JPH06235704A - Monochromatic x-ray ct system - Google Patents
Monochromatic x-ray ct systemInfo
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- JPH06235704A JPH06235704A JP5044505A JP4450593A JPH06235704A JP H06235704 A JPH06235704 A JP H06235704A JP 5044505 A JP5044505 A JP 5044505A JP 4450593 A JP4450593 A JP 4450593A JP H06235704 A JPH06235704 A JP H06235704A
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- monochromatic
- single crystal
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、Ｘ線源として平行度が
高い白色Ｘ線（例えばシンクロトロン放射光）から、単
結晶等を利用して任意の波長で単色化および拡大を行う
ことにより、高分解能および高コントラストな断層像を
得ることができる単色Ｘ線ＣＴ装置に関する。BACKGROUND OF THE INVENTION The present invention uses a single crystal or the like for monochromaticization and expansion from white X-rays (for example, synchrotron radiation) having a high degree of parallelism as an X-ray source. , A monochromatic X-ray CT apparatus capable of obtaining a high resolution and high contrast tomographic image.
【０００２】[0002]
【従来の技術】Ｘ線ＣＴ法は、現在では医療診断の有力
な手法として、広く医療機関で用いられている。最近、
本手法は工業材料の特定元素分布や微小欠陥の観察に応
用されるなど、その広い技術的可能性が注目されてい
る。このような背景のもとに、Ｘ線ＣＴ装置において被
検体に対する高分解能および定量的な断層面計測の機能
を実現する試みがなされている。2. Description of the Related Art The X-ray CT method is now widely used in medical institutions as a powerful method for medical diagnosis. Recently,
This method has been attracting attention for its wide technical potential, such as being applied to the observation of specific element distributions and minute defects in industrial materials. Against this background, attempts have been made to realize a high-resolution and quantitative tomographic plane measurement function for an object in an X-ray CT apparatus.
【０００３】定量的な元素・密度分布計測には、単色Ｘ
線を利用する必要があり、シンクロトロン放射光などの
指向性が強い白色Ｘ線を結晶分光器により単色化し、そ
れを光源としたＣＴ装置によりＣＴ画像を得る方法があ
る。単色Ｘ線を利用する理由は、物質のＸ線吸収係数が
Ｘ線の波長に依存しており、波長幅が狭い単色Ｘ線を用
いると波長依存性による影響を低減することができ、こ
れにより定量性が優れた測定を行えることによる。For quantitative element / density distribution measurement, single color X
There is a method in which it is necessary to use a line, and white X-rays having strong directivity such as synchrotron radiation are made monochromatic by a crystal spectroscope and a CT image is obtained by a CT device using the same as a light source. The reason for using monochromatic X-rays is that the X-ray absorption coefficient of a substance depends on the wavelength of X-rays, and using monochromatic X-rays with a narrow wavelength width can reduce the effect of wavelength dependence. This is because the measurement can be performed with excellent quantification.
【０００４】一方、高分解能なＸ線ＣＴ装置は、被検体
透過後の単色・平行な透過Ｘ線を、単結晶の非対称反射
を利用することにより拡大する手法となっている。ここ
に、単結晶の非対称反射とは、結晶表面とブラッグ反射
を生じる格子面が平行でない場合にブラッグ反射後に入
射Ｘ線像が拡大される現象のことである。したがって、
小さい物体に対して単結晶の非対称反射を利用して投影
像を拡大することによって、検出器の一画素の大きさが
一定であっても、相対的に検出器の画素の大きさを小さ
くし、かつ有効画素数を増大させることができ、これに
より高分解能ＣＴ像を得ることができる。On the other hand, the high-resolution X-ray CT apparatus is a method of enlarging the monochromatic and parallel transmitted X-rays that have passed through the object by utilizing the asymmetric reflection of a single crystal. Here, the asymmetric reflection of a single crystal is a phenomenon in which an incident X-ray image is enlarged after Bragg reflection when the crystal surface and the lattice plane that causes Bragg reflection are not parallel. Therefore,
By enlarging the projected image by using asymmetric reflection of a single crystal for a small object, even if the size of one pixel of the detector is constant, the size of the pixel of the detector can be made relatively small. In addition, the number of effective pixels can be increased, whereby a high resolution CT image can be obtained.
【０００５】図３は、これらの方法を用いた従来のＸ線
ＣＴ装置を示している。この装置では、まず白色Ｘ線
（入射Ｘ線１１）を結晶分光器の単結晶１２ａ，１２ｂ
のブラッグ反射を用いて所望のＸ線エネルギーに単色化
し、これを被検体１５に照射する。そして、透過したＸ
線像を単結晶１３の非対称反射を利用して拡大し、この
拡大された投影像は、Ｘ線検出器１４によって検出され
る。上記のような単色Ｘ線を利用したＸ線ＣＴ装置とし
て、例えば特開昭６３−５３４５６号公報、特開昭６１
−２５６２４３号公報等により開示されている。FIG. 3 shows a conventional X-ray CT apparatus using these methods. In this apparatus, first, white X-rays (incident X-rays 11) are converted into single crystals 12a and 12b of a crystal spectroscope.
