WO2019167146A1 - Collimator production method - Google Patents

Collimator production method Download PDF

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WO2019167146A1
WO2019167146A1 PCT/JP2018/007362 JP2018007362W WO2019167146A1 WO 2019167146 A1 WO2019167146 A1 WO 2019167146A1 JP 2018007362 W JP2018007362 W JP 2018007362W WO 2019167146 A1 WO2019167146 A1 WO 2019167146A1
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radiation
ray
collimator
manufacturing
radiation shielding
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PCT/JP2018/007362
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French (fr)
Japanese (ja)
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久史 森井
隆治 奥之山
克之 都木
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株式会社ANSeeN
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Priority to PCT/JP2018/007362 priority Critical patent/WO2019167146A1/en
Priority to JP2020503141A priority patent/JP6967312B2/en
Priority to TW108102280A priority patent/TWI689947B/en
Publication of WO2019167146A1 publication Critical patent/WO2019167146A1/en

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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/06Diaphragms

Abstract

Provided is a collimator production method whereby a collimator can be readily produced that has a minute radiation transmission section having a small aspect ratio. This collimator 20 production method is for a collimator 20 comprising: a radiation shielding section 22; and a radiation transmission section 21 that is provided penetrating the radiation shielding section 22 and has a lower radiation shielding rate than the radiation shielding section 22. The production method comprises: an arrangement step in which a columnar member 21a erect installation member, having a columnar member 21a that forms the radiation transmission section 21 installed erect in a holding substrate 23, is arranged in a casting mold 40; an inflow step in which a material for the radiation shielding section 22 is poured into the casting mold 40 in a liquid state; and a removal step in which, after the radiation shielding section 22 has cured, the columnar member 21a erect installation member and the radiation shielding section 22 are removed from the casting mold 40.

Description

コリメータ製造方法Collimator manufacturing method
 本発明は、コリメータ製造方法に関する。 The present invention relates to a collimator manufacturing method.
 放射線を用いて被検体を非破壊で検査する、例えばX線CT(Computed Tomography)等の放射線検査装置は、被検体に放射線を照射し、被検体を透過した放射線をもとにCT画像を生成する装置である。
 このような放射線検査装置は、放射線発生装置と放射線検出装置とを備える。また、被検体に照射された放射線は、被検体において一部散乱される。散乱した放射線を放射線検出装置が検出すると、検出精度が劣化する。この散乱放射線を除去するために、放射線検出装置には、コリメータが設けられている。
Radiation inspection equipment such as X-ray CT (Computed Tomography), which inspects a subject non-destructively using radiation, irradiates the subject with radiation and generates a CT image based on the radiation transmitted through the subject. It is a device to do.
Such a radiation inspection apparatus includes a radiation generation apparatus and a radiation detection apparatus. Moreover, the radiation irradiated to the subject is partially scattered in the subject. When the radiation detection apparatus detects scattered radiation, the detection accuracy deteriorates. In order to remove the scattered radiation, the radiation detection apparatus is provided with a collimator.
 このようなコリメータとして、例えば、チャネル方向とスライス方向とに散乱X線の除去が可能な2次元コリメータが開発されている(例えば特許文献1参照)。 As such a collimator, for example, a two-dimensional collimator capable of removing scattered X-rays in the channel direction and the slice direction has been developed (for example, see Patent Document 1).
特開2012-177655号公報JP 2012-177655 A
 しかし、上記の2次元コリメータは、チャネル方向に並ぶ複数のコリメータ板と、スライス方向に並ぶ複数のコリメータ板とを互いに交差させることにより、X線を通過させるX線通過部を形成している。このため、製造工程が複雑で、且つ微細化も容易ではなかった。
 本発明は、微細且つアスペクト比の小さな放射線透過部を有するコリメータを容易に製造することができるコリメータ製造方法を提供することを目的とする。
However, the above-described two-dimensional collimator forms an X-ray passage portion that allows X-rays to pass by crossing a plurality of collimator plates arranged in the channel direction and a plurality of collimator plates arranged in the slice direction. For this reason, the manufacturing process is complicated and miniaturization is not easy.
An object of this invention is to provide the collimator manufacturing method which can manufacture easily the collimator which has a radiation transmission part with a small and small aspect ratio.
 上記課題を解決するために、本発明は以下のものを提供する。
 放射線遮蔽部と、前記放射線遮蔽部を貫通して設けられ、且つ前記放射線遮蔽部よりも放射線遮蔽率が低い放射線透過部と、を備えるコリメータの製造方法であって、前記放射線透過部を形成する柱状部材が保持基板に立設された柱状部材立設部材を鋳造型に配置する配置工程と、前記鋳造型に、前記放射線遮蔽部の材料を液状で流入する流入工程と、前記放射線遮蔽部が硬化した後、前記柱状部材立設部材と前記放射線遮蔽部とを前記鋳造型から取り出す取り出し工程と、を備えるコリメータの製造方法。
In order to solve the above problems, the present invention provides the following.
A collimator manufacturing method comprising: a radiation shielding part; and a radiation transmissive part provided through the radiation shielding part and having a radiation shielding rate lower than that of the radiation shielding part, wherein the radiation transmissive part is formed. An arrangement step of placing a columnar member standing member with a columnar member standing on a holding substrate in a casting mold, an inflow step of flowing the material of the radiation shielding portion into the casting mold in liquid form, and the radiation shielding portion A method for manufacturing a collimator, comprising: a step of taking out the columnar member standing member and the radiation shielding portion from the casting mold after curing.
