JP5075490B2 - X-ray CT system - Google Patents

X-ray CT system Download PDF

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JP5075490B2
JP5075490B2 JP2007151204A JP2007151204A JP5075490B2 JP 5075490 B2 JP5075490 B2 JP 5075490B2 JP 2007151204 A JP2007151204 A JP 2007151204A JP 2007151204 A JP2007151204 A JP 2007151204A JP 5075490 B2 JP5075490 B2 JP 5075490B2
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洋之 小林
智恒 吉岡
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Hitachi Healthcare Manufacturing Ltd
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Description

本発明は、X線源のシフト(即ち焦点移動)の補正を行なうX線CT装置に関する。   The present invention relates to an X-ray CT apparatus that corrects an X-ray source shift (that is, focal shift).

X線CT装置とは、被検体にX線を照射するX線源であるX線管装置と、被検体を透過したX線量を投影データとして検出するX線検出器と、を被検体の周囲で回転させて、X線検出器により検出された複数角度の投影データを用いて被検体の断層画像を再構成し、再構成された断層画像を表示して、画像診断に供するものである。   An X-ray CT apparatus is an X-ray tube apparatus that is an X-ray source that irradiates a subject with X-rays, and an X-ray detector that detects an X-ray dose that has passed through the subject as projection data. The tomographic image of the subject is reconstructed using the projection data of a plurality of angles detected by the X-ray detector, and the reconstructed tomographic image is displayed for image diagnosis.

X線管装置は、電子ビームを放出する陰極と、陰極から放出された電子ビームを衝突させることでX線を発生する陽極と、を備える。電子ビームは、陰極と陽極の間に印加される高電圧により加速され、陽極に衝突した際に陽極内の表面近傍でX線に変換される。加速された電子ビームのエネルギーの一部はX線に変換されるが、残りのほとんどは熱に変換され陽極を加熱し熱膨張させる。その結果、実質的にX線の発生点となる陽極表面の位置が変動する。X線発生点の変動は、X線検出器で取得する投影データの計測誤差となり、再構成後に得られる断層像上にアーチファクト(偽像)を生じさせる原因となる。   The X-ray tube device includes a cathode that emits an electron beam, and an anode that generates X-rays by colliding the electron beam emitted from the cathode. The electron beam is accelerated by a high voltage applied between the cathode and the anode, and is converted into X-rays near the surface in the anode when it collides with the anode. Part of the energy of the accelerated electron beam is converted to X-rays, but most of the rest is converted to heat, heating the anode and causing thermal expansion. As a result, the position of the anode surface that substantially becomes the X-ray generation point varies. The fluctuation of the X-ray generation point becomes a measurement error of the projection data acquired by the X-ray detector, and causes an artifact (false image) on the tomographic image obtained after the reconstruction.

断層像上にアーチファクトが生じた場合、X線ＣＴ装置の診断性能を著しく劣化させるので、X線発生点の変動を低減させる必要がある。特許文献1では、X線発生点の変動、特に被検体の体軸方向(以下、スライス方向)の位置のシフトを検出するシフト検出器を用いてX線発生点の変動量を検出し、検出値に基づき、X線発生装置の位置制御を行い、X線発生点の変動を低減させている。
When artifacts occur on the tomographic image, the diagnostic performance of the X-ray CT apparatus is remarkably deteriorated, so it is necessary to reduce fluctuations in the X-ray generation point. In Patent Document 1, the amount of change in the X-ray generation point is detected and detected using a shift detector that detects the shift in the X-ray generation point, particularly the shift in the body axis direction (hereinafter referred to as the slice direction) of the subject. Based on the values, the position of the X-ray generator is controlled to reduce fluctuations in the X-ray generation point.

特開2005-143812号公報JP 2005-143812 JP

ところで、X線発生装置から発生したX線は、シフト検出器に入射する範囲と、それ以外の範囲に分離される。シフト検出器に入射する範囲のX線は、シフト検出器で散乱され、それ以外の範囲のX線とは線量・線質が異なるため、投影データを検出するためのX線に用いるには適さず、被検体にとっては無効被曝となる。被検体の無効被爆を低減するためには、シフト検出器に入射するX線の範囲をできる限り狭くする必要がある。   Incidentally, X-rays generated from the X-ray generator are separated into a range incident on the shift detector and a range other than that. X-rays in the range incident on the shift detector are scattered by the shift detector, and the dose and quality are different from other X-rays, so they are suitable for use in X-rays for detecting projection data. First, it becomes an invalid exposure for the subject. In order to reduce the ineffective exposure of the subject, it is necessary to make the X-ray range incident on the shift detector as narrow as possible.