The target 15 is irradiated with the desired X-ray energy by using the Bragg reflection. And the transmitted X
The line image is magnified by utilizing the asymmetric reflection of the single crystal 13, and the magnified projected image is detected by the X-ray detector 14. As an X-ray CT apparatus using the above-mentioned monochromatic X-ray, for example, JP-A-63-53456 and JP-A-61.
It is disclosed in Japanese Patent Publication No. 2562633.
【０００６】[0006]
【発明が解決しようとする課題】従来の技術では、上述
のように単結晶３の非対称反射により透過Ｘ線を拡大す
ることで、相対的な検出器の分解能の向上を図ってい
る。しかしながら、かかる従来装置の光学系おいて、以
下の問題があった。In the conventional technique, the transmitted X-rays are enlarged by the asymmetrical reflection of the single crystal 3 as described above, so that the relative resolution of the detector is improved. However, the optical system of such a conventional device has the following problems.
【０００７】シンクロトロン放射光などの指向性が強い
白色Ｘ線の場合、Ｘ線に偏光性があり、この偏光ベクト
ルは、シンクロトロン放射光の軌道面に水平な方向であ
る。また、結晶素子を利用して偏光ベクトルを含む平面
内でのＸ線の回折は、θB をブラッグ反射角としたとき
ｃｏｓ２θB 倍の強度減少を伴い、偏光ベクトルを含む
平面に対する直交方向への回折は強度減少が伴わないこ
とが知られている。In the case of white X-rays having a strong directivity such as synchrotron radiation, the X-rays have polarizability, and this polarization vector is a direction horizontal to the orbital plane of the synchrotron radiation. The diffraction of X-rays in a plane including the polarization vector by using a crystal element, theta B with the intensity decrease of the cos B times when the Bragg reflection angle, in the direction perpendicular to the plane including the polarization vector It is known that diffraction is not accompanied by a decrease in intensity.
【０００８】ところが、従来の装置は、指向性が強い白
色Ｘ線（入射Ｘ線１１）からの連続Ｘ線を結晶分光器
（１２ａ，１２ｂ）により単色化し、それを光源に用い
て、図３に示すように、被検体１４の投影データをビー
ム幅が広い水平方向で検出するように非対称結晶素子１
３を配置する。このため、回折したＸ線は拡大による強
度減少に加えて、偏光性によるｃｏｓ２θB 倍の強度減
少が生じていた。したがって、従来装置では強度低下を
抑えるためにはθB はできるだけ小さくする必要があ
る。そして低指数の回折面の使用に限定される、あるい
は単色化するＸ線の波長が限定されるという問題があっ
た。また、θB を小さくすることから結晶表面の加工精
度を著しく良くしなければ、品質の良い反射Ｘ線が得ら
れないといった問題もあった。However, in the conventional device, the continuous X-rays from the white X-rays (incident X-rays 11) having a strong directivity are monochromaticized by the crystal spectroscopes (12a, 12b) and used as a light source, and as shown in FIG. As shown in FIG. 1, the asymmetric crystal element 1 is designed to detect the projection data of the subject 14 in the horizontal direction where the beam width is wide.
Place 3. Therefore, the diffracted X-ray had a cos 2θ B- fold intensity decrease due to the polarization property in addition to the intensity decrease due to expansion. Therefore, in the conventional device, it is necessary to make θ B as small as possible in order to suppress the strength reduction. Then, there is a problem that the use of a diffractive surface having a low index is limited, or the wavelength of an X-ray that is monochromatic is limited. Further, there is also a problem that a high-quality reflected X-ray cannot be obtained unless the processing accuracy of the crystal surface is remarkably improved because θ B is made small.
【０００９】ここで、図４は、非対称反射単結晶による
入射Ｘ線の拡大光学系の原理を示している。非対称反射
単結晶は、結晶表面２０と所望の回折面３０とが角度α
をなす結晶分光素子である。入射Ｘ線１１は、非対称反
射単結晶の回折面３０によってブラッグ反射される。そ
して、結晶表面２０に対する入射角（θIN）と反射角
（θOUT ）が異なるために、入射Ｘ線１１は拡大されて
反射される。非対称因子ｂをｂ＝ｓｉｎθOUT ／ｓｉｎ
θINとすると、Ｘ線幅の拡大率はＬOUT ／ＬIN＝ｂで表
される。ここで、θIN＝θB −α、θOUT ＝θB ＋α、
θB はブラッグ角であり、次式で示される。 θB ＝ｓｉｎ-1（λ・（ｈ2 ＋ｋ2 ＋ｌ2 ）1/2 ／ｄ） 但し、λは回折Ｘ線の波長、（ｈｋｌ）は結晶格子面、
ｄは結晶格子定数である。したがって、偏光性による強
度減少を抑えるためにθB を小さくするには、低指数の
結晶格子面、あるいは短波長を選択する必要があった。
また結晶の表面粗さｒはｒ＝ｓｉｎθINで決定されるの
で、θB が小さくなると入射角θINが小さくなることか
ら、表面粗さｒの許容範囲も小さくなり平面加工精度も
厳しいものとなる。Here, FIG. 4 shows the principle of an incident X-ray magnifying optical system using an asymmetric reflection single crystal. In the asymmetric reflection single crystal, the crystal surface 20 and the desired diffraction surface 30 form an angle α.