 前記放射線透過部は、可視光遮蔽率が高い材料で製造してもよい。 The radiation transmitting part may be made of a material having a high visible light shielding rate.
 前記放射線透過部は、前記放射線遮蔽部の材料よりも融点が高い材料で製造してもよい。 The radiation transmitting part may be manufactured from a material having a higher melting point than the material of the radiation shielding part.
 前記放射線透過部は、カーボンで製造してもよい。 The radiation transmitting part may be made of carbon.
 前記放射線遮蔽部は、錫で製造してもよい。 The radiation shielding part may be made of tin.
 前記取り出し工程の後、前記柱状部材を除去する除去工程を備えてもよい。 A removal step of removing the columnar member may be provided after the extraction step.
 さらに、上記課題を解決するために、本発明は以下のものを提供する。
 液状の放射線遮蔽部と、前記放射線遮蔽部を貫通して設けられ、前記放射線遮蔽部よりも放射線遮蔽率が低い放射線透過部とが容器内に密封されたコリメータの製造方法であって、前記放射線透過部を形成する複数の柱状部材を、開口した状態の前記容器内に立設する立設工程と、前記容器内に、液状の前記放射線遮蔽部の材料を流入する流入工程と、前記容器を密封する密封工程と、を備えるコリメータの製造方法。
Furthermore, in order to solve the above problems, the present invention provides the following.
A method of manufacturing a collimator in which a liquid radiation shielding portion and a radiation transmission portion provided through the radiation shielding portion and having a radiation shielding rate lower than that of the radiation shielding portion are sealed in a container, A standing step of standing a plurality of columnar members forming a transmission part in the opened container, an inflow step of flowing the liquid radiation shielding material into the container, and the container A collimator manufacturing method comprising: a sealing step of sealing.
 本発明によれば、微細且つアスペクト比の小さな放射線透過部を有するコリメータを容易に製造することができるコリメータ製造方法を提供することができる。 According to the present invention, it is possible to provide a collimator manufacturing method capable of easily manufacturing a collimator having a fine and small aspect ratio radiation transmitting portion.
放射線検査装置の一実施形態であるX線CT装置1の概略図である1 is a schematic view of an X-ray CT apparatus 1 that is an embodiment of a radiation inspection apparatus. 第1実施形態の1つのX線検出部10の断面斜視図である。It is a section perspective view of one X-ray detection part 10 of a 1st embodiment. 第1実施形態のコリメータ20の製造方法を説明する図である。It is a figure explaining the manufacturing method of the collimator 20 of 1st Embodiment. 第1実施形態のコリメータ20の製造方法を説明するフローチャートである。It is a flowchart explaining the manufacturing method of the collimator 20 of 1st Embodiment. X線スペクトルのシミュレーション計算値を示したグラフである。It is the graph which showed the simulation calculation value of the X-ray spectrum. カーボン(C)、アルミニウム(Al)、銅(Cu)によるX線の吸収率を示したグラフである。It is the graph which showed the absorption factor of the X-ray by carbon (C), aluminum (Al), and copper (Cu). X線発生装置2からX線を発生させて、被検体Bに照射し、X線検出素子30で検出されたX線のカウント値を示したグラフある。6 is a graph showing X-ray count values detected by the X-ray detection element 30 when X-rays are generated from the X-ray generator 2 and irradiated on the subject B; 第2実施形態のコリメータ120の製造方法を説明する図である。It is a figure explaining the manufacturing method of the collimator 120 of 2nd Embodiment.
 図1は本発明の放射線検査装置の実施形態であるX線CT装置(X線検査装置)1の概略図である。なお、本発明はX線CT装置1に限らず、ガンマ線等の他の放射線を用いた放射線検査装置であってもよい。X線CT装置1は、X線発生装置(放射線発生装置)2と、被検体Bを配置する架台3と、X線発生装置2を中心とした円周に沿って配置されるX線検出装置(放射線検出装置)4と、を備える。X線検出装置4は、複数のX線検出部(放射線検出部)10を備えている。 FIG. 1 is a schematic view of an X-ray CT apparatus (X-ray inspection apparatus) 1 which is an embodiment of the radiation inspection apparatus of the present invention. The present invention is not limited to the X-ray CT apparatus 1 and may be a radiation inspection apparatus using other radiation such as gamma rays. The X-ray CT apparatus 1 includes an X-ray generation apparatus (radiation generation apparatus) 2, a gantry 3 on which the subject B is disposed, and an X-ray detection apparatus disposed along a circumference centered on the X-ray generation apparatus 2. (Radiation detection device) 4. The X-ray detection apparatus 4 includes a plurality of X-ray detection units (radiation detection units) 10.
(第1実施形態)
 図2は第1実施形態の1つのX線検出部10の断面斜視図である。X線検出部10は、それぞれ、コリメータ20と、複数のX線検出素子(放射線検出素子)30とを備える。
(First embodiment)
FIG. 2 is a cross-sectional perspective view of one X-ray detection unit 10 of the first embodiment. Each X-ray detection unit 10 includes a collimator 20 and a plurality of X-ray detection elements (radiation detection elements) 30.