しかしながら、上記公知文献では、シフト検出器に入射するX線の範囲を狭くすることに関して配慮されてなかった。また、上記文献では、シフト検出器の基板部から発生する散乱線についての配慮がなされていなかった。   However, in the above-mentioned known documents, no consideration is given to narrowing the range of X-rays incident on the shift detector. Further, in the above document, no consideration has been given to scattered rays generated from the substrate portion of the shift detector.

そこで本発明は、シフト検出器を備えたX線CT装置において、被検体の無効被爆を低減することを目的とする。   Accordingly, an object of the present invention is to reduce invalid exposure of a subject in an X-ray CT apparatus including a shift detector.

前記課題を解決するために、本発明は以下の様に構成される。   In order to solve the above-described problems, the present invention is configured as follows.

被検体にX線を照射するX線源と、前記X線源に対向配置され前記被検体を透過したX線を検出するX線検出器と、前記X線源と前記X線検出器を搭載し前記被検体の周囲を回転するスキャナと、前記X線検出器で検出した透過X線量に基づき被検体の断層像を再構成する画像再構成装置と、前記画像再構成装置で再構成した断層像を表示する画像表示装置と、X線を光に変換するシンチレータと前記シンチレータの発光を受光して電気信号を生成する光電変換素子と前記光電変換素子を搭載する基板とを有して成り前記X線検出器に入射するX線の位置のシフト量を検出するシフト検出器と、前記シフト検出器の検出値に基づき前記X線源の位置をシフトさせて前記X線検出器に入射するX線の位置をシフトさせるX線シフト装置と、を備えたX線CT装置において、前記シンチレータは、前記基板の端部よりも前記スキャナの回転中心側に突出した突出部を有し、該突出部がX線照射野内に位置している。   Equipped with an X-ray source that irradiates the subject with X-rays, an X-ray detector that is disposed opposite to the X-ray source and detects X-rays transmitted through the subject, and the X-ray source and the X-ray detector A scanner that rotates around the subject, an image reconstruction device that reconstructs a tomographic image of the subject based on a transmitted X-ray amount detected by the X-ray detector, and a tomogram reconstructed by the image reconstruction device An image display device that displays an image; a scintillator that converts X-rays into light; a photoelectric conversion element that receives light emitted from the scintillator to generate an electrical signal; and a substrate on which the photoelectric conversion element is mounted. A shift detector that detects the shift amount of the position of the X-ray incident on the X-ray detector, and an X-ray that is incident on the X-ray detector by shifting the position of the X-ray source based on the detection value of the shift detector In an X-ray CT apparatus provided with an X-ray shift apparatus that shifts the position of a line, The scintillator has a protrusion that protrudes toward the rotation center of the scanner from the end of the substrate, and the protrusion is located in the X-ray irradiation field.

以上、本発明によれば、X線の位置のシフト量を検出するシフト検出器に入射するX線の範囲をできる限り狭くできるので、被検体の無効被爆を低減することができる。   As described above, according to the present invention, the range of X-rays incident on the shift detector that detects the shift amount of the X-ray position can be made as narrow as possible, so that the ineffective exposure of the subject can be reduced.

本発明を適用してなるX線CT装置について図を用いて説明する。   An X-ray CT apparatus to which the present invention is applied will be described with reference to the drawings.