It is a crystal spectroscopic element that forms The incident X-ray 11 is Bragg-reflected by the diffractive surface 30 of the asymmetric reflection single crystal. Since the incident angle (θ IN ) and the reflection angle (θ OUT ) with respect to the crystal surface 20 are different, the incident X-ray 11 is magnified and reflected. The asymmetry factor b is b = sin θ OUT / sin
When θ IN is set, the expansion rate of the X-ray width is represented by L OUT / L IN = b. Where θ IN = θ B −α, θ OUT = θ B + α,
θ B is the Bragg angle and is represented by the following equation. θ B = sin −1 (λ · (h 2 + k 2 + l 2 ) 1/2 / d) where λ is the wavelength of the diffracted X-ray, (hkl) is the crystal lattice plane,
d is a crystal lattice constant. Therefore, in order to reduce θ B in order to suppress the intensity decrease due to the polarization property, it is necessary to select a crystal lattice plane with a low index or a short wavelength.
Further, since the surface roughness r of the crystal is determined by r = sin θ IN , the incident angle θ IN becomes smaller as θ B becomes smaller. Therefore, the allowable range of the surface roughness r becomes smaller and the surface processing accuracy becomes severe. Become.
【００１０】本発明は上記事情に基づいてなされたもの
であり、簡便な手段によりＸ線の偏光性の影響なしに、
微小な被検体を観察する際に高分解能なＣＴ画像が得ら
れ、かつ大きな被検体のＣＴ画像を観察する場合にも好
適な単色Ｘ線ＣＴ装置を提供することを目的とするもの
である。The present invention has been made based on the above circumstances, and it is possible to use a simple means without affecting the polarization of X-rays.
It is an object of the present invention to provide a monochromatic X-ray CT apparatus that can obtain a high-resolution CT image when observing a minute subject and is suitable for observing a CT image of a large subject.
【００１１】[0011]
【課題を解決するための手段】本発明の単色Ｘ線ＣＴ装
置は、指向性が強い白色Ｘ線から任意の波長を取り出す
Ｘ線分光器と、被検体を走査・回転することができる被
検体ステージと、二次元Ｘ線検出器と、該二次元Ｘ線検
出器からの信号の収集，Ｘ線分光器及び前記被検体の位
置制御を行うコンピュータと、ＣＴ画像再構成用のソフ
トウェアまたはハードウェアとを備えている 特に、指向性が強い白色Ｘ線の直進偏光ベクトルの方向
をｘ方向、ｘ方向に垂直な方向をｙ方向として、被検体
後方に、被検体を透過した透過Ｘ線をｙ方向に回折する
非対称反射単結晶素子を設け、ｘ方向あるいはｙ方向に
検出走査を行いかつ検出領域が任意に変化できる二次元
Ｘ線検出器を設け、被検体を透過した二次元投影像を前
記非対称反射単結晶素子で回折させた後、前記二次元Ｘ
線検出器で検出する際に、微小な被検体を高分解能な断
層像で観察するｘ方向と被検体の回転軸とを一致させる
高分解能用被検体ステージと、ｘ方向にＸ線ビームをコ
リメートする手段と、を設けたものである。A monochromatic X-ray CT apparatus of the present invention is an X-ray spectroscope for extracting an arbitrary wavelength from a white X-ray having a strong directivity, and an object capable of scanning and rotating the object. Stage, two-dimensional X-ray detector, computer for collecting signals from the two-dimensional X-ray detector, X-ray spectroscope and position control of the subject, and software or hardware for CT image reconstruction In particular, the direction of the straight polarization vector of the white X-ray having strong directivity is the x direction, and the direction perpendicular to the x direction is the y direction, and the transmitted X-ray transmitted through the subject is y behind the subject. A two-dimensional X-ray detector, which is provided with an asymmetric reflection single crystal element that diffracts in the direction, performs a scanning scan in the x direction or the y direction, and can arbitrarily change the detection region, Asymmetric reflective single crystal element After folding, the two-dimensional X
When detecting with a line detector, a high-resolution object stage for observing a minute object with a high-resolution tomographic image so that the x-direction and the rotation axis of the object coincide with each other, and an X-ray beam is collimated in the x-direction. And means for doing so.