 X線検出素子30は、約0.1~2.00mmの間隔(ピッチ)aで配置されている。X線検出素子30は、後述するコリメータ20に設けられた個々のX線透過部21にそれぞれ対応して配置されている。 The X-ray detection elements 30 are arranged at an interval (pitch) a of about 0.1 to 2.00 mm. The X-ray detection elements 30 are arranged corresponding to the individual X-ray transmission parts 21 provided in the collimator 20 described later.
 X線検出素子30は、間接変換型であってもよく、直接変換型であってもよい。間接変換型のX線検出素子30は、シンチレータと、光電子増倍管等の光センサとから構成され、入射したX線をシンチレータによって光に変換し、変換された光を光電変素子によって電気信号に変換する。
 直接変換型のX線検出素子30は、複数のテルル化カドミウム(CdTe)系の半導体素子で構成され、入射したX線を、直接、電気信号に変換する。
The X-ray detection element 30 may be an indirect conversion type or a direct conversion type. The indirect conversion type X-ray detection element 30 includes a scintillator and an optical sensor such as a photomultiplier tube, converts incident X-rays into light by the scintillator, and converts the converted light into an electrical signal by the photoelectric conversion element. Convert to
The direct conversion type X-ray detection element 30 is composed of a plurality of cadmium telluride (CdTe) -based semiconductor elements, and converts incident X-rays directly into electrical signals.
 (コリメータ20)
 コリメータ20は、所定厚みの板状のX線遮蔽部(放射線遮蔽部)22と、X線遮蔽部22を貫通して格子状に配置された、複数の柱状のX線透過部(放射線透過部)21と、を備える。
(Collimator 20)
The collimator 20 includes a plate-shaped X-ray shielding part (radiation shielding part) 22 having a predetermined thickness and a plurality of columnar X-ray transmission parts (radiation transmission parts) arranged in a lattice pattern through the X-ray shielding part 22. 21).
(X線遮蔽部22)
 X線遮蔽部22は、X線及び可視光の遮蔽率が高い(透過率が低い)材料で製造されている。
 実施形態でX線遮蔽部22の材料は錫である。ただし、これに限らず、X線遮蔽部22の材料は、モリブデン、タンタル、鉛、タングステン等の原子番号が大きい、可視光及びX線遮蔽能力(阻止能)の高い、又は重い金属、或いはこれらの重い金属を含む合金などであってもよい。なお、錫の融点は231°Cであり、後述の製造方法で製造する場合、融点が錫と同程度の比較的低いものを用いることで製造を容易に行える。X線遮蔽部22の厚さbは、約1~50mmである。
(X-ray shielding part 22)
The X-ray shielding part 22 is made of a material having a high shielding rate (low transmittance) for X-rays and visible light.
In the embodiment, the material of the X-ray shielding part 22 is tin. However, the material of the X-ray shielding part 22 is not limited to this, and the material having a large atomic number such as molybdenum, tantalum, lead, tungsten, etc., a high visible light and high X-ray shielding ability (stopping ability), or a heavy metal, or these An alloy containing a heavy metal may be used. Note that the melting point of tin is 231 ° C., and in the case of manufacturing by the manufacturing method described later, the manufacturing can be easily performed by using a relatively low melting point similar to that of tin. The thickness b of the X-ray shielding part 22 is about 1 to 50 mm.
(X線透過部21)
 X線透過部21は、実施形態において、例えば円柱状であり、中実で、円柱の中心軸Aは、それぞれX線発生装置2又は被検体Bを向く方向に延びている。X線透過部21における、X線発生装置2又は被検体Bと逆側の面には、それぞれ対応するX線検出素子30が、互いの間に可視光が入射しないように密接して取り付けられている。
 X線透過部21の径Rは約0.07~0.2mmであり、X線透過部21の深さは、X線遮蔽部22の厚さbと等しく約1~50mmである。すなわち、X線透過部21は、径Rが深さbに対して小さい(アスペクト比の高い、細長い)形状である。なお、X線透過部21は円柱状に限らず、楕円柱や角柱形状であってもよい。
(X-ray transmission part 21)
In the embodiment, the X-ray transmission part 21 is, for example, a columnar shape, is solid, and the center axis A of the column extends in a direction facing the X-ray generation device 2 or the subject B, respectively. The corresponding X-ray detection elements 30 are closely attached to the surface opposite to the X-ray generator 2 or the subject B in the X-ray transmission part 21 so that visible light does not enter between them. ing.
The diameter R of the X-ray transmission part 21 is about 0.07 to 0.2 mm, and the depth of the X-ray transmission part 21 is equal to the thickness b of the X-ray shielding part 22 and is about 1 to 50 mm. In other words, the X-ray transmission part 21 has a shape in which the diameter R is smaller than the depth b (a long and narrow aspect ratio). The X-ray transmission part 21 is not limited to a cylindrical shape, and may be an elliptical column or a prismatic shape.
 X線透過部21は、X線の遮蔽率が低く(透過率が高く)、可視光の遮蔽率が高い(透過率が低い)材料、例えばカーボンで製造されている。
 なお、これに限らず、カーボン以外の、X線遮蔽部22より原子番号が小さい、X線遮蔽率が低い、又は軽いアルミニウム等の他の材料であってもよい。
 また、後述の製造方法で製造する場合は、X線透過部21の材料の融点は、X線遮蔽部22の材料の融点より高いものである。
The X-ray transmission part 21 is made of a material having a low X-ray shielding rate (high transmittance) and a high visible light shielding rate (low transmittance), for example, carbon.