図1は本発明を適用したX線CT装置1の全体構成図である。X線CT装置1は、被検体10にX線を照射するX線源1と、X線源1に対向配置され被検体10を透過したX線を検出するX線検出器2と、X線源1とX線検出器2を搭載し被検体10の周囲を回転するスキャナと、X線検出器2で検出した透過X線量に基づき被検体10の断層像を再構成する画像再構成装置と、画像再構成装置で再構成した断層像を表示する画像表示装置と、X線検出器2に入射するX線の位置のシフト量を検出するシフト検出器7と、シフト検出器7の検出値に基づきX線の位置を制御する位置制御装置9と、を備える。   FIG. 1 is an overall configuration diagram of an X-ray CT apparatus 1 to which the present invention is applied. The X-ray CT apparatus 1 includes an X-ray source 1 that irradiates a subject 10 with X-rays, an X-ray detector 2 that is disposed opposite to the X-ray source 1 and detects X-rays that have passed through the subject 10, and an X-ray A scanner that includes the source 1 and the X-ray detector 2 and rotates around the subject 10, and an image reconstruction device that reconstructs a tomographic image of the subject 10 based on the transmitted X-ray dose detected by the X-ray detector 2. An image display device that displays a tomogram reconstructed by the image reconstruction device, a shift detector 7 that detects the shift amount of the position of the X-ray incident on the X-ray detector 2, and a detection value of the shift detector 7 And a position control device 9 for controlling the X-ray position based on the above.

X線源1は、電子ビームを放出する陰極と、陰極から放出された電子ビームを衝突させることでX線を発生する陽極と、を備え、陰極と陽極間に印加される高電圧に応じたエネルギーのX線を出力する。X線源1は、支持機構5によって支持されてスキャナに搭載される。   The X-ray source 1 includes a cathode that emits an electron beam and an anode that generates X-rays by colliding the electron beam emitted from the cathode, in accordance with a high voltage applied between the cathode and the anode. Outputs energy X-rays. The X-ray source 1 is supported by the support mechanism 5 and mounted on the scanner.

X線源1から出力されるX線は、コリメータ6により、スライス方向に所定の厚さを持ったファンビーム(扇状ビーム)に整形され、被検体10に照射される。被検体10を透過したX線は、X線検出器2により投影データとして検出される。X線源1とX線検出器2を搭載したスキャナを回転させながら、被検体へのX線照射と、透過X線の検出を、行うことにより複数角度の投影データが取得される。   X-rays output from the X-ray source 1 are shaped into a fan beam (fan beam) having a predetermined thickness in the slicing direction by the collimator 6 and irradiated onto the subject 10. X-rays transmitted through the subject 10 are detected as projection data by the X-ray detector 2. By rotating a scanner equipped with the X-ray source 1 and the X-ray detector 2, X-ray irradiation to the subject and detection of transmitted X-rays are performed, thereby obtaining projection data at a plurality of angles.

画像再構成装置では、取得した複数角度の投影データに対し逆投影法による再構成処理が実施され、被検体10の断層像が生成される。生成された断層像は、画像表示装置に表示され、画像診断に用いられる。   In the image reconstruction apparatus, a reconstruction process by back projection is performed on the acquired projection data at a plurality of angles, and a tomographic image of the subject 10 is generated. The generated tomographic image is displayed on an image display device and used for image diagnosis.

X線源1から出力されるX線の発生点の位置は、X線源内の陽極の熱膨張により変動する。シフト検出器7は、X線の発生点の位置の変動で生じるシフト量を検出するためのものである。シフト検出器7の検出値は、位置制御装置9に入力される。位置制御装置9は、シフト検出器7の検出値に基づき、X線の発生点の位置を調整するための信号を、X線源1の位置調整装置や、X線源1を支持する支持機構5の位置調整装置、コリメータ6の位置調整装置に出力する。これらの位置調整装置の少なくとも一つを制御することにより、X線の発生点の位置の変動を補償することができる。   The position of the generation point of X-rays output from the X-ray source 1 varies due to thermal expansion of the anode in the X-ray source. The shift detector 7 is for detecting a shift amount caused by a change in the position of the X-ray generation point. The detection value of the shift detector 7 is input to the position control device 9. The position control device 9 is a signal for adjusting the position of the X-ray generation point based on the detection value of the shift detector 7, and a position adjustment device for the X-ray source 1 or a support mechanism for supporting the X-ray source 1. 5 is output to the position adjusting device of the collimator 6. By controlling at least one of these position adjusting devices, it is possible to compensate for variations in the position of the X-ray generation point.