【００１２】また、本発明の単色Ｘ線ＣＴ装置は、大き
な被検体を観察する際に、上記ｙ方向と被検体の回転軸
とを一致させる大型被検体ステージを設け、上記高分解
能用被検体ステージと該大型被検体ステージを適宜切り
替える移動手段を設けたものである。Further, the monochromatic X-ray CT apparatus of the present invention is provided with a large-sized subject stage for aligning the y-direction with the rotation axis of the subject when a large subject is observed, A moving means for appropriately switching the stage and the large subject stage is provided.
【００１３】[0013]
【作用】本発明に係る単色Ｘ線ＣＴ装置は上記の構成に
よって、Ｘ線分光器の単結晶のロッキング・カーブの分
散角によって支配される分散角を持つ単色Ｘ線束が、被
検体に照射される。微小な被検体を高分解能で観察する
際には、高分解能用被検体ステージにより、ｘ方向と被
検体の回転軸とが一致するように設定されて、被検体を
透過後の二次元投影像が被検体後方に設けた、ｙ方向に
回折する非対称反射単結晶素子に入射される。このとき
Ｘ線分光器の単結晶のロッキング・カーブによって決定
されるｙ方向の分散角は数秒から数十秒と極めて小さい
ので、二次元投影像は分散角により生じる投影像のボケ
が低減される。被検体後方に設置した、ｙ方向に回折す
る非対称反射単結晶素子は、Ｘ線の直進偏光ベクトルを
含む平面に対して鉛直方向に回折するので、Ｘ線の偏光
性による強度減少を生じること無く、被検体に照射され
たＸ線の波長以外の散乱Ｘ線を除去する。またｙ方向に
投影像を拡大し、ｘ方向をコリメートする手段によりｘ
方向に生じる散乱線の影響が低減されるので、ｙ方向に
分解能が高い二次元投影像が得られる。In the monochromatic X-ray CT apparatus according to the present invention, the subject is irradiated with a monochromatic X-ray flux having a dispersion angle dominated by the dispersion angle of the rocking curve of the single crystal of the X-ray spectroscope. It When observing a minute object with high resolution, the high-resolution object stage is set so that the x-direction and the rotation axis of the object are aligned, and a two-dimensional projection image after passing through the object is obtained. Is incident on an asymmetric reflective single crystal element diffracted in the y direction, which is provided behind the subject. At this time, the dispersion angle in the y direction determined by the rocking curve of the single crystal of the X-ray spectroscope is as small as several seconds to several tens seconds, so that the two-dimensional projection image has a reduced blur of the projection image caused by the dispersion angle. . Since the asymmetric reflection single crystal element diffracted in the y direction, which is installed behind the object, diffracts in the vertical direction with respect to the plane containing the linear polarization vector of the X-ray, there is no decrease in the intensity due to the polarization of the X-ray. The scattered X-rays other than the wavelength of the X-rays irradiated on the subject are removed. In addition, the projection image is magnified in the y direction and x
Since the influence of scattered rays generated in the direction is reduced, a two-dimensional projection image with high resolution in the y direction can be obtained.
【００１４】得られた二次元投影像は検出走査を垂直方
向に行いかつ検出領域が任意に変化可能な二次元Ｘ線検
出器によって、二次元投影像の拡大率に適した有効画素
数で、二次元投影像の高分解能なｙ方向成分が再構成投
影データとして収集される。したがって、Ｘ線の影響を
考慮することなく任意の波長を選択することができ、か
つ高次の結晶格子面を任意に選択できるので、結晶表面
の加工精度も緩くて何ら差し支えない。The obtained two-dimensional projection image is detected by a two-dimensional X-ray detector that performs detection scanning in the vertical direction and the detection area can be arbitrarily changed, and has an effective pixel number suitable for the magnification of the two-dimensional projection image. The high-resolution y-direction component of the two-dimensional projection image is collected as reconstructed projection data. Therefore, an arbitrary wavelength can be selected without considering the influence of X-rays, and a high-order crystal lattice plane can be arbitrarily selected, so that the processing accuracy of the crystal surface is low and there is no problem.