However, the present invention is not limited to this, and other materials such as aluminum other than carbon having an atomic number smaller than that of the X-ray shielding part 22, a low X-ray shielding rate, or light weight may be used.
Moreover, when manufacturing with the below-mentioned manufacturing method, the melting point of the material of the X-ray transmissive part 21 is higher than the melting point of the material of the X-ray shielding part 22.
(X線CT装置1の動作)
 次に、本実施形態のX線CT装置1の動作について説明する。
 X線発生装置2により発生されたX線は、被検体Bに照射される。被検体Bに照射された光は、被検体Bを透過し、一部は散乱される。被検体Bを透過した直進X線と、被検体Bで散乱された散乱X線とがコリメータ20に到達する。
 コリメータ20に到達したX線のうち、X線透過部21に入射するX線以外は、X線遮蔽部22のX線遮蔽率が高いのでX線遮蔽部22で遮蔽される。
 一方、X線透過部21に到達したX線は、X線透過部21の遮蔽率が低いので、X線透過部21内に入射する。可視光は、X線透過部21の可視光遮蔽率が高いので遮蔽される。
(Operation of X-ray CT apparatus 1)
Next, the operation of the X-ray CT apparatus 1 of this embodiment will be described.
X-rays generated by the X-ray generator 2 are applied to the subject B. The light irradiated to the subject B passes through the subject B and is partially scattered. The straight X-ray transmitted through the subject B and the scattered X-ray scattered by the subject B reach the collimator 20.
Of the X-rays that have reached the collimator 20, those other than the X-rays that enter the X-ray transmitting part 21 are shielded by the X-ray shielding part 22 because the X-ray shielding part 22 has a high X-ray shielding rate.
On the other hand, the X-rays that have reached the X-ray transmission part 21 enter the X-ray transmission part 21 because the shielding rate of the X-ray transmission part 21 is low. Visible light is shielded because the visible light shielding rate of the X-ray transmission part 21 is high.
 X線透過部21内に入射したX線のうち、X線透過部21の中心軸Aに対して、所定角度以上の散乱X線は、X線透過部21を通り抜ける前にX線透過部21の側面に到達するのでX線遮蔽部22によって遮蔽される。
 すなわち、X線透過部21に入射するX線のうち、直進性の高いX線のみX線透過部21を通過して、X線検出素子30に到達する。
Of the X-rays that have entered the X-ray transmission unit 21, scattered X-rays having a predetermined angle or more with respect to the central axis A of the X-ray transmission unit 21 pass through the X-ray transmission unit 21 before passing through the X-ray transmission unit 21. Is thus shielded by the X-ray shield 22.
That is, of the X-rays incident on the X-ray transmission part 21, only the X-rays having high straightness pass through the X-ray transmission part 21 and reach the X-ray detection element 30.
 X線検出素子30に到達したX線は、間接変換型のX線検出素子30の場合、シンチレータによって光に変換され、変換された光が光電変素子によって電気信号に変換される。直接変換型のX線検出素子30の場合、入射したX線は、直接、電気信号に変換される。
 電気信号に変換されたX線の強度情報は、処理部5によって処理されてX線CT画像データが作成され、表示部6によりX線CT画像が表示される。
In the case of the indirect conversion type X-ray detection element 30, the X-ray that has reached the X-ray detection element 30 is converted into light by the scintillator, and the converted light is converted into an electric signal by the photoelectric conversion element. In the case of the direct conversion type X-ray detection element 30, the incident X-ray is directly converted into an electric signal.
The X-ray intensity information converted into the electrical signal is processed by the processing unit 5 to generate X-ray CT image data, and the display unit 6 displays the X-ray CT image.
(コリメータ20の製造方法)
 図3は第1実施形態のコリメータ20の製造方法を説明する図である。図4は第1実施形態のコリメータ20の製造方法を説明するフローチャートである。第1実施形態のコリメータ20は鋳造により製造される。
 まず、X線透過部21を形成する複数の柱状部材が保持基板23に立設された柱状部材立設部材24を用意する(図3(a))。
 第1実施形態では、柱状部材21a及び保持基板23、すなわち柱状部材立設部材24全体がカーボンで製造されている。ただし、これに限らず、柱状部材21aと保持基板23とは別体であってもよい。
(Manufacturing method of the collimator 20)
FIG. 3 is a diagram illustrating a method for manufacturing the collimator 20 of the first embodiment. FIG. 4 is a flowchart illustrating a method for manufacturing the collimator 20 according to the first embodiment. The collimator 20 of the first embodiment is manufactured by casting.
First, a columnar member standing member 24 is prepared in which a plurality of columnar members forming the X-ray transmission part 21 are erected on the holding substrate 23 (FIG. 3A).
In the first embodiment, the columnar member 21 a and the holding substrate 23, that is, the entire columnar member standing member 24 are made of carbon. However, the present invention is not limited thereto, and the columnar member 21a and the holding substrate 23 may be separate.
 柱状部材立設部材24を、鋳造型40の内部に配置する(図3(b),図4(ステップS1))。 The columnar member standing member 24 is disposed inside the casting mold 40 (FIG. 3B, FIG. 4 (step S1)).
 鋳造型40に、融点以上に熱せられて液状となったX線遮蔽部22の材料、実施形態では錫、を流入させる(図3(c),図4(ステップS2))。なお、錫の融点は231度である。 The material of the X-ray shielding part 22 that is heated to the melting point or higher and becomes liquid, in the embodiment, tin, is caused to flow into the casting mold 40 (FIG. 3C, FIG. 4 (step S2)). The melting point of tin is 231 degrees.
