JPH0938075A - Radial rays exposure device - Google Patents
Radial rays exposure deviceInfo
- Publication number
- JPH0938075A JPH0938075A JP7192135A JP19213595A JPH0938075A JP H0938075 A JPH0938075 A JP H0938075A JP 7192135 A JP7192135 A JP 7192135A JP 19213595 A JP19213595 A JP 19213595A JP H0938075 A JPH0938075 A JP H0938075A
- Authority
- JP
- Japan
- Prior art keywords
- radiation
- calibration
- sensitivity data
- output
- detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001514 detection method Methods 0.000 claims abstract description 45
- 230000035945 sensitivity Effects 0.000 claims abstract description 28
- 230000005855 radiation Effects 0.000 claims description 65
- 238000003384 imaging method Methods 0.000 claims description 19
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000003745 diagnosis Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は医療用の画像診断装
置であるＸ線ＣＴ装置やデジタル撮像装置、ガンマカメ
ラなどの放射線撮像装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation imaging apparatus such as an X-ray CT apparatus which is a medical image diagnostic apparatus, a digital imaging apparatus, and a gamma camera.
【０００２】[0002]
【従来の技術】例えばＸ線ＣＴ装置に使われているよう
な、放射線が入射することによって発光する蛍光素子
と、そこからの光を受けて電気信号を出力する光電変換
素子の組み合わせからなる検出素子を多数個一次元状に
並べて構成した放射線検出器は、個々の検出素子の製造
上のばらつきに起因する個体差のほかに、放射線の被照
射量に応じて検出素子の感度（特に蛍光素子の感度）が
低下するという現象があった。このために、この放射線
検出器を用いた放射線撮像装置を継続的に使用して行く
にしたがって各検出素子（各チャンネル）の感度の低下
やばらつきが大きくなり、Ｘ線ＣＴ装置などでは最終的
に得られる断層像に虚像を生じるという問題があった。
従来は、被写体がない場合の検出素子の出力が所定の値
になるように補正する操作、いわゆるキャリブレーショ
ンを定期的あるいは撮像の開始直前に行うことによって
この問題を回避していたが、このキャリブレーションを
行うためには余分な時間がかかり、診断を一時中断する
ことになり非常に効率が悪かった。2. Description of the Related Art Detection, which is composed of a combination of a fluorescent element that emits light upon incidence of radiation and a photoelectric conversion element that receives light from the fluorescent element and outputs an electric signal, as used in an X-ray CT apparatus A radiation detector composed of a large number of elements arranged in a one-dimensional array is not only an individual difference due to manufacturing variations of individual detection elements, but also the sensitivity of detection elements (especially fluorescent elements) depending on the radiation dose. However, there was a phenomenon that the For this reason, as the radiation imaging apparatus using this radiation detector is continuously used, the sensitivity of each detection element (each channel) decreases and the variation becomes large, and finally in an X-ray CT apparatus or the like. There is a problem that a virtual image is generated in the obtained tomographic image.
In the past, this problem was circumvented by performing a so-called calibration operation for correcting the output of the detection element to a predetermined value when there is no subject, so-called calibration, which has been performed. It took extra time to perform the operation, and the diagnosis was temporarily suspended, which was very inefficient.
【０００３】[0003]
【発明が解決しようとする課題】本発明は上記従来技術
に伴う問題点に鑑みて発明されたものであり、本発明が
解決しようとする課題は、検出素子の製造上のばらつき
に起因する固体差や、放射線の被照射量に応じて起こる
放射線検出器の個々の検出素子の感度変化を克服し、診
断途中での余分なキャリブレーションのために時間を費
やすことなく、常に良好な画像を得ることができる放射
線撮像装置を提供することである。The present invention has been invented in view of the problems associated with the above-mentioned prior art, and the problem to be solved by the present invention is a solid state caused by variations in manufacturing of detection elements. Overcome differences and sensitivity changes of individual detection elements of the radiation detector that occur depending on the radiation dose, and always obtain good images without spending time for extra calibration during diagnosis It is to provide a radiation imaging apparatus capable of performing the above.