被検体10に照射されるX線は、角度αの範囲のX線3と角度βの範囲のX線4から成る。シフト検出器7には、角度βの範囲のX線4が照射される。角度βの範囲のX線4は、シフト検出器7で散乱されるので、被検体10の投影データを取得するには適さず、被検体10にとって無効被爆となる。無効被曝を低減するには、角度βをできる限り狭くする必要がある。   The X-rays irradiated to the subject 10 include X-rays 3 in the range of the angle α and X-rays 4 in the range of the angle β. The shift detector 7 is irradiated with X-rays 4 in the range of the angle β. Since the X-ray 4 in the range of the angle β is scattered by the shift detector 7, it is not suitable for acquiring projection data of the subject 10, and becomes invalid exposure to the subject 10. In order to reduce the ineffective exposure, it is necessary to make the angle β as narrow as possible.

角度βを狭くするためのシフト検出器7の実施形態を図2と図3に示す。図2はシフト検出器7の平面図、すなわちX線源1側から見た図であり、図3はシフト検出器7の側面図、すなわちスキャナの回転軸方向から見た図である。   2 and 3 show an embodiment of the shift detector 7 for narrowing the angle β. FIG. 2 is a plan view of the shift detector 7, that is, a view seen from the X-ray source 1 side, and FIG. 3 is a side view of the shift detector 7, ie, a view seen from the rotation axis direction of the scanner.

シフト検出器7は、X線を光に変換するシンチレータ11と、シンチレータ11の発光を受光して電気信号を出力する光電変換素子12と、光電変換素子12を搭載する基板13と、から構成される。シンチレータ11に入射したX線量に応じてシンチレータ11の発光量は変化し、光電変換素子12が受光した光量に応じて光電変換素子12が出力する電気信号は変化するため、シフト検出器7に入射したX線量に応じた電気信号が出力される。   The shift detector 7 includes a scintillator 11 that converts X-rays into light, a photoelectric conversion element 12 that receives light emitted from the scintillator 11 and outputs an electrical signal, and a substrate 13 on which the photoelectric conversion element 12 is mounted. The The amount of light emitted from the scintillator 11 changes in accordance with the X-ray dose incident on the scintillator 11, and the electric signal output from the photoelectric conversion element 12 changes in accordance with the amount of light received by the photoelectric conversion element 12, so that it enters the shift detector 7. An electrical signal corresponding to the X-ray dose is output.

シンチレータ11は可視光を透過するので、外部からシンチレータ11へ入射する可視光を遮光することが望ましい。外部からの可視光を遮光しない場合、入射した可視光はシンチレータ11を透過して光電変換素子12に達し、ノイズ信号として出力される。遮光方法の一例には、エポキシ樹脂に黒鉛粉末などの光吸収率の高い物質を混ぜ合わせた黒色樹脂をシンチレータ11の表面に塗布する方法がある。また別の方法として、エポキシ樹脂に酸化チタン粉末などの光反射率の高い物質を混ぜ合わせた白色樹脂をシンチレータ11の表面に塗布する方法もある。白色樹脂を用いた場合、シンチレータ11内で発生した光を効率よく光電素子12へ導くことができる。白色樹脂を塗布した後、さらに黒色樹脂を塗布しても良い。   Since the scintillator 11 transmits visible light, it is desirable to block visible light incident on the scintillator 11 from the outside. When the visible light from the outside is not blocked, the incident visible light passes through the scintillator 11, reaches the photoelectric conversion element 12, and is output as a noise signal. As an example of the light shielding method, there is a method of applying to the surface of the scintillator 11 a black resin obtained by mixing an epoxy resin with a material having a high light absorption rate such as graphite powder. As another method, there is a method in which a white resin obtained by mixing an epoxy resin with a material having high light reflectance such as titanium oxide powder is applied to the surface of the scintillator 11. When white resin is used, light generated in the scintillator 11 can be efficiently guided to the photoelectric element 12. After applying the white resin, a black resin may be further applied.

シンチレータ11は、分離帯16により感応領域14と15に分離されており、光電変換素子12も感応領域14と15に対応するように分離されている。このような構造のシフト検出器7に、コリメータ6によって整形されたスライス方向に所定の厚さWを持つX線の一部であるX線4が照射される。図2に示したX線4とシフト検出器7の位置関係は、X線発生点の位置がシフトしていない状態である。   The scintillator 11 is separated into sensitive regions 14 and 15 by a separation band 16, and the photoelectric conversion element 12 is also separated so as to correspond to the sensitive regions 14 and 15. The shift detector 7 having such a structure is irradiated with X-rays 4 which are a part of X-rays having a predetermined thickness W in the slice direction shaped by the collimator 6. The positional relationship between the X-ray 4 and the shift detector 7 shown in FIG. 2 is a state in which the position of the X-ray generation point is not shifted.