 融点以下に温度を下げ、X線遮蔽部22を硬化させる(図4(ステップS3))。 The temperature is lowered below the melting point and the X-ray shielding part 22 is cured (FIG. 4 (step S3)).
 硬化して柱状部材立設部材24と一体となったX線遮蔽部22を、鋳造型40より取り外す(図3(d),図4(ステップS4))。 The X-ray shielding portion 22 that is cured and integrated with the columnar member standing member 24 is removed from the casting mold 40 (FIG. 3 (d), FIG. 4 (step S4)).
 一体となった柱状部材立設部材24とX線遮蔽部22の、少なくとも保持基板23の面を研磨して、保持基板23を除去する(図3(e),図4(ステップS5))。
 これにより、本実施形態のコリメータ20が製造される。
At least the surface of the holding substrate 23 of the integrated columnar member standing member 24 and the X-ray shielding portion 22 is polished to remove the holding substrate 23 (FIG. 3E, FIG. 4 (step S5)).
Thereby, the collimator 20 of this embodiment is manufactured.
 以下、本実施形態の効果について説明する。
(1)図5は、X線発生装置2に好適に用いられる一例に係るX線光源におけるX線スペクトルのシミュレーション計算値を示したグラフであり、縦軸がX線の線量、横軸がX線のエネルギーである。図示するように本例に係るX線スペクトルは、エネルギー22keV付近で線量がピークとなり、高エネルギーになるに従い線量が減少していく。また、22keV付近より低エネルギー側においても線量が減少していく。
Hereinafter, the effect of this embodiment will be described.
(1) FIG. 5 is a graph showing a simulation calculation value of an X-ray spectrum in an X-ray light source according to an example suitably used for the X-ray generator 2, where the vertical axis represents the X-ray dose and the horizontal axis represents X The energy of the line. As shown in the figure, in the X-ray spectrum according to the present example, the dose reaches a peak near the energy of 22 keV, and the dose decreases as the energy increases. In addition, the dose decreases on the low energy side from around 22 keV.
 図6は、30mmの厚さのカーボン(C)、アルミニウム(Al)、銅(Cu)によるX線の吸収率を示したグラフである。図示するように、カーボン(C)、アルミニウム(Al)、銅(Cu)は、高エネルギー側のX線の吸収率が低く、低エネルギーが側のX線の吸収率が高い。
 特にカーボンは、低エネルギーのX線の選択的な吸収性が高く、エネルギー約150keV以上では、吸収率は略0%であるが、約150keVよりエネルギーが小さくなると、急激に吸収率が増加する。この選択的な吸収性は、銅(Cu)、アルミニウム(Al)、カーボン(C)の順で高くなる。
FIG. 6 is a graph showing the X-ray absorption rate of carbon (C), aluminum (Al), and copper (Cu) having a thickness of 30 mm. As shown in the figure, carbon (C), aluminum (Al), and copper (Cu) have low X-ray absorption on the high energy side and high X-ray absorption on the low energy side.
Carbon, in particular, has a high selective absorption of low energy X-rays, and the absorption rate is approximately 0% at an energy of about 150 keV or higher, but when the energy becomes smaller than about 150 keV, the absorption rate increases rapidly. This selective absorbency increases in the order of copper (Cu), aluminum (Al), and carbon (C).
 図7は、図5に示すスペクトルを有するX線光源を用いたX線発生装置2からX線を発生させて、被検体Bに照射し、X線検出素子30で検出されたX線のカウント値を示したグラフある。カウント値Pは、X線検出素子30と被検体Bとの間に、実際に製造した実施形態のコリメータ20を配置した場合、カウント値Qは、X線検出素子30と被検体Bとの間にコリメータ自体を配置しなかった場合である。コリメータ20としては、X線遮蔽部22として厚さ30mmの錫を用い、直径0.2mm、長さ(30mm)の貫通穴にカーボンが充填されたX線透過部21を形成したものを用いた。 FIG. 7 shows a count of X-rays generated by the X-ray generator 2 using the X-ray light source having the spectrum shown in FIG. It is a graph showing values. When the collimator 20 of the actually manufactured embodiment is arranged between the X-ray detection element 30 and the subject B, the count value Q is between the X-ray detection element 30 and the subject B. This is a case where the collimator itself is not arranged. As the collimator 20, a 30 mm thick tin was used as the X-ray shielding part 22, and a through hole having a diameter of 0.2 mm and a length (30 mm) formed with an X-ray transmission part 21 filled with carbon was used. .
 X線検出素子30と被検体Bとの間にコリメータ自体を配置しなかった場合、カウント値Qのように、X線検出素子30で検出されるX線は、被検体Bにおいて散乱されてエネルギーが減少された低エネルギーのX線を多く含む。したがって、解像度の高いX線画像を得ることができない。 When the collimator itself is not disposed between the X-ray detection element 30 and the subject B, the X-rays detected by the X-ray detection element 30 like the count value Q are scattered by the subject B and energy Contains a lot of low energy X-rays. Therefore, an X-ray image with high resolution cannot be obtained.
