JP3951624B2

JP3951624B2 - Biomagnetic field measurement device

Info

Publication number: JP3951624B2
Application number: JP2001086633A
Authority: JP
Inventors: 豪宮下; 啓二塚田; 明彦神鳥; 昭二近藤; 笹渕　　仁
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1999-10-06
Filing date: 2001-03-26
Publication date: 2007-08-01
Anticipated expiration: 2020-08-07
Also published as: JP2001299714A

Description

【０００１】
【発明の属する技術分野】
本発明は，生体から発する微弱磁場の検出を行なう超伝導デバイスであるＳＱＵＩＤ（ＳｕｐｅｒｃｏｎｄｕｃｔｉｎｇＱｕａｎｔｕｍＩｎｔｅｒｆｅｒｅｎｃｅＤｅｖｉｃｅ：超伝導量子干渉素子）磁束計を用いた生体磁場計測装置に関し，特に，心臓の活動に関する機能情報と心臓の形態画像とを容易に合成できる生体磁場計測装置及び生体磁場計測方法，生体磁場計測装置のためのデータ処理方法及び検査対象の位置決め方法に関する。
【０００２】
【従来の技術】
図１６に示すように，脳機能を計測する従来の生体磁場計測装置では，複数の検出コイル１２を，外形を頭部の曲率に合わせたデユアの底部１１に配置し，頭部の複数個所に設置した磁場発生コイル１３に通電して発生する磁場を検出コイル１２により計測して，磁場発生コイル１３により発生する磁場と検出コイル１２の出力との関係をシミュレートする。検出コイル１２による計測データとシミュレートした検出コイル１２の出力との差を最小とする磁場発生コイル１３の位置を推定することによって，磁場発生コイル１３を配置した頭部の個所の位置座標を特定している（例えば，特開平４−３０３４１６号公報）。
【０００３】
図１７に示すように，ＭＲＩ（核磁気共鳴）装置による頭部の形態画像の計測では，図１６に示す磁場発生コイル１３を配置した頭部の箇所と同一の個所に，ＭＲＩマーカ２１を配置して，ＭＲＩマーカ２１，及び頭部全体を含む頭部の断層像を計測して，ＭＲＩマーカ２１の位置座標をＭＲＩ画像を使用して特定している（例えば，特開平４−３０３４１６号公報）。
【０００４】
脳磁場の計測結果と形態を表わす頭部のＭＲＩ画像との合成では，磁場発生コイル１３の位置座標とＭＲＩマーカ２１の位置座標との関係を求め，例えば，脳磁場の計測によって得られた脳の活動部位の位置を形態画像上に表示する際には，ＭＲＩ装置による頭部の断層像を用いて活動部位の位置に対応する座標を含むように頭部の断層画像を再構成して，脳の活動部位とＭＲＩ画像とを合成して表示している（例えば，Ａ．Ｕｃｈｉｄａｅｔａｌ．，ＡＶＳＴＭｂａｓｅｄＢｒａｉｎＡｃｔｉｖｉｔｙＡｎａｌｙｓｉｓＳｙｓｔｅｍｗｉｔｈａＲｅａｌＨｅａｄＳｈａｐｅ，ＲｅｃｅｎｔＡｄｖａｎｃｅｓｉｎＢｉｏｍａｇｎｅｔｉｓｍ，ＥｄｉｔｅｄｂｙＴ．Ｙｏｓｈｉｍｏｔｏｅｔａｌ．，ＴｏｈｏｋｕＵｎｉｖｅｒｓｉｔｙＰｒｅｓｓ，ｐｐ１７７−１８０，１９９９）。
【０００５】
従来技術では，生体磁場計測装置に於いて，ベッドに搭載された検査対象とデュアの位置関係を設定する各種の方法が報告されている（例えば，特開平３−２４４４３３号公報，特開平２−１８０２４４号公報，特開平４−１０９９２９号公報）。
【０００６】
【発明が解決しようとする課題】
脳磁場の計測に於ける上記従来技術を，単純に胸部から発する生体磁場の計測に適用する場合，上記従来技術では，脳磁場の計測に於いて，頭部の位置座標を特定するために配置された磁場発生コイルの位置座標を特定するために，複雑なシミュレーション計算を必要とする問題，ＭＲＩ画像ではＭＲＩマーカの座標の読み取りを必要とする問題があった。更に，脳磁場の計測結果とＭＲＩ画像との合成では，磁場発生コイルの座標とＭＲＩマーカの座標との関係を求め，ＭＲＩ装置による断層像を用いて脳の活動部位の位置に対応する座標を含むように頭部の断層画像を再構成する計算を必要とする問題があった。
【０００７】
本発明の目的は，上記従来の問題点を解決する生体磁場計測装置を提供することにあり，本発明の目的は，特に，心臓から発する磁場を検出する際に，検査対象の心臓の位置とセンサアレイの位置合わせと，ＳＱＵＩＤ（ＳｕｐｅｒｃｏｎｄｕｃｔｉｎｇＱｕａｎｔｕｍＩｎｔｅｒｆｅｒｅｎｃｅＤｅｖｉｃｅ：超伝導量子干渉素子）磁束計から大きな信号出力を得る操作を，短時間に，しかも容易に実現できる生体磁場計測装置，及び生体磁場計測方法を提供することにある。
【０００８】
また，本発明の目的は，生体磁場計測装置により得られる心臓の活動に関する機能情報と生体磁場計測装置以外の撮像装置により得られる形態画像との合成画像を容易に作成して，合成画像を表示できる生体磁場計測装置を提供することにある。
【０００９】
更に，本発明の目的は，生体磁場計測装置に於いて合成画像を表示するためのデータ処理方法，合成画像の表示するさいの生体磁場計測装置のための検査対象の好適な位置決め方法を提供することにある。
【００１０】
【課題を解決するための手段】
本発明の生体磁場計測装置の代表的な構成について説明する。本発明の生体磁場計測装置は，検査対象を搭載するベッドと，ベッドを保持する保持台と，複数のＳＱＵＩＤ磁束計を冷却する低温容器と，低温容器を床面に対して既知の距離に保持する床面に固定されたガントリーとを具備する。低温容器の底面，及びベッドの上面は床面に対してほぼ平行に配置される。
【００１１】
低温容器はその底部の外周面に於いて座標系（ｘ，ｙ，ｚ）のｘｚ面を表わすｘｚ標識，及びｙｚ面を表わすｙｚ標識を有し，座標系（ｘ，ｙ，ｚ）に於いて，ｘｙ面は低温容器の底面に平行であり，ｚ軸は低温容器の底面に垂直である。
【００１２】
複数のＳＱＵＩＤ磁束計は，低温容器内部の底面に近傍に，ｘ方向，及びｙ方向にそれぞれ配列され，例えば，検査対象の心臓から発生する磁場のＺ方向の成分を検出する磁束計である。複数のＳＱＵＩＤ磁束計として，検査対象の心臓から発生する磁場のｘ方向の成分，及びｙ方向の成分を検出する磁束計を使用してもよい。
【００１３】
低温容器の底面とベッドとの位置関係の調整に使用する光学系として，ｘｚ面内で扇状に広がる第１の扇状レーザを発生する第１のレーザ源と，ｙｚ面内で扇状に広がる第２の扇状レーザを発生する第２のレーザ源と，第１，及び第２の扇状レーザに交叉して，斜め方向からベッドの面に照射される点状のレーザビームを発生する第３のレーザ源とを使用する。第１のレーザ源はガントリーに固定されるフレームに固定され，第２のレーザ源は保持台に固定されるフレームに固定され，第３のレーザ源は床面，天井，壁面の何れかに固定されるフレームに固定される。
【００１４】
３つのレーザ源から発生するレーザの照射方向を変更する手段として，第１の扇状レーザがｘｚ標識を照射するように，第１の扇状レーザの照射方位を変更する第１の位置変更手段と，第２の扇状レーザがｙｚ標識を照射するように，第２の扇状レーザの照射方位を変更する第２の位置変更手段と，点状のレーザビームが，第１の扇状レーザと第２の扇状レーザの交叉する線，及び，ｚ軸とベッドの面との交叉点を照射するように，点状のレーザビームの照射方向を変更する第３の位置変更手段とを使用する。
【００１５】
低温容器の底面に対してベッドの位置を移動させる手段として，床面で保持台をｘ方向に移動させるｘ方向移動手段と，保持台の上でベッドをｙ方向に移動させるｙ方向移動手段と，保持台の上でベッドをｚ方向に移動させるｚ方向移動手段とを使用する。
【００１６】
低温容器の底面に対するベッドの位置の移動とともに，ベッドと床面との間の距離は，距離測定手段により自動的に測定され測定値が表示器に表示される。
【００１７】
この構成では，第１のレーザ源からの第１の扇状レーザ，第２のレーザ源からの第２の扇状レーザ，及び，第３のレーザ源からの点状のレーザビームの照射方向の変更と，ベッドのｘ，ｙ，ｚ方向の移動を行ない，簡単な構成により，ベッドの高さ位置を計測でき，ベッドに搭載された検査対象と低温容器の底面との位置関係を調整することができる。
【００１８】
本発明の生体磁場計測装置の他の代表的な構成では，検査対象の心臓から発生する磁場の法線方向の磁場成分を検出する複数のＳＱＵＩＤ磁束計が，低温容器（デュア）の内部の底部に２次元に配列され，低温に冷却されている。ＳＱＵＩＤ磁束計は駆動回路駆動により駆動され，ＳＱＵＩＤ磁束計により検出される法線方向の磁場成分の磁場波形の信号は，演算処理，装置の各部の制御を行なう計算機等の演算処理装置により収集される。計測に先立って，検査対象の胸部の第１の点の体表面に第１の基準点を示す第１のマーカが，検査対象の胸部の第２の点の体表面に第２の基準点を示す第２のマーカが，それぞれ配置される。
【００１９】
生体磁場計測装置には座標系（ｘ，ｙ，ｚ）が設定され，ｘｚ面内で扇状に広がる扇状レーザ，ｙｚ面に平行な内で扇状に広がる扇状レーザ，及び，これら２つの扇状レーザに交叉して，斜め方向からベッドの面に照射される点状のレーザビームの合計３つのレーザを用いて，ベッド上の検査対象の胸部の面とデュアの底部面との位置関係を調整する。座標系（ｘ，ｙ，ｚ）のｘｙ面はＳＱＵＩＤ磁束計による計測面に設定される。デュアの底面は，ｘｙ面，計測面，及びベッドの上面に平行で，ベッドの上面とデュアの底面との間の距離は既知である。
【００２０】
ベッドを最も低い高さとして検査対象を搭載した時の検査対象の体表面の高さより十分高い位置までベッドをｚ方向に移動させ，３つのレーザを用いて，ｚ軸とベッドの面との交叉点に上記の点状のレーザビームが照射されるように，上記の点状のレーザビームの照射方向を設定し，デュアの底面とベッドの上面との間の距離を測定する。ベッドを低い位置に下げて検査対象をベッドに搭載し，ｙｚ面に平行な面内で扇状に広がる扇状レーザが第１の基準点，及び第２の基準点を通るように，ｙｚ面に平行な面内で扇状に広がる扇状レーザをｘ方向に移動させて，第１の基準点，及び第２の基準点とを結ぶ線が，ＳＱＵＩＤ磁束計の中心が配列する１方向に平行に，又は，ＳＱＵＩＤ磁束計の中心が配列する１方向に一致するように，検査対象の位置を調整する。
【００２１】
次に，ｘｚ面内で扇状に広がる扇状レーザが，第１の基準点を通るようにベッドをｙ方向に移動させ，ｙｚ面に平行な面内で扇状に広がる扇状レーザがｙｚ面に一致するようにベッドをｘ方向に移動させた後に，上記の点状のレーザビームの照射点が第１の基準点に一致するまで，ベッドをｚ方向に移動させる。次に，検査対象の体表面がデュアの底面に接するまでベッドをｚ方向で移動させて，移動量を求め，デュアの底面に接して検査対象の胸部を配置するので，デュアの底面と第１の基準点との間の距離を求めることができる。剣状突起，及び頸切痕の位置は触診により再現性良く容易に判定できるので，第１の点として検査対象の剣状突起の体表面位置，第２の点として検査対象の頸切痕の体表面位置を選ぶのが好ましい。
【００２２】
演算処理装置は，（１）磁場波形の信号から検査対象の心臓の活動に関する機能情報を表わす画像を作成する処理，（２）検査対象の胸部の第１の点の体表面に第１の基準点を示す第１のマーカが配置されて，撮像装置により撮影された検査対象の胸部の形態画像の画素の大きさに，機能情報を表わす画像の画素の大きさを一致させ，形態画像と同じ大きさの画素を持つ機能画像を作成する処理，（３）機能画像に於ける第１の基準点の位置と，形態画像に於ける第１のマーカの位置とを一致させる処理，（４）機能画像と形態画像との合成画像を作成する処理とを含むデータ処理方法を実行する。また，（４）の処理に先立って，（３’）形態画像を第１の基準点を中心に回転させて，形態画像に於ける検査対象の体軸方向と，機能画像に於ける検査対象の体軸方向の画素の配列方向とを一致させる処理を行なう。
【００２３】
更に，演算処理装置は，以下のデータ処理方法を実行して（１）の処理を行なう。（ａ）計測された法線方向の磁場成分の磁場波形の信号を用いて，検査対象の心臓の活性化部位を電流源として推定する処理と，機能情報を表わす画像として，電流源の位置を含む画像を作成する処理とを行なう。計測された法線方向の磁場成分から，検査対象の心臓から発生する磁場の接線方向の磁場成分を求める処理を行ない，接線方向の磁場成分の磁場波形の信号を用いて，次の処理を行なう。（ｂ）等しい磁場強度をもつ座標点を結ぶ等磁場線図を作成する処理を行ない，機能情報を表わす画像として等磁場線図を得る。（ｃ）検査対象の心臓の活性化部位を２次元の電流分布として表示するアローマップを作成する処理を行ない，機能情報を表わす画像としてアローマップを得る。（ｄ）検査対象の心臓の活動の特定の時相を含む時間区間で磁場波形を積分して積分強度を求め，等しい積分強度をもつ座標点を結ぶ等磁場積分図を作成する処理を行ない，機能情報を表わす画像として等磁場積分図を得る。（ｅ）検査対象の心臓の活動の異なる２つの時相を含む時間区間でそれぞれ接線方向の磁場成分の磁場波形を積分して積分強度を求め，異なる２つの時相を含む時間区間での積分強度の差が等しい値をもつ座標点を結ぶ等磁場積分図を作成する処理を行ない，機能情報を表わす画像として等磁場積分図を得る。
【００２４】
形態画像は，例えば，ＭＲＩ装置により撮影された検査対象の胸部の面にほぼ平行又は垂直な断層像，３次元ＸＣＴ装置により撮影された検査対象の胸部の面にほぼ平行又は垂直な断層像，Ｘ線撮影装置により撮影された検査対象の胸部Ｘ線画像の何れかから選択される。選択された形態画像と，（ａ）から（ｅ）により得られた機能情報を表わす画像の何れかとを使用して，演算処理装置は，（２）から（４），（３’）の処理をを含むデータ処理方法を実行する。
【００２５】
以上説明した本発明の構成によれば，検査対象の心臓から発する磁場の検出に先立ち，２つの扇状レーザ，点状のレーザビームの合計３つのレーザを用いて，簡単な構成により，ベッド上の検査対象の胸部の面とデュアの底部面との位置関係を調整することができる。この結果，心臓のセンサアレイの面への投影のほぼ全体がセンサアレイの領域内に位置し，検査対象の胸部の体表がデュアの下面に接することになり，大きな信号出力が得られる。上記の位置関係の調整を行なう操作は，短時間に，しかも容易に実行で可能であ。
【００２６】
また，本発明によれば，磁場源を推定するための磁場発生のシミュレーション計算，及び断層像の再構成計算のような複雑な計算を実行せず，生体磁場計測装置により得られる生体機能情報，特に，心臓から発する磁場の計測により得られる磁場波形から求めた等磁場線図，アローマップ，等磁場積分図，電流ダイポールの位置推定の結果等により表わされる心臓の活動に関する機能情報と，核磁気共鳴（ＭＲＩ）装置，３次元ＸＣＴ装置等により得られる胸部の面にほぼ平行又は垂直な形態画像（断層像）との合成画像，あるいは，Ｘ線撮影装置により得られる胸部Ｘ線画像のような透過像との合成画像を容易に作成して合成画像を表示できる。
【００２７】
多くの場合，ＭＲＩ装置，３次元ＸＣＴ装置では，検査対象が搭載されるベッドは水平に保持されており，画像撮影では，検査対象はベッドの長軸方向と検査対象の体軸がほぼ一致するようにベッドに搭載される。また，Ｘ線撮影装置による胸部Ｘ線画像（Ｘ線透過像）は，検査対象は立位，又は椅子に座った正座位で撮影されることが多く，一般病棟のベッドに寝た状態で撮影されることもある。
【００２８】
ＭＲＩ装置，３次元ＸＣＴ装置に於ける撮影に於いて，ベッドの長軸方向と検査対象の体軸が正確に一致しない場合でも，（３’）の処理を行なうことにより，形態画像に於ける検査対象の体軸方向と，機能画像に於ける検査対象の体軸方向（第１の基準点と第２の基準点とを結ぶ方向）の画素の配列方向とを一致させることができる。
【００２９】
即ち，形態画像を第１の基準点（ＭＲＩマーカの像の中心の位置，又はＸ線マーカの像の中心の位置）を中心に回転させた画像と機能画像との合成画像を作成できるので，機能画像と形態画像とのより正確な合成画像を作成できる。例えば，胸部Ｘ線画像（Ｘ線透過像）に於ける背骨の中心ラインと，機能画像に於ける検査対象の体軸方向の画素の配列方向とを一致させるように，形態画像を第１の基準点（Ｘ線マーカの像の中心の位置）を中心に回転させて，機能画像と形態画像とのより正確な合成画像を作成できる。
【００３０】
本発明に於ける，生体機能情報を表わす画像と形態画像との合成画像を得る生体磁場計測装置の代表的な構成を，図２を参照して要約すると次の通りである。検査対象３５の剣状突起の体表面に第１の基準点を示す第１のマーカ３７が，頸切痕の体表面に第２の基準点を示す第２のマーカ３８がそれぞれ配置され，第１，第２の基準点を結ぶ線が，低温容器３６の内部でＳＱＵＩＤ磁束計が配列する１方向に沿うように，低温容器の底面の下部に胸部が配置される。演算処理装置は，（１）磁場波形の信号から心臓の活動に関する機能情報を表わす画像を作成する処理，（２）剣状突起の体表面に第１の基準点を示す第１のマーカが配置されて，撮像装置により撮影された心臓を含む形態画像の画素の大きさに，機能情報を表わす画像の画素の大きさを一致させ，形態画像と同じ大きさの画素を持つ機能画像を作成する処理，（３）機能画像に於ける第１の基準点の位置と，形態画像に於ける第１の基準点の位置を一致させる処理，（４）機能画像と形態画像との合成画像を作成する処理とを実行する。
【００３１】
【発明の実施の形態】
本発明の生体磁場計測装置は，ベッドと，ベッドを保持する保持台，低温容器，ガントリーを具備している。低温容器内部の底面の近傍の面に，ｘ方向，及びｙ方向にそれぞれ複数のＳＱＵＩＤ磁束計が配列され，冷却されている。低温容器の底部の外周面に於いて座標系（ｘ，ｙ，ｚ）のｘｚ面を表わすｘｚ標識，及びｙｚ面を表わすｙｚ標識が印されている。座標系（ｘ，ｙ，ｚ）に於いて，ｘｙ面は低温容器の底面に平行であり，ｚ軸は低温容器の底面に垂直である。
