of directional forces are imaged by synchronizing and rotating the subject and the imaging surface in the tomosynthesis apparatus of the second embodiment of the present invention.
[図 9]第 1実施形愈のトモシンセシス装置で実際に撮影した X線画像である。  FIG. 9 is an X-ray image actually taken with the tomosynthesis apparatus of the first embodiment type IV.
[図 10]第 2実施形態のトモシンセシス装置で実際に撮影した X ^画像である。  FIG. 10 is an X ^ image actually taken by the tomosynthesis apparatus of the second embodiment.
[図 11]第 2実施形態のトモシンセシス装置で実際に撮影した X線画像である。  FIG. 11 is an X-ray image actually taken by the tomosynthesis apparatus of the second embodiment.
符号の説明  Explanation of symbols
[0023] 1, 11 :トモシンセシス装置、 2， 12 :X線発生源、 3a, 13a :モノクロメータ、 3b, 13b ：コリメ一タ、 4, 14 :被検体、 6， 16 :撮影装置、 7, 17 :処理装置、 20 :角度分析板 発明を実施するための形態 [0024] (第 1実施形態） [0023] 1, 11: Tomosynthesis device, 2, 12: X-ray generation source, 3a, 13a: Monochromator, 3b, 13b: Collimator, 4, 14: Subject, 6, 16: Imaging device, 7, 17: Processing device, 20: Angle analysis plate Mode for carrying out the invention [0024] (First embodiment)
以下、本発明の第 1実施形態について説明する。図 1はトモシンセシス装置 1の概 略構成図である。図示するようにトモシンセシス装置 1は、 発生源 2より発生され た X線を単色且つ平行（コリメート）にするモノクロメータ 3a及びコリメータ 3bを備える。 さらにトモシンセシス装置 1は、モノクロメータ 3a及びコリメータ 3bよりも X棣の進行方 向の下流に配置されるとともに被検体 4を載置する載置台 5と、被検体 4を透過した X 線の投影画像を撮影する撮影装置 6と、撮影装置 6によって撮影された X線の投影 画像を合成してトモシンセシス画像を作成する処理装置 7と、を備える。  Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of the tomosynthesis apparatus 1. As shown in the figure, the tomosynthesis apparatus 1 includes a monochromator 3a and a collimator 3b that make the X-rays generated from the source 2 monochromatic and parallel (collimated). Furthermore, the tomosynthesis apparatus 1 is arranged downstream of the monochromator 3a and the collimator 3b in the X direction, and a stage 5 on which the subject 4 is placed, and an X-ray projection image transmitted through the subject 4 And a processing device 7 that generates a tomosynthesis image by synthesizing projected images of X-rays photographed by the photographing device 6.
[0025] トモシンセシス装置 1に入射する X線を発生させる X線発生源 2としては、本実施形 態ではシンクロトロンを使用する。また、放射線として X線を用いる力 これに限定され ■ない。被検体 4に応じて任意に変更可能で、 X線発生源 2は、他の X線発生源であつ てもよレ、。また、 X線以外の他の放射線、例えば電磁波を用いてもよぐまた電磁波に 限らず中性子線や電子線等の粒子線を用いてもよい。なお、本実施形態においてト モシンセシス装置 1は X線発生源 2から出射した X線を用いる形で説明する力 これ に限定されず、トモシンセシス装置自体が小型の X線発生源を含んでいてもよい。  In this embodiment, a synchrotron is used as the X-ray generation source 2 that generates X-rays incident on the tomosynthesis apparatus 1. In addition, power using X-rays as radiation is not limited to this. The X-ray generation source 2 can be any other X-ray generation source. Further, other radiation other than X-rays, for example, electromagnetic waves may be used, and not only electromagnetic waves but also particle beams such as neutron beams and electron beams may be used. In this embodiment, the tomosynthesis apparatus 1 is not limited to the force described using the X-rays emitted from the X-ray generation source 2, and the tomosynthesis apparatus itself may include a small X-ray generation source. .
[0026] モノクロメータ 3aは、 ¾镍発生源から出射されるビームライン BLに設置された、 X線 を単色化するダブルクリスタルモノクロメータである。コリメ一タ 3bは、モノクロメータ 3a 力 出射された X線をさらに単色平行化し且つ拡大する非対称反射型モノクロメータ -コリメータである。ただし、これに限定されず、モノクロメータとして放物線状ミラーに 多層膜モノクロミラーを用いたものを使用してもよい。また、放物線状反射ミラーある いはキヤビラリ一で集光して平行ビーム化した後、モノクロメータあるいは非対称モノ クロメータにより単色化することも可能であり、従来公知の各種手段を適宜用いること ができる。  [0026] The monochromator 3a is a double crystal monochromator, which is installed in the beam line BL emitted from the 镍 镍 generating source and monochromatizes the X-rays. The collimator 3b is an asymmetric reflection type monochromator-collimator that further collimates and expands the monochromatic X-ray emitted from the monochromator 3a. However, the present invention is not limited to this, and a monochromator that uses a multilayer monochromatic mirror as a parabolic mirror may be used. In addition, the light beam can be condensed with a parabolic reflecting mirror or a single beam to be converted into a parallel beam, and then monochromatic with a monochromator or an asymmetric monochromator. Various conventionally known means can be appropriately used.