図4に、シフト検出器7の出力に基づいて、X線の発生点の位置の変動を補償するためのシステムブロック図を示す。感応領域14と15にそれぞれ対応する光電変換素子12の出力をシフト検出器7は検出信号S1とS2として出力する。シフト検出器7の検出信号S1とS2は位置制御装置9に入力され、位置制御装置9はS1とS2に基づいて位置調整装置17を制御する。   FIG. 4 shows a system block diagram for compensating for the variation in the position of the X-ray generation point based on the output of the shift detector 7. The shift detector 7 outputs the outputs of the photoelectric conversion elements 12 corresponding to the sensitive regions 14 and 15, respectively, as detection signals S1 and S2. Detection signals S1 and S2 of the shift detector 7 are input to the position control device 9, and the position control device 9 controls the position adjustment device 17 based on S1 and S2.

図2に示したX線4のシフト検出器7の位置関係の場合、感応領域14と15には均等にX線が入射し、感応領域14と15にそれぞれ対応する検出信号S1とS2は等しい値となる。X線発生点の位置が図2中に示す点線aまたはbの方向にシフトすると、検出信号S1とS2に差異が生じる。例えば、図2中の点線aの方向にシフトするとS1＜S2となり、点線bの方向ではS1＞S2となる。つまり、検出信号S1とS2の差分(S1−S2)がシフト量となり、位置制御装置9で差分(S1−S2)を算出し、X線源1や支持機構5等の位置調整装置16を検出信号S1とS2の差分値がゼロになるように制御すればX線発生点の位置を補償することができる。   In the case of the positional relationship of the X-ray 4 shift detector 7 shown in FIG. 2, the X-rays are equally incident on the sensitive regions 14 and 15, and the detection signals S1 and S2 corresponding to the sensitive regions 14 and 15 are equal. Value. When the position of the X-ray generation point is shifted in the direction of the dotted line a or b shown in FIG. 2, a difference occurs between the detection signals S1 and S2. For example, when shifting in the direction of the dotted line a in FIG. 2, S1 <S2 and in the direction of the dotted line b, S1> S2. In other words, the difference (S1-S2) between the detection signals S1 and S2 becomes the shift amount, and the position controller 9 calculates the difference (S1-S2) to detect the position adjustment device 16 such as the X-ray source 1 or the support mechanism 5. If the control is performed so that the difference value between the signals S1 and S2 becomes zero, the position of the X-ray generation point can be compensated.

ここで、本発明のシフト検出器7の構造の特徴を、図5に示す従来のシフト検出器7'と比較して説明する。光電変換素子12と基板13の相互位置関係は、従来のシフト検出器7'と本発明のシフト検出器7では違いはなく、光電変換素子12の破損防止や配線スペースの確保などの実装上の制限から、光電変換素子12は基板13上からはみ出すことなく配置される。   Here, the characteristics of the structure of the shift detector 7 of the present invention will be described in comparison with the conventional shift detector 7 ′ shown in FIG. The mutual positional relationship between the photoelectric conversion element 12 and the substrate 13 is not different between the conventional shift detector 7 ′ and the shift detector 7 of the present invention, and on mounting such as damage prevention of the photoelectric conversion element 12 and securing of wiring space. Due to restrictions, the photoelectric conversion element 12 is arranged without protruding from the substrate 13.

光電変換素子12上にはさらにシンチレータ11が配置されるが、従来のシフト検出器7'では光電変換素子12上からはみ出すことなくシンチレータ11が配置される。これに対し、本発明のシフト検出器7では、シンチレータ11は基板13よりもスキャナの回転中心側に突出している。このような構造とすることにより、従来のシフト検出器７'の構造に比べ、角度βを狭くできる。以下、その理由について説明する。   A scintillator 11 is further disposed on the photoelectric conversion element 12, but the scintillator 11 is disposed without protruding from the photoelectric conversion element 12 in the conventional shift detector 7 ′. On the other hand, in the shift detector 7 of the present invention, the scintillator 11 protrudes from the substrate 13 toward the rotation center side of the scanner. By adopting such a structure, the angle β can be made narrower than the structure of the conventional shift detector 7 ′. The reason will be described below.