 これに対して、X線検出素子30と被検体Bとの間に、実際に製造した実施形態のカーボンが充填されたコリメータ20を配置した場合、X線透過部21において、図6に示したように、カーボンが被検体Bで散乱された低エネルギー側のX線が吸収(遮蔽)される。したがって、カウント値Pに示すように、シミュレーション計算値のX線スペクトルの形状(図5)と似たようなエネルギー分布(カーブの形状)を有するX線を検出することができる。
 すなわち、実施形態のコリメータ20によると、散乱X線がより良好に除去可能であるので、X線検出素子30で検出されるX線に含まれるノイズが少なく、解像度の高いX線画像を得ることができる。
On the other hand, in the case where the collimator 20 filled with carbon of the actually manufactured embodiment is disposed between the X-ray detection element 30 and the subject B, the X-ray transmission unit 21 shown in FIG. As described above, X-rays on the low energy side in which carbon is scattered by the subject B are absorbed (shielded). Therefore, as indicated by the count value P, X-rays having an energy distribution (curve shape) similar to the shape of the X-ray spectrum of the simulation calculation value (FIG. 5) can be detected.
That is, according to the collimator 20 of the embodiment, since scattered X-rays can be removed more satisfactorily, there is little noise contained in the X-rays detected by the X-ray detection element 30, and an X-ray image with high resolution can be obtained. Can do.
 なお、X線透過部21をカーボンに限らず、適宜選択して図6に示したようなアルミニウムや銅のような他の材料にすることによって、用途に応じて不要な波長の光を除去することができる。 The X-ray transmission part 21 is not limited to carbon, and is appropriately selected to use other materials such as aluminum and copper as shown in FIG. 6, thereby removing light having an unnecessary wavelength depending on the application. be able to.
(2)従来のX線検出装置においては、X線検出素子への可視光の入射を防止するための遮光構造が設けられている。特に、シンチレータの場合、X線を一旦可視光に変換してから光を検出するため、外部からの可視光の入射を防止する必要があるため遮光構造が重要である。
 しかし、本実施形態では、コリメータ20のX線透過部21がカーボンで充填されて中実となっている。また、コリメータ20とX線検出素子30との間は可視光が入射しないように密接している。
 したがって、可視光はX線検出素子30へ到達しないので、別途、遮光構造を設ける必要がない。ゆえに、製造コストが削減可能であるとともに、製造工程の時間短縮となる。
(2) In the conventional X-ray detection apparatus, a light shielding structure for preventing the incidence of visible light to the X-ray detection element is provided. In particular, in the case of a scintillator, since light is detected after converting X-rays into visible light once, it is necessary to prevent the incidence of visible light from the outside, and thus a light shielding structure is important.
However, in this embodiment, the X-ray transmission part 21 of the collimator 20 is filled with carbon and is solid. Further, the collimator 20 and the X-ray detection element 30 are in close contact so that no visible light is incident.
Therefore, since visible light does not reach the X-ray detection element 30, it is not necessary to provide a separate light shielding structure. Therefore, the manufacturing cost can be reduced and the manufacturing process time can be shortened.
(3)例えば、比較として、X線遮蔽部に対してドリル等で貫通穴としてのX線透過部を開けることも可能である。
 しかし、X線遮蔽部は、X線を遮蔽可能とするために原子番号の大きな金属で製造されている。ゆえに、硬度が高く、微細且つアスペクト比の小さな貫通穴を開けることは容易でなく、製造コストがかかり、製造時間もかかる。さらに、ドリルで貫通穴を開けていく際に発生した切り粉を、回転するドリルが巻き込んで回転を続け、高精度且つ微細な貫通穴を開けることがより困難となる場合もある。
 しかし、本実施形態のコリメータ20は、柱状のX線透過部21が立設された保持基板23を鋳造型40に入れて、その鋳造型40に溶解したX線遮蔽部22の材料を流入して硬化させることで製造する。すなわち、ドリルにより貫通穴を開ける方法とは異なり、微細且つアスペクト比の小さなX線透過部21を、容易に製造することができる。したがって、より指向性の高いコリメータ20を製造可能である。
(3) For example, for comparison, it is also possible to open an X-ray transmission part as a through hole with a drill or the like with respect to the X-ray shielding part.
However, the X-ray shielding part is made of a metal having a large atomic number so that X-rays can be shielded. Therefore, it is not easy to make a through hole having high hardness, fineness and a small aspect ratio, and manufacturing cost and manufacturing time are increased. Furthermore, there is a case where it is more difficult to open a high-precision and fine through-hole by cutting a chip generated when a through-hole is drilled with a rotating drill.
However, in the collimator 20 of the present embodiment, the holding substrate 23 on which the columnar X-ray transmission part 21 is erected is placed in the casting mold 40, and the material of the X-ray shielding part 22 dissolved in the casting mold 40 flows into the collimator 20. It is manufactured by curing. That is, unlike the method of making a through hole with a drill, the X-ray transmission part 21 having a small and small aspect ratio can be easily manufactured. Therefore, the collimator 20 with higher directivity can be manufactured.
 なお、本実施形態では、X線透過部21がカーボンで充填されて中実となっている形態について説明したが、これに限らず、X線透過部21に充填されたカーボンを、エッチング等によって取り除いてもよい。この場合も、ドリルにより貫通穴を開ける方法とは異なり、微細且つアスペクト比の小さな貫通穴を有するX線透過部21を、容易に製造することができる。したがって、より指向性の高いコリメータ20を製造可能である。 In the present embodiment, the X-ray transmission part 21 is filled with carbon and has a solid form. However, the present invention is not limited to this, and the carbon filled in the X-ray transmission part 21 may be etched or the like. May be removed. Also in this case, unlike the method of making a through hole with a drill, the X-ray transmissive part 21 having a through hole with a fine and small aspect ratio can be easily manufactured. Therefore, the collimator 20 with higher directivity can be manufactured.