[0027] 載置台 5は、被検体 4を載置する台であり、被検体 4に X線が異なる角度で入射可 能となるように被検体 4を回転させる回転機構 9が取り付けられている。回転機構 9は 、 X線の進行方向と垂直な方向を基準方向としたときに、被検体 4を基準方向からプ ラス方向とマイナス方向に、少なくとも 1° の間隔で角度 Θ回転することができ、その 位置で固定可能となっている。 [0028] 撮影装置 6は、その撮影面 6aに X線画像を結像することが可能な装置で、例えば、 フラットパネルディテクタ、フィルムカメラ、 CCDカメラ、原子核乾板等である。撮影面 6aの X線に対する露出時間は、トモシンセシス画像を得るための個々の X線画像（以 下、基礎画像という）においては、通常の適正なコントラストを有する X線画像 (以下、 通常の 镍画像という）を得るために必要な露出時間より少なくてよい。例えば 10枚 の基礎画像を重ねてトモシンセシス画像を得る場合は、基礎画像の露出時間は通常 の X線画像の露出時間の 1/10の時間でよく、また 20枚の基礎画像を重ねてトモシ ンセシス画像を得る場合は、 1/20の露出時間でよレ、。すなわち、トモシンセシス画 像を得る場合、複数枚の基礎画像を得る必要があるが、複数枚の基礎画像を得る際 の合計の X線線量は、 1枚の通常の X線画像を得る際の X線線量と同じである。さら に一度複数枚の基礎画像を取得してしまえば、これらの基礎画像のみ力 任意の深 さでの断層像を複数枚合成できる。 The mounting table 5 is a table on which the subject 4 is placed, and a rotation mechanism 9 that rotates the subject 4 so that X-rays can be incident on the subject 4 at different angles is attached. . The rotation mechanism 9 can rotate the subject 4 from the reference direction to the plus direction and the minus direction by an angle Θ at an interval of at least 1 ° when the direction perpendicular to the X-ray traveling direction is the reference direction. It is possible to fix at that position. The imaging device 6 is a device capable of forming an X-ray image on its imaging surface 6a, and is, for example, a flat panel detector, a film camera, a CCD camera, a nuclear plate, or the like. The exposure time for the X-ray of the imaging surface 6a is the X-ray image (hereinafter referred to as a normal 镍 image) having a normal appropriate contrast in the individual X-ray images (hereinafter referred to as basic images) for obtaining a tomosynthesis image. Less than the exposure time required to obtain For example, to obtain a tomosynthesis image by overlaying 10 basic images, the exposure time of the basic image may be 1/10 of the exposure time of a normal X-ray image, and tomosynthesis by overlapping 20 basic images. To get an image, use an exposure time of 1/20. That is, when obtaining a tomosynthesis image, it is necessary to obtain a plurality of basic images, but the total X-ray dose when obtaining a plurality of basic images is the X-ray dose for obtaining one normal X-ray image. It is the same as the radiation dose. Furthermore, once a plurality of basic images are acquired, it is possible to synthesize a plurality of tomographic images at an arbitrary depth only with these basic images.
[0029] 処理装置 7は、撮影装置 6により撮影された画像を合成し、トモシンセシス画像を得 ることのできるマイクロコンピュータ等の演算可能な装置である。なお、トモシンセシス 画像を生成するアルゴリズムには、 （1)シフト加算法（シフトアンドアツド'トモシンセシ ス法)と、（2)フーリエ斜影定理に基づくフーリエ技術による手法と、（3)連立方程式 のシリーズを解く代数法とが存在するが、本実施形態では、最も簡単なアルゴリズム であるシフト加算法を使用する。  The processing device 7 is an arithmetic device such as a microcomputer that can synthesize images taken by the photographing device 6 and obtain a tomosynthesis image. The tomosynthesis image generation algorithm includes (1) shift addition method (shift and attach 'tomosynthesis method), (2) Fourier technology based on Fourier oblique theorem, and (3) series of simultaneous equations. There is an algebraic method for solving the above, but in this embodiment, the shift addition method, which is the simplest algorithm, is used.
[0030] 次に、本実施形態のトモシンセシス装置 1の動作について説明する。まず、被検体 4を載置台 5に載置する。 X線発生源 2より発生された X線はモノクロメータ 3aにより単 色化され、コリメータ 3bによりさらに単色平行化されるとともに進行方向と垂直な方向 に拡大される。この拡大された X線は被検体 4に照射される。被検体 4を透過する X線 は、被検体 4の内部構造における密度や構成材料により透過の程度が異なる。この 被検体 4を透過した X線は、撮影装置 6によって撮影され、被検体 4の内部構造にお ける密度や構成材料のそれぞれの透過率の差が反映された透過 X線画像が生成さ れる。  [0030] Next, the operation of the tomosynthesis apparatus 1 of the present embodiment will be described. First, the subject 4 is placed on the placing table 5. X-rays generated from the X-ray generation source 2 are monochromatized by the monochromator 3a, further collimated by the collimator 3b, and expanded in a direction perpendicular to the traveling direction. This expanded X-ray is irradiated to the subject 4. The degree of transmission of X-rays that pass through the subject 4 varies depending on the density and constituent materials in the internal structure of the subject 4. The X-ray transmitted through the subject 4 is imaged by the imaging device 6, and a transmission X-ray image reflecting the density in the internal structure of the subject 4 and the difference in transmittance of each constituent material is generated. .
[0031] 図 2は、トモシンセシス装置 1において、被検体 4を回転させて複数の方向力 撮影 した場合の、撮影面 6aに撮影される X線画像を模式的に示した図である。図中黒丸 は、被検体 4の回転中心を通る支点面 F上にある部位、白丸は支点面 Fから hだけコ リメータ 3b側の平面 Hにある部位を示している。図 2 (b)は X線の進行方向に対して 支点面 Fが垂直な場合、図 2 (a)は X線の進行方向に対して支点面 Fが— Θの角度 をなす場合、図 2 (c)は X線の進行方向に対して支点面 Fが + Θの角度をなす場合 である。このように、 X線の進行方向に対して支点面 Fが異なる角度を有するように被 検体 4を回転させて撮影した複数の基礎画像は、処理装置 7によって被検体 4の支 点面 Fと平行な平面 (斜影面）に斜影変換された後シフト加算法により移動されて重 ね合わされ、トモシンセシス画像が生成される。 FIG. 2 is a diagram schematically showing an X-ray image taken on the imaging surface 6a when the tomosynthesis apparatus 1 rotates the subject 4 and images a plurality of directional forces. Black circle in the figure Indicates a part on the fulcrum plane F passing through the rotation center of the subject 4, and a white circle indicates a part on the plane H on the collimator 3b side from the fulcrum plane F by h. Fig. 2 (b) shows the case where the fulcrum plane F is perpendicular to the X-ray direction, and Fig. 2 (a) shows the case where the fulcrum surface F makes an angle of Θ with respect to the X-ray direction. (c) is the case where the fulcrum plane F forms an angle of + Θ with respect to the X-ray traveling direction. As described above, a plurality of basic images obtained by rotating the subject 4 so that the fulcrum plane F has different angles with respect to the traveling direction of the X-ray are obtained by the processing device 7 from the fulcrum plane F of the subject 4. A tomosynthesis image is generated after the oblique transformation is performed on the parallel plane (the oblique surface), and is moved and overlapped by the shift addition method.