【００３２】
低温容器を保持するガントリーは床面に固定されている。低温容器の底面と床面との間の距離は予め設定された既知の値であり，低温容器の底面は床面に対して固定された位置にある。低温容器の底面，及びベッドの上面は床面に対してほぼ平行に配置される。
【００３３】
複数のＳＱＵＩＤ磁束計は，Ｚ方向の磁場成分を検出する磁束計，又は，ｘ方向の成分，及びｙ方向の磁場成分を検出する磁束計を使用する。
【００３４】
低温容器の底面とベッドとの位置関係の調整に使用する光学系として，ｘｚ面内で扇状に広がる第１の扇状レーザを発生する第１のレーザ源と，ｙｚ面内で扇状に広がる第２の扇状レーザを発生する第２のレーザ源と，第１，及び第２の扇状レーザに交叉するように，斜め方向からベッドの面に照射する点状のレーザビームを発生する第３のレーザ源とを使用する。第１のレーザ源はガントリーに固定されるフレームに固定され，第２のレーザ源は保持台に固定されるフレームに固定され，第３のレーザ源は床面，天井，壁面の何れかに固定されるフレームに固定されている。
【００３５】
３つのレーザ源から発生するレーザの照射方向を変更する手段として，第１の扇状レーザがｘｚ標識を照射するように，第１の扇状レーザの照射方位を変更する第１の位置変更手段と，第２の扇状レーザがｙｚ標識を照射するように，第２の扇状レーザの照射方位を変更する第２の位置変更手段と，点状のレーザビームが，第１の扇状レーザと第２の扇状レーザの交叉する線，及び，ｚ軸とベッドの面との交叉点を照射するように，点状のレーザビームの照射方向を変更する第３の位置変更手段とを使用する。
【００３６】
低温容器の底面に対してベッドの位置を移動させる手段として，床面で保持台をｘ方向に移動させるｘ方向移動手段と，保持台の上でベッドをｙ方向に移動させるｙ方向移動手段と，保持台の上でベッドをｚ方向に移動させるｚ方向移動手段とを使用する。
【００３７】
低温容器の底面に対するベッドの位置の移動とともに，ベッドと床面との間の距離は，自動的に距離測定手段により測定され，距離が表示器に表示される。
【００３８】
上記の生体磁場計測装置には以下に説明する代表的な位置決め方法，及び，生体磁場計測方法が適用される。
【００３９】
本発明の代表的な，生体磁場計測装置のための検査対象の位置決め方法は，（１）第１の扇状レーザがｘｚ標識を照射するように，第１の扇状レーザの照射方位を設定し，（２）第２の扇状レーザがｙｚ標識を照射するように，第２の扇状レーザの照射方位を設定し，（３）点状のレーザビームが，第１の扇状レーザと第２の扇状レーザの交叉する線，及び，ｚ軸とベッドの面との交叉点を照射するように，点状のレーザビームの照射方向を設定し，（４）ｙｚ面内で第２の扇状レーザが，検査対象の胸部の第１の点の体表面に配置された第１のマーカにより示される第１の基準点，及び検査対象の胸部の第２の点の体表面に配置された第２のマーカにより示される第２の基準点を通るように，第２の扇状レーザの照射方位を設定し，（５）第２の扇状レーザがｙｚ標識を照射するようにベッドをｘ方向に移動させ，（６）ｙｚ面内で第１の扇状レーザが第１の基準点を通るように，ベッドをｙ方向に移動させることにより，第１の基準点と第２の基準点とを結ぶ線が，ＳＱＵＩＤ磁束計の中心が配列する１方向に一致，又は平行となるように，検査対象の胸部が低温容器の底面の下部に配置される。
【００４０】
上記の位置決め方法は，更に，（７）点状のレーザビームの照射点が，第１の基準点に一致するまでベッドをｚ方向に移動させ，（８）検査対象の体表面が，低温容器の底面に接するまでベッドをｚ方向で移動させて，第１の基準点と低温容器の底面との間の距離を求める。また，第１の点として検査対象の剣状突起を，第２の点として検査対象の頸切痕をそれぞれ使用する。
【００４１】
本発明の代表的な，生体磁場計測装置のための生体磁場計測方法は，（１）ｘｚ面内で扇状に広がる第１の扇状レーザがｘｚ標識を照射するように，第１の扇状レーザの照射方位を設定し，（２）ｙｚ面内で扇状に広がる第２の扇状レーザがｙｚ標識を照射するように，第２の扇状レーザの照射方位を設定し，（３）第１の扇状レーザ，及び第２の扇状レーザに交叉するように，斜め方向からベッドの面に照射される点状のレーザビームが，第１の扇状レーザと第２の扇状レーザの交叉する線，及び，ｚ軸とベッドの面との交叉点を照射するように，点状のレーザビームの照射方向を設定し，（４）ｙｚ面内で第２の扇状レーザが，検査対象の剣状突起の体表面に配置された第１のマーカにより示される第１の基準点，及び検査対象の頸切痕の体表面に配置された第２のマーカにより示される第２の基準点を通るように，第２の扇状レーザの照射方位を設定し，（５）第２の扇状レーザがｙｚ標識を照射するようにベッドをｘ方向に移動させ，（６）ｙｚ面内で第１の扇状レーザが第１の基準点を通るように，ベッドをｙ方向に移動させ，（７）点状のレーザビームの照射点が第１の基準点に一致するまでベッドをｚ方向に移動させ，（８）検査対象の体表面が低温容器の底面に接するまでベッドをｚ方向で移動させて第１の基準点と低温容器の底面との間の距離を求め，その後，（９）検査対象の心臓から発する磁場を検出する。第１の基準点と第２の基準点とを結ぶ線が，ＳＱＵＩＤ磁束計の中心が配列する１方向に一致，又は平行となるように，検査対象の胸部が低温容器の底面の下部に配置される。
【００４２】
以下，本発明の実施例を図面に基づいて詳細に説明する。
（第１の実施例）
図１は，本発明の第１の実施例の生体磁場計測装置の全体の構成例を示す図であり，図２は，本発明の第１の実施例の生体磁場計測装置の構成例の詳細を説明する図である。図１に示すように，磁気シールドルーム２の内部に，検査対象３５が横たわるベッド３１と，デュア（低温容器）３６を保持するガントリー４６とが配置されている。生体から発生するｚ方向（法線方向）の磁場信号を検出するための複数のセンサ（ＳＱＵＩＤ磁束計）が，デュア３６の内部の底部の近傍にｘ，ｙ方向に格子状に２次元に配置されている（２次元に配置された複数のセンサをセンサアレイと呼ぶ）。
【００４３】
図４に示すように，心臓から発生する微弱な磁場を測定する６４個のＳＱＵＩＤ磁束計は，低温容器（デュア）３６の内部の底部に，８×８の正方格子の各格子点に２次元に配置されている。各ＳＱＵＩＤ磁束計は，検出コイルと補償コイルとを有する１次微分型検出コイルを有し，法線方向（ｚ方向，体表面に対して垂直な方向）の磁場を検出する。
【００４４】
センサアレイは駆動回路６により駆動され，センサアレイからの出力はアンプフィルタユニット７により増幅されフイルタ処理がなされた後に，計算機（演算処理装置）８に収集される。
【００４５】
計算機（演算処理装置）８は，センサアレイにより検出された心臓から発生する磁場の法線方向の平均磁場波形又は加算磁場波形を求める演算等を実行した後に，法線方向の平均磁場波形又は加算磁場波形から，心臓から発生する磁場の接線方向の磁場成分を求める。更に，接線方向の磁場成分を使用して，計算機８は，複数のセンサが配列される座標点での，磁場分布の解析，等しい磁場強度をもつ座標点を結ぶ等磁場線図の作成，検査対象の心臓の活性化部位を２次元の電流分布として表示するアローマップの作成，心臓の活動の特定の時相（時間帯）を含む時間区間で磁場波形を積分して積分強度を求め等しい積分強度をもつ座標点を結ぶ等磁場積分図の作成，法線方向の磁場成分から電流源の位置を推定する等の各種の演算処理を行ない，処理結果を表示装置に表示する。
【００４６】
なお，法線方向の磁場成分から接線方向の磁場成分を求める方法，接線方向の磁場成分を用いて，等磁場線図を作成する方法，等磁場積分図を作成する方法は，本発明者らにより初めて開発された方法であり，公知の技術である（特開平１０−３０５０１９号公報を参照）。
【００４７】
ｔを時間変数，ＳＱＵＩＤ磁束計の座標を（ｘ，ｙ）とし，計測された法線方向の磁場成分をＢｚ（ｘ，ｙ，ｔ）とする時，接線方向の磁場成分Ｂｘ（ｘ，ｙ，ｔ），Ｂｙ（ｘ，ｙ，ｔ）は（数１），（数２）により得られる。
【００４８】
【数１】
Ｂｘ（ｘ，ｙ，ｔ）＝∂Ｂｚ（ｘ，ｙ，ｔ）／∂ｘ …（数１）
【００４９】
【数２】
Ｂｙ（ｘ，ｙ，ｔ）＝∂Ｂｚ（ｘ，ｙ，ｔ）／∂ｙ …（数２）
図２に示すように，第１の実施例の生体磁場計測装置は，検査対象３５が搭載されるベッド３１を，左右方向（ｙ軸方向）３２に移動させるｙ軸方向移動手段と，前後方向（ｘ軸方向）３３に移動させるｘ軸方向移動手段と，上下方向（ｚ軸方向）３４に移動させるｚ軸方向移動手段とを具備している。ベッド３１の上面はデュア３６の底面と平行，即ちｘｙ面と平行に常に保持されている。ベッド３１はベッド保持台３１−１に保持され，送り用レール３１−２の上でｘ軸方向３３に図示しない前後送りハンドルの操作により移動可能であり，ベッド３１はベッド保持台３１−１の上でｙ軸方向３２に左右送りハンドル３１−３の操作により移動可能であり，また，ベッド３１はベッド保持台３１−１の上で油圧ポンプハンドル３１−４によりｚ軸方向３４に移動可能である。
【００５０】
なお，本発明の生体磁場計測装置ではデュア３６の空間位置は固定されおり，計測面（図５に示す４０１）をｘｙ面として，例えば，検出コイルを具備するセンサ（ＳＱＵＩＤ磁束計）（図５に示す４０２）の各座標点（ｘ，ｙ）の重心位置を原点（０，０，０）とする生体磁場計測装置の座標系（ｘ，ｙ，ｚ）が設定される。座標系（ｘ，ｙ，ｚ）の原点として，センサアレイの特定の位置に配置されるセンサの位置を原点（０，０，０）としても良い。センサはデュア３６の内部の底部の近傍の，ベッド３１に平行な計測面（図５に示す４０１）にｘ，ｙ方向に格子状に２次元に配置されている。
【００５１】
また，デュア３６の下部の外周の側面には座標系（ｘ，ｙ，ｚ）のｘｚ面と外周の側面の交線を示すｘｚ標識３６−１，及び，ｙｚ面と外周の側面の交線を示すｙｚ標識３６−２が記されている。
【００５２】
第１の実施例の生体磁場計測装置は，ベッド３１の上の検査対象３５をデュア３６の底面に対して，一定の向き，及び一定の位置に配置するために，ベッド３１の長軸方向３９に広がる扇状のレーザ４０を発するレーザ発振器４１，ベッド３１の短軸方向４２に広がる扇状のレーザ４３を発するレーザ発振器４４，照射方向を変化させることにより，座標系（ｘ，ｙ，ｚ）のｚ軸と交叉する点状のレーザ４７を発するレーザ発振器４８，及び，ベッド３１の床面からの変位を計測する超音波変位センサ４５等を具備している。ｙｚ面に平行な面に扇状に照射されるレーザ４０，及び，ｘｚ面に平行な面に扇状に照射されるレーザ４３の広がりの角度はそれぞれ変更可能である。扇状のレーザ４０と扇状のレーザ４３との交線４９は座標系（ｘ，ｙ，ｚ）のｚ軸と平行である。レーザ４０，レーザ４３，レーザ４８の波長は３００ｎｍ〜８５０ｎｍであり，レーザ４０，レーザ４３，レーザ４８の代わりに，波長範囲３００ｎｍ〜８５０ｎｍの光を放射する他の光源を使用しても良い。
【００５３】
レーザ発振器４１は発振器ホルダ４１−１に保持され，発振器ホルダ４１−１はベッド保持台３１−１に固定されるパイプフレーム４１−２に，レーザ４０の照射方位が変化可能に，且つ，照射方位が特定方位となるように固定可能である（第２の位置変更手段）。同様に，レーザ発振器４４は，発振器ホルダ４４−１に保持され，発振器ホルダ４４−１はガントリー４６に固定されるパイプフレーム４４−２に，レーザ４３の照射方位が変化可能に，且つ，照射方位が特定方位となるように固定可能である。即ち，発振器ホルダ４１−１は，パイプフレーム４１−２の上でｘ軸方向３３に移動可能であり，パイプフレーム４１−２の軸の周りで回転（チルト）可能である（第１の位置変更手段）。
【００５４】
同様に，発振器ホルダ４４−１は，パイプフレーム４４−２の上でｙ軸方向３２に移動可能であり，パイプフレーム４１−２の軸の周りで回転（チルト）可能である。パイプフレーム４１−２は，ベッド３１に搭載される人体の足部の側のベッド保持台３１−１に固定され，波長範囲３００ｎｍ〜８５０ｎｍの光が目に入らないようにしている。パイプフレーム４４−２は，デュア３６の位置よりも上方で水平方向に迫り出している。
【００５５】
レーザ発振器４８は，発振器ホルダ４８−１に保持され，発振器ホルダ４８−１は床面，天井，壁面の何れかに固定されるパイプフレーム４８−２に，点状のレーザ４７の照射方向が変化可能に，且つ，照射方向が特定方位となるように固定可能である。発振器ホルダ４８−１は，パイプフレーム４８−２の上でｙ軸方向３２に移動可能であり，パイプフレーム４８−２の軸の周りで回転（チルト）可能である。パイプフレーム４８−２は，磁気シールドルームの内部の床面，又は壁面に固定される。
【００５６】
検査対象３５の心臓から発する磁場を計測するために，検査対象３５をデュア３６の底面に対して，即ち，座標系（ｘ，ｙ，ｚ）に於いて，一定の向き，一定の位置に配置する操作，例えば，心臓のセンサアレイの面への投影のほぼ全体がセンサアレイの領域内に位置し，検査対象３５の胸部の体表がデュア３６の下面に接するように配置するための操作を以下に，図３，図４を参照して説明する。
【００５７】
図３は，本発明の第１の実施例に於ける，ベッドに搭載される検査対象をデュアの下面に配置する手順の例を示す概略図，図４は，本発明の第１の実施例に於ける，ベッドに搭載される検査対象をデュアの下面に配置する際に使用する３つレーザの照射方向を調整を説明する図である。
【００５８】
以下の説明する第１の実施例では，心臓のｘｙ面への投影のほぼ全体がセンサアレイの領域内に位置するようにするため，座標系（ｘ，ｙ，ｚ）のｚ軸が予め設定したセンサーの位置を通るようにする。即ち，検査対象の剣状突起がｚ軸を通るように，センサアレイに対して検査対象の位置を調整し，心臓のセンサアレイの面への投影のほぼ全体がセンサアレイの領域内に位置するようにする。
【００５９】
工程１（参照番号５１）：まず，ベッド３１をｘ方向又は／及びｙ方向に移動させて，ベッド３１をデュア３６の下方に移動させる。次に，ベッド３１をｚ軸方向３４に移動させて，ベッド３１の上面の高さを，ベッド３１を最も低い高さとして検査対象３５を搭載した時の検査対象の体表面の高さより高い位置となるように設定する。この時，ベッド３１の床面からの高さＨＬは，超音波変位センサ４５により測定される。ベッド３１の床面からの高さの測定は，一般的な変位センサ（距離測定手段）により可能であり，例えば，超音波変位センサ４５の代わりに光学的に変位を検出する光学変位センサを使用することもできる。なお，ベッド３１の床面からの高さは，ベッド３１の上面と床面との間の距離，又は，ベッド３１の上面から一定の距離のｚ軸方向３４の位置にベッド３１の任意の位置に取り付けられ，ｚ軸方向３４のｚ軸方向移動手段によりベッド３１の上面と共に移動する変位センサの位置と床面との間の距離である。
【００６０】
発振器ホルダ４４−１の位置をパイプフレーム４４−２の上で移動させて，レーザ発振器（第１のレーザ光源）４４から発振されｘｚ面に平行な面に扇状に広がるレーザ４３（第１の扇状レーザ）の広がりの角度を必要に応じて変化させて，レーザ４３が，デュア３６の下部の外周の側面に記されたｘｚ標識３６−１を通りベッド３１の上面を照射する位置で，発振器ホルダ４４−１の位置がパイプフレーム４４−２に固定される。
【００６１】
発振器ホルダ４１−１の位置をパイプフレーム４１−２の上で移動させて，レーザ発振器（第２のレーザ光源）４１から発振されｙｚ面に平行な面に扇状に広がるレーザ４０（第２の扇状レーザ）の広がりの角度を必要に応じて変化させて，レーザ４０が，デュア３６の下部の外周の側面に記されたｙｚ標識３６−２を通りベッド３１の上面を照射する位置で，発振器ホルダ４１−１の位置がパイプフレーム４１−２に固定される。扇状のレーザ４０と扇状のレーザ４３は交叉して，座標系（ｘ，ｙ，ｚ）のｚ軸と平行な交叉線４９を形成する。
【００６２】
図４は，以下で説明する工程２に於ける３つレーザの照射方向の調整を説明する図である。
【００６３】
工程２（参照番号５２）：発振器ホルダ４８−１の位置のパイプフレーム４８−２の上でのｙ軸方向３２の移動と，発振器ホルダ４８−１の位置のパイプフレーム４８−２の軸の周りで回転（チルト）とにより，レーザ発振器（第３のレーザ光源）４８から発振される点状のレーザ（レーザビーム）（第３のレーザ）４７の照射方向を変化させて，レーザ４７が座標系（ｘ，ｙ，ｚ）のｚ軸と平行な交叉線４９とベッド３１の面で交叉するように，発振器ホルダ４８−１の位置をパイプフレーム４８−２に固定する。即ち，まずレーザ４７がｘｚ標識３６−１を照射するように発振器ホルダ４８−１の位置を設定した後に，発振器ホルダ４８−１をパイプフレーム４８−２の軸の周りで回転（チルト）させて，レーザ４７と交叉線４９とがベッド３１の面で交叉するように発振器ホルダ４８−１の位置を固定する（第３の位置変更手段）。
【００６４】
工程３（参照番号５３）：超音波変位センサ４５により，レーザ４７と交叉線４９とがベッド３１の面で交叉する点と，デュア３６の下面との間の垂直距離Ｈ０を求める。ベッド３１の面がデュア３６の下面に接するようにベッド３１をｚ軸方向に移動させて，床面からのベッドの高さＨＨを超音波変位センサ４５により測定する。Ｈ０＝（ＨＨ−ＨＬ）である。
【００６５】
工程４（参照番号５４）：ベッド３１がデュア３６の底部の床への投影位置から十分離れ，検査対象３５をベッド３１に搭載する際に，デュア３６が障害とならない位置までベッド３１をｘ軸方向３３に移動させ，ベッド３１をｚ軸方向に移動させ，ベッド３１の高さを低い高さにする。検査対象３５の体軸方向がほぼベッド３１の長軸方向３９と平行となるように，検査対象３５がベッド３１に搭載される。検査対象３５の体軸に沿った胸部の体表に２個の基準点（第１，第２の基準点）３７，３８を設ける。