(第2実施形態)
 次に、本発明の第2実施形態について説明する。第2実施形態が第1実施形態と異なる点はコリメータ120の構造及び製造方法である。他の点は第1実施形態と同様であるので同様な部分の説明は省略する。第1実施形態のコリメータ20はX線遮蔽部22に錫を用いたが、第2実施形態のコリメータ120はX線遮蔽部122に、常温で液体の水銀等を用いる。
(Second Embodiment)
Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in the structure and manufacturing method of the collimator 120. Since other points are the same as those of the first embodiment, description of similar parts is omitted. The collimator 20 of the first embodiment uses tin for the X-ray shielding part 22, but the collimator 120 of the second embodiment uses mercury or the like that is liquid at room temperature for the X-ray shielding part 122.
 図8は第2実施形態のコリメータ120の製造方法を説明する図である。第2実施形態のコリメータ120は、図8(c)に示すように、容器150と、容器150内に封入された、水銀である液状のX線遮蔽部122と、上端及び下端が容器150における対向する2つの面の間に固定され、X線遮蔽部122よりもX線遮蔽率の低い、例えばカーボンである固体材料で製造された複数のX線透過部121と、を備える。 FIG. 8 is a diagram for explaining a method of manufacturing the collimator 120 of the second embodiment. As shown in FIG. 8C, the collimator 120 according to the second embodiment includes a container 150, a liquid X-ray shield 122 that is mercury enclosed in the container 150, and an upper end and a lower end in the container 150. And a plurality of X-ray transmission parts 121 which are fixed between two opposing surfaces and have a lower X-ray shielding rate than the X-ray shielding part 122 and are made of a solid material, for example, carbon.
 容器150は、上部が開口した下容器151と、下容器151の上部を覆う蓋体152とを備える。下容器151の底部の内面側には、円柱状のX線透過部21の下端を差し込むことで保持可能な複数の有底穴151aが設けられている。
 蓋体152の下面には、有底穴151aに対応する位置に、円柱状のX線透過部21の上端を差し込むことで保持可能な有底穴152aが設けられている。
 容器150の材料としては、剛性を有し、水銀の侵蝕に強いものが好ましく、例えば樹脂、ガラス、セラミックを用いる。
The container 150 includes a lower container 151 whose upper part is open, and a lid 152 that covers the upper part of the lower container 151. A plurality of bottomed holes 151 a that can be held by inserting the lower end of the columnar X-ray transmission part 21 are provided on the inner surface side of the bottom part of the lower container 151.
A bottomed hole 152a that can be held by inserting the upper end of the columnar X-ray transmission part 21 is provided on the lower surface of the lid 152 at a position corresponding to the bottomed hole 151a.
The material of the container 150 is preferably a material that is rigid and resistant to mercury erosion. For example, resin, glass, or ceramic is used.
 第2実施形態のコリメータ120は、以下のように製造する。
 下容器151の有底穴151aにX線透過部21を差し込んで保持する(図8(a))。
 下容器151に、X線遮蔽部22となる水銀を流入する(図8(b))。このとき、X線透過部121の上端は水銀の表面より上に出ている。
 下容器151に蓋体152を被せ、水銀を容器150の中に密封する。このとき、蓋体152の有底穴152aにX線透過部121の上端を嵌め込む(図8(c))。
 これにより、容器150の中に封入された、水銀である液状のX線遮蔽部122と、上端及び下端が容器の互いに対向する2つの面の間に固定され、X線遮蔽部122よりもX線遮蔽率の低い、例えばカーボンである固体材料で製造された複数のX線透過部121とを備える、第2実施形態のコリメータ120が製造される。
The collimator 120 of the second embodiment is manufactured as follows.
The X-ray transmitting part 21 is inserted and held in the bottomed hole 151a of the lower container 151 (FIG. 8A).
Mercury that becomes the X-ray shielding part 22 flows into the lower container 151 (FIG. 8B). At this time, the upper end of the X-ray transmission part 121 protrudes above the surface of mercury.
The lower container 151 is covered with a lid 152, and mercury is sealed in the container 150. At this time, the upper end of the X-ray transmission part 121 is fitted into the bottomed hole 152a of the lid 152 (FIG. 8C).
As a result, the liquid X-ray shielding part 122 made of mercury enclosed in the container 150 and the upper and lower ends are fixed between the two opposing surfaces of the container. The collimator 120 according to the second embodiment is manufactured, which includes a plurality of X-ray transmission parts 121 made of a solid material having a low ray shielding rate, for example, carbon.
 第2実施形態のコリメータ120によると、第1実施形態の効果に加え、容器150の形状を変えることで、種々の形状のコリメータ120を製造可能である。ゆえに、例えば、湾曲したコリメータ120を容易に製造することができる。
 また、容器150の材料自体を可撓性のある材料で製造した場合、製造後の変形も容易となるので、汎用性の高いコリメータ120を製造することができる。
According to the collimator 120 of the second embodiment, various shapes of the collimator 120 can be manufactured by changing the shape of the container 150 in addition to the effects of the first embodiment. Therefore, for example, the curved collimator 120 can be easily manufactured.