[0032] このように、単色平行化された X線を用いると、 発生源力 離れるほど投影面積 が広がる発散 X線を用いた場合と比べて、記録媒体への斜め入射がないので記録さ れた像のボケが無ぐ従来法に比して高い空間解像度が得られる。また、トモシンセ シス画像を得る際の処理が容易になる。以下、処理が容易になる理由を説明する。 説明のため、比較例として、平行化された X線を用いずに、投影面積が被検体^か らの距離によって異なる通常の X線を使用するトモシンセシス装置^を図 3に示す。 図 3の場合、 X線発生源 2 '力 照射される の中心軸 Ζと被検体 4の支点面 Fと垂 直な面との間の角度を Θとしたときに、支点面 Fから距離 h離間した平面 Ηに存在し てレ、る点をフォーカスするための移動量 dは、以下の式で表される。 d=htan 0 (a + b) / (a-h) (1) [0032] As described above, when using X-rays that are made parallel to a single color, recording is performed because there is no oblique incidence on the recording medium as compared with the case of using divergent X-rays in which the projected area increases as the generation source force increases. High spatial resolution can be obtained as compared with the conventional method in which there is no blurred image. In addition, processing for obtaining a tomosynthesis image is facilitated. Hereinafter, the reason why the processing becomes easy will be described. For explanation, as a comparative example, Fig. 3 shows a tomosynthesis device ^ that uses normal X-rays with different projected areas depending on the distance from the subject without using parallelized X-rays. In the case of Fig. 3, the distance h from the fulcrum surface F when the angle between the central axis の of the X-ray source 2 'force irradiated and the fulcrum surface F of the subject 4 and the vertical surface is Θ. The amount of movement d for focusing on a point existing on the separated plane Η is expressed by the following equation. d = htan 0 (a + b) / (a-h) (1)
[0033] ここで、 aは 镍発生源 2'と支点面 Fとの間の距離、 bは撮影面 6 と支点面 Fとの 間の距離である。移動量 dは、 hが正の値の場合、 X線の中心に向力い、 hが負の値 の場合、 の中心力も離れる方向に移動させる量である。また、支点面 Fから距離 h 離間した平面 Hにおける画像の拡大率 Mは、以下の式で表される。 [0033] Here, a is the distance between the wrinkle source 2 'and the fulcrum surface F, and b is the distance between the imaging surface 6 and the fulcrum surface F. The movement amount d is the amount that moves toward the center of the X-ray when h is positive, and moves away from the center force when h is negative. Further, the magnification M of the image in the plane H that is separated from the fulcrum plane F by the distance h is expressed by the following equation.
M= (a + b) / (a-h) (2) M = (a + b) / (a-h) (2)
[0034] 平面 H上の被検体 4の白丸で表す部位は、距離 dだけ X線画像を移動して、それら を重ね合わせることによってフォーカスさせることができる。他方、焦点平面の外の構 造は、ぼやけて不鮮明になる。図 2に示す本実施形態によると、平行にされた X線を 使用してレ、るので、被検体 4の支点面 Fと平行な面に斜影変換された後における基 礎画像の拡大率 Mは 1とみなすことができる。 X線は平行であるため、拡大が生じな レ、からである。したがって、移動量 dは式（1)ではなぐ単純に次のように与えられる。 d=htan Θ (3) [0034] The part represented by the white circle of the subject 4 on the plane H moves the X-ray image by a distance d, Can be focused by overlapping. On the other hand, structures outside the focal plane are blurred and blurred. According to the present embodiment shown in FIG. 2, since X-rays made parallel are used, the enlargement ratio M of the basic image after being obliquely transformed into a plane parallel to the fulcrum plane F of the subject 4 Can be regarded as 1. This is because the X-rays are parallel and do not expand. Therefore, the movement amount d is simply given as follows, instead of the equation (1). d = htan Θ (3)
[0035] このように平行にされた 棣を用いると、トモシンセシス法において移動量 dを簡単 に表すことができ、シフト加算法における移動及び重ね合わせの計算が非常に容易 になる。このため、例えば処理装置 7における演算処理において処理速度を高速化 することができ、また高度な処理が不要となるため、処理装置 7として安価な処理装 置を使用することができる。 [0035] By using the parallel kites in this way, the movement amount d can be simply expressed in the tomosynthesis method, and the movement and superposition calculation in the shift addition method becomes very easy. For this reason, for example, the processing speed in the arithmetic processing in the processing device 7 can be increased, and an advanced processing is not required. Therefore, an inexpensive processing device can be used as the processing device 7.
[0036] また、上述の効果に加え、本実施形態によると、撮影装置の露出時間は、トモシン セシス画像を得るための個々の基礎画像においては、通常の適正なコントラストを有 する X線画像を得るために必要な露出時間より少なくてよい。すなわち、複数枚の画 像を得る必要がある力 トモシンセシス画像を得るための総線量は通常の 1枚の X線 画像を得るために照射される X線線量に対して増加しなレ、。また、平行化した X線を 用いるので、得られる画像が鮮明である。  [0036] Further, in addition to the above-described effects, according to the present embodiment, the exposure time of the imaging apparatus is an X-ray image having a normal appropriate contrast in each basic image for obtaining a tomosynthesis image. Less exposure time required to obtain. That is, it is necessary to obtain multiple images. The total dose for obtaining tomosynthesis images does not increase with respect to the X-ray dose irradiated to obtain a normal X-ray image. In addition, since parallelized X-rays are used, the resulting image is clear.