【００６６】
例えば，基準点３７の位置として剣状突起の位置（第１の基準点）を，基準点３８の位置として頸切痕（第２の基準点）をそれぞれ選ぶ。剣状突起，及び頸切痕の位置は触診により容易に判定でき，剣状突起，頸切痕の体表面位置を基準点とできる。基準点３７，３８には，後で説明するマーカが貼付される。
【００６７】
工程５（参照番号５５）：発振器ホルダ４１−１をパイプフレーム４１−２の上で移動させ，レーザ発振器４１から発振されｙｚ面に平行な面に扇状に広がるレーザ４０の照射方位を変化させて，レーザ４０が基準点３７，３８の各中心を通るように，発振器ホルダ４１−１の位置のパイプフレーム４１−２の上での移動，及び／又は，ベッド３１の上での検査対象３５の移動を行なう。
【００６８】
この結果，基準点３７，３８の各中心を通る線がベッド３１の長軸方向３９に平行になり，扇状のレーザ４０が基準点３７，３８の各中心を通るように発振器ホルダ４１−１の位置がパイプフレーム４１−２に固定される。
【００６９】
工程６（参照番号５６）：レーザ発振器４４から発振される扇状のレーザ４３の広がりの角度を必要に応じて変化させて，レーザ４３が基準点３７の中心を通るように，ベッド３１をｙ軸方向３２に動かす。この結果，レーザ４０，レーザ４３による十字ビームパターンの交線４９と基準点３７の中心とが一致する。この状態で，ベッド３１のｙ軸方向３２での移動はロックされる。
【００７０】
工程７（参照番号５７）：レーザ発振器４１から発振される扇状のレーザ４０の広がりの角度を必要に応じて変化させて，レーザ４０が，デュア３６の下部の外周の側面に記されたｙｚ標識３６−２を通るように，ベッド３１をｘ軸方向３３に移動させる。レーザ４０がｙｚ標識３６−２を通る位置で，ベッド３１のｘ軸方向３３での移動はロックされる。この結果，座標系（ｘ，ｙ，ｚ）のｚ軸が基準点３７の中心を通る状態が実現される。
【００７１】
工程８（参照番号５８）：レーザ４７が基準点３７の中心を通るように，ベッド３１をｚ軸方向３４に移動させた後に，超音波変位センサ４５により，ベッド３１の床面からの高さＨ１を測定する。この結果，検査対象の３５体型にかかわらず，基準点３７とデュア３６の底面との間の垂直距離が，常に，Ｈ０＝（ＨＨ−ＨＬ）に設定できる。
【００７２】
工程９（参照番号５９）：最後に，ベッド３１を，ｚ軸方向３４に移動させて，検査対象３５の胸部の体表をデュア３６の下面に近接させて，大きな信号出力得られるようにする。次に，超音波変位センサ４５により，ベッド３１の床面からの高さＨ２を測定する。検査対象３５の胸部の体表をデュア３６の下面に近接させた時の，基準点３７とデュア３６の底面との間の垂直距離Ｈ３は，検査対象３５の体型に異なるが，Ｈ３＝｛Ｈ０−（Ｈ２−Ｈ１）｝となる。
【００７３】
以上説明したように，基準点３７，３８，３つのレーザ光源を使用することにより，心臓のセンサアレイの面への投影のほぼ全体がセンサアレイの領域内に位置し，検査対象３５の胸部の体表がデュア３６の下面に接し，大きな信号出力が得られるようにする操作を，短時間に，しかも容易に実現できる。
【００７４】
ＭＲＩ装置による形態画像の撮像では，基準点３７の中心位置と同一の胸部の位置にＭＲＩマーカの中心を配置し，体軸をＭＲＩ装置のベッド３１の長軸に合わせ，ベッドの面に平行で深さの異なる複数の断層像を撮影する。勿論，これらの複数の断層像はＭＲＩマーカが撮影されている断層像を含んでいる。
【００７５】
図５は，本発明の第１の実施例の生体磁場計測装置を用いた計測及び解析により得られる情報の表示画面の例であり，活動部位の推定位置を表わす画像の表示例を示す図である。図５に示す例は，ベッド３１に平行な計測面４０１に配置された複数のセンサ４０２のうちの特定位置に配置されたセンサ４００の位置に座標系（ｘ，ｙ，ｚ）の原点を設定し，検査対象３５の剣状突起の位置４０４に基準点３７を貼付して，剣状突起４０４が座標系のｚ軸を通るように検査対象３５を配置し，心臓から発する磁場を計測した結果である。図５は，剣状突起４０４が計測面４０１に平行な深さｃにある面４０３にあり，計測面４０１に平行な深さｄにある面４０５と，座標系のｚ軸との交点（白抜きの×印）４００−１から実線で示す矢印４０６−１の先端位置に白抜きの矢印で示す活動部位４０６が特定されたことを示す，生体磁場計測装置の表示装置での表示画面の例である。
【００７６】
計測面４０１とデュア３６の下面との間の垂直距離Ｈ４は既知であり，計測面４０１から剣状突起４０４までの深さｃは，ｃ＝（Ｈ３＋Ｈ４）＝｛Ｈ０−（Ｈ２−Ｈ１）＋Ｈ４｝である。
【００７７】
図４に示すように，図５に示す例では，剣状突起の位置をｚ軸が通り，センサアレイの特定の位置に配置されるセンサの位置をｚ軸が通る座標系（ｘ，ｙ，ｚ）が設定されている。電流源の位置の推定，即ち，活動部位の推定は電流源を推定する各種の解析方法で可能なことは周知である。
【００７８】
活動部位の推定位置が存在するか否かを表わす画像は，ｘ，ｙ方向に格子状に２次元に配置されたＳＱＵＩＤ磁束計に対応する座標をもつ複数の画素を有し，活動部位の推定位置が存在する深さ（ｚ）の面での画像に於いて，活動部位の推定位置の座標（ｘ，ｙ）の画素に電流源の大きさが付与され，活動部位が存在しないと推定された座標（ｘ，ｙ）の画素にはゼロが付与される。あるいは，図５，後で示す図７の例のように，活動部位４０６の推定位置に，電流源の向きと大きさを表わす白抜きの矢印を示すデータ（電流源の向きと大きさ）を付与しても良い。
【００７９】
ここで，生体磁場計測装置の表示装置での表示画面での活動部位の推定位置を表わす画像のｘ，ｙ方向での大きさをａ，ｂ（図５），ｘ，ｙ方向での画素数をｎｘ，ｎｙ，ｘ，ｙ方向での画素の大きさをΔｘ，Δｙとする。ａ＝ｎｘΔｘ，ｂ＝ｎｙΔｙである。ＳＱＵＩＤ磁束計が計測面にｘ，ｙ方向に格子状に２次元に配置された計測領域をＰｘ，Ｐｙとすると，生体磁場計測装置で得られる画像のｘ，ｙ方向での撮影倍率は（ａ／Ｐｘ），（ｂ／Ｐｙ）となる。
【００８０】
図６は，本発明の第１の実施例に於いて生体磁場計測装置により得られる活動部位の推定位置を表わす画像と合成するＭＲＩ装置による断層像（形態画像）の位置を示す表示の例を示し，ＭＲＩマーカが撮影されている断層像を含む複数の断層像の，生体磁場計測装置の表示装置での表示画面の例を示す図である。
【００８１】
ＭＲＩ装置による撮像では，基準点３７に配置したＭＲＩマーカ４０８を含み，ベッドの面に平行な断層像４０７と，断層像４０７に平行な深さ（ｚ）の異なる複数の断層像が撮影可能である。
【００８２】
ここで，ＭＲＩ装置による断層像の画像のｘ，ｙ方向の大きさをｅ，ｆ（図６），ｘ，ｙ方向での画素数をＮＸ，ＮＹ，ｘ，ｙ方向での画素の大きさをΔＸ，ΔＹとする。ＭＲＩ装置による断層像の撮像領域をＱｘ，Ｑｙとすると，断層像のｘ方向での撮影倍率は（ｅ／Ｑｘ）であり，断層像のｙ方向での撮影倍率は（ｆ／Ｑｙ）となる。ｅ＝ＮＸΔＸ，ｆ＝ＮＹΔＹである。
【００８３】
本発明の第１の実施例に於いて生体磁場計測装置により得られる活動部位の推定位置を表わす画像とＭＲＩ装置による形態画像とを合成するためには，ＭＲＩ装置により撮影され，断層像４０７に平行な深さの異なる複数の断層像の中から，図５に示す距離（ｄ−ｃ）に相当する深さｇに於ける断層像４０９を抽出する必要がある。深さｇに於ける断層像４０９は，断層像の厚さをＬとする時，断層像４０７から｛（ｄ−ｃ）／Ｌ｝番目の断層である。図６に於いて，白抜きの＋印４０８−１は断層像４０９での剣状突起の位置を示す。
【００８４】
図７は，本発明の第１の実施例に於いて生体磁場計測装置により得られる活動部位の推定位置を表わす画像とＭＲＩ装置により得られる形態画像（断層像）との合成画像の，生体磁場計測装置の表示装置での表示画面の例を示す図である。活動部位の推定位置を表わす画像とＭＲＩ装置による断層像との合成画像を作成する手順を以下に説明する。
【００８５】
まず，２つの画像を合成するには，活動部位の推定位置を表わす画像４０５の撮影倍率と，断層像４０７の撮影倍率とを同じにする必要がある。即ち，２つの画像の画素を同じ大きさにする必要がある。
【００８６】
ａ＝ｎｘΔｘ，ｂ＝ｎｙΔｙ，ｅ＝ＮＸΔＸ，ｆ＝ＮＹΔＹであるから，画像４０５の画素の大きさΔｘ，Δｙを，断層像の画素の大きさΔＸ，ΔＹに等しくするには，Δｘを（ΔＸ／Δｘ）倍，Δｙを（ΔＹ／Δｙ）倍すればよい。即ち，画像４０５の画素のｘ方向での画素の大きさΔｘを｛（ｅ／ａ）・（ｎｘ／Ｎｘ）｝倍，ｙ方向での大きさ画素の大きさΔｙを｛（ｆ／ｂ）・（ｎｙ／ＮＹ）｝倍した画像４０５’を作成する。この時，画像４０５’のｘ方向のサイズは｛ｅ・（ｎｘ／Ｎｘ）｝，ｙ方向のサイズは｛ｆ・（ｎｙ／ＮＹ）｝となる。
【００８７】
一般に，ｎｘ≠Ｎｘ，ｎｙ≠ＮＹであり，しかも，画像４０５’での基準点の位置と，断層像４０７でのＭＲＩマーカの中心位置が異なるので，画像４０５’と断層像４０７とを合成する場合には，２つの画像の間で，基準点の位置とＭＲＩマーカの中心位置とを一致させる処理を行ない，断層像４０７と重なる画像４０５’の画素だけを合成の対象とする。
【００８８】
次に，断層像４０７に画像４０５’を，ＭＲＩマーカ４０８の中心位置と基準点３７の中心位置（剣状突起の位置４０４の生体磁場装置での座標系（ｘ，ｙ，ｚ）での位置（ｘ，ｙ））とが一致するように重ね合わせる。この時，記憶メモリに，断層像４０７のデータと画像４０５’のデータとを対応させて記憶メモリに記憶すると同時に，断層像４０７と一緒に断層像４０７に平行な複数の断層像のデータと画像４０５’のデータとを対応させて記憶メモリに記憶する。断層像４０７に平行な複数の断層像に断層像４０７のＭＲＩマーカ４０８の中心位置が投影されて，記憶メモリに記憶される。
【００８９】
次に，記憶メモリに記憶された，活動部位４０６を示す白抜きの矢印を含む画像４０５’と断層像４０９とを読み出して１枚の画像データとして合成し，合成画像４１０を作成する。図５に示す白抜きの×印４００−１が拡大された白抜きの×印４００'−１の位置と，図６に示す白抜きの＋印４０８−１が拡大された白抜きの＋印４０８'−１の位置とが重ねて表示され，図５に示す矢印４０６−１が拡大された矢印４０６'−１，及び，図５に示す白抜きの矢印で示す活動部位４０６を表わす白抜きの矢印が拡大された白抜きの矢印４０６'，断層像を含む合成画像４１０が表示される。合成された画像を表示する際に，例えば，画像４０５’と断層像４０９とを異なる色で表示する。
【００９０】
以上説明した，合成画像の作成方法によれば，記憶メモリ上で，断層像４０７に平行な複数の断層像に，断層像４０７のＭＲＩマーカ４０８の中心位置が投影されているので，画像４０５’と，断層像４０９以外の断層像とを容易に合成できるので，心臓の各部と活動部位４０６との相対位置関係を容易に理解できる。活動部位４０６が複数検出されている場合には，それぞれの活動部位４０６について以上で説明した処理を実行すれば良い。
【００９１】
以上の説明では，形態画像としてＭＲＩ装置よる断層像を例にとり説明したが，ＭＲＩ装置よる断層像の代わりに，血流状態を表わすＭＲＩ装置よる断層像を使用しても良い。
（第２の実施例）
図８は，本発明の第２の実施例であり，生体磁場計測装置により得られる等磁場線図とＭＲＩ装置による断層像（形態画像）との合成画像６０１の，生体磁場計測装置の表示装置での表示画面の例を示す図である。第１の実施例と同様にして，等磁場線図を表わす画像の画素の大きさを断層像の画素の大きさに一致させる処理と，等磁場線図に於ける基準点の中心位置（生体磁場計測装置の座標系（ｘ，ｙ，ｚ）のｚ軸が通る計測面の位置に対応する）と，断層像に撮影されている基準点（ＭＲＩマーカの像の中心位置）とを一致させる処理とを行なう。
【００９２】
第１の実施例に於いて，画像４０５に代えて，複数のＳＱＵＩＤ磁束計によりある時刻に計測される磁場強度の等しい点を結ぶ等磁場線図を使用することにより，図６に示す断層像４０７に平行な複数の断層像から任意の断層像を選択して，選択された任意の断層像と等磁場線図との合成画像６０１を作成し表示装置に表示できる。
【００９３】
図８に於いて，太い線はＭＲＩ装置による断層像を示し，細い線は，生体磁場計測装置に於ける計測領域６００での等磁場線図を示す。表示装置の表示画面に表示する内容は各種可能である。例えば，断層像を次々と深さ方向を変化させてマウス等で選択して指定し，異なる複数の深さの位置での断層像と等磁場線図との合成画像を表示できる。また，刻々変化する等磁場線図とマウス等で複数の断層像から選択した断層像との合成画像も表示でき，選択した断層像に重畳し刻々変化する等磁場線図を表示できるので，断層像で示される形態情報と機能情報である等磁場線図の変化の状況との比較により，有意な診断情報を得ることができる。
【００９４】
図９は，本発明の第２の実施例であり，生体磁場計測装置により得られるアローマップと，ＭＲＩ装置による断層像（形態画像）との合成画像７０２の，生体磁場計測装置の表示装置での表示画面の例を示す図である。図９に示す例は，図８に示す例に於いて，等磁場線図の代わりに，検査対象の心臓の活性化部位を２次元の電流分布として表示するアローマップを使用する。
【００９５】
図９に於いて，太い線はＭＲＩ装置による断層像を示し，矢印はアローマップを示し，表示装置の表示画面に表示する内容は，図８と同様にして各種可能である。例えば，アローマップの時間変化を，選択した断層像と共に表示できる。
【００９６】
図１０は，本発明の第２の実施例であり，生体磁場計測装置により得られる等磁場積分図とＭＲＩ装置による断層像（形態画像）との合成画像７０１の，生体磁場計測装置の表示装置での表示画面の例を示す図である。図１０に示す例は，図８に示す例に於いて，等磁場線図の代わりに，心臓の活動の特定の時相を含む時間区間で磁場波形を積分して積分強度を求め，等しい積分強度をもつ座標点を結ぶ等磁場積分図，又は，異なる２つの時相を含む時間区間でそれぞれ接線方向の磁場成分の磁場波形を積分して積分強度を求め，異なる２つの時相を含む時間区間での積分強度の差が等しい値をもつ座標点を結ぶ等磁場積分図を使用する。
【００９７】
図１０に於いて，太い線はＭＲＩ装置による断層像を示し，細い線は等磁場積分図を示し，表示装置の表示画面に表示する内容は，図８と同様にして各種可能である。例えば，等磁場積分図を異なる複数の深さ位置での断層像と共に表示できる。
【００９８】
図１１は，本発明の第２の実施例であり，生体磁場計測装置により得られる活性化部位及び等磁場線図と，ＭＲＩ装置による断層像（形態画像）との合成画像８０１の，生体磁場計測装置の表示装置での表示画面の例を示す図である。図１１に示す例では，等磁場線図，活性化部位を表わす画像，及びＭＲＩ装置による断層像の３画像の合成画像を表示する例であり，活性化部位は白抜きの矢印の方向と矢印の長さで示され，活性化部位を含む断層が等磁場線図，活性化部位と共に表示されている。図１１に於いて，太い線はＭＲＩ装置による断層像を示し，細い線は等磁場線図を示し，表示装置の表示画面に表示する内容は，図８，図９，図１０と同様にして各種可能である。例えば，刻々変化する等磁場線図，断層像，及び活性化部位を表わす３画像の合成画像も表示できる。
【００９９】
図１２は，本発明の第２の実施例であり，生体磁場計測装置により得られる等磁場線図及びアローマップと，ＭＲＩ装置による断層像（形態画像）との合成画像７０３の，生体磁場計測装置の表示装置での表示画面の例を示す図である。図１２に示す例は，等磁場線図，アローマップ，及びＭＲＩ装置による断層像の３画像の合成画像を表示する例であり，活性化部位を２次元の電流分布として表示するアローマップが等磁場線図と共に表示されている。図１２に於いて，太い線はＭＲＩ装置による断層像を示し，細い線は等磁場線図を示し，矢印はアローマップを示し，表示装置の表示画面に表示する内容は，図８，図９，図１０，と同様にして各種可能である。例えば，刻々変化する等磁場線図，断層像，及びアローマップの３画像の合成画像も表示できる。
【０１００】
なお，図８に示す例に於いて，更に，活性化部位を表わす画像，等磁場線図，アローマップ，及びＭＲＩ装置による断層像の４画像の合成画像を表示しても良い。更に，図８，図９，図１０，図１１，図１２に示す例に於いて，ＭＲＩ装置による断層像（形態画像）の代りに血流状態を表わすＭＲＩ装置よる断層像を使用しても良い。
（第３の実施例）
図１３は，本発明の第３の実施例であり，生体磁場計測装置により実際の患者に関して計測された等磁場積分図と，ＭＲＩ装置による断層像（形態画像）との合成画像の，生体磁場計測装置の表示装置での表示画面の例を示す図である。合成画像の作成の方法は先に第１，及び第２の実施例で説明した方法で行なう。
【０１０１】
図１３に示す例は，心臓の活動のＱＲＳ波の出現する時相（時間帯），及びＴの出現する時相（時間帯）含む時間区間でそれぞれ磁場波形を積分して積分強度を求め，異なる２つの時相を含む時間区間での積分強度の差が等しい値をもつ座標点を結ぶ等磁場積分図を使用する。
【０１０２】
図１３に於いて，太い線はＭＲＩ装置による断層像を示し，細い線は等磁場積分図を示し，等磁場積分図は複数の断層像から選択した断層像と共に表示されている。図１３では，患者の心臓に於ける心筋活動の不活性部位６０２を黒塗の部分で示している。不活性部位６０２では積分強度が負となっている。この心筋活動の不活性部位の検出は狭心症や心筋梗塞等の心筋虚血の診断に非常に有効と考えられる。
（第４の実施例）
図１４は，本発明の第４の実施例であり，生体磁場計測装置により実際に患者に関して計測された等磁場線図及びアローマップと，ＭＲＩ装置による断層像（形態画像）との合成画像の，生体磁場計測装置の表示装置での表示画面の例を示す図である。なお，図１３に関する患者と，図１４に関する患者とは異なる。合成画像の作成の方法は先に第１，及び第２の実施例で説明した方法で行なう。