シフト検出器7の検出信号は、シンチレータ11に入射するX線4の面積に比例するので、シフト検出器7の検出信号を必要な検出精度などによって決まる値以上にするためには、シンチレータ11に入射するX線4の面積を所定の値以上にする必要がある。シンチレータ11が基板13よりも突出した構造では、シンチレータ11に入射するX線4の面積だけで角度βが決まる(図3参照)。これに対し、従来のシフト検出器7'の構造では、シンチレータ11に入射するX線(図5中の角度β1に相当)の面積に加えて、基板13に照射されるX線(図5中の角度β2に相当)の面積も含めて角度β(＝β1+β2)が決まることになる。すなわち、シンチレータ11が突出した構造のほうがシフト検出器7に照射されるX線の面積が角度β2に相当する分だけ小さくなるので、角度βを狭くできる。   Since the detection signal of the shift detector 7 is proportional to the area of the X-ray 4 incident on the scintillator 11, in order to make the detection signal of the shift detector 7 more than a value determined by the required detection accuracy, the scintillator 11 The area of the incident X-ray 4 needs to be a predetermined value or more. In the structure in which the scintillator 11 protrudes from the substrate 13, the angle β is determined only by the area of the X-ray 4 incident on the scintillator 11 (see FIG. 3). In contrast, in the structure of the conventional shift detector 7 ′, in addition to the area of the X-rays incident on the scintillator 11 (corresponding to the angle β1 in FIG. 5), the X-rays irradiated on the substrate 13 (in FIG. 5) The angle β (= β1 + β2) is determined including the area of the angle β2). That is, in the structure in which the scintillator 11 protrudes, the area of the X-rays irradiated to the shift detector 7 is reduced by an amount corresponding to the angle β2, so that the angle β can be narrowed.

また、本実施形態では、角度βの範囲のX線4はシンチレータ11にのみへ照射され、従来技術のように基板へは照射されない。したがって、本実施形態では基板へ照射されたX線による散乱線が発生することがないので、被検者の無効被曝の低減を図れる。   Further, in the present embodiment, the X-ray 4 in the range of the angle β is irradiated only to the scintillator 11 and is not irradiated to the substrate as in the prior art. Therefore, in the present embodiment, scattered radiation due to X-rays irradiated to the substrate is not generated, so that it is possible to reduce the invalid exposure of the subject.

次に第二の実施形態について図を用いて説明する。図6に第二の実施形態のシフト検出器７を示す。第一の実施形態と異なる点は、シフト検出器7の構造である。図3の構造では、X線源1側から、シンチレータ11、光電素子12、基板13といった順に並ぶのに対し、本実施形態では、基板13、光電素子12、シンチレータ11といった順に並ぶ。このような構成にした場合、X線4を検出する位置が、図3の場合に比べてX線源1から離れることになる。X線はX線源1から離れるに従い照射範囲が広がるので、X線源1から離れた場所でX線を検出したほうが、X線の位置のより小さな変動を検知できるようになる。すなわち、X線源1からより離れた場所でX線の位置を検出したほうが、シフト検出器7の検出精度を向上できる。
Next, a second embodiment will be described with reference to the drawings. FIG. 6 shows the shift detector 7 of the second embodiment. The difference from the first embodiment is the structure of the shift detector 7. In the structure of FIG. 3, the scintillator 11, the photoelectric element 12, and the substrate 13 are arranged in this order from the X-ray source 1 side. In the present embodiment, the substrate 13, the photoelectric element 12, and the scintillator 11 are arranged in this order. In such a configuration, the position where the X-ray 4 is detected is farther from the X-ray source 1 than in the case of FIG. Since the irradiation range of X-rays increases as the distance from the X-ray source 1 increases, detection of X-rays at a location distant from the X-ray source 1 makes it possible to detect smaller fluctuations in the X-ray position. That is, the detection accuracy of the shift detector 7 can be improved by detecting the position of the X-ray at a location farther from the X-ray source 1.