[0037] さらに、図 3で示すトモシンセシス装置 Γは、被検体 が固定で X線発生源 2'と撮 影面 6a'とが移動する構成となっている。しかし、例えば X線発生源 2'としてシンクロ トロン装置等を用いた場合、 X線発生源 2'を移動させることは困難である。図 2に示 す本実施形態によると、被検体 4の载置台 5が回転するので、 X線発生源 2を移動さ せる必要がなぐ不動であるシンクロトロン装置等を X線発生源として用いることができ る。また、載置台 5のみを回転させればよいので回転機構が容易である。ただし、第 1 実施形態の変形例として、図 4に示すように被検体 4 (載置台 5)と撮影面 6aとを同期 させて被検体 4の支点面 Fと撮影面 6aとの間の平行関係を維持したまま回転させるこ ともできる。この場合、被検体 4と撮影面 6aとを同期して回転させる機構が必要となる ため回転機構が複雑化するが、得られた画像の処理はさらに容易になる。 Further, the tomosynthesis apparatus Γ shown in FIG. 3 has a configuration in which the subject is fixed and the X-ray generation source 2 ′ and the imaging surface 6a ′ move. However, for example, when a synchrotron device or the like is used as the X-ray generation source 2 ′, it is difficult to move the X-ray generation source 2 ′. According to this embodiment shown in FIG. 2, since the mounting table 5 of the subject 4 rotates, the synchrotron device that does not need to move the X-ray generation source 2 is used as the X-ray generation source. You can. Further, since only the mounting table 5 needs to be rotated, the rotation mechanism is easy. However, as a modification of the first embodiment, as shown in FIG. 4, the object 4 (mounting table 5) and the imaging surface 6a are synchronized, and the parallel between the fulcrum surface F of the object 4 and the imaging surface 6a is achieved. It can also be rotated while maintaining the relationship. In this case, a mechanism for rotating the subject 4 and the imaging surface 6a in synchronization is required. Therefore, the rotation mechanism becomes complicated, but the processing of the obtained image becomes easier.
[0038] 図 5は、トモシンセシス画像を生成する際の支点面 Fと、その支点面 Fと平行な複数 のトモシンセシス画像との関係を示した図である。図 5 (a)は、 1つの支点面 Fと、その 支点面 Fと平行な複数のトモシンセシス画像を示した図である。しかし支点面 Fを、被 検体 4の回転中心を通るようにして複数設け、それらの支点面 Fに対応する複数のト モシンセシス画像を得ることもできる。図 5 (b)は複数の支点面 Fの関係を示した図で あり、図 5 (c)は、それらの支点面 Fのそれぞれに対するトモシンセシス画像の関係を 示した図である。このように、支点面 Fを複数設けると、被検体を、複数の角度からの トモシンセシス画像で観察することができる。なお、これらの複数のトモシンセシス画 像は、単に計算上の処理のみで容易に得ることができる。 FIG. 5 is a diagram showing the relationship between the fulcrum surface F and the plurality of tomosynthesis images parallel to the fulcrum surface F when the tomosynthesis image is generated. FIG. 5 (a) shows one fulcrum plane F and a plurality of tomosynthesis images parallel to the fulcrum plane F. FIG. However, a plurality of fulcrum surfaces F can be provided so as to pass through the center of rotation of the subject 4, and a plurality of tomosynthesis images corresponding to the fulcrum surfaces F can be obtained. FIG. 5 (b) is a diagram showing the relationship between a plurality of fulcrum surfaces F, and FIG. 5 (c) is a diagram showing the relationship of tomosynthesis images to each of those fulcrum surfaces F. FIG. Thus, when a plurality of fulcrum planes F are provided, the subject can be observed with tomosynthesis images from a plurality of angles. Note that these tomosynthesis images can be easily obtained by simple computational processing.
[0039] (第 2実施形態） [0039] (Second Embodiment)
次に、本発明の第 2実施形態について説明する。図 6は第 2実施形態のトモシンセ シス装置 11の概略構成図である。第 1実施形態と異なる点は、載置台 15と撮影装置 16との間に、放射線分離手段として角度分析板 20を備える点である。この角度分析 板 20は、厚みを調整することで、直進する X線は透過させず、被検体 4によって屈折 された ¾線のみ透過させることができるように構成されたものである（詳細については 以下の文献を参照、応用物理 第 74卷 第 4号 (2005年) 446頁〜 452頁 (解説文） 、 M. An do,  Next, a second embodiment of the present invention will be described. FIG. 6 is a schematic configuration diagram of the tomosynthesis apparatus 11 of the second embodiment. The difference from the first embodiment is that an angle analysis plate 20 is provided as a radiation separating means between the mounting table 15 and the imaging device 16. This angle analysis plate 20 is configured so that, by adjusting the thickness, it does not transmit X-rays that travel straight, but can transmit only the third line refracted by the subject 4 (for details). Refer to the following documents, Applied Physics 74-No. 4 (2005), pp. 446 to 452 (explanatory text), M. An do,
A. aksimenko, ri. i>ugiyama, W. Pattanasinwisawa, K. Hyodo and C. Uyama, Jpn. J. Appl. Phys. 41 No.9A，B (2002) L1016- L1018 (最初のエックス線喑視野法提唱の 論文)、 Masami Ando, Hiroshi Sugiyama, Toshiyuki Kunisada, Daisuke Shimao, Ken Takeda, Hiroyuki Hashizume and Hajime Inoue, Jpn. J. Appl. Phys. 43, Part 2, No.9 A/B,  A. aksimenko, ri. I> ugiyama, W. Pattanasinwisawa, K. Hyodo and C. Uyama, Jpn. J. Appl. Phys. 41 No.9A, B (2002) L1016- L1018 ), Masami Ando, Hiroshi Sugiyama, Toshiyuki Kunisada, Daisuke Shimao, Ken Takeda, Hiroyuki Hashizume and Hajime Inoue, Jpn. J. Appl. Phys. 43, Part 2, No. 9 A / B,
L1175-L1177, 2004 (エックス線喑視野法を用いた最初の軟骨観察の論文）、 Masami Ando,  L1175-L1177, 2004 (first paper on cartilage observation using X-ray acupuncture), Masami Ando,
Katsuhito Yamasaki, Fukai Toyofuku, Hiroshi Sugiyama, Chiho Obayashi, Gang Li, Lin Pan, Xiaoming Jiang, Wanwisa Pattanasiriwisawa,  Katsuhito Yamasaki, Fukai Toyofuku, Hiroshi Sugiyama, Chiho Obayashi, Gang Li, Lin Pan, Xiaoming Jiang, Wanwisa Pattanasiriwisawa,
Daisuke Shimao, Elko Hashimoto, Tatsuro Kimura, Masazumi Tsuneyoshi, Ei Ueno, Kenji Tokumori, Anton Maksimenko, Yoshiharu Higashida, Masatsugu Hirano Jpn. J. Appl. Phys. 44, Part 2, No.3B, L528- L531, 2005 (エックス線喑視野法を用いた最初 の乳がん観察の論文)）。 Daisuke Shimao, Elko Hashimoto, Tatsuro Kimura, Masazumi Tsuneyoshi, Ei Ueno, Kenji Tokumori, Anton Maksimenko, Yoshiharu Higashida, Masatsugu Hirano Jpn. J. Appl. Phys.