【００１５】また、大きな被検体の三次元断層像を観察
する際は、高分解能用被検体ステージと大型用被検体ス
テージを切り替える手段により、大型被検体ステージに
切り替えられる。そしてＸ線分光器により拡大された入
射Ｘ線が、ｙ方向と被検体の回転軸とを一致させる大型
被検体ステージにより、ｘ方向のビーム幅と同程度の大
きさの被検体二次元投影像として被検体後方に設置した
非対称反射単結晶素子に入射される。上述したようにＸ
線の偏光性により強度減少なしにＳ／Ｎ比の良い高コン
トラストな投影像が反射され、検出走査をｘ方向に行
い、かつ検出領域が任意に変化可能な二次元Ｘ線検出器
によって、二次元投影像の大きさに適した有効画素数で
ｘ方向成分が再構成投影データとして収集される。Further, when observing a three-dimensional tomographic image of a large subject, the means for switching between the high-resolution subject stage and the large subject stage can be switched to the large subject stage. Then, the incident X-ray magnified by the X-ray spectroscope is subjected to a two-dimensional projection image of the subject having a size almost equal to the beam width in the x direction by the large subject stage that matches the y-direction with the rotation axis of the subject. Is incident on the asymmetric reflection single crystal element installed behind the subject. X as above
Due to the polarizability of the line, a high-contrast projected image with a good S / N ratio is reflected without intensity reduction, the detection scan is performed in the x-direction, and a two-dimensional X-ray detector capable of arbitrarily changing the detection region is used to The x-direction component is collected as reconstructed projection data with the number of effective pixels suitable for the size of the three-dimensional projection image.
【００１６】[0016]
【実施例】以下に、本発明による単色Ｘ線ＣＴ装置の一
実施例について図面を参照して、詳細に説明する。図１
及び図２は、本発明の単色Ｘ線ＣＴ装置の一実施例によ
る主構成部分の配置関係を示す図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a monochromatic X-ray CT apparatus according to the present invention will be described in detail below with reference to the drawings. Figure 1
2 and 2 are views showing the arrangement relationship of the main constituent parts according to one embodiment of the monochromatic X-ray CT apparatus of the present invention.
【００１７】本発明装置は、白色で平行なＸ線１が結晶
分光器２の単結晶２ａ，２ｂにより単色化されたＸ線束
８、被検体に入射するＸ線の形状を決めるコリメータ
５、被検体を支持する回転・走査可能な高分解能用被検
体ステージ６、大型用被検体ステージ７、Ｘ線像の垂直
成分を拡大する単結晶素子３及び二次元Ｘ線検出器４に
より構成される。図１において高分解能で断層像を観察
したい微小被検体をＡ、また図２において高コントラス
トで断層像を観察したい大型被検体をＢにより、それぞ
れ示してある。また図中、Ｘ線の直進偏光ベクトルの方
向をｘ軸、このｘ軸に垂直な方向をｙ軸として示してあ
る。The apparatus of the present invention comprises an X-ray flux 8 in which white and parallel X-rays 1 are monochromatized by the single crystals 2a and 2b of the crystal spectroscope 2, a collimator 5 for determining the shape of X-rays incident on the subject, and an object to be examined. It is composed of a rotatable and scannable high-resolution subject stage 6 that supports the subject, a large-sized subject stage 7, a single crystal element 3 that magnifies the vertical component of the X-ray image, and a two-dimensional X-ray detector 4. In FIG. 1, a small object for which a tomographic image is to be observed with high resolution is indicated by A, and a large object for which a tomographic image is to be observed with high contrast is indicated by B in FIG. Further, in the figure, the direction of the linearly polarized light vector of the X-ray is shown as the x-axis, and the direction perpendicular to this x-axis is shown as the y-axis.
【００１８】本実施例では、シンクロトロン放射光の白
色Ｘ線源から、ビームサイズが水平方向（ｘ方向）、垂
直方向（ｙ方向）にそれぞれ１５０ｍｍ、３ｍｍのＸ線
１が結晶分光器２の単結晶２ａに入射される。結晶分光
器２の単結晶２ａ，２ｂ、非対称反射単結晶素子３には
Ｇｅ単結晶を用い、回折を生じさせる単結晶２ａ，２ｂ
及び３の結晶格子面をそれぞれ（３３３），（５１１）
及び（５１１）に選定し、単結晶２ａ，３の結晶格子面
（５１１）と実際の結晶表面とのなす角αを３０°に設
定する。また二次元Ｘ線検出器としては、蛍光体でＸ線
像を可視光に変換し、光学レンズ系を用いて二次元ＣＣ
Ｄ上で結像する検出器が使用される。In the present embodiment, from the white X-ray source of synchrotron radiation, X-rays 1 having a beam size of 150 mm and 3 mm in the horizontal direction (x direction) and the vertical direction (y direction) are emitted from the crystal spectrometer 2. It is incident on the single crystal 2a. Ge single crystals are used for the single crystals 2a and 2b of the crystal spectroscope 2 and the asymmetric reflection single crystal element 3, and the single crystals 2a and 2b for causing diffraction are used.
And the crystal lattice planes of 3 are (333) and (511), respectively.
And (511), and the angle α between the crystal lattice plane (511) of the single crystals 2a and 3 and the actual crystal surface is set to 30 °. As a two-dimensional X-ray detector, a fluorescent substance converts an X-ray image into visible light, and an optical lens system is used to generate a two-dimensional CC.
A detector that images on D is used.