【０１０３】
図１４に示す例は，心臓の活動のＰ波の出現する時相（時間帯）で，計測された法線方向の磁場成分から導出された接線方向の磁場成分の等しい磁場強度をもつ座標点を結ぶ等磁場線図，及び，アローマップを使用する。
【０１０４】
図１４に於いて，太い線はＭＲＩ装置による断層像を示し，細い線は計測領域６００での等磁場線図，矢印はアローマップを示す。図１４（ａ）から図１４（ｆ）は，表示装置の表示画面に表示される等磁場線図の時間変化の実際の計測例を示し，等磁場線図は複数の断層像から選択した１つの断層像と共に表示されている。図１４（ａ）から図１４（ｆ）は，Ｐ波の出現する時相での２５ｍｓ毎の時間経過を示す等磁場線図を示している。
【０１０５】
図１４（ａ）から図１４（ｆ）に示すアローマップの矢印の動きの変化から明らかなように，心臓の左右の心房のまわりを環状に流れる電流（環状電流）が存在することが明確に示されている。この環状電流の存在は，心房性頻拍と密接に関連しており，環状電流の検出は心房性頻拍の診断に非常に有効と考えられる。（第５の実施例）
第１，及び第２の実施例に於いて，ＭＲＩ装置よる複数の断層像の代わりに，３次元ＸＣＴ装置により得られ胸部面にほぼ平行な複数の断層像を使用して各種の合成画像を作成して表示できる。合成画像を得るための処理は，第１，及び第２の実施例と同様であり，生体磁場計測装置より得られる機能画像（等磁場線図，アローマップ，等磁場積分図，活性化部位（電流源）の推定位置等の心臓の活動に関する機能情報を表わす。）の画素の大きさを，３次元ＸＣＴ装置により得られる断層像の画素の大きさに一致させる処理と，生体磁場計測装置より得られる機能画像に於ける基準点の中心位置（生体磁場計測装置の座標系（ｘ，ｙ，ｚ）のｚ軸が通る計測面の位置に対応する）と，断層像に撮影されている基準点（Ｘ線マーカの像の中心点）とを一致させる処理とを含む。
（第６の実施例）
第１の実施例に於いて，ＭＲＩ装置よる断層像４０７の代わりに，Ｘ線撮影装置による胸部Ｘ線画像（Ｘ線透過像）を使用して，胸部Ｘ線画像と，生体磁場計測装置より得られる機能画像（等磁場線図，アローマップ，等磁場積分図，活性化部位（電流源）の推定位置等の心臓の活動に関する機能情報を表わす。）との間で，各種の合成画像を作成して表示できる。合成画像を得るための処理は，生体磁場計測装置より得られる機能画像の画素の大きさを，胸部Ｘ線画像の画素の大きさに一致させる処理と，生体磁場計測装置より得られる機能画像に於ける基準点（第１の基準点）の中心位置（生体磁場計測装置の座標系（ｘ，ｙ，ｚ）のｚ軸が通る計測面の位置に対応する）と，胸部Ｘ線画像に撮影されている第１の基準点（Ｘ線マーカの像の中心点）とを一致させる処理と，胸部Ｘ線画像を第１の基準点のを中心に回転させて，胸部Ｘ線画像に於ける検査対象の体軸方向と，機能画像に於ける検査対象の体軸方向（第１の基準点と第２の基準点とを結ぶ方向）の画素の配列方向とを一致させる処理とを含む。
【０１０６】
胸部Ｘ線画像を第１の基準点（Ｘ線マーカの像の中心点）を中心に回転させた画像と機能画像との合成画像を作成できるので，機能画像と形態画像とのより正確な合成画像を作成できる。例えば，胸部Ｘ線画像に於ける背骨の中心ラインと，機能画像に於ける検査対象の体軸方向の画素の配列方向とを一致させように，形態画像を第１の基準点（Ｘ線マーカの像の中心点）を中心に回転させて，機能画像と形態画像とのより正確な合成画像を作成できる。
【０１０７】
以上説明した各実施例に於いて，生体磁場計測装置による計測では，基準点３７，３８に貼付するマーカとして，例えば，鉛（大きさ５ｍｍ×５ｍｍ，厚さ５ｍｍ），ビタミン剤（大きさ５ｍｍ×５ｍｍ，厚さ５ｍｍ）等を使用する。ＭＲＩ装置よる断層像，血流画像の撮影では，基準点３７にＭＲＩマーカとして，例えば，ビタミン剤（大きさ５ｍｍ×５ｍｍ，厚さ５ｍｍ）を貼付する。ビタミン剤はＭＲＩ装置より撮影される画像に映し出される。Ｘ線撮影装置による胸部Ｘ線画像の撮影，３次元Ｘ線ＣＴ装置による断層像の撮影では，基準点３７にＸ線マーカとして，例えば，鉛（大きさ５ｍｍ×５ｍｍ，厚さ５ｍｍ）等を貼付する。鉛は，胸部Ｘ線画像，Ｘ線ＣＴ断層像に映し出される。胸部Ｘ線画像に於いて，剣状突起の識別が困難な場合には，検査対象の頸切痕と剣状突起との間の距離を，例えば，物差し等で計測して，計測した頸切痕と剣状突起との間の距離に対して，胸部Ｘ線画像の撮影倍率の影響を補正した補正距離を求め，胸部Ｘ線画像上で，頸切痕から検査対象の中心軸に沿って補正距離だけ離れた位置に剣状突起が存在すると仮定して，剣状突起の位置を割り出すことができる。
【０１０８】
また，以上説明した各実施例に於いて，ＭＲＩ装置による断層像のデータ，血流画像のデータの生体磁場計測装置の記憶装置への取り込み，及び，Ｘ線撮影装置による胸部Ｘ線画像のデータ，３次元ＸＣＴ装置による断層像のデータの生体磁場計測装置の記憶装置への取り込みは，以下の方法で行なう。
【０１０９】
生体磁場計測装置，ＭＲＩ装置，３次元ＸＣＴ装置，胸部Ｘ線画像のフイルムの濃淡をデジタル化して画像データとして読み取る画像読み取り装置等が，ＰＡＣＳ（ＰｉｃｔｕｒｅＡｒｃｈｉｖｉｎｇａｎｄＣｏｍｍｕｎｉｃａｔｉｏｎｓＳｙｓｔｅｍｓ）を構成する場合には，各装置からオンラインで生体磁場計測装置の記憶装置へ画像データを読み込む構成とする。
【０１１０】
また，ＭＲＩ装置，３次元ＸＣＴ装置，Ｘ線撮影装置等による画像がフイルムで得られている場合には，フイルムの濃淡をデジタル化して画像データとして読み取る画像読み取り装置を使用して，デジタル化された画像データデータを可搬媒体に記憶して，可搬媒体を介して生体磁場計測装置の記憶装置へ画像データの読み込む構成とする。あるいは，画像読み取り装置と生体磁場計測装置とをオンラインで接続し，画像読み取り装置の出力データ（デジタル化された画像データ）を直接，生体磁場計測装置の記憶装置へ取り込む構成としても良い。
【０１１１】
図１５は，本発明の各実施例に於ける生体機能画像と形態画像との合成画像の作成の手順の例を示す概略図である。以下，図１５を用いて手順を要約して説明する。
【０１１２】
工程１（参照番号７１）：ＭＲＩ装置，３次元Ｘ線ＣＴ装置，Ｘ線撮影装置等により，胸部を含む形態画像を撮影する。ＭＲＩ装置，３次元Ｘ線ＣＴ装置による撮影では，検査対象の胸部の面に平行な複数の断層像が撮影される。Ｘ線撮影装置では，正面から撮影された胸部Ｘ線画像（Ｘ線透過像）が撮影される。これらの形態画像に撮影では，検査対象の剣状突起の体表面に第１の基準点を示す第１のマーカを配置して行なう。
【０１１３】
工程２（参照番号７２）：工程１（参照番号７１）で撮影された形態画像を選択する。
【０１１４】
工程３（参照番号７３）：検査対象の剣状突起の体表面に第１の基準点を示す第１のマーカを，検査対象の頸切痕の体表面に第２の基準点を示す第２のマーカをそれぞれ貼付して，心臓から発生する磁場の法線方向の磁場成分を計測する。
【０１１５】
工程４（参照番号７４）：計測された法線方向の磁場成分から心臓から発生する磁場の接線方向の磁場成分を推定して，接線方向の磁場成分を用いて，心臓の活動に関する機能情報を表わす機能画像（等磁場線図，アローマップ，等磁場積分図，電流源の推定位置等）を作成する。
【０１１６】
工程５（参照番号７５）：工程４（参照番号７４）で作成された機能画像を選択する。
【０１１７】
工程６（参照番号７６）：機能画像の素子サイズを形態画像の画素サイズに一致させる処理を行なう。
【０１１８】
工程７（参照番号７７）：機能画像の第１の基準点と形態画像の第１の基準点とを一致させる処理を行なう。
【０１１９】
工程８（参照番号７８）：形態画像での検査対象の体軸方向と，機能画像での検査対象の体軸方向の画素の配列方向とが一致していない場合，形態画像を第１の基準点を中心に回転させて，形態画像での検査対象の体軸方向と，機能画像での検査対象の体軸方向の画素の配列方向とを一致させる処理を行なう。
【０１２０】
工程９（参照番号７９）：機能画像と形態画像とを１つの画像に合成して合成画像を得る。
【０１２１】
なお，工程１（参照番号７１）と，工程３（参照番号７３）はどちらを先に実行しても良い。また，工程５（参照番号７５）に於いて，工程４（参照番号７４）で作成された機能画像を複数選択して，工程６（参照番号７６）〜工程９（参照番号７９）により，複数の機能画像と形態画像との合成画像を作成して，表示しても良い。更に，複数の機能画像と，例えば，工程１（参照番号７１）撮影された検査対象の胸部の面に平行な複数の断層像から選択される複数の断層像の各断層像との合成画像を作成して，表示しても良い。工程８（参照番号７８）の実行を省略することもできる。
【０１２２】
以上説明したように，本発明では，複雑な計算を必要とすることなく短時間で，生体磁場計測装置により得られる，等磁場線図，アローマップ，等磁場積分図，活性化部位（電流源）の推定位置等の心臓の活動に関する機能情報を表わす機能画像の画素の大きさを，ＭＲＩ装置，３次元ＸＣＴ装置，Ｘ線撮影装置等により得られる，心臓の形態を表わす形態画像の画素大きさに一致させる処理と，機能画像に於ける第１の基準点の中心位置（生体磁場計測装置の座標系（ｘ，ｙ，ｚ）のｚ軸が通る計測面の位置に対応する）と，形態画像に撮影されている第１の基準点（ＭＲＩマーカの像の中心点，又はＸ線マーカの像の中心点）とを一致させる処理とを行なう。
【０１２３】
更に，形態画像に撮影されている第１の基準点（ＭＲＩマーカの像の中心点，又はＸ線マーカの像の中心点）を中心に形態画像を回転させて，形態画像に於ける検査対象の体軸方向と，機能画像に於ける検査対象の体軸方向（第１の基準点と第２の基準点とを結ぶ方向）の画素の配列方向とを一致させる処理を行ない，機能画像と形態画像とのより正確な合成画像を作成できる。
【０１２４】
この結果，本発明では，ＭＲＩ装置又は３次元ＸＣＴ装置等により得られる胸部面にほぼ平行な複数の断層像から任意の断層像を選択し，選択された断層像と，時間変化する等磁場線図，又は時間変化するアローマップとの合成画像を刻々と表示できる。
【０１２５】
また，活性化部位を表わす画像と，ＭＲＩ装置又は３次元ＸＣＴ装置等により得られる胸部面にほぼ平行であり活性化部位を含む断層像と，時間変化する等磁場線図，又は時間変化する等磁場積分図との合成画像を刻々と表示できる。活性化部位を表わす画像は，例えば，矢印により表わされ，矢印の根本の位置が電流源の推定位置を示し，矢印の長さが電流源の大きさを示し，矢印の方向が（ｘ，ｙ）面へ投影した電流源を表わすベクトルの方向を示す。
【０１２６】
更に，Ｘ線撮影装置による胸部Ｘ線画像（形態画像）と，時間変化する等磁場線図，又は時間変化する等磁場積分図との合成画像を刻々と表示できる。また，胸部Ｘ線画像（Ｘ線透過像）と，活性化部位を表わす画像と，時間変化する等磁場線図，又は時間変化する等磁場積分図との合成画像を刻々と表示できる。
【０１２７】
【発明の効果】
本発明によれば，特に，検査対象の心臓から発する磁場を検出する際に，心臓のセンサアレイの面への投影のほぼ全体がセンサアレイの領域内に位置し，検査対象の胸部の体表がデュアの下面に接し，大きな信号出力が得られるようにする操作を，短時間に，しかも容易に実現できる。
【０１２８】
また，本発明によれば，磁場発生のシミュレーション計算，及び断層像の再構成計算のような複雑な計算を実行せず，生体磁場計測装置により得られる生体機能情報，特に，心臓から発する磁場の計測により得られる磁場波形から求めた等磁場線図，アローマップ，等磁場積分図，電流ダイポールの位置推定の結果等により表わされる心臓の活動に関する機能情報と，核磁気共鳴（ＭＲＩ）装置，３次元ＸＣＴ装置等により得られる胸部の面にほぼ平行な形態画像（断層像）との合成画像，あるいは，Ｘ線撮影装置により得られる胸部Ｘ線画像のような透過像との合成画像を容易に作成して合成画像を表示できる。
【図面の簡単な説明】
【図１】本発明の第１の実施例の生体磁場計測装置の全体の構成例を示す図。
【図２】本発明の第１の実施例の生体磁場計測装置の構成例の詳細を説明する図。
【図３】本発明の第１の実施例に於ける，ベッドに搭載される検査対象をデュアの下面に配置する手順の例を示す概略図。
【図４】本発明の第１の実施例に於ける，ベッドに搭載される検査対象をデュアの下面に配置する際に使用する３つレーザの照射方向を調整を説明する図。
【図５】本発明の第１の実施例の生体磁場計測装置により得られる情報の表示画面の例であり，活動部位の推定位置を表わす画像の表示例を示す図。
【図６】本発明の第１の実施例に於いて生体磁場計測装置により得られる活動部位の推定位置を表わす画像と合成するＭＲＩ装置による断層像の位置を示す表示画面の例を示す図。
【図７】本発明の第１の実施例に於いて生体磁場計測装置により得られる活動部位の推定位置を表わす画像とＭＲＩ装置で得られる断層像との合成画像の表示例を示す図。
【図８】本発明の第２の実施例であり，生体磁場計測装置により得られる等磁場線図とＭＲＩ装置による断層像との合成画像の表示例を示す図。
【図９】本発明の第２の実施例であり，生体磁場計測装置により得られるアローマップと，ＭＲＩ装置による断層像との合成画像の表示例を示す図。
【図１０】本発明の第２の実施例であり，生体磁場計測装置により得られる等磁場積分図とＭＲＩ装置による断層像との合成画像の表示例を示す図。
【図１１】本発明の第２の実施例であり，生体磁場計測装置により得られる活性化部位及び等磁場線図と，ＭＲＩ装置による断層像との合成画像の表示例を示す図。
【図１２】本発明の第２の実施例であり，生体磁場計測装置により得られる等磁場線図及びアローマップと，ＭＲＩ装置による断層像との合成画像の表示例を示す図。
【図１３】本発明の第３の実施例であり，生体磁場計測装置により実際の患者に関して計測された等磁場積分図と，ＭＲＩ装置による断層像との合成画像の表示装置での表示画面の例を示す図。
【図１４】本発明の第４の実施例であり，生体磁場計測装置により実際に患者に関して計測された等磁場線図及びアローマップと，ＭＲＩ装置による断層像との合成画像の表示装置での表示画面の例を示す図。
【図１５】本発明の各実施例に於ける生体機能画像と形態画像との合成画像の作成の手順の例を示す概略図。
【図１６】脳磁場の計測を行なう生体磁場計測に於ける頭部の個所の位置座標を特定する従来技術の例を説明する図。
【図１７】脳磁場の計測結果と頭部のＭＲＩ画像とを合成するためにマーカの位置座標をＭＲＩ画像を使用して特定する従来技術の例を説明する図。
【符号の説明】
２…磁気シールドルーム，６…駆動回路，７…アンプフィルタユニット，８…計算機，１１…デユアの底部，１２…検出コイル，１３…磁場発生コイル，２１…ＭＲＩマーカ，３５…検査対象，３１…ベッド，３１−１…ベッド保持台，３１−２…送り用レール，３１−３…左右送りハンドル，３１−４…油圧ポンプハンドル，３６…デュア（低温容器），３６−１…ｘｚ標識，３６−２…ｙｚ標識，３２…左右方向（ｙ軸方向），３３…前後方向（ｘ軸方向），３４…上下方向（ｚ軸方向），３７，３８…基準点，３９…ベッドの長軸方向，４０…レーザ（第２のレーザ），４１…レーザ発振器（第２のレーザ光源），４１−１…発振器ホルダ，４１−２…ベッド保持台に固定されるパイプフレーム，４２…ベッドの短軸方向，４３…レーザ（第１のレーザ），４４…レーザ発振器（第１のレーザ光源），４４−１…発振器ホルダ，４４−２…ガントリーに固定されるパイプフレーム，４５…ベッドの床面からの変位を計測する超音波変位センサ，４６…ガントリー，４７…レーザ（第３のレーザ），４８…レーザ発振器（第３のレーザ光源），４８−１…発振器ホルダ，４８−２…床に固定されるパイプフレーム，４００…特定位置に配置されたセンサ（ＳＱＵＩＤ磁束計），４００'−１…拡大された白抜きの×印，４０１…ベッドに平行な計測面，４０２…複数のセンサ（ＳＱＵＩＤ磁束計），４０３…計測面に平行な深さｃにある面，４０４…剣状突起の位置，４０５…計測面に平行な深さｄにある面，４０６…活動部位を示す白抜きの矢印，４０６'…白抜きの矢印，４０６'−１…拡大された矢印，４０５’…画素サイズが補正された画像，４０７…断層像，４０８…ＭＲＩマーカ，４０８−１…白抜きの＋印，４０８'−１…拡大された白抜きの＋印，４０９…断層像，６００…計測領域，６０２…心筋活動の不活性部位，４１０，６０１，７０１，７０２，７０３，８０１…合成画像。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biomagnetic field measurement apparatus using a SQUID (Superconducting Quantum Interference Device) magnetometer, which is a superconducting device that detects a weak magnetic field emitted from a living body, and in particular, functional information relating to the activity of the heart. The present invention relates to a biomagnetic field measurement apparatus and biomagnetic field measurement method that can easily synthesize a morphological image of a heart and a heart, a data processing method for the biomagnetic field measurement apparatus, and an inspection object positioning method.