[0040] この第 2実施形態のトモシンセシス装置 11の動作について説明する。まず、第 1実 施形態同様に被検体 14を載置台 15に載置する。次いで、 X線発生源 12より X線を 発生させると、その X線はモノクロメータ 13aにより単色化され、コリメ一タ 13bによりさ らに単色平行化にされるとともに進行方向と垂直な方向に拡大される。この拡大され た X線は、被検体 14に照射される。  [0040] The operation of the tomosynthesis apparatus 11 of the second embodiment will be described. First, the subject 14 is mounted on the mounting table 15 as in the first embodiment. Next, when X-rays are generated from the X-ray generation source 12, the X-rays are made monochromatic by the monochromator 13a, made monochromatic by the collimator 13b, and expanded in the direction perpendicular to the traveling direction. Is done. This expanded X-ray is irradiated to the subject 14.
[0041] 例えば、被検体 14が軟骨等の軟部組織を有する部位である場合、軟部組織は X 線を吸収しにくいので、通り抜けてしまうが、軟部組織の辺縁部等では屈折作用を受 けてわずかに方向が変化する。角度分析板 20は直進する X線は透過せず、屈折し た X線のみを透過させるフィルターのような役割を示すので、直進する X線のバックグ ラウンドのな！、、軟骨等の軟部組織の情報を有する X線画像 (X線喑視野画像)を得 ること力できる。  [0041] For example, when the subject 14 is a site having a soft tissue such as cartilage, the soft tissue is difficult to absorb X-rays and thus passes through, but the soft tissue receives a refracting action at the edge of the soft tissue. Change direction slightly. The angle analyzer 20 does not transmit straight X-rays, but acts as a filter that transmits only refracted X-rays, so it is a background of straight X-rays! It is possible to obtain an X-ray image (X-ray image) having information on soft tissues such as cartilage.
[0042] 図 7は、トモシンセシス装置 11において、被検体 14を回転させて複数の方向から 撮影した場合の、撮影面 16aに撮影される X線画像を模式的に示した図 2と同様の 図である。図 7 (b)は X線の進行方向に対して支点面 Fが垂直な場合、図 7 (a)は X線 の進行方向に対して支点面 Fがー Θの角度をなす場合、図 7 (c)は X線の進行方向 に対して支点面 Fが + Θの角度をなす場合である。このように、 X線の進行方向に対 して支点面 Fが異なる角度を有するように回転させた複数の画像は、処理装置 17に よって、斜影画像に変換された後、シフト加算法により移動されて重ね合わされ、トモ シンセシス画像が生成される。  FIG. 7 is a view similar to FIG. 2 schematically showing an X-ray image photographed on the photographing surface 16a when the subject 14 is rotated and photographed from a plurality of directions in the tomosynthesis apparatus 11. It is. Fig. 7 (b) shows the case where the fulcrum plane F is perpendicular to the X-ray direction, and Fig. 7 (a) shows the case where the fulcrum plane F makes an angle of Θ with respect to the X-ray direction. (c) is the case where the fulcrum plane F forms an angle of + Θ with respect to the X-ray traveling direction. As described above, the plurality of images rotated so that the fulcrum plane F has a different angle with respect to the X-ray traveling direction are converted into oblique images by the processing device 17 and then moved by the shift addition method. And superimposed to generate a tomosynthesis image.
[0043] また、第 2実施形態の場合も、第 1実施形態と同様に、被検体 14の回転中心を通る 複数の支点面 Fに対応させて複数のトモシンセシス画像を得ることもできる。  Also in the second embodiment, a plurality of tomosynthesis images can be obtained corresponding to a plurality of fulcrum planes F passing through the rotation center of the subject 14 as in the first embodiment.
[0044] 以上、本発明の第 2実施形態によると、上記第 1実施形態の効果に加え、以下の効 果を有する。例えば被検体が指や膝等の関節を有する部分や***である場合、関 節軟骨や***のガン巣は従来の透過型 X線装置で明確に特定することが困難であ る。これに対し、 X線暗視野画像は、直進する X線を排除するため、関節軟骨や*** のガン巣等、その辺縁部において を僅かに屈折させる部位を観察することができ る。しかし、 1枚の X線喑視野画像からは、被検体の所定部位の深さ方向の情報を把 握することができない。本実施形態によると、 喑視野画像をトモシンセシス法によ り画像処理するため、 X線喑視野画像の断層像を得ることができる。したがって従来 の透過型 ¾镍装置では観察することのできな力つた関節軟骨や***のガン巣等の深 さ方向の情報を含む投影画像を得ることができる。 [0044] As described above, according to the second embodiment of the present invention, in addition to the effects of the first embodiment, the following effects are obtained. For example, when the subject is a part having a joint such as a finger or knee or a breast, articular cartilage and breast cancer nests are difficult to identify clearly with a conventional transmission X-ray apparatus. In contrast, X-ray dark-field images eliminate articular cartilage and breasts to eliminate straight X-rays. It is possible to observe a part that slightly refracts at the edge of the cancer nest. However, it is not possible to grasp the depth information of a predetermined part of the subject from one X-ray X-ray image. According to this embodiment, since the eyelid image is image-processed by the tomosynthesis method, a tomographic image of the X-ray eyelid image can be obtained. Accordingly, it is possible to obtain a projection image including information in the depth direction such as a strong articular cartilage or a breast cancer nest that cannot be observed with a conventional transmission type ridge apparatus.