【０００４】[0004]
【課題を解決するための手段】上記課題を解決するため
に、本発明は、放射線の検出素子を一次元または二次元
的に複数個並べてなる放射線検出器を有する放射線撮像
装置において、前記放射線検出器の前面に前記検出素子
の並び方向に走査可能に設置された較正用放射線源と、
前記各検出素子の感度データを格納する記憶手段と、こ
の感度データに基づき各検出素子の出力を補正する補正
手段を備え、前記較正用放射線源を前記放射線検出器の
前面で走査することによって得られる各検出素子の感度
データに基づいて、撮像段階における各検出素子の出力
を補正するようにした。In order to solve the above problems, the present invention provides a radiation imaging apparatus having a radiation detector in which a plurality of radiation detection elements are arranged one-dimensionally or two-dimensionally. A calibration radiation source installed on the front surface of the vessel so as to be scannable in the arrangement direction of the detection elements,
Storage means for storing the sensitivity data of each of the detection elements and correction means for correcting the output of each of the detection elements based on the sensitivity data are provided, and are obtained by scanning the calibration radiation source in front of the radiation detector. The output of each detection element in the imaging stage is corrected based on the sensitivity data of each detection element.
【０００５】撮像をしていないときに、放射線量が安定
した較正用放射線源を放射線検出器の前面で走査しなが
ら各検出素子の出力を測定することによって感度記憶メ
モリに各検出素子の感度データを記憶し、撮像をすると
きにはその記憶されている最新の感度データに基づき各
検出素子の出力を補正するので、撮像を中断するような
余分なキャリブレーションのために時間を費やすことな
く虚像のない良好な撮影像を常に得ることができる。The sensitivity data of each detection element is stored in the sensitivity storage memory by measuring the output of each detection element while scanning the calibration radiation source with a stable radiation dose on the front surface of the radiation detector when the imaging is not performed. Is stored, and the output of each detection element is corrected based on the latest sensitivity data stored when imaging, so there is no virtual image without spending time for extra calibration that interrupts imaging. A good captured image can always be obtained.
【０００６】[0006]
【発明の実施の形態】図１は本発明の一実施例であるＸ
線ＣＴ装置の概略図である。Ｘ線管１から放射されたＸ
線２は被検体３を透過して円弧状の一次元的ラインセン
サである放射線検出器４によって検出される。この放射
線検出器４は、Ｘ線があたると光を発する蛍光素子５
と、この蛍光素子５からの光を電気的信号に変換する例
えばフォトダイオードなどの光電変換素子６の組からな
る検出素子７をＸ線管を中心とする円弧状に１０００個
程度の複数個並べて形成したものである。放射線検出器
４の前面（Ｘ線が当たる面）付近には較正用放射線源８
が配置されており、この較正用放射線源８は円弧状のレ
ール９と駆動モータ１０などからなる走査機構により放
射線検出器４の前面で検出素子の並び方向に沿って走査
されるようになっている。さらに放射線検出器４の端近
傍には較正用放射線源８を収納でき、鉛板などで囲われ
て放射線が漏れないように作られた遮蔽箱１２が備えら
れている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment X of the present invention.
It is a schematic diagram of a line CT device. X emitted from the X-ray tube 1
The line 2 passes through the subject 3 and is detected by a radiation detector 4 which is an arc-shaped one-dimensional line sensor. The radiation detector 4 includes a fluorescent element 5 that emits light when exposed to X-rays.
And a plurality of detection elements 7, each of which is composed of a set of photoelectric conversion elements 6 such as photodiodes, for converting the light from the fluorescent element 5 into an electric signal, are arranged in an arc shape around the X-ray tube. It was formed. A calibration radiation source 8 is provided near the front surface of the radiation detector 4 (the surface on which the X-rays strike).
Is arranged, and the calibration radiation source 8 is configured to be scanned on the front surface of the radiation detector 4 along the direction in which the detection elements are arranged by a scanning mechanism including an arcuate rail 9 and a drive motor 10. There is. Further, near the end of the radiation detector 4, a calibration radiation source 8 can be housed, and a shielding box 12 surrounded by a lead plate or the like to prevent radiation from leaking is provided.
【０００７】この較正用放射線源８はＣｓ137 などの放
射性同位体から構成され一定の強さの較正用放射線１１
を常に放射しているものである。撮像をしていない合間
に、この較正用放射線源８が放射線検出器４の前面に沿
って走査されることにより、較正用放射線１１が放射線
検出器４を構成する各検出素子に次々に入射し、そのと
きの各検出素子からの出力が測定される。照射される放
射線の強度は一定であるから放射線検出器４からの出力
（あるいはその最大値を１として規格化した値）は各検
出素子の感度のばらつきを表すものとなる。これらの出
力は出力検出回路２１、スイッチＳ１を介して感度デー
タメモリ２２に記憶される。ここで出力検出回路２１は
放射線検出器４の各検出素子からのアナログ出力を増幅
・デジタル化などを行いデジタルデータとして出力する
ものである。The calibration radiation source 8 is composed of a radioactive isotope such as Cs137 and has a constant intensity.