[0002]
[Prior art]
As shown in FIG. 16, in a conventional biomagnetic field measuring apparatus that measures brain function, a plurality of detection coils 12 are arranged on the bottom 11 of a dewar whose outer shape is matched to the curvature of the head, and are provided at a plurality of locations on the head. The magnetic field generated by energizing the installed magnetic field generating coil 13 is measured by the detection coil 12, and the relationship between the magnetic field generated by the magnetic field generating coil 13 and the output of the detection coil 12 is simulated. By identifying the position of the magnetic field generating coil 13 that minimizes the difference between the measurement data obtained by the detection coil 12 and the output of the simulated detection coil 12, the position coordinates of the position of the head where the magnetic field generating coil 13 is arranged are specified. (For example, JP-A-4-303416).
[0003]
As shown in FIG. 17, in the measurement of the morphological image of the head by the MRI (nuclear magnetic resonance) apparatus, the MRI marker 21 is arranged at the same position as the head where the magnetic field generating coil 13 shown in FIG. 16 is arranged. Then, the tomographic image of the head including the MRI marker 21 and the entire head is measured, and the position coordinates of the MRI marker 21 are specified using the MRI image (for example, JP-A-4-303416). ).
[0004]
In the synthesis of the brain magnetic field measurement result and the MRI image of the head representing the form, the relationship between the position coordinates of the magnetic field generating coil 13 and the position coordinates of the MRI marker 21 is obtained, for example, the brain obtained by measuring the brain magnetic field. When the position of the active site is displayed on the morphological image, the tomographic image of the head is reconstructed to include the coordinates corresponding to the position of the active site using the tomographic image of the head by the MRI apparatus, The brain active region and MRI images are synthesized and displayed (for example, A. Uchida et al., AVSTM based Brain Activity Analysis with the Real Head Shape Emerged in Biomass, Regent Advances in Biom. ., Tohoku Univers ty Press, pp177-180,1999).
[0005]
In the prior art, various methods for setting the positional relationship between the inspection object mounted on the bed and the dua in the biomagnetic field measuring apparatus have been reported (for example, Japanese Patent Laid-Open No. 3-244433 and Japanese Patent Laid-Open No. 180244, JP-A-4-109929).
[0006]
[Problems to be solved by the invention]
When applying the above-mentioned conventional technology in the measurement of the cerebral magnetic field to the measurement of the biomagnetic field generated simply from the chest, the above-mentioned conventional technology is arranged to specify the position coordinates of the head in the measurement of the cerebral magnetic field. In order to specify the position coordinates of the magnetic field generating coil, there is a problem that requires complicated simulation calculation, and there is a problem that it is necessary to read the coordinates of the MRI marker in the MRI image. Furthermore, in the synthesis of the brain magnetic field measurement results and the MRI image, the relationship between the coordinates of the magnetic field generating coil and the coordinates of the MRI marker is obtained, and the coordinates corresponding to the position of the active site of the brain are obtained using the tomographic image by the MRI apparatus. There was a problem that required calculation to reconstruct the tomographic image of the head to include.
[0007]
An object of the present invention is to provide a biomagnetic field measuring apparatus that solves the above-mentioned conventional problems. The object of the present invention is to detect the position of the heart to be examined, particularly when detecting a magnetic field emitted from the heart. Biomagnetic field measurement apparatus and biomagnetic field measurement method capable of easily and easily realizing alignment of a sensor array and obtaining a large signal output from a SQUID (Superconducting Quantum Interference Device) magnetometer Is to provide.
[0008]
Another object of the present invention is to easily create a composite image of functional information related to heart activity obtained by a biomagnetic field measurement device and a morphological image obtained by an imaging device other than the biomagnetic field measurement device, and display the composite image It is providing the biomagnetic field measuring device which can be performed.
[0009]
Furthermore, an object of the present invention is to provide a data processing method for displaying a composite image in a biomagnetic field measurement apparatus, and a suitable positioning method for a test object for the biomagnetic field measurement apparatus when displaying a composite image. There is.
[0010]
[Means for Solving the Problems]
A typical configuration of the biomagnetic field measurement apparatus of the present invention will be described. The biomagnetic field measurement apparatus of the present invention includes a bed on which a test object is mounted, a holding table for holding the bed, a cryogenic container for cooling a plurality of SQUID magnetometers, and a cryogenic container held at a known distance from the floor surface. And a gantry fixed to the floor surface. The bottom surface of the cryogenic container and the top surface of the bed are arranged substantially parallel to the floor surface.
[0011]
The cryogenic container has an xz label representing the xz plane of the coordinate system (x, y, z) and a yz label representing the yz plane on the outer peripheral surface of the bottom thereof, and in the coordinate system (x, y, z) The xy plane is parallel to the bottom surface of the cryogenic container, and the z axis is perpendicular to the bottom surface of the cryogenic container.
[0012]
The plurality of SQUID magnetometers are arranged in the x direction and the y direction, respectively, in the vicinity of the bottom surface inside the cryogenic container, and are, for example, magnetometers that detect the Z direction component of the magnetic field generated from the heart to be examined. As a plurality of SQUID magnetometers, a magnetometer that detects a component in the x direction and a component in the y direction of the magnetic field generated from the heart to be examined may be used.
[0013]
As an optical system used for adjusting the positional relationship between the bottom surface of the cryogenic container and the bed, a first laser source that generates a first fan-shaped laser that expands in a fan shape in the xz plane, and a second that expands in a fan shape in the yz plane. A second laser source for generating a fan-shaped laser, and a third laser source for generating a point-shaped laser beam irradiated onto the bed surface from an oblique direction, crossing the first and second fan-shaped lasers And use. The first laser source is fixed to the frame fixed to the gantry, the second laser source is fixed to the frame fixed to the holding table, and the third laser source is fixed to any one of the floor, ceiling, and wall surface. Fixed to the frame.
[0014]
As a means for changing the irradiation direction of the laser generated from the three laser sources, a first position changing means for changing the irradiation direction of the first fan laser so that the first fan laser irradiates the xz label; Second position changing means for changing the irradiation direction of the second fan-shaped laser so that the second fan-shaped laser irradiates the yz label, and the point-like laser beam includes the first fan-shaped laser and the second fan-shaped laser. Third position changing means for changing the irradiation direction of the point-like laser beam so as to irradiate the crossing line of the laser and the crossing point between the z-axis and the surface of the bed is used.
[0015]
As means for moving the position of the bed relative to the bottom surface of the cryogenic container, x-direction moving means for moving the holding table in the x direction on the floor surface, and y-direction moving means for moving the bed in the y direction on the holding table; , Z direction moving means for moving the bed in the z direction on the holding table is used.
[0016]
Along with the movement of the bed position with respect to the bottom surface of the cryogenic container, the distance between the bed and the floor surface is automatically measured by the distance measuring means, and the measured value is displayed on the display.
[0017]
In this configuration, the irradiation direction of the first fan laser from the first laser source, the second fan laser from the second laser source, and the point laser beam from the third laser source is changed. The bed can be moved in the x, y, and z directions, and the height of the bed can be measured with a simple configuration, and the positional relationship between the inspection object mounted on the bed and the bottom of the cryogenic container can be adjusted. .
[0018]
In another representative configuration of the biomagnetic field measurement apparatus of the present invention, a plurality of SQUID magnetometers that detect magnetic field components in the normal direction of the magnetic field generated from the heart to be examined are provided at the bottom inside the cryogenic container (dure). Are two-dimensionally arranged and cooled to a low temperature. The SQUID magnetometer is driven by the drive circuit drive, and the signal of the magnetic field waveform of the normal magnetic field component detected by the SQUID magnetometer is collected by an arithmetic processing device such as a computer that performs arithmetic processing and control of each part of the device. The Prior to the measurement, the first marker indicating the first reference point on the body surface of the first point of the chest to be examined has the second reference point on the body surface of the second point of the chest to be examined. Second markers shown are respectively arranged.
[0019]
A coordinate system (x, y, z) is set in the biomagnetic field measuring apparatus, and a fan-shaped laser that extends in a fan shape within the xz plane, a fan-shaped laser that extends in a fan shape in parallel to the yz plane, and these two fan-shaped lasers Crossover is performed to adjust the positional relationship between the chest surface to be examined on the bed and the bottom surface of the deer by using a total of three lasers of point-like laser beams irradiated on the bed surface from an oblique direction. The xy plane of the coordinate system (x, y, z) is set as a measurement plane by the SQUID magnetometer. The bottom surface of the dewar is parallel to the xy plane, the measurement surface, and the top surface of the bed, and the distance between the top surface of the bed and the bottom surface of the dewar is known.
[0020]
The bed is moved in the z direction to a position sufficiently higher than the height of the body surface of the inspection object when the inspection object is mounted at the lowest height, and the crossing of the z axis and the surface of the bed is performed using three lasers. The irradiation direction of the point laser beam is set so that the point is irradiated with the dot laser beam, and the distance between the bottom surface of the dewar and the upper surface of the bed is measured. The bed is lowered to a low position, the inspection object is mounted on the bed, and the fan-shaped laser spreading in a fan shape in a plane parallel to the yz plane is parallel to the yz plane so that it passes through the first reference point and the second reference point. A fan-shaped laser that spreads in a fan-like manner in a plane is moved in the x direction, and the line connecting the first reference point and the second reference point is parallel to one direction in which the centers of the SQUID magnetometers are arranged, or The position of the inspection object is adjusted so that the center of the SQUID magnetometer coincides with one direction in which the centers are arranged.
[0021]
Next, the fan-shaped laser spreading in a fan shape in the xz plane moves the bed in the y direction so as to pass through the first reference point, and the fan-shaped laser spreading in a fan shape in a plane parallel to the yz plane matches the yz plane. After moving the bed in the x direction as described above, the bed is moved in the z direction until the irradiation point of the above-described point-like laser beam coincides with the first reference point. Next, the bed is moved in the z direction until the body surface to be inspected contacts the bottom surface of the dure, the amount of movement is obtained, and the chest to be inspected is placed in contact with the bottom surface of the dure. The distance from the reference point can be obtained. Since the position of the xiphoid process and the cervical notch can be easily determined by palpation with good reproducibility, the body surface position of the xiphoid process to be examined is used as the first point, and the cervical notch of the test object is used as the second point. The body surface position is preferably selected.
[0022]
The arithmetic processing unit (1) creates an image representing functional information related to the activity of the heart to be examined from the signal of the magnetic field waveform, and (2) applies a first reference to the body surface of the first point of the chest to be examined. The first marker indicating a point is arranged, and the pixel size of the image representing functional information is made the same as the size of the pixel of the morphological image of the chest image to be inspected photographed by the imaging device, and the same as the morphological image Processing to create a functional image having pixels of size, (3) processing to match the position of the first reference point in the functional image with the position of the first marker in the morphological image, (4) A data processing method including a process of creating a composite image of a functional image and a morphological image is executed. Prior to the processing of (4), (3 ′) the morphological image is rotated around the first reference point, the body axis direction of the inspection object in the morphological image, and the inspection object in the functional image. A process for matching the pixel arrangement direction in the body axis direction is performed.
[0023]
Further, the arithmetic processing unit executes the following data processing method to perform the process (1). (A) Using the signal of the magnetic field waveform of the measured magnetic field component in the normal direction to estimate the activation site of the heart to be examined as a current source, and to display the position of the current source as an image representing functional information And processing to create an image including it. From the measured normal magnetic field component, the tangential magnetic field component of the magnetic field generated from the heart to be examined is processed, and the following processing is performed using the magnetic field waveform signal of the tangential magnetic field component . (B) Processing for creating an isomagnetic field diagram connecting coordinate points having equal magnetic field strength is performed, and an isomagnetic field diagram is obtained as an image representing functional information. (C) Processing for creating an arrow map for displaying the activated part of the heart to be examined as a two-dimensional current distribution is performed, and an arrow map is obtained as an image representing functional information. (D) Integrating a magnetic field waveform in a time interval including a specific time phase of the activity of the heart to be examined to obtain an integral intensity, and performing processing to create an equimagnetic field integral diagram connecting coordinate points having equal integral intensity, An isomagnetic integral diagram is obtained as an image representing functional information. (E) Integration of magnetic field waveforms of magnetic field components in the tangential direction in each time interval that includes two different time phases of the subject's heart activity to obtain an integrated intensity, and integration in a time interval that includes two different time phases A process for creating an isomagnetic field integral diagram that connects coordinate points having the same intensity difference is performed, and an isomagnetic field integral diagram is obtained as an image representing functional information.
[0024]
The morphological image is, for example, a tomographic image that is substantially parallel or perpendicular to the surface of the subject's chest taken by the MRI apparatus, a tomographic image that is substantially parallel or perpendicular to the surface of the subject's chest taken by the three-dimensional XCT apparatus, It is selected from any of chest X-ray images to be examined that have been imaged by an X-ray imaging apparatus. Using the selected morphological image and any one of the images representing the function information obtained from (a) to (e), the arithmetic processing unit performs the processes (2) to (4) and (3 ′). A data processing method including
[0025]
According to the configuration of the present invention described above, prior to the detection of the magnetic field emitted from the heart to be examined, a total of three lasers of two fan-shaped lasers and a pointed laser beam are used, and a simple configuration is used on the bed. The positional relationship between the chest surface to be examined and the bottom surface of the dewar can be adjusted. As a result, almost the entire projection of the heart onto the surface of the sensor array is located within the area of the sensor array, and the body surface of the subject's chest touches the lower surface of the dewar, resulting in a large signal output. The operation for adjusting the positional relationship described above can be performed easily in a short time.