In addition, when the material of the container 150 is manufactured with a flexible material, deformation after the manufacturing is facilitated, so that the highly versatile collimator 120 can be manufactured.
 A  中心軸
 B  被検体
 1  X線CT装置(放射線検査装置)
 2  X線発生装置(放射線発生装置)
 3  架台
 4  X線検出装置(放射線検出装置
 5  処理部
 6  表示部
 10  X線検出部(放射線検出部)
 20  コリメータ
 21a  柱状部材
 21  X線透過部(放射線透過部)
 22  X線遮蔽部(放射線遮蔽部)
 23  保持基板
 24  柱状部材立設部材
 30  X線検出素子(放射線検出素子)
 40  鋳造型
 120  コリメータ
 121  X線透過部(放射線透過部)
 122  X線遮蔽部(放射線遮蔽部)
 150  容器
 151  下容器
 151a  有底孔
 152  蓋体
 152a  有底穴
A Central axis B Subject 1 X-ray CT apparatus (radiological examination apparatus)
2 X-ray generator (radiation generator)
3 frame 4 X-ray detection device (radiation detection device 5 processing unit 6 display unit 10 X-ray detection unit (radiation detection unit)
20 Collimator 21a Columnar member 21 X-ray transmission part (radiation transmission part)
22 X-ray shielding part (radiation shielding part)
23 holding substrate 24 columnar member standing member 30 X-ray detection element (radiation detection element)
40 Casting mold 120 Collimator 121 X-ray transmission part (radiation transmission part)
122 X-ray shielding part (radiation shielding part)
150 container 151 lower container 151a bottomed hole 152 lid 152a bottomed hole

Claims (7)

  1.  放射線遮蔽部と、
     前記放射線遮蔽部を貫通して設けられ、且つ前記放射線遮蔽部よりも放射線遮蔽率が低い放射線透過部と、を備えるコリメータの製造方法であって、
     前記放射線透過部を形成する柱状部材が保持基板に立設された柱状部材立設部材を鋳造型に配置する配置工程と、
     前記鋳造型に、前記放射線遮蔽部の材料を液状で流入する流入工程と、
     前記放射線遮蔽部が硬化した後、前記柱状部材立設部材と前記放射線遮蔽部とを前記鋳造型から取り出す取り出し工程と、
    を備えるコリメータの製造方法。
    A radiation shield,
    A radiation transmitting part provided through the radiation shielding part and having a radiation shielding rate lower than that of the radiation shielding part,
    An arrangement step of arranging a columnar member standing member in which a columnar member forming the radiation transmitting portion is erected on a holding substrate in a casting mold;
    An inflow step of flowing the material of the radiation shielding portion into the casting mold in a liquid state;
    After the radiation shielding portion is cured, a step of taking out the columnar member standing member and the radiation shielding portion from the casting mold,
    A method for manufacturing a collimator comprising:
  2.  前記放射線透過部を、可視光遮蔽率が高い材料で製造する、
     請求項1に記載のコリメータの製造方法。
    The radiation transmitting part is manufactured with a material having a high visible light shielding rate,
    A method for manufacturing a collimator according to claim 1.
  3.  前記放射線透過部を、前記放射線遮蔽部の材料よりも融点が高い材料で製造する、
     請求項1または2に記載のコリメータの製造方法。
    The radiation transmitting part is manufactured with a material having a higher melting point than the material of the radiation shielding part,
    The manufacturing method of the collimator of Claim 1 or 2.
  4.  前記放射線透過部を、カーボンで製造する、
    請求項1から3のいずれか1項に記載のコリメータの製造方法。
    The radiation transmitting part is made of carbon;
    The manufacturing method of the collimator of any one of Claim 1 to 3.
  5.  放射線遮蔽部を、錫で製造する、
    請求項1から4のいずれか1項に記載のコリメータの製造方法。
    The radiation shield is made of tin,
    The manufacturing method of the collimator of any one of Claim 1 to 4.
  6.  前記取り出し工程の後、
     前記柱状部材を除去する除去工程を備える、
    請求項1から5のいずれか1項に記載のコリメータの製造方法。
    After the removal step,
    A removal step of removing the columnar member;
    The method for manufacturing a collimator according to any one of claims 1 to 5.
  7.  液状の放射線遮蔽部と、
     前記放射線遮蔽部を貫通して設けられ、前記放射線遮蔽部よりも放射線遮蔽率が低い放射線透過部とが容器内に密封されたコリメータの製造方法であって、
     前記放射線透過部を形成する複数の柱状部材を、開口した状態の前記容器内に立設する立設工程と、
     前記容器内に、液状の前記放射線遮蔽部の材料を流入する流入工程と、
     前記容器を密封する密封工程と、
    を備えるコリメータの製造方法。
    A liquid radiation shield,
    A method of manufacturing a collimator, which is provided through the radiation shielding part and sealed with a radiation transmitting part having a radiation shielding rate lower than that of the radiation shielding part,
    An erecting step of erecting a plurality of columnar members forming the radiation transmitting portion in the container in an opened state;
    An inflow process for flowing the liquid radiation shielding material into the container;
    A sealing step for sealing the container;
    A method for manufacturing a collimator comprising:
PCT/JP2018/007362 2018-02-27 2018-02-27 Collimator production method WO2019167146A1 (en)

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JP2002040196A (en) * 2000-07-24 2002-02-06 Fuji Photo Film Co Ltd Scattered radiation absorbing grid and method for manufacturing the same
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