Is always radiated. The calibration radiation source 8 is scanned along the front surface of the radiation detector 4 during the period when the imaging is not performed, so that the calibration radiation 11 is sequentially incident on each detection element constituting the radiation detector 4. The output from each detection element at that time is measured. Since the intensity of the applied radiation is constant, the output from the radiation detector 4 (or the value standardized with its maximum value being 1) represents the variation in the sensitivity of each detection element. These outputs are stored in the sensitivity data memory 22 via the output detection circuit 21 and the switch S1. Here, the output detection circuit 21 amplifies and digitizes the analog output from each detection element of the radiation detector 4 and outputs it as digital data.
【０００８】実際の撮像を行う場合には、較正用放射線
源８は放射線検出器４の脇に配置された遮蔽箱１２の中
に収納される。そうすることによって較正用放射線１１
は遮蔽箱１２から漏れ出すことがないので、測定時にバ
ックグラウンドとなるような余分の放射線を放射線検出
器４に照射することがなく、測定データに余分なノイズ
が入ることはない。ただし、この遮蔽箱１２は必ずしも
必要ではなく、放射線検出器４の前から避けた場所に退
避した較正用放射線源８の収容容器の放射線放出口に蓋
をするようにしてもよい。When performing an actual image pickup, the calibration radiation source 8 is housed in a shielding box 12 arranged beside the radiation detector 4. By doing so, the calibration radiation 11
Does not leak from the shielding box 12, so that the radiation detector 4 is not irradiated with extra radiation that becomes the background during measurement, and no extra noise is included in the measurement data. However, the shielding box 12 is not always necessary, and the radiation emitting port of the container for the calibration radiation source 8 that has been retracted from the front of the radiation detector 4 may be covered.
【０００９】撮像時においては放射線検出器４の出力は
出力検出回路２１とスイッチＳ１を介して補正器３３に
接続される。得られた撮像用のデータは、補正器３３に
よって感度データメモリ２２に記憶されている較正用感
度データで割り算することにより補正され各検出素子間
の特性のばらつきの影響を受けないデータとなる。この
データは、制御器２４によって断層画像データとして再
構成され、ＣＲＴなどからなる表示器２５に画像が表示
される。ここで制御器２４は感度データメモリ２２や補
正器２３、スイッチＳ１などをそれぞれの役割を果たす
ように制御する動作も行っている。なお、制御器２４、
補正器２３、感度データメモリ２２、スイッチＳ１など
の機能はまとめて一つのコンピュータによってソフト的
に処理することもできる。During imaging, the output of the radiation detector 4 is connected to the corrector 33 via the output detection circuit 21 and the switch S1. The obtained imaging data is corrected by being divided by the calibration sensitivity data stored in the sensitivity data memory 22 by the compensator 33 to be corrected, and becomes data which is not affected by the characteristic variation among the detection elements. This data is reconstructed as tomographic image data by the controller 24, and the image is displayed on the display 25 such as a CRT. Here, the controller 24 also performs an operation of controlling the sensitivity data memory 22, the compensator 23, the switch S1 and the like so as to play their respective roles. The controller 24,
The functions of the compensator 23, the sensitivity data memory 22, the switch S1 and the like can be collectively processed by one computer as software.
【００１０】本発明は次のような構成を含むものであ
る。蛍光素子と光電変換素子との組み合わせからなる検
出素子を複数個並べてなる放射線検出器を有するＸ線Ｃ
Ｔ装置において、前記放射線検出器の前面に前記検出素
子の並列方向に走査可能に設置された較正用放射線源
と、この較正用放射線源を収納する放射線遮蔽箱と、前
記各検出素子の感度データを格納する記憶手段と、この
感度データに基づき各検出素子の出力を補正する演算手
段を備え、撮像の準備段階で前記較正用放射線源を前記
放射線検出器の前面で走査しながら各検出素子の出力を
測定することによって前記記憶手段に各検出素子の感度
データを記憶し、撮像の段階では前記較正用放射線源を
前記遮蔽箱に収納し、撮像のときに得られる各検出素子
の出力を前記感度データに基づいて前記演算手段によっ
て補正することを特徴とするＸ線ＣＴ装置。The present invention includes the following configurations. X-ray C having a radiation detector formed by arranging a plurality of detection elements each including a combination of a fluorescent element and a photoelectric conversion element
In the T apparatus, a calibration radiation source installed on the front surface of the radiation detector so as to be able to scan in the parallel direction of the detection elements, a radiation shielding box housing the calibration radiation source, and sensitivity data of each of the detection elements. And a calculation means for correcting the output of each detection element based on this sensitivity data, and while scanning the calibration radiation source on the front surface of the radiation detector in the preparation stage of imaging, Sensitivity data of each detection element is stored in the storage means by measuring the output, the calibration radiation source is housed in the shielding box at the time of imaging, and the output of each detection element obtained at the time of imaging is described above. An X-ray CT apparatus characterized in that it is corrected by the calculation means based on sensitivity data.