[0045] なお、第 1実施形態と同様に、第 2実施形態の変形例として、図 8に示すように被検 体 14と撮影面 16aとを同期させて回転させてもよい。この場合においても、被検体 14 と撮影面 16aとを同期して回転させる機構が必要となるため回転機構が複雑化する 、得られた画像の処理はさらに容易になる。  [0045] As in the first embodiment, as a modification of the second embodiment, the subject 14 and the imaging surface 16a may be rotated in synchronization as shown in FIG. Even in this case, since a mechanism for rotating the subject 14 and the imaging surface 16a in synchronism is required, the rotation mechanism becomes complicated, and the processing of the obtained image becomes easier.
実施例  Example
[0046] (第 1実施例）  [0046] (First embodiment)
上述の第 1実施形態に対応する装置で、以下の条件で X線画像を撮影し、トモシン セシス画像を得た結果について説明する。茨城県つくば市の高エネルギー加速器 研究機構の放射光施設におけるビームライン 14Bにて縦型ウィダラー光源によるシン クロトロン X線を使用して実際に基礎画像を撮影し、トモシンセシス法により断層像を 合成した。入射难は、 Si(333)回折面によるダブルクリスタルモノクロメータ 3aによ り 36. OkeVに単色ィ匕した。コリメータ 3bは、 Si(220)反射面力ら、 α =4. 9° の非 対称の角度で切断された非対称反射型モノクロメータ'コリメータを使用した。非対称 因子はこの条件下で 0. 025であり、コリメ一タ 3bにより入射 X線ビームの横寸法は約 40倍に拡大された。  A description will be given of the result of obtaining a tomosynthesis image by photographing an X-ray image under the following conditions with an apparatus corresponding to the first embodiment described above. A basic image was taken using synchrotron X-rays with a vertical widerer light source at the beamline 14B at the synchrotron radiation facility of Tsukuba City, Ibaraki Prefecture, and a tomogram was synthesized by the tomosynthesis method. The incident light was monochromatic to 36. OkeV by a double crystal monochromator 3a with a Si (333) diffraction plane. As the collimator 3b, an asymmetrical reflective monochromator collimator cut at an asymmetric angle of α = 4.9 ° from Si (220) reflecting surface force was used. The asymmetry factor was 0.025 under these conditions, and the collimator 3b expanded the lateral dimension of the incident X-ray beam by about 40 times.
[0047] 被検体 4は献体力 切断されホルマリンに浸けられた、インタタトな状態（スライス処 理ゃ、要部のむき出し処理等行っていないそのままの状態）の近位指節間関節（PIP J)を用いた。被検体 4を載置台に載置して、回転機構 9により、 X線の進行方向と垂 直な方向に対して 0 =— 5° 〜5° の範囲で 1° の間隔で回転した。そして全体とし て 11枚の投影画像を撮影した。  [0047] Subject 4 has a dedicated power. Proximal interphalangeal joint (PIP J) in an interrupted state that has been cut and soaked in formalin (without slicing or stripping the main part) Was used. The subject 4 was placed on the mounting table, and rotated by the rotation mechanism 9 at an interval of 1 ° in the range of 0 = −5 ° to 5 ° with respect to the X-ray traveling direction and the perpendicular direction. In total, 11 projected images were taken.
[0048] 撮影用のフィルムは、 Kodak社製のマンモグラフィー用フィルム Min—R2000を使 用した。高解像度取得のため、スクリーンは使用しなかった。露出時間は、基礎画像 において 5秒とした。なお、通常の 1枚で適正なコントラストを得ることのできる露出時 間は 55秒であるので、基礎画像を 11枚重ねることで、適正なコントラストを得ることが できる。この露出時間は、 2. 5GeV運転時のシンクロトロン 'リングにおいて、約 360 mAのリング電流で規格化した。このときの被検体 4表面における空間線量率は、約 0 . 15 (mGyZs)であった。 [0048] As a film for photography, Kodak's mammography film Min-R2000 was used. The screen was not used to obtain high resolution. Exposure time is the basic image 5 seconds. Note that the exposure time for obtaining a proper contrast with a normal image is 55 seconds, so it is possible to obtain an appropriate contrast by overlaying 11 basic images. This exposure time was normalized with a ring current of about 360 mA in a synchrotron ring during 2.5 GeV operation. At this time, the air dose rate on the surface of the subject 4 was about 0.15 (mGyZs).
[0049] 各 Θにおいて撮影した投影画像データを、処理装置 7により支点面 Fから距離 hだ け離れた平面に対して式 (3)により計算された距離 dだけ移動した。そして、 11枚の 基礎画像をシフト加算法により適切に移動して重ね合わせ、支点面 Fと平行で h ( = — 5mm)だけ離れた位置におけるトモシンセシス画像を合成した。この画像を、図 9 ( a)に示す。画像は、 X線量が少ない領域が白くなるように処理した。図 9 (b)は、トモ シンセシス画像を得るための 1枚の基礎画像である。露出時間が 5秒と短いため、コ ントラストがかなり低い。しかし、これらを重ね合わせることにより、図 9 (a)に示すように 、十分な S/N比を有する鮮明なコントラストを備えたトモシンセシス画像を得ることが できた。 [0049] The projection image data photographed at each Θ was moved by the processing device 7 by a distance d calculated by Equation (3) with respect to a plane separated from the fulcrum plane F by a distance h. Then, the 11 basic images were appropriately moved and overlaid by the shift addition method, and a tomosynthesis image at a position parallel to the fulcrum plane F and separated by h (= — 5 mm) was synthesized. This image is shown in Fig. 9 (a). Images were processed so that areas with low X-ray dose were white. Figure 9 (b) shows one basic image for obtaining a tomosynthesis image. Contrast is quite low due to the short exposure time of 5 seconds. However, by superimposing these, as shown in FIG. 9 (a), a tomosynthesis image with a clear contrast having a sufficient S / N ratio could be obtained.