以上、本発明の実施形態を述べたが、本発明はこれらに限定されるものではなく、種々変形して実施可能である。   As mentioned above, although embodiment of this invention was described, this invention is not limited to these, Various deformation | transformation can be implemented.

本発明の全体構成を説明するための図。The figure for demonstrating the whole structure of this invention. 第一の実施形態のシフト検出器7の平面図。The top view of the shift detector 7 of 1st embodiment. 第一の実施形態のシフト検出器7の側面図。The side view of the shift detector 7 of 1st embodiment. X線発生点のシフト補償システムのブロック図。The block diagram of the shift compensation system of the X-ray generation point. 従来のシフト検出器7'の側面図。The side view of the conventional shift detector 7 '. 第二の実施形態のシフト検出器7の側面図。The side view of the shift detector 7 of 2nd embodiment.

符号の説明Explanation of symbols

１ X線源、2 X線検出器、3 角度αの範囲のX線、4 角度βの範囲のX線、5 支持機構、6 コリメータ、7 シフト検出器、8 シフト検出器用コリメータ、9 位置制御装置、10 被検体、11 シンチレータ、12 光電変換素子、13 基板、14 S1に対応する感応領域、15 S2に対応する感応領域、16 分離帯、17 位置調整装置。   1 X-ray source, 2 X-ray detector, 3 X-ray in the range of angle α, 4 X-ray in the range of angle β, 5 Support mechanism, 6 Collimator, 7 Shift detector, 8 Collimator for shift detector, 9 Position control Device, 10 subject, 11 scintillator, 12 photoelectric conversion element, 13 substrate, sensitive region corresponding to 14 S1, sensitive region corresponding to 15 S2, 16 separation band, 17 position adjustment device.

Claims (1)

被検体にＸ線を照射するＸ線源と、前記Ｘ線源に対向配置され前記被検体を透過したＸ線を検出するＸ線検出器と、前記Ｘ線源と前記Ｘ線検出器を搭載し前記被検体の周囲を回転するスキャナと、前記Ｘ線検出器で検出した透過Ｘ線量に基づき被検体の断層像を再構成する画像再構成装置と、前記画像再構成装置で再構成した断層像を表示する画像表示装置と、Ｘ線を光に変換するシンチレータと前記シンチレータの発光を受光して電気信号を生成する光電変換素子と前記光電変換素子を搭載する基板とを有して成り前記Ｘ線検出器に入射するＸ線の位置のシフト量を検出するシフト検出器と、前記シフト検出器の検出値に基づき前記Ｘ線源の位置をシフトさせて前記Ｘ線検出器に入射するＸ線の位置をシフトさせるＸ線シフト装置と、を備えたＸ線ＣＴ装置において、
前記シンチレータは、前記基板の端部よりも前記スキャナの回転中心側に突出した突出部を有し、該突出部がＸ線照射野内に位置しており、
前記シフト検出器は、前記Ｘ線源側から基板、光電変換素子、シンチレータの順で並ぶことを特徴とするＸ線ＣＴ装置。 Equipped with an X-ray source for irradiating a subject with X-rays, an X-ray detector arranged to face the X-ray source and detecting X-rays transmitted through the subject, and the X-ray source and the X-ray detector A scanner that rotates around the subject, an image reconstruction device that reconstructs a tomographic image of the subject based on the transmitted X-ray dose detected by the X-ray detector, and a tomogram that is reconstructed by the image reconstruction device An image display device that displays an image; a scintillator that converts X-rays into light; a photoelectric conversion element that receives light emitted from the scintillator to generate an electrical signal; and a substrate on which the photoelectric conversion element is mounted. A shift detector that detects the shift amount of the position of the X-ray incident on the X-ray detector, and an X that is incident on the X-ray detector after shifting the position of the X-ray source based on the detection value of the shift detector X-ray shift device for shifting the position of the line In X-ray CT apparatus,
The scintillator has a protrusion that protrudes toward the rotation center of the scanner from the end of the substrate, and the protrusion is located in the X-ray irradiation field .
The X-ray CT apparatus , wherein the shift detector is arranged in the order of a substrate, a photoelectric conversion element, and a scintillator from the X-ray source side .
JP2007151204A 2007-06-07 2007-06-07 X-ray CT system Expired - Fee Related JP5075490B2 (en)

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