[0026]
In addition, according to the present invention, the biological function information obtained by the biomagnetic field measurement apparatus without performing complicated calculations such as simulation calculation of magnetic field generation for estimating the magnetic field source and tomographic reconstruction calculation, In particular, functional information about the activity of the heart represented by isomagnetic field diagrams, arrow maps, isomagnetic field integral diagrams, current dipole position estimation results, etc., obtained from the magnetic field waveform obtained from the measurement of the magnetic field emitted from the heart, and nuclear magnetism A composite image with a morphological image (tomographic image) substantially parallel or perpendicular to the chest surface obtained by a resonance (MRI) apparatus, a three-dimensional XCT apparatus, or the like, or a chest X-ray image obtained by an X-ray imaging apparatus A composite image with a transmission image can be easily created and displayed.
[0027]
In many cases, in the MRI apparatus and the three-dimensional XCT apparatus, the bed on which the inspection object is mounted is held horizontally, and in the image photographing, the inspection object substantially coincides with the long axis direction of the bed and the body axis of the inspection object. So that it is mounted on the bed. In addition, chest X-ray images (X-ray transmission images) obtained by an X-ray imaging device are often taken while the subject is in a standing position or sitting in a sitting position on a chair. Sometimes it is done.
[0028]
Even when the long axis direction of the bed and the body axis of the inspection object do not exactly coincide with each other in the imaging by the MRI apparatus and the three-dimensional XCT apparatus, by performing the process (3 ′), The body axis direction of the inspection object and the arrangement direction of the pixels in the body axis direction of the inspection object in the function image (direction connecting the first reference point and the second reference point) can be matched.
[0029]
That is, a composite image of an image obtained by rotating the morphological image around the first reference point (the center position of the MRI marker image or the center position of the X-ray marker image) and the functional image can be created. A more accurate composite image of the functional image and the morphological image can be created. For example, the morphological image may be the first image so that the center line of the spine in the chest X-ray image (X-ray transmission image) matches the pixel arrangement direction in the body axis direction of the inspection object in the functional image. By rotating around the reference point (the center position of the X-ray marker image), a more accurate composite image of the functional image and the morphological image can be created.
[0030]
A typical configuration of a biomagnetic field measurement apparatus for obtaining a composite image of an image representing biofunction information and a morphological image in the present invention is summarized as follows with reference to FIG. A first marker 37 indicating the first reference point is disposed on the body surface of the xiphoid process of the inspection object 35, and a second marker 38 indicating the second reference point is disposed on the body surface of the neck notch, respectively. The chest is arranged at the lower part of the bottom surface of the cryogenic container so that the line connecting the first and second reference points is along one direction in which the SQUID magnetometer is arranged inside the cryogenic container 36. The arithmetic processing unit has (1) a process of creating an image representing functional information related to cardiac activity from a signal of a magnetic field waveform, and (2) a first marker indicating a first reference point is arranged on the surface of the xiphoid process. Then, the size of the pixel of the image representing the functional information is matched with the size of the pixel of the morphological image including the heart imaged by the imaging device, and the functional image having the same size as the morphological image is created. Processing, (3) processing for matching the position of the first reference point in the functional image with the position of the first reference point in the morphological image, and (4) creating a composite image of the functional image and the morphological image The process to perform is performed.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
The biomagnetic field measurement apparatus of the present invention includes a bed, a holding table for holding the bed, a cryogenic container, and a gantry. A plurality of SQUID magnetometers are arranged in the x-direction and the y-direction on the surface near the bottom surface inside the cryogenic vessel and cooled. An xz label representing the xz plane of the coordinate system (x, y, z) and a yz label representing the yz plane are marked on the outer peripheral surface of the bottom of the cryogenic container. In the coordinate system (x, y, z), the xy plane is parallel to the bottom surface of the cryocontainer and the z axis is perpendicular to the bottom surface of the cryocontainer.
[0032]
The gantry holding the cryocontainer is fixed to the floor. The distance between the bottom surface of the cryogenic container and the floor surface is a known value set in advance, and the bottom surface of the cryogenic container is in a fixed position with respect to the floor surface. The bottom surface of the cryogenic container and the top surface of the bed are arranged substantially parallel to the floor surface.
[0033]
The plurality of SQUID magnetometers use a magnetometer that detects a magnetic field component in the Z direction or a flux meter that detects a magnetic component in the x direction and a magnetic field component in the y direction.
[0034]
As an optical system used for adjusting the positional relationship between the bottom surface of the cryogenic container and the bed, a first laser source that generates a first fan-shaped laser that expands in a fan shape in the xz plane, and a second that expands in a fan shape in the yz plane. A second laser source for generating a fan-shaped laser and a third laser source for generating a point-like laser beam that irradiates the surface of the bed from an oblique direction so as to cross the first and second fan-shaped lasers And use. The first laser source is fixed to the frame fixed to the gantry, the second laser source is fixed to the frame fixed to the holding table, and the third laser source is fixed to any one of the floor, ceiling, and wall surface. Is fixed to the frame.
[0035]
As a means for changing the irradiation direction of the laser generated from the three laser sources, a first position changing means for changing the irradiation direction of the first fan laser so that the first fan laser irradiates the xz label; Second position changing means for changing the irradiation direction of the second fan-shaped laser so that the second fan-shaped laser irradiates the yz label, and the point-like laser beam includes the first fan-shaped laser and the second fan-shaped laser. Third position changing means for changing the irradiation direction of the point-like laser beam so as to irradiate the crossing line of the laser and the crossing point between the z-axis and the surface of the bed is used.
[0036]
As means for moving the position of the bed relative to the bottom surface of the cryogenic container, x-direction moving means for moving the holding table in the x direction on the floor surface, and y-direction moving means for moving the bed in the y direction on the holding table; , Z direction moving means for moving the bed in the z direction on the holding table is used.
[0037]
Along with the movement of the bed position with respect to the bottom surface of the cryogenic container, the distance between the bed and the floor surface is automatically measured by the distance measuring means, and the distance is displayed on the display.
[0038]
A typical positioning method and a biomagnetic field measurement method described below are applied to the biomagnetic field measurement apparatus.
[0039]
The representative positioning method for a biomagnetic field measuring apparatus according to the present invention includes (1) setting the irradiation direction of the first fan-shaped laser so that the first fan-shaped laser irradiates the xz label, (2) The irradiation direction of the second fan-shaped laser is set so that the second fan-shaped laser irradiates the yz label, and (3) the point-shaped laser beam is the first fan-shaped laser and the second fan-shaped laser. The irradiation direction of the dotted laser beam is set so as to irradiate the intersecting line of the z axis and the intersection of the z axis and the bed surface, and (4) the second fan laser is inspected in the yz plane. By a first reference point indicated by a first marker placed on the body surface of the first point of the subject's chest and a second marker placed on the body surface of the second point of the subject's chest The irradiation direction of the second fan-shaped laser is set so as to pass through the second reference point shown, (5) The bed is moved in the x direction so that the two fan lasers irradiate the yz label, and (6) the bed is moved in the y direction so that the first fan laser passes through the first reference point in the yz plane. As a result, the chest to be inspected is located on the bottom surface of the cryogenic container so that the line connecting the first reference point and the second reference point coincides with or is parallel to one direction in which the center of the SQUID magnetometer is arranged. Located at the bottom.
[0040]
In the above positioning method, (7) the bed is moved in the z direction until the point of irradiation of the dotted laser beam coincides with the first reference point, and (8) the body surface to be inspected is a cryogenic container. The bed is moved in the z-direction until it touches the bottom surface of the plate, and the distance between the first reference point and the bottom surface of the cryogenic container is obtained. Further, the xiphoid process to be examined is used as the first point, and the neck notch to be examined is used as the second point.
[0041]
A typical biomagnetic field measurement method for a biomagnetic field measurement apparatus according to the present invention includes (1) the first fan-shaped laser so that the first fan-shaped laser spreading in a fan shape in the xz plane irradiates the xz label. The irradiation direction is set, (2) the irradiation direction of the second fan-shaped laser is set so that the second fan-shaped laser spreading in a fan shape in the yz plane irradiates the yz label, and (3) the first fan-shaped laser. , And the second fan-shaped laser, a point-like laser beam irradiated on the bed surface from an oblique direction is crossed by a line intersecting the first fan-shaped laser and the second fan-shaped laser, and the z-axis. (4) In the yz plane, the second fan-shaped laser is applied to the body surface of the sword-shaped projection to be inspected. The first reference point indicated by the first marker placed and the neck notch to be examined The irradiation direction of the second fan-shaped laser is set so as to pass through the second reference point indicated by the second marker arranged on the body surface, and (5) the second fan-shaped laser irradiates the yz label. (6) Move the bed in the y direction so that the first fan-shaped laser passes the first reference point in the yz plane, and (7) Irradiate the point-shaped laser beam. The bed is moved in the z-direction until the point coincides with the first reference point, and (8) the bed is moved in the z-direction until the body surface to be inspected contacts the bottom surface of the cryogenic container. The distance from the bottom of the container is obtained, and then (9) a magnetic field emitted from the heart to be examined is detected. The chest to be examined is placed below the bottom of the cryogenic container so that the line connecting the first reference point and the second reference point coincides with or is parallel to one direction in which the center of the SQUID magnetometer is arranged. Is done.
[0042]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing an overall configuration example of a biomagnetic field measurement apparatus according to a first embodiment of the present invention, and FIG. 2 is a detailed configuration example of the biomagnetic field measurement apparatus according to the first embodiment of the present invention. FIG. As shown in FIG. 1, a bed 31 on which an inspection object 35 lies and a gantry 46 that holds a dua (cold container) 36 are arranged inside the magnetic shield room 2. A plurality of sensors (SQUID magnetometers) for detecting a magnetic field signal in the z direction (normal direction) generated from a living body are two-dimensionally arranged in a lattice pattern in the x and y directions in the vicinity of the bottom of the interior of the dewar 36. (A plurality of sensors arranged in two dimensions is called a sensor array).
[0043]
As shown in FIG. 4, 64 SQUID magnetometers for measuring the weak magnetic field generated from the heart are two-dimensionally arranged at the lattice points of an 8 × 8 square lattice at the bottom of the cryogenic vessel (dure) 36. Is arranged. Each SQUID magnetometer has a first-order differential detection coil having a detection coil and a compensation coil, and detects a magnetic field in the normal direction (z direction, direction perpendicular to the body surface).
[0044]
The sensor array is driven by a drive circuit 6, and the output from the sensor array is amplified by an amplifier filter unit 7 and filtered, and then collected in a computer (arithmetic processing unit) 8.
[0045]
The computer (arithmetic processing unit) 8 executes an operation for obtaining an average magnetic field waveform or an additional magnetic field waveform in the normal direction of the magnetic field generated from the heart detected by the sensor array, and then performs an average magnetic field waveform or addition in the normal direction. The magnetic field component in the tangential direction of the magnetic field generated from the heart is obtained from the magnetic field waveform. Furthermore, using the magnetic field component in the tangential direction, the computer 8 analyzes the magnetic field distribution at the coordinate points where a plurality of sensors are arranged, creates an isomagnetic field diagram connecting the coordinate points having the same magnetic field strength, and checks them. Creates an arrow map that displays the active part of the target heart as a two-dimensional current distribution, integrates the magnetic field waveform in a time interval that includes a specific time phase (time zone) of the heart activity, finds the integrated intensity, and equalizes the integration Various calculation processes such as creation of an isomagnetic field integral diagram connecting coordinate points having strength and estimation of the position of the current source from the magnetic field component in the normal direction are performed, and the processing results are displayed on the display device.
[0046]
Note that the present inventors have described a method for obtaining a tangential magnetic field component from a normal magnetic field component, a method for creating an isomagnetic field diagram using a tangential magnetic field component, and a method for creating an isomagnetic field integral diagram. This is a method developed for the first time, and is a known technique (see Japanese Patent Laid-Open No. 10-305019).
[0047]
When t is a time variable, the coordinates of the SQUID magnetometer are (x, y), and the measured normal magnetic field component is Bz (x, y, t), the tangential magnetic field component Bx (x, y) , T), By (x, y, t) is obtained by (Equation 1) and (Equation 2).
[0048]
[Expression 1]
Bx (x, y, t) = ∂Bz (x, y, t) / ∂x (Equation 1)
[0049]
[Expression 2]
By (x, y, t) = ∂Bz (x, y, t) / ∂y (Expression 2)
As shown in FIG. 2, the biomagnetic field measurement apparatus according to the first embodiment includes a y-axis direction moving unit that moves a bed 31 on which an examination target 35 is mounted in the left-right direction (y-axis direction) 32, and the front-rear direction. X-axis direction moving means for moving in the (x-axis direction) 33 and z-axis direction moving means for moving in the vertical direction (z-axis direction) 34 are provided. The upper surface of the bed 31 is always held parallel to the bottom surface of the dewar 36, that is, parallel to the xy plane. The bed 31 is held by a bed holding table 31-1, and can be moved on the feeding rail 31-2 in the x-axis direction 33 by operating a front / rear feed handle (not shown). The bed 31 can be moved in the y-axis direction 32 by operating the left / right feed handle 31-3, and the bed 31 can be moved in the z-axis direction 34 by the hydraulic pump handle 31-4 on the bed holding base 31-1. is there.
[0050]
In the biomagnetic field measurement apparatus of the present invention, the spatial position of the due 36 is fixed, and the measurement surface (401 shown in FIG. 5) is taken as the xy plane, for example, a sensor (SQUID magnetometer) having a detection coil (FIG. 5). The coordinate system (x, y, z) of the biomagnetic field measurement apparatus is set with the center of gravity of each coordinate point (x, y) of 402) shown in FIG. As the origin of the coordinate system (x, y, z), the position of a sensor arranged at a specific position in the sensor array may be the origin (0, 0, 0). The sensor is two-dimensionally arranged in a lattice pattern in the x and y directions on a measurement surface (401 shown in FIG. 5) parallel to the bed 31 in the vicinity of the bottom inside the dewar 36.
[0051]
Further, on the outer peripheral side surface of the lower portion of the dua 36, an xz mark 36-1 indicating an intersection line between the xz plane of the coordinate system (x, y, z) and the outer peripheral side surface, and an intersection line between the yz plane and the outer peripheral side surface Yz label | marker 36-2 which shows is described.
[0052]
The biomagnetic field measurement apparatus according to the first embodiment has a long axis direction 39 of the bed 31 in order to place the inspection object 35 on the bed 31 in a fixed direction and a fixed position with respect to the bottom surface of the dewar 36. A laser oscillator 41 that emits a fan-shaped laser 40 that spreads in the direction of a laser beam, a laser oscillator 44 that emits a fan-shaped laser 43 that spreads in the minor axis direction 42 of the bed 31, and z in the coordinate system (x, y, z) by changing the irradiation direction. A laser oscillator 48 that emits a point-shaped laser 47 that intersects the axis, an ultrasonic displacement sensor 45 that measures the displacement of the bed 31 from the floor surface, and the like are provided. The spread angle of the laser 40 irradiated in a fan shape on a plane parallel to the yz plane and the spread of the laser 43 irradiated in a fan shape on a plane parallel to the xz plane can be changed. An intersection line 49 between the fan-shaped laser 40 and the fan-shaped laser 43 is parallel to the z-axis of the coordinate system (x, y, z). The wavelengths of the laser 40, the laser 43, and the laser 48 are 300 nm to 850 nm. Instead of the laser 40, the laser 43, and the laser 48, another light source that emits light having a wavelength range of 300 nm to 850 nm may be used.
[0053]
The laser oscillator 41 is held by the oscillator holder 41-1, and the oscillator holder 41-1 is capable of changing the irradiation direction of the laser 40 on the pipe frame 41-2 fixed to the bed holder 31-1, and the irradiation direction. Can be fixed in a specific direction (second position changing means). Similarly, the laser oscillator 44 is held by the oscillator holder 44-1, and the oscillator holder 44-1 can change the irradiation direction of the laser 43 to the pipe frame 44-2 fixed to the gantry 46. Can be fixed in a specific direction. That is, the oscillator holder 41-1 is movable in the x-axis direction 33 on the pipe frame 41-2 and can be rotated (tilted) around the axis of the pipe frame 41-2 (first position change). means).
[0054]
Similarly, the oscillator holder 44-1 can move in the y-axis direction 32 on the pipe frame 44-2, and can rotate (tilt) around the axis of the pipe frame 41-2. The pipe frame 41-2 is fixed to the bed holder 31-1 on the side of the foot of the human body mounted on the bed 31, and prevents light having a wavelength range of 300 nm to 850 nm from entering the eyes. The pipe frame 44-2 protrudes in the horizontal direction above the position of the due 36.
[0055]
The laser oscillator 48 is held by an oscillator holder 48-1, and the irradiation direction of the dotted laser 47 changes to a pipe frame 48-2 fixed to any one of a floor surface, a ceiling, and a wall surface. It is possible to fix the irradiation direction to a specific direction. The oscillator holder 48-1 can move in the y-axis direction 32 on the pipe frame 48-2, and can rotate (tilt) around the axis of the pipe frame 48-2. The pipe frame 48-2 is fixed to the floor surface or wall surface inside the magnetic shield room.
[0056]
In order to measure the magnetic field generated from the heart of the inspection object 35, the inspection object 35 is arranged with respect to the bottom surface of the dewar 36, that is, in a fixed direction and a fixed position in the coordinate system (x, y, z). For example, an operation for placing the heart so that the entire projection of the heart onto the surface of the sensor array is located within the area of the sensor array and the body surface of the chest of the test object 35 is in contact with the lower surface of the dewar 36. Hereinafter, a description will be given with reference to FIGS.