【００１１】[0011]
【発明の効果】本発明では較正用放射線源とその走査機
構によって、放射線検出器の各検出素子の特性のばらつ
きおよび感度の低下を撮像の合間や準備段階で簡単に補
正しておくことができるので、診断のための撮影を中断
したり余分な時間を費やすことなく、常に良好な画像が
得られる。According to the present invention, the calibration radiation source and its scanning mechanism make it possible to easily correct variations in the characteristics of the detection elements of the radiation detector and a reduction in sensitivity during the imaging or during the preparation stage. Therefore, a good image can always be obtained without interrupting photographing for diagnosis or spending extra time.
【図１】本発明の一実施例を示すＸ線ＣＴ装置の概略図
である。FIG. 1 is a schematic diagram of an X-ray CT apparatus showing an embodiment of the present invention.
１…Ｘ線管 ２…Ｘ線 ３…被検体 ４…放射線検出器 ５…蛍光素子 ６…光電変換素子 ７…検出素子 ８…較正用放射線源 ９…レール １０…モータ １１…較正用放射線 １２…遮蔽箱 ２１…出力検出回路 ２２…感度データメモリ ２３…補正器 ２４…制御器 ２５…表示器 DESCRIPTION OF SYMBOLS 1 ... X-ray tube 2 ... X-ray 3 ... Test object 4 ... Radiation detector 5 ... Fluorescent element 6 ... Photoelectric conversion element 7 ... Detection element 8 ... Calibration radiation source 9 ... Rail 10 ... Motor 11 ... Calibration radiation 12 ... Shield box 21 ... Output detection circuit 22 ... Sensitivity data memory 23 ... Corrector 24 ... Controller 25 ... Indicator
Claims (1)
的に複数個並べてなる放射線検出器を有する放射線撮像
装置において、前記放射線検出器の前面に前記検出素子
の並び方向に走査可能に設置された較正用放射線源と、
前記各検出素子の感度データを格納する記憶手段と、こ
の感度データに基づき各検出素子の出力を補正する補正
手段を備え、前記較正用放射線源を前記放射線検出器の
前面で走査することによって得られる各検出素子の感度
データに基づいて、撮像段階における各検出素子の出力
を補正することを特徴とする放射線撮像装置。1. A radiation imaging apparatus having a radiation detector in which a plurality of radiation detection elements are arranged one-dimensionally or two-dimensionally, and is installed on the front surface of the radiation detector so as to be scannable in the arrangement direction of the detection elements. A calibration radiation source,
Storage means for storing the sensitivity data of each of the detection elements and correction means for correcting the output of each of the detection elements based on the sensitivity data are provided, and are obtained by scanning the calibration radiation source in front of the radiation detector. A radiation imaging apparatus characterized by correcting the output of each detection element in the imaging stage based on the sensitivity data of each detection element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7192135A JPH0938075A (en) | 1995-07-27 | 1995-07-27 | Radial rays exposure device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7192135A JPH0938075A (en) | 1995-07-27 | 1995-07-27 | Radial rays exposure device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0938075A true JPH0938075A (en) | 1997-02-10 |
Family
ID=16286273
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7192135A Pending JPH0938075A (en) | 1995-07-27 | 1995-07-27 | Radial rays exposure device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0938075A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014518147A (en) * | 2011-07-12 | 2014-07-28 | コーニンクレッカ フィリップス エヌ ヴェ | Calibration of detectors in imaging systems |
| JP2016014579A (en) * | 2014-07-02 | 2016-01-28 | 株式会社堀場製作所 | Gamma camera adjusting device and gamma camera system |
-
1995
- 1995-07-27 JP JP7192135A patent/JPH0938075A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014518147A (en) * | 2011-07-12 | 2014-07-28 | コーニンクレッカ フィリップス エヌ ヴェ | Calibration of detectors in imaging systems |
| JP2016014579A (en) * | 2014-07-02 | 2016-01-28 | 株式会社堀場製作所 | Gamma camera adjusting device and gamma camera system |
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