【００１９】まず、図１において、結晶分光器２により
白色Ｘ線から波長１．５４オングストロームのＸ線を単
色化し、被検体Ａの断層像を高分解能に観察する場合に
ついて説明する。結晶分光器２によって単色化される波
長１．５４オングストロームのＸ線束８は、単結晶２ｂ
によって縦の広がりが１１．２ｍｍのＸ線束に拡大され
る。すなわちＸ線束８は３．３７倍に拡大される。被検
体Ａは高分解能用被検体ステージ６によって、ｘ方向と
該被検Ａ体の回転軸とが一致するように設定される。こ
のため、被検体Ａを透過し、被検体Ａの波長１．５４オ
ングストロームのＸ線吸収係数に依存した強度分布を有
する、ｙ方向の広がり１１．２ｍｍのＸ線束は、非対称
反射結晶素子３の（５１１）面で回折・拡大されて、縦
方向の広がり４１．８ｍｍのＸ線束となる。そして、二
次元Ｘ線検出器４で拡大率に適した有効画素数で被検体
Ａの断面方向（垂直方向）に検出走査され、投影データ
として収集される。First, referring to FIG. 1, a case will be described in which the X-ray having a wavelength of 1.54 angstrom is converted into a monochromatic color from the white X-ray by the crystal spectroscope 2 and the tomographic image of the subject A is observed with high resolution. The X-ray flux 8 having a wavelength of 1.54 angstrom which is monochromatic by the crystal spectrometer 2 is a single crystal 2b.
Extends the longitudinal extent to an X-ray flux of 11.2 mm. That is, the X-ray flux 8 is magnified 3.37 times. The subject A is set by the high-resolution subject stage 6 so that the x direction and the rotation axis of the subject A body coincide with each other. For this reason, an X-ray flux having an intensity distribution dependent on the X-ray absorption coefficient of the wavelength of 1.54 angstroms of the subject A and having a spread of 11.2 mm in the y-direction is generated by the asymmetric reflection crystal element 3. It is diffracted / enlarged by the (511) plane to form an X-ray flux having a longitudinal spread of 41.8 mm. Then, the two-dimensional X-ray detector 4 detects and scans in the cross-sectional direction (vertical direction) of the subject A with the number of effective pixels suitable for the magnification, and collects it as projection data.
【００２０】このとき非対称反射結晶素子３は、二次元
投影像をＸ線の偏光ベクトルの方向に対して鉛直方向に
回折・拡大しているので、偏光性による強度減少は生じ
ない。非対称反射単結晶素子３に入射する二次元投影像
の被検体断面方向の成分は分散角により生じるボケや散
乱Ｘ線による投影データの劣化を著しく低減することが
できる。さらに上記のように、３．７３倍に拡大される
ので、Ｘ線検出器固有の分解能に対し３．７３倍の空間
分解能で、偏光性による強度減少を生じることなく投影
データを収集することが可能となる。At this time, since the asymmetric reflection crystal element 3 diffracts and enlarges the two-dimensional projection image in the direction perpendicular to the direction of the polarization vector of the X-ray, the intensity reduction due to the polarization does not occur. The component of the two-dimensional projection image incident on the asymmetric reflection single crystal element 3 in the cross-sectional direction of the subject can significantly reduce the blurring caused by the dispersion angle and the deterioration of the projection data due to scattered X-rays. Further, as described above, since the magnification is 3.73 times, projection data can be collected with a spatial resolution of 3.73 times the resolution specific to the X-ray detector without causing intensity decrease due to polarization. It will be possible.
【００２１】次に、図２において、大きな被検体を観察
する場合について説明する。高分解能用被検体ステージ
６及び大型被検体ステージ７は、観察する被検体の目的
により、図には示さない適宜の移動機構により切り替わ
るように設定されている。図２に示すように大きな被検
体は，大型被検体ステージ７に設置された構成となる。
大型被検体Ｂは大型被検体ステージ７によって、ｙ方向
と被検体の回転軸とが一致するように設定される。これ
により水平方向のビームサイズ１５０ｍｍ以内の断面の
観察が可能となる。本実施例のような光学系では水平方
向の拡大は行われることはないので、被検体Ｂを透過
し、被検体Ｂの波長１．５４オングストロームのＸ線の
吸収係数に依存した強度を有する、ｘ方向の広がり１５
０ｍｍのＸ線束が、非対称反射結晶素子３の（５５１）
面で回折され、二次元Ｘ線検出器２０で断面方向（水平
方向）に検出走査され、投影データとして収集される。Next, referring to FIG. 2, a case of observing a large object will be described. The high-resolution subject stage 6 and the large-sized subject stage 7 are set so as to be switched by an appropriate moving mechanism (not shown) depending on the purpose of the subject to be observed. As shown in FIG. 2, a large subject is installed on the large subject stage 7.