[0057]
FIG. 3 is a schematic diagram showing an example of a procedure for arranging an inspection object mounted on a bed on the lower surface of a dewar in the first embodiment of the present invention, and FIG. 4 is a first embodiment of the present invention. It is a figure explaining adjustment of the irradiation direction of three lasers used when arrange | positioning the test object mounted in a bed in the lower surface of a deer in FIG.
[0058]
In the first embodiment described below, the z-axis of the coordinate system (x, y, z) is set in advance so that the entire projection of the heart onto the xy plane is located within the region of the sensor array. Pass through the sensor position. That is, the position of the inspection target is adjusted with respect to the sensor array so that the xiphoid process to be inspected passes through the z-axis, and almost the entire projection of the heart onto the surface of the sensor array is located within the area of the sensor array. Like that.
[0059]
Step 1 (reference number 51): First, the bed 31 is moved in the x direction and / or the y direction, and the bed 31 is moved below the dewar 36. Next, the bed 31 is moved in the z-axis direction 34 so that the height of the upper surface of the bed 31 is higher than the height of the body surface of the inspection object when the inspection object 35 is mounted with the bed 31 as the lowest height. Set to be. At this time, the height HL of the bed 31 from the floor surface is measured by the ultrasonic displacement sensor 45. The height of the bed 31 from the floor surface can be measured by a general displacement sensor (distance measuring means). For example, an optical displacement sensor that optically detects displacement is used instead of the ultrasonic displacement sensor 45. You can also The height of the bed 31 from the floor surface is the distance between the upper surface of the bed 31 and the floor surface, or an arbitrary position of the bed 31 at a certain distance from the upper surface of the bed 31 in the z-axis direction 34. Is a distance between the position of the displacement sensor that moves together with the upper surface of the bed 31 by the z-axis direction moving means in the z-axis direction 34 and the floor surface.
[0060]
The position of the oscillator holder 44-1 is moved on the pipe frame 44-2 to oscillate from the laser oscillator (first laser light source) 44 and spread in a fan shape on a plane parallel to the xz plane (first fan shape). (Laser) spread angle is changed as necessary, and the laser holder 43 passes through the xz mark 36-1 marked on the outer peripheral side surface of the lower portion 36 and irradiates the upper surface of the bed 31 with the oscillator holder. The position of 44-1 is fixed to the pipe frame 44-2.
[0061]
The position of the oscillator holder 41-1 is moved on the pipe frame 41-2 to oscillate from the laser oscillator (second laser light source) 41 and spread in a fan shape on a plane parallel to the yz plane (second fan shape). (Laser) spread angle is changed as necessary, and the laser 40 passes through the yz mark 36-2 marked on the outer peripheral side surface of the lower portion 36 and irradiates the upper surface of the bed 31 with the oscillator holder. The position of 41-1 is fixed to the pipe frame 41-2. The fan-shaped laser 40 and the fan-shaped laser 43 intersect to form a cross line 49 parallel to the z-axis of the coordinate system (x, y, z).
[0062]
FIG. 4 is a diagram for explaining adjustment of irradiation directions of three lasers in step 2 described below.
[0063]
Step 2 (reference number 52): movement in the y-axis direction 32 on the pipe frame 48-2 at the position of the oscillator holder 48-1 and around the axis of the pipe frame 48-2 at the position of the oscillator holder 48-1. The rotation direction (tilt) of the laser 47 changes the irradiation direction of a point-like laser (laser beam) (third laser) 47 oscillated from a laser oscillator (third laser light source) 48 so that the laser 47 is in the coordinate system. The position of the oscillator holder 48-1 is fixed to the pipe frame 48-2 so that the crossing line 49 parallel to the z-axis of (x, y, z) and the surface of the bed 31 cross. That is, first, after setting the position of the oscillator holder 48-1 so that the laser 47 irradiates the xz mark 36-1, the oscillator holder 48-1 is rotated (tilted) around the axis of the pipe frame 48-2. The position of the oscillator holder 48-1 is fixed so that the laser 47 and the cross line 49 cross at the surface of the bed 31 (third position changing means).
[0064]
Step 3 (reference number 53): The ultrasonic displacement sensor 45 obtains the vertical distance H0 between the point where the laser 47 and the cross line 49 cross at the surface of the bed 31 and the lower surface of the dewar 36. The bed 31 is moved in the z-axis direction so that the surface of the bed 31 is in contact with the lower surface of the dewar 36, and the bed height HH from the floor surface is measured by the ultrasonic displacement sensor 45. H0 = (HH−HL).
[0065]
Step 4 (reference number 54): The bed 31 is sufficiently separated from the projection position on the floor of the bottom of the dure 36, and the bed 31 is moved to the position where the dua 36 does not become an obstacle when the inspection object 35 is mounted on the bed 31. The bed 31 is moved in the direction 33, the bed 31 is moved in the z-axis direction, and the height of the bed 31 is lowered. The inspection object 35 is mounted on the bed 31 so that the body axis direction of the inspection object 35 is substantially parallel to the long axis direction 39 of the bed 31. Two reference points (first and second reference points) 37 and 38 are provided on the body surface of the chest along the body axis of the inspection object 35.
[0066]
For example, the position of the xiphoid process (first reference point) is selected as the position of the reference point 37, and the neck notch (second reference point) is selected as the position of the reference point 38. The position of the xiphoid process and cervical notch can be easily determined by palpation, and the body surface position of the xiphoid process and cervical notch can be used as a reference point. Markers described later are attached to the reference points 37 and 38.
[0067]
Step 5 (reference number 55): The oscillator holder 41-1 is moved on the pipe frame 41-2 to change the irradiation direction of the laser 40 which is oscillated from the laser oscillator 41 and spreads in a fan shape in a plane parallel to the yz plane. The position of the oscillator holder 41-1 is moved on the pipe frame 41-2 so that the laser 40 passes through the centers of the reference points 37 and 38, and / or the inspection target 35 on the bed 31 is moved. Move.
[0068]
As a result, the lines passing through the centers of the reference points 37 and 38 are parallel to the long axis direction 39 of the bed 31, and the oscillator holder 41-1 is arranged so that the fan-shaped laser 40 passes through the centers of the reference points 37 and 38. The position is fixed to the pipe frame 41-2.
[0069]
Step 6 (reference number 56): The fan 31 oscillated from the laser oscillator 44 changes the angle of spread of the fan 43 as necessary, and the bed 31 is moved along the y-axis so that the laser 43 passes through the center of the reference point 37. Move in direction 32. As a result, the cross line 49 of the cross beam pattern by the laser 40 and the laser 43 coincides with the center of the reference point 37. In this state, the movement of the bed 31 in the y-axis direction 32 is locked.
[0070]
Step 7 (reference number 57): The spread angle of the fan-shaped laser 40 oscillated from the laser oscillator 41 is changed as necessary, and the laser 40 is yz-marked on the outer peripheral side of the lower portion of the dewar 36. The bed 31 is moved in the x-axis direction 33 so as to pass through 36-2. The movement of the bed 31 in the x-axis direction 33 is locked at the position where the laser 40 passes through the yz mark 36-2. As a result, a state in which the z axis of the coordinate system (x, y, z) passes through the center of the reference point 37 is realized.
[0071]
Step 8 (reference number 58): After the bed 31 is moved in the z-axis direction 34 so that the laser 47 passes through the center of the reference point 37, the height of the bed 31 from the floor surface is measured by the ultrasonic displacement sensor 45. Measure H1. As a result, regardless of the 35 body types to be inspected, the vertical distance between the reference point 37 and the bottom surface of the dewar 36 can always be set to H0 = (HH−HL).
[0072]
Step 9 (reference number 59): Finally, the bed 31 is moved in the z-axis direction 34 so that the body surface of the chest of the examination object 35 is brought close to the lower surface of the dewar 36 so that a large signal output can be obtained. . Next, the height H2 from the floor surface of the bed 31 is measured by the ultrasonic displacement sensor 45. The vertical distance H3 between the reference point 37 and the bottom surface of the deer 36 when the body surface of the chest of the test object 35 is brought close to the lower surface of the deer 36 is different depending on the body shape of the test object 35, but H3 = {H0 -(H2-H1)}.
[0073]
As described above, by using the reference points 37 and 38 and the three laser light sources, almost the entire projection of the heart onto the surface of the sensor array is located in the region of the sensor array, and An operation for bringing the body surface into contact with the lower surface of the dewar 36 and obtaining a large signal output can be easily realized in a short time.
[0074]
In imaging of morphological images by the MRI apparatus, the center of the MRI marker is placed at the same chest position as the center position of the reference point 37, the body axis is aligned with the long axis of the bed 31 of the MRI apparatus, and parallel to the bed surface. Take multiple tomographic images with different depths. Of course, these plurality of tomographic images include tomographic images in which the MRI marker is photographed.
[0075]
FIG. 5 is an example of a display screen of information obtained by measurement and analysis using the biomagnetic field measurement apparatus according to the first embodiment of the present invention, and is a diagram showing a display example of an image representing an estimated position of an active site. is there. In the example shown in FIG. 5, the origin of the coordinate system (x, y, z) is set at the position of the sensor 400 arranged at a specific position among the plurality of sensors 402 arranged on the measurement surface 401 parallel to the bed 31. The result of measuring the magnetic field emitted from the heart by placing the reference point 37 at the position 404 of the xiphoid process of the test object 35, placing the test object 35 so that the xiphoid process 404 passes through the z-axis of the coordinate system It is. In FIG. 5, the sword-like projection 404 is on the surface 403 at a depth c parallel to the measurement surface 401, and the intersection (white) of the surface 405 at the depth d parallel to the measurement surface 401 and the z axis of the coordinate system. Example of a display screen on the display device of the biomagnetic field measurement device indicating that the active site 406 indicated by the white arrow is specified at the tip position of the arrow 406-1 indicated by the solid line from the blank 400-1) It is.
[0076]
The vertical distance H4 between the measurement surface 401 and the lower surface of the dewar 36 is known, and the depth c from the measurement surface 401 to the sword projection 404 is c = (H3 + H4) = {H0− (H2−H1) + H4. }.
[0077]
As shown in FIG. 4, in the example shown in FIG. 5, a coordinate system (x, y, x, y) passes through the z-axis through the position of the xiphoid process and passes through the z-axis through the position of the sensor arranged at a specific position in the sensor array. z) is set. It is well known that the estimation of the position of the current source, that is, the estimation of the active site can be performed by various analysis methods for estimating the current source.
[0078]
An image indicating whether or not an active site estimation position exists has a plurality of pixels having coordinates corresponding to SQUID magnetometers arranged in a two-dimensional grid in the x and y directions. In the image at the depth (z) plane where the position exists, the size of the current source is given to the pixel of the coordinate (x, y) of the estimated position of the active site, and it is estimated that there is no active site. Zero is assigned to the pixel at the coordinate (x, y). Alternatively, as shown in FIG. 5 and the example of FIG. 7 shown later, data (direction and size of the current source) indicating a white arrow indicating the direction and size of the current source at the estimated position of the active site 406. May be given.
[0079]
Here, the size in the x and y directions of the image representing the estimated position of the active site on the display screen of the display device of the biomagnetic field measuring device is the number of pixels in the a and b (FIG. 5) and x and y directions. Are the pixel sizes in the nx, ny, x, and y directions as Δx and Δy. a = nxΔx, b = nyΔy. If the measurement area in which the SQUID magnetometer is two-dimensionally arranged in a grid in the x and y directions on the measurement surface is Px and Py, the imaging magnification in the x and y directions of the image obtained by the biomagnetic field measurement apparatus is (a / Px) and (b / Py).
[0080]
FIG. 6 is a display example showing the position of a tomographic image (morphological image) by the MRI apparatus to be combined with the image representing the estimated position of the active site obtained by the biomagnetic field measurement apparatus in the first embodiment of the present invention. FIG. 3 is a diagram showing an example of a display screen on a display device of a biomagnetic field measurement apparatus of a plurality of tomographic images including a tomographic image taken with an MRI marker.
[0081]
In the imaging by the MRI apparatus, a tomographic image 407 including the MRI marker 408 arranged at the reference point 37 and parallel to the bed surface and a plurality of tomographic images having different depths (z) parallel to the tomographic image 407 can be taken. is there.
[0082]
Here, the size in the x and y directions of the tomographic image by the MRI apparatus is e and f (FIG. 6), the number of pixels in the x and y directions is the size of the pixels in the NX, NY, x and y directions. Are ΔX and ΔY. Assuming that the imaging area of the tomographic image by the MRI apparatus is Qx and Qy, the imaging magnification in the x direction of the tomographic image is (e / Qx), and the imaging magnification in the y direction of the tomographic image is (f / Qy). . e = NXΔX and f = NYΔY.
[0083]
In the first embodiment of the present invention, in order to synthesize an image representing an estimated position of an active site obtained by the biomagnetic field measurement apparatus and a morphological image obtained by the MRI apparatus, the image is taken by the MRI apparatus and is taken into a tomographic image 407. It is necessary to extract a tomographic image 409 at a depth g corresponding to the distance (dc) shown in FIG. 5 from a plurality of tomographic images having different parallel depths. The tomographic image 409 at the depth g is the {(dc) / L} th tomographic image from the tomographic image 407, where L is the thickness of the tomographic image. In FIG. 6, a white + mark 408-1 indicates the position of the xiphoid process in the tomographic image 409.
[0084]
FIG. 7 shows a biomagnetic field of a composite image of an image representing an estimated position of an active site obtained by the biomagnetic field measurement apparatus and a morphological image (tomographic image) obtained by the MRI apparatus in the first embodiment of the present invention. It is a figure which shows the example of the display screen in the display apparatus of a measuring device. A procedure for creating a composite image of an image representing an estimated position of an active site and a tomographic image by the MRI apparatus will be described below.
[0085]
First, in order to synthesize two images, the imaging magnification of the image 405 representing the estimated position of the active site and the imaging magnification of the tomographic image 407 need to be the same. That is, it is necessary to make the pixels of the two images the same size.
[0086]
Since a = nxΔx, b = nyΔy, e = NXΔX, and f = NYΔY, in order to make the pixel sizes Δx, Δy of the image 405 equal to the pixel sizes ΔX, ΔY of the tomographic image, Δx is ( ΔX / Δx) times and Δy may be multiplied by (ΔY / Δy) times. That is, the pixel size Δx in the x direction of the pixel of the image 405 is {(e / a) · (nx / Nx)} times, and the pixel size Δy in the y direction is {(f / b) Create a (ny / NY)} multiplied image 405 ′. At this time, the size of the image 405 ′ in the x direction is {e · (nx / Nx)}, and the size in the y direction is {f · (ny / NY)}.
[0087]
In general, nx ≠ Nx, ny ≠ NY, and the position of the reference point in the image 405 ′ is different from the center position of the MRI marker in the tomographic image 407, so the image 405 ′ and the tomographic image 407 are synthesized. In this case, a process for matching the position of the reference point and the center position of the MRI marker is performed between the two images, and only the pixel of the image 405 ′ that overlaps the tomographic image 407 is set as a synthesis target.
[0088]
Next, the image 405 ′ is displayed on the tomographic image 407, the center position of the MRI marker 408 and the center position of the reference point 37 (the position of the xiphoid process position 404 in the coordinate system (x, y, z) in the biomagnetic field device). Overlay so that (x, y)) matches. At this time, the data of the tomographic image 407 and the data of the image 405 ′ are stored in the storage memory in correspondence with each other in the storage memory, and at the same time, the data and the images of the plurality of tomographic images parallel to the tomographic image 407 together with the tomographic image 407 are stored. The data of 405 ′ is stored in the storage memory in association with it. The center position of the MRI marker 408 of the tomographic image 407 is projected onto a plurality of tomographic images parallel to the tomographic image 407 and stored in the storage memory.
[0089]
Next, the image 405 ′ including the white arrow indicating the active site 406 and the tomographic image 409 stored in the storage memory are read out and combined as one piece of image data to create a combined image 410. The position of the white cross mark 400′-1 where the white cross mark 400-1 shown in FIG. 5 is enlarged, and the white + mark where the white + mark 408-1 shown in FIG. 6 is enlarged. The position of 408'-1 is displayed in an overlapped manner, and the arrow 406-1 shown in FIG. 5 is enlarged, and the active site 406 shown by the white arrow shown in FIG. A white arrow 406 ′ in which the arrow is enlarged and a composite image 410 including a tomographic image are displayed. When displaying the synthesized image, for example, the image 405 ′ and the tomographic image 409 are displayed in different colors.
[0090]
According to the composite image creation method described above, the center position of the MRI marker 408 of the tomographic image 407 is projected onto a plurality of tomographic images parallel to the tomographic image 407 on the storage memory. And a tomographic image other than the tomographic image 409 can be easily synthesized, so that the relative positional relationship between each part of the heart and the active site 406 can be easily understood. When a plurality of active sites 406 are detected, the processing described above for each active site 406 may be executed.
[0091]
In the above description, the tomographic image by the MRI apparatus has been described as an example of the morphological image, but a tomographic image by the MRI apparatus representing the blood flow state may be used instead of the tomographic image by the MRI apparatus.
(Second embodiment)
FIG. 8 is a second embodiment of the present invention, and is a display device of a biomagnetic field measurement apparatus for a composite image 601 of an isomagnetic field diagram obtained by a biomagnetic field measurement apparatus and a tomographic image (morphological image) obtained by an MRI apparatus. It is a figure which shows the example of the display screen in. Similar to the first embodiment, the processing for matching the size of the pixel of the image representing the isomagnetic field diagram with the size of the pixel of the tomographic image, and the center position of the reference point in the isomagnetic field diagram (biological body) The coordinate system (corresponding to the position of the measurement plane through which the z axis of the coordinate system (x, y, z) of the magnetic field measurement apparatus passes) and the reference point (center position of the image of the MRI marker) photographed in the tomographic image are matched. Process.
[0092]
In the first embodiment, instead of the image 405, a tomographic image shown in FIG. 6 is obtained by using an isomagnetic field diagram connecting points having the same magnetic field intensity measured at a certain time by a plurality of SQUID magnetometers. An arbitrary tomographic image can be selected from a plurality of tomographic images parallel to 407, and a composite image 601 of the selected arbitrary tomographic image and isomagnetic field diagram can be created and displayed on the display device.