[0050] また、図 9 (c)は、比較のための露出時間 55秒の通常の X線投影画像である。図 9 ( a)と比べると、深さ方向の情報が少なレ、ことがわかる。このようにトモシンセシス画像 によると、深さ方向の情報を得ることができる。  [0050] FIG. 9 (c) is a normal X-ray projection image with an exposure time of 55 seconds for comparison. Compared to Fig. 9 (a), there is less information in the depth direction. Thus, according to the tomosynthesis image, information in the depth direction can be obtained.
[0051] (第 2実施例）  [0051] (Second embodiment)
第 2実施形態に対応して、第 1実施例の載置台と撮影面との間に角度分析板を配 置し他状態で X線画像を撮影した。角度分析板は、 X線回折を利用してシリコン (22 0)面を同定して切削し且つ鏡面研磨したものである。角度分析板の厚みは、 1070 /z mであった。それを、 X線が通る実効的な厚さが 1107 μ ιηになるように傾けた。こ れにより直進する全ての X線は回折されて前方へ進まないブラッグ角度位置にセット された。他の条件は第 1実施例と同様で 镍画像を撮影した。  Corresponding to the second embodiment, an angle analysis plate was placed between the mounting table of the first example and the imaging surface, and X-ray images were taken in other states. The angle analysis plate is obtained by identifying, cutting, and mirror-polishing a silicon (220) surface using X-ray diffraction. The thickness of the angle analysis plate was 1070 / z m. It was tilted so that the effective thickness through which X-rays pass was 1107 μιη. As a result, all X-rays traveling straight were diffracted and set at the Bragg angle position where they did not travel forward. Other conditions were the same as in the first example, and a cocoon image was taken.
[0052] 図 10 (a) , (b)及び（c)は図 9 (a) , (b)及び (c)にそれぞれ相当する。図示するよう に、 X線喑視野法にトモシンセシス法を適用したことにより、従来の X線写真によって 見ることのできない関節軟骨部分を深さ方向の情報も含めて観察することができた。  [0052] FIGS. 10 (a), (b) and (c) correspond to FIGS. 9 (a), (b) and (c), respectively. As shown in the figure, by applying the tomosynthesis method to the X-ray acupuncture field method, it was possible to observe the articular cartilage portion that cannot be seen by conventional X-ray photographs, including information in the depth direction.
[0053] (第 3実施例） 第 2実施形態に対応して、第 2実施例と同様に撮影面との間に角度分析板を配置 した状態で X線画像を撮影した。また、この第 3実施例は、第 1実施形態の図 5 (b)及 び (c)で示した手法を第 2実施形態に適応し、複数の支点面 Fのそれぞれに対する 複数のトモシンセシス画像を求めた。 [0053] (Third embodiment) Corresponding to the second embodiment, an X-ray image was taken with an angle analysis plate placed between the imaging plane and the second embodiment as in the second example. Further, in this third example, the method shown in FIGS. 5B and 5C of the first embodiment is applied to the second embodiment, and a plurality of tomosynthesis images for each of a plurality of fulcrum surfaces F are obtained. Asked.
[0054] まず、回転機構 9により、 X線の進行方向と垂直な方向に対して Θ =—40° 〜40[0054] First, the rotation mechanism 9 makes Θ = --40 ° to 40 with respect to the direction perpendicular to the X-ray traveling direction.
° の範囲で 1° の間隔で回転した。そして全体として 81枚の投影画像を撮影した。 他の条件は第 2実施例と同様で X線画像を撮影した。 Rotated at 1 ° intervals in the range of °. A total of 81 projected images were taken. The other conditions were the same as in the second example, and an X-ray image was taken.
[0055] 第 1、 2実施例と同様に被検体 4は献体力 切断されホルマリンに浸けられた、イン タクトな状態 (スライス処理や、要部のむき出し処理等行っていないそのままの状態） の近位指節間関節 (PIPJ)を用レ、た。 [0055] As in the first and second embodiments, the subject 4 was cut off in the contact state and immersed in formalin, which was close to the intact state (the state in which the slicing process and the main part bare process were not performed). The interphalangeal joint (PIPJ) was used.
[0056] 撮影用の画像検出器は、 Photonic Science社製の CCDカメラ X-FDIを使用した。露 出時間は、基礎画像において 7秒（リング電流が 250mAのとき）とした。これは第 1、 2 実施形態における撮影線量と同等である。 [0056] A CCD camera X-FDI manufactured by Photonic Science was used as an image detector for photographing. The exposure time was 7 seconds (when the ring current was 250 mA) in the basic image. This is equivalent to the imaging dose in the first and second embodiments.
[0057] 81枚の基礎画像から連続する 11枚の基礎画像を取り出し、第 1、 2実施例と同様 にシフト加算すると、この 11枚の基礎画像の中心の基礎画像（支点面 Fにおける画 像）に平行なトモシンセシス画像が得られる。即ち、 0 =— 35° 〜35° の範囲で 1[0057] Eleven consecutive basic images are extracted from the 81 basic images, and shifted and added in the same manner as in the first and second embodiments, the basic image at the center of these 11 basic images (the image on the fulcrum plane F). Tomosynthesis image parallel to) is obtained. That is, 0 = — 1 in the range of 35 ° to 35 °
。 間隔の位置での基礎画像に平行な任意のトモシンセシス画像が放射状に得られ る。 . Arbitrary tomosynthesis images parallel to the basic image at intervals are obtained in a radial fashion.