The large subject B is set by the large subject stage 7 so that the y-direction and the rotation axis of the subject match. This makes it possible to observe a cross section within a horizontal beam size of 150 mm. In the optical system as in the present embodiment, since the horizontal expansion is not performed, the light having the intensity which is transmitted through the subject B and depends on the X-ray absorption coefficient of the subject B having a wavelength of 1.54 angstroms is obtained. Spread in the x direction 15
The 0 mm X-ray flux is (551) of the asymmetric reflection crystal element 3
The light is diffracted on the surface, detected and scanned in the cross-sectional direction (horizontal direction) by the two-dimensional X-ray detector 20, and collected as projection data.
【００２２】[0022]
【発明の効果】以上説明したように本発明によれば、Ｘ
線源として平行度が高い白色Ｘ線（例えばシンクロトロ
ン放射光）から単結晶等を利用して任意の波長で単色化
および拡大を行うことにより、高分解能および高コント
ラストな断層像を得る単色Ｘ線ＣＴ装置において、Ｘ線
の偏光性による強度減少、選択波長や結晶格子面の選択
の制限に関係せずに、微小な被検体を観察する際には高
分解能なＣＴ画像が得られ、また大きな被検体のＣＴ画
像も得ることができるＸ線ＣＴ装置を実現することがで
きる。これにより工業材料、生体などの検査に大きく寄
与する等の利点を有している。As described above, according to the present invention, X
A monochromatic X that obtains a high-resolution and high-contrast tomographic image by performing monochromaticization and expansion at a desired wavelength from a white X-ray with high parallelism (eg, synchrotron radiation) as a radiation source using a single crystal or the like. In a linear CT apparatus, a high-resolution CT image can be obtained when observing a minute object regardless of a decrease in intensity due to the polarization of X-rays and restrictions on selection wavelength and selection of crystal lattice planes. It is possible to realize an X-ray CT apparatus capable of obtaining a CT image of a large subject. This has the advantage that it greatly contributes to the inspection of industrial materials and living bodies.
【図１】本発明の単色Ｘ線ＣＴ装置の一実施例による構
成例を示す斜視図である。FIG. 1 is a perspective view showing a configuration example according to an embodiment of a monochromatic X-ray CT apparatus of the present invention.
【図２】本発明の上記単色Ｘ線ＣＴ装置において、大き
な被検体を観察する場合の構成例を示す斜視図である。FIG. 2 is a perspective view showing a configuration example when a large subject is observed in the monochromatic X-ray CT apparatus of the present invention.
【図３】従来の単色Ｘ線ＣＴ装置の構成を示す図であ
る。FIG. 3 is a diagram showing a configuration of a conventional monochromatic X-ray CT apparatus.
【図４】従来の単色Ｘ線ＣＴ装置における非対称単結晶
素子により入射Ｘ線を単色・拡大する原理を説明するた
めの上記非対称単結晶素子の部分拡大図である。FIG. 4 is a partially enlarged view of the asymmetric single crystal element for explaining the principle of monochromatic / enlarged incident X-ray by the asymmetric single crystal element in the conventional monochromatic X-ray CT apparatus.
１ 白色で平行なＸ線 ２ 結晶分光器 ２ａ，２ｂ 結晶分光器の単結晶 ３ 非対称反射単結晶素子 ４ 二次元Ｘ線検出器 ５ コリメータ ６ 高分解能用被検体ステージ ７ 大型被検体ステージ ８ 単色Ｘ線束 １１ 入射Ｘ線 １２ａ，１２ｂ 結晶分光器の単結晶 １３ 非対称反射単結晶素子 １４ Ｘ線検出器 ２０ 結晶表面 ３０ 結晶の回折面 ５０ 被検体 Ａ 微小被検体 Ｂ 大型被検体 1 White and parallel X-rays 2 Crystal spectrometers 2a, 2b Single crystal of crystal spectrometer 3 Asymmetric reflection single crystal element 4 Two-dimensional X-ray detector 5 Collimator 6 High resolution sample stage 7 Large sample stage 8 Monochromatic X Ray bundle 11 Incident X-rays 12a, 12b Single crystal of crystal spectroscope 13 Asymmetric reflection single crystal element 14 X-ray detector 20 Crystal surface 30 Crystal diffraction surface 50 Specimen A Small specimen B Large specimen
───────────────────────────────────────────────────── フロントページの続き (72)発明者 永田 泰昭 相模原市淵野辺５−10−１ 新日本製鐵株 式会社エレクトロニクス研究所内 (72)発明者 林 一雄 相模原市淵野辺５−10−１ 新日本製鐵株 式会社エレクトロニクス研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuaki Nagata 5-10-1 Fuchinobe, Sagamihara-shi Nippon Steel Corp. Electronics Research Laboratories (72) Inventor Kazuo Hayashi 5-10-1, Fuchinobe, Sagamihara-shi New Japan Electronics Co., Ltd. Electronics Research Laboratory
Claims (2)
取り出すＸ線分光器と、被検体を走査・回転することが
できる被検体ステージと、二次元Ｘ線検出器と、該二次
元Ｘ線検出器からの信号の収集，Ｘ線分光器及び前記被
検体の位置制御を行うコンピュータと、ＣＴ画像再構成
用のソフトウェアまたはハードウェアからなる単色Ｘ線
ＣＴ装置において、 指向性が強い白色Ｘ線の直進偏光ベクトルの方向をｘ方
向、ｘ方向に垂直な方向をｙ方向として、前記被検体後
方に、該被検体を透過した透過Ｘ線をｙ方向に回折する
非対称反射単結晶素子を設け、 ｘ方向あるいはｙ方向に検出走査を行いかつ検出領域が
任意に変化できる二次元Ｘ線検出器を設け、 被検体を透過した二次元投影像を前記非対称反射単結晶
素子で回折させた後、前記二次元Ｘ線検出器で検出する
際に、微小な被検体を高分解能な断層像で観察するｘ方
向と被検体の回転軸とを一致させる高分解能用被検体ス
テージと、 ｘ方向にＸ線ビームをコリメートする手段と、を設けた
ことを特徴とする単色Ｘ線ＣＴ装置。1. An X-ray spectroscope for extracting an arbitrary wavelength from a highly directional white X-ray, an object stage capable of scanning and rotating an object, a two-dimensional X-ray detector, and the two-dimensional X-ray detector. A monochromatic X-ray CT apparatus including a computer that collects signals from an X-ray detector, an X-ray spectroscope, and a position control of the subject, and software or hardware for CT image reconstruction. An asymmetric reflective single crystal element that diffracts a transmitted X-ray transmitted through the subject in the y-direction behind the subject with the direction of the linearly polarized vector of the X-ray as the x-direction and the direction perpendicular to the x-direction as the y-direction. Provided is a two-dimensional X-ray detector that performs detection scanning in the x direction or the y direction and the detection area can be changed arbitrarily, and after diffracting the two-dimensional projection image transmitted through the subject with the asymmetric reflection single crystal element , The two-dimensional When detecting with an X-ray detector, a high-resolution object stage for observing a minute object with a high-resolution tomographic image so that the x-direction and the rotation axis of the object coincide with each other, and an X-ray beam is emitted in the x-direction. A monochromatic X-ray CT apparatus provided with a means for collimating.
向とその被検体の回転軸とを一致させる大型被検体ステ
ージを設け、上記高分解能用被検体ステージと該大型被
検体ステージを適宜切り替える移動手段を設けたことを
特徴とする請求項１記載の単色Ｘ線ＣＴ装置。2. When observing a large object, a large-sized object stage for aligning the y direction with the rotation axis of the object is provided, and the high-resolution object stage and the large object stage are appropriately used. The monochromatic X-ray CT apparatus according to claim 1, further comprising a moving means for switching.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5044505A JPH06235704A (en) | 1993-02-09 | 1993-02-09 | Monochromatic x-ray ct system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5044505A JPH06235704A (en) | 1993-02-09 | 1993-02-09 | Monochromatic x-ray ct system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06235704A true JPH06235704A (en) | 1994-08-23 |
Family
ID=12693414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5044505A Withdrawn JPH06235704A (en) | 1993-02-09 | 1993-02-09 | Monochromatic x-ray ct system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06235704A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0961379A (en) * | 1995-08-25 | 1997-03-07 | Sumitomo Electric Ind Ltd | Soft x-ray tomography |
| WO2004010125A1 (en) * | 2002-07-18 | 2004-01-29 | Hitachi Zosen Corporation | X-ray inspection device and x-ray inspection method |
| EP3723103A1 (en) | 2019-04-09 | 2020-10-14 | European XFEL GmbH | Method and apparatus for x-ray shaft expansion and/or compression and/or collimation and/or focusing and/or x-ray magnification |
| KR20210138260A (en) * | 2020-05-12 | 2021-11-19 | 경북대학교 산학협력단 | Synchrotron Radiation Based Monochromatic X-ray Large Area CT Imaging Device |
-
1993
- 1993-02-09 JP JP5044505A patent/JPH06235704A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0961379A (en) * | 1995-08-25 | 1997-03-07 | Sumitomo Electric Ind Ltd | Soft x-ray tomography |
| WO2004010125A1 (en) * | 2002-07-18 | 2004-01-29 | Hitachi Zosen Corporation | X-ray inspection device and x-ray inspection method |
| EP3723103A1 (en) | 2019-04-09 | 2020-10-14 | European XFEL GmbH | Method and apparatus for x-ray shaft expansion and/or compression and/or collimation and/or focusing and/or x-ray magnification |
| KR20210138260A (en) * | 2020-05-12 | 2021-11-19 | 경북대학교 산학협력단 | Synchrotron Radiation Based Monochromatic X-ray Large Area CT Imaging Device |
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