[0058] 図 11 (a) , (b)及び (c)は 0 = _ 30° 、0° 、 30° を基準にして、前後— 5° 〜5 。 における 11枚の基礎画像を用いて h ( =— 2mm)だけ離れた位置におけるトモシ ンセシス画像を示す。図示するように、異なる方向力 被検体 4のトモシンセシス画像 を観察することができる。  [0058] Figures 11 (a), (b) and (c) are 0 = _ 30 °, 0 ° and 30 ° as front and back-5 ° to 5 °. The tomosynthesis image at a position separated by h (= — 2 mm) is shown using 11 basic images. As shown in the figure, tomosynthesis images of different directional force subjects 4 can be observed.

Claims

請求の範囲 The scope of the claims
[1] 平行放射線を被検体に照射し、 [1] Irradiate the subject with parallel radiation,
前記被検体を透過した放射線を検出して行う前記被検体の投影画像の撮影を、前 記被検体を回転させることにより前記放射線を異なる角度で前記被検体に入射させ て複数回行い、  Imaging of the projection image of the subject performed by detecting the radiation transmitted through the subject is performed a plurality of times by rotating the subject so that the radiation is incident on the subject at different angles,
該複数回の撮影により得られた前記被検体の複数の投影画像を合成してトモシン セシス画像を作成するトモシンセシス画像取得方法。  A tomosynthesis image obtaining method for creating a tomosynthesis image by synthesizing a plurality of projection images of the subject obtained by the plurality of times of imaging.
[2] 前記被検体を透過した前記放射線のうちの、前記被検体により屈折された放射線 のみを検出してトモシンセシス画像を作成することを特徴とする請求項 1に記載のトモ シンセシス画像取得方法。 [2] The tomosynthesis image acquisition method according to [1], wherein only the radiation refracted by the subject out of the radiation transmitted through the subject is detected to create a tomosynthesis image.
[3] 前記投影画像が、前記複数回の撮影において不動の位置で撮影されることを特徴 とする請求項 1又は 2に記載のトモシンセシス画像取得方法。 [3] The tomosynthesis image acquisition method according to [1] or [2], wherein the projected image is captured at a fixed position in the plurality of capturing operations.
[4] 前記投影画像が、前記複数回の撮影において前記被検体の回転と同期して回転 した位置で撮影されることを特徴とする請求項 1又は 2に記載のトモシンセシス画像 取得方法。 4. The tomosynthesis image acquisition method according to claim 1, wherein the projection image is captured at a position rotated in synchronization with rotation of the subject in the plurality of imaging.
[5] 前記放射線が X線又は中性子線であることを特徴とする請求項 1〜4のいずれか 1 項に記載のトモシンセシス画像取得方法。  5. The tomosynthesis image acquisition method according to any one of claims 1 to 4, wherein the radiation is an X-ray or a neutron beam.
[6] 前記トモシンセシス画像を、前記被検体の回転中心を通る複数の支点面に対して それぞれ求めることを特徴とする請求項 1〜5のいずれ力 1項に記載のトモシンセシス 画像取得方法。 6. The tomosynthesis image acquisition method according to any one of claims 1 to 5, wherein the tomosynthesis image is obtained for each of a plurality of fulcrum surfaces passing through the rotation center of the subject.
[7] 入射する放射線を平行にする平行化手段と、 [7] collimating means for collimating incident radiation;
, 前記平行にされた放射線の照射位置に配置される被検体を回転させる回転手段と 前記被検体を透過した放射線を検出して前記被検体の投影画像を撮影する撮影 手段と、  Rotating means for rotating the subject arranged at the radiation irradiation position made parallel, and imaging means for detecting the radiation transmitted through the subject and photographing the projection image of the subject;
前記回転手段により前記被検体を回転させることにより前記放射線を異なる角度で 前記被検体に入射させて撮影された前記被検体の複数の投影画像を合成してトモ シンセシス画像を作成する処理手段と、 を備えるトモシンセシス装置。 Processing means for creating a tomosynthesis image by combining a plurality of projection images of the subject imaged by causing the radiation to enter the subject at different angles by rotating the subject by the rotating means; A tomosynthesis apparatus comprising:
[8] 前記平行化手段に入射する放射線を発生する放射線発生源をさらに備えることを 特徴とする請求項 7に記載のトモシンセシス装置。 8. The tomosynthesis apparatus according to claim 7, further comprising a radiation generation source that generates radiation incident on the collimating means.
[9] 前記被検体と前記撮影手段との間に配置されるとともに、前記被検体を透過した前 記放射線のうちの前記被検体により屈折された放射線のみを透過させる放射線分離 手段をさらに備えることを特徴とする請求項 7又は 8に記載のトモシンセシス装置。 [9] The apparatus further includes a radiation separating unit that is disposed between the subject and the imaging unit and transmits only the radiation refracted by the subject out of the radiation transmitted through the subject. The tomosynthesis apparatus according to claim 7 or 8.
[10] 前記撮影手段の撮影面が、前記複数の撮影において不動であることを特徴とする 請求項 7〜9のいずれ力 1項に記載のトモシンセシス装置。 10. The tomosynthesis apparatus according to any one of claims 7 to 9, wherein a photographing surface of the photographing unit is immovable in the plurality of photographings.
[11] 前記撮影手段の撮影面が、前記複数の撮影において前記被検体の回転と同期し て回転することを特徴とする請求項 7〜9のいずれ力 1項に記載のトモシンセシス装 置。 11. The tomosynthesis apparatus according to any one of claims 7 to 9, wherein an imaging surface of the imaging unit rotates in synchronization with rotation of the subject in the plurality of imaging.
[12] 前記放射線力 線又は中性子線であることを特徴とする請求項 7〜： 11のいずれか [12] The method according to any one of [7] to [11], wherein the radiation force line or the neutron beam is used.
1項に記載のトモシンセシス装置。 The tomosynthesis apparatus according to item 1.
[13] 前記処理手段が、前記トモシンセシス画像を、前記被検体の回転中心を通る複数 の支点面に対してそれぞれ求めることを特徴とする請求項 7〜： 12のいずれ力 4項に 記載のトモシンセシス装置。 [13] The tomosynthesis according to any one of [7] to [12], wherein the processing means obtains the tomosynthesis image with respect to a plurality of fulcrum surfaces passing through the rotation center of the subject. apparatus.
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