[0093]
In FIG. 8, a thick line indicates a tomographic image obtained by the MRI apparatus, and a thin line indicates an isomagnetic field diagram in the measurement region 600 of the biomagnetic field measurement apparatus. Various contents can be displayed on the display screen of the display device. For example, the tomographic images can be selected and designated with a mouse or the like while changing the depth direction one after another, and a composite image of the tomographic images and isomagnetic field diagrams at different depth positions can be displayed. In addition, it is possible to display a composite image of an isomagnetic field diagram that changes every moment and a tomographic image selected from a plurality of tomographic images with a mouse or the like, and an isomagnetic field diagram that changes over time on the selected tomographic image can be displayed. Significant diagnostic information can be obtained by comparing the morphological information shown in the image with the state of change of the isomagnetic field map, which is functional information.
[0094]
FIG. 9 is a display device of the biomagnetic field measurement apparatus according to the second embodiment of the present invention, which is a composite image 702 of an arrow map obtained by the biomagnetic field measurement apparatus and a tomographic image (morphological image) obtained by the MRI apparatus. It is a figure which shows the example of a display screen. The example shown in FIG. 9 uses an arrow map that displays the activated part of the heart to be examined as a two-dimensional current distribution instead of the isomagnetic field diagram in the example shown in FIG.
[0095]
In FIG. 9, the thick line indicates a tomographic image by the MRI apparatus, the arrow indicates an arrow map, and the contents displayed on the display screen of the display apparatus can be various as in FIG. 8. For example, the time change of the arrow map can be displayed together with the selected tomographic image.
[0096]
FIG. 10 is a second embodiment of the present invention, and is a display device of a biomagnetic field measurement apparatus for a composite image 701 of an isomagnetic field integral diagram obtained by a biomagnetic field measurement apparatus and a tomographic image (morphological image) obtained by an MRI apparatus. It is a figure which shows the example of the display screen in. The example shown in FIG. 10 is the same as the example shown in FIG. 8 except that the integrated intensity is obtained by integrating the magnetic field waveform in the time interval including a specific time phase of the heart activity instead of the isomagnetic field diagram. Integral magnetic field integration diagram that connects coordinate points with strength, or integration of the magnetic field waveform of the magnetic field component in the tangential direction in the time interval including two different time phases to obtain the integrated strength, and the time including two different time phases Use an isomagnetic integration diagram that connects coordinate points that have the same difference in integral intensity in the interval.
[0097]
In FIG. 10, the thick line indicates a tomographic image obtained by the MRI apparatus, the thin line indicates an isomagnetic field integration diagram, and the contents displayed on the display screen of the display device can be various as in FIG. For example, an isomagnetic field integral diagram can be displayed with tomographic images at a plurality of different depth positions.
[0098]
FIG. 11 is a second embodiment of the present invention, and a biomagnetic field of a composite image 801 of an activated region and isomagnetic field diagram obtained by a biomagnetic field measurement apparatus and a tomographic image (morphological image) obtained by an MRI apparatus. It is a figure which shows the example of the display screen in the display apparatus of a measuring device. The example shown in FIG. 11 is an example in which an isomagnetic field diagram, an image representing an activated region, and a composite image of three tomographic images obtained by an MRI apparatus are displayed. The fault including the activation site is displayed along with the isomagnetic field diagram and the activation site. In FIG. 11, the thick line indicates the tomographic image obtained by the MRI apparatus, the thin line indicates the isomagnetic field diagram, and the contents displayed on the display screen of the display device are the same as those shown in FIGS. Various types are possible. For example, it is possible to display a composite image of three images representing an isomagnetic field diagram, a tomographic image, and an activated region that change every moment.
[0099]
FIG. 12 is a second embodiment of the present invention, and a biomagnetic field measurement of a composite image 703 of an isomagnetic field diagram and an arrow map obtained by a biomagnetic field measurement apparatus and a tomographic image (morphological image) obtained by an MRI apparatus. It is a figure which shows the example of the display screen in the display apparatus of an apparatus. The example shown in FIG. 12 is an example in which an isomagnetic field map, an arrow map, and a composite image of three tomographic images by an MRI apparatus are displayed, and an arrow map for displaying an activated region as a two-dimensional current distribution is the same. It is displayed together with the magnetic field diagram. In FIG. 12, a thick line indicates a tomographic image by the MRI apparatus, a thin line indicates an isomagnetic field map, an arrow indicates an arrow map, and the contents displayed on the display screen of the display device are as shown in FIGS. Various types are possible in the same manner as in FIG. For example, a composite image of three images of an isomagnetic field diagram, a tomographic image, and an arrow map that change every moment can be displayed.
[0100]
In addition, in the example shown in FIG. 8, an image representing an activated region, an isomagnetic field diagram, an arrow map, and a composite image of four images of tomograms by an MRI apparatus may be displayed. Further, in the examples shown in FIGS. 8, 9, 10, 11, and 12, a tomographic image obtained by an MRI apparatus representing a blood flow state may be used instead of a tomographic image (morphological image) obtained by an MRI apparatus. good.
(Third embodiment)
FIG. 13 is a third embodiment of the present invention, and a biomagnetic field of a composite image of an isomagnetic field integral diagram measured for an actual patient by a biomagnetic field measurement apparatus and a tomographic image (morphological image) by an MRI apparatus. It is a figure which shows the example of the display screen in the display apparatus of a measuring device. The method of creating the composite image is performed by the method described in the first and second embodiments.
[0101]
In the example shown in FIG. 13, the integrated intensity is obtained by integrating the magnetic field waveform in the time period including the time phase (time zone) in which the QRS wave of the heart activity appears and the time phase (time zone) in which T appears. An isomagnetic field integral diagram is used to connect coordinate points having the same difference in integral intensity in a time interval including two different time phases.
[0102]
In FIG. 13, a thick line indicates a tomographic image obtained by the MRI apparatus, a thin line indicates an isomagnetic field integral diagram, and the isomagnetic field integral diagram is displayed together with a tomographic image selected from a plurality of tomographic images. In FIG. 13, the inactive site 602 of myocardial activity in the patient's heart is indicated by a black portion. In the inactive site 602, the integrated intensity is negative. This detection of the inactive site of myocardial activity is considered to be very effective for diagnosis of myocardial ischemia such as angina pectoris and myocardial infarction.
(Fourth embodiment)
FIG. 14 shows a fourth embodiment of the present invention, which is a composite image of isomagnetic field diagrams and arrow maps actually measured for a patient by a biomagnetic field measurement apparatus and a tomographic image (morphological image) by an MRI apparatus. It is a figure which shows the example of the display screen in the display apparatus of a biomagnetic field measuring device. The patient related to FIG. 13 is different from the patient related to FIG. The method of creating the composite image is performed by the method described in the first and second embodiments.
[0103]
The example shown in FIG. 14 is a coordinate point having the same magnetic field strength of the tangential magnetic field component derived from the measured normal magnetic field component at the time phase (time zone) in which the P wave of the heart activity appears. Use an isomagnetic diagram and an arrow map to connect.
[0104]
In FIG. 14, a thick line indicates a tomographic image obtained by the MRI apparatus, a thin line indicates an isomagnetic field diagram in the measurement region 600, and an arrow indicates an arrow map. FIG. 14A to FIG. 14F show an actual measurement example of the temporal change of the isomagnetic field diagram displayed on the display screen of the display device, and the isomagnetic field diagram is selected from a plurality of tomographic images. It is displayed with two tomographic images. FIG. 14A to FIG. 14F show isomagnetic field diagrams showing a time lapse every 25 ms in the time phase where the P wave appears.
[0105]
As is clear from the change in the movement of the arrows in the arrow map shown in FIGS. 14 (a) to 14 (f), it is clear that there is an annular current (annular current) that flows around the left and right atria of the heart. It is shown. The presence of this ring current is closely related to atrial tachycardia, and detection of the ring current is considered to be very effective in the diagnosis of atrial tachycardia. (Fifth embodiment)
In the first and second embodiments, various composite images are obtained using a plurality of tomographic images obtained by a three-dimensional XCT apparatus and substantially parallel to the chest surface instead of a plurality of tomographic images obtained by an MRI apparatus. Can be created and displayed. The process for obtaining the composite image is the same as in the first and second embodiments, and a functional image (isomagnetic field diagram, arrow map, isomagnetic field integral diagram, activated part ( The function information on the heart activity such as the estimated position of the current source) is represented by the processing for matching the pixel size with the pixel size of the tomographic image obtained by the three-dimensional XCT apparatus, and the biomagnetic field measurement device. The center position of the reference point in the obtained functional image (corresponding to the position of the measurement plane through which the z axis of the coordinate system (x, y, z) of the biomagnetic field measurement apparatus passes) and the reference imaged in the tomographic image And a process of matching the point (the center point of the image of the X-ray marker).
(Sixth embodiment)
In the first embodiment, a chest X-ray image (X-ray transmission image) by an X-ray imaging apparatus is used in place of the tomographic image 407 by the MRI apparatus, and a chest X-ray image and a biomagnetic field measurement apparatus are used. Various composite images are displayed between the obtained functional images (isomagnetic field diagram, arrow map, isomagnetic field integral diagram, functional information related to the heart activity such as the estimated position of the activation site (current source)). Can be created and displayed. The process for obtaining the composite image includes the process of matching the pixel size of the functional image obtained from the biomagnetic field measurement device with the pixel size of the chest X-ray image, and the function image obtained from the biomagnetic field measurement device. Taken at the center position of the reference point (first reference point) (corresponding to the position of the measurement plane through which the z axis of the coordinate system (x, y, z) of the biomagnetic field measurement apparatus passes) and the chest X-ray image In the chest X-ray image by matching the first reference point (the center point of the X-ray marker image) and the chest X-ray image about the first reference point. A process of matching the body axis direction of the inspection object with the pixel arrangement direction in the body axis direction of the inspection object in the functional image (the direction connecting the first reference point and the second reference point).
[0106]
A composite image of the image obtained by rotating the chest X-ray image around the first reference point (the center point of the X-ray marker image) and the functional image can be created, so that the functional image and the morphological image can be combined more accurately. You can create an image. For example, the morphological image is set to the first reference point (X-ray marker) so that the center line of the spine in the chest X-ray image coincides with the arrangement direction of the pixels in the body axis direction of the inspection object in the functional image. The image can be rotated around the center point of the image to create a more accurate composite image of the functional image and the morphological image.
[0107]
In each embodiment described above, in the measurement by the biomagnetic field measurement device, as a marker to be attached to the reference points 37 and 38, for example, lead (size 5 mm × 5 mm, thickness 5 mm), vitamin agent (size 5 mm) × 5 mm, thickness 5 mm) or the like. In taking a tomographic image and a blood flow image by the MRI apparatus, for example, a vitamin agent (size 5 mm × 5 mm, thickness 5 mm) is attached to the reference point 37 as an MRI marker. Vitamins are projected on images taken by the MRI system. In imaging a chest X-ray image with an X-ray imaging apparatus and tomographic imaging with a three-dimensional X-ray CT apparatus, for example, lead (size 5 mm × 5 mm, thickness 5 mm) or the like is used as an X-ray marker at the reference point 37. Affix it. Lead is projected on chest X-ray images and X-ray CT tomograms. If it is difficult to identify the xiphoid process on the chest X-ray image, the distance between the cervical notch and the xiphoid process to be examined is measured, for example with a ruler, and the measured cervical incision A correction distance is obtained by correcting the influence of the imaging magnification of the chest X-ray image with respect to the distance between the scar and the xiphoid process, and on the chest X-ray image along the central axis of the examination object from the neck notch Assuming that the xiphoid process exists at a position separated by the correction distance, the position of the xiphoid process can be determined.
[0108]
In each of the embodiments described above, the tomographic image data by the MRI apparatus, the blood flow image data are taken into the storage device of the biomagnetic field measuring apparatus, and the chest X-ray image data by the X-ray imaging apparatus. The acquisition of the tomographic image data to the storage device of the biomagnetic field measurement apparatus by the three-dimensional XCT apparatus is performed by the following method.
[0109]
When a biomagnetic field measurement device, an MRI device, a three-dimensional XCT device, an image reading device that digitizes the density of a film of a chest X-ray image and reads it as image data, etc. constitutes PACS (Picture Archiving and Communications Systems) The image data is read from each device online to the storage device of the biomagnetic field measurement device.
[0110]
In addition, when an image obtained by an MRI apparatus, a three-dimensional XCT apparatus, an X-ray imaging apparatus or the like is obtained in a film, it is digitized by using an image reading apparatus that digitizes the density of the film and reads it as image data. The image data is stored in a portable medium, and the image data is read into the storage device of the biomagnetic field measurement apparatus via the portable medium. Alternatively, the image reading device and the biomagnetic field measurement device may be connected online, and the output data (digitized image data) of the image reading device may be directly taken into the storage device of the biomagnetic field measurement device.
[0111]
FIG. 15 is a schematic diagram showing an example of a procedure for creating a composite image of a biological function image and a morphological image in each embodiment of the present invention. Hereinafter, the procedure will be summarized with reference to FIG.
[0112]
Step 1 (reference number 71): A morphological image including the chest is captured by an MRI apparatus, a three-dimensional X-ray CT apparatus, an X-ray imaging apparatus, or the like. In imaging using an MRI apparatus or a three-dimensional X-ray CT apparatus, a plurality of tomographic images parallel to the chest surface to be examined are acquired. In the X-ray imaging apparatus, a chest X-ray image (X-ray transmission image) taken from the front is taken. In photographing these morphological images, the first marker indicating the first reference point is arranged on the body surface of the xiphoid process to be inspected.
[0113]
Step 2 (reference number 72): The morphological image taken in step 1 (reference number 71) is selected.
[0114]
Step 3 (reference number 73): a first marker indicating the first reference point on the body surface of the xiphoid process to be inspected and a second reference point indicating the second reference point on the body surface of the neck notch to be inspected The magnetic field components in the normal direction of the magnetic field generated from the heart are measured.
[0115]
Step 4 (reference number 74): Estimating the tangential magnetic field component of the magnetic field generated from the heart from the measured normal magnetic field component, and using the tangential magnetic field component, functional information regarding the heart activity is obtained. Create functional images (isomagnetic field diagram, arrow map, isomagnetic field integral diagram, estimated position of current source, etc.).
[0116]
Step 5 (reference number 75): The function image created in step 4 (reference number 74) is selected.
[0117]
Step 6 (reference number 76): A process of matching the element size of the functional image with the pixel size of the morphological image is performed.
[0118]
Step 7 (reference number 77): A process of matching the first reference point of the functional image with the first reference point of the morphological image is performed.
[0119]
Step 8 (reference number 78): When the body axis direction of the inspection target in the morphological image and the arrangement direction of the pixels in the body axis direction of the inspection target in the functional image do not match, the morphological image is determined as the first reference. By rotating around the point, the body axis direction of the inspection object in the morphological image is matched with the pixel arrangement direction in the body axis direction of the inspection object in the functional image.
[0120]
Step 9 (reference number 79): The function image and the morphological image are combined into one image to obtain a combined image.
[0121]
Note that either step 1 (reference number 71) or step 3 (reference number 73) may be executed first. In step 5 (reference number 75), a plurality of function images created in step 4 (reference number 74) are selected, and a plurality of function images are obtained in steps 6 (reference number 76) to step 9 (reference number 79). A composite image of the functional image and the morphological image may be created and displayed. Further, a composite image of a plurality of functional images and, for example, each tomographic image of a plurality of tomographic images selected from a plurality of tomographic images parallel to the chest surface to be inspected that has been imaged in step 1 (reference number 71). It may be created and displayed. Execution of step 8 (reference number 78) may be omitted.
[0122]
As described above, according to the present invention, an isomagnetic field diagram, an arrow map, an isomagnetic field integral diagram, an activation site (current source) obtained by a biomagnetic field measurement apparatus in a short time without requiring complicated calculation. The pixel size of the morphological image representing the form of the heart obtained by the MRI apparatus, the three-dimensional XCT apparatus, the X-ray imaging apparatus, etc. The center position of the first reference point in the functional image (corresponding to the position of the measurement plane through which the z axis of the coordinate system (x, y, z) of the biomagnetic field measurement apparatus passes), A process of matching the first reference point (the center point of the image of the MRI marker or the center point of the image of the X-ray marker) captured in the morphological image is performed.
[0123]
Further, the inspection object in the morphological image is rotated by rotating the morphological image around the first reference point (the center point of the MRI marker image or the X-ray marker image) captured in the morphological image. The function image and the body image direction are aligned with the pixel arrangement direction in the body axis direction (direction connecting the first reference point and the second reference point) of the inspection object in the function image. A more accurate composite image with the morphological image can be created.
[0124]
As a result, according to the present invention, an arbitrary tomographic image is selected from a plurality of tomographic images substantially parallel to the chest surface obtained by an MRI apparatus or a three-dimensional XCT apparatus, and the selected tomographic image and time-varying isomagnetic field lines. A composite image with a map or an arrow map that changes over time can be displayed momentarily.
[0125]
In addition, an image showing an activated site, a tomographic image including the activated site that is substantially parallel to the chest surface obtained by an MRI apparatus or a three-dimensional XCT apparatus, a time-changing isomagnetic field diagram, or a time-changing image, etc. A composite image with a magnetic field integral diagram can be displayed every moment. The image representing the activation site is represented, for example, by an arrow, the root position of the arrow indicates the estimated position of the current source, the length of the arrow indicates the size of the current source, and the direction of the arrow indicates (x, y) indicates the direction of the vector representing the current source projected onto the plane.
[0126]
Furthermore, a composite image of a chest X-ray image (morphological image) obtained by an X-ray imaging apparatus and a time-changing isomagnetic field diagram or a time-changing isomagnetic field integral diagram can be displayed every moment. In addition, a composite image of a chest X-ray image (X-ray transmission image), an image representing an activated region, and a time-changing isomagnetic field diagram or a time-changing isomagnetic field integration diagram can be displayed every moment.
[0127]
【The invention's effect】
According to the present invention, in particular, when detecting a magnetic field generated from the heart to be examined, almost the entire projection of the heart onto the surface of the sensor array is located in the region of the sensor array, and the body surface of the chest to be examined is detected. The operation of touching the lower surface of the dewar and obtaining a large signal output can be realized in a short time and easily.
[0128]
In addition, according to the present invention, the biological function information obtained by the biomagnetic field measurement apparatus, in particular, the magnetic field generated from the heart is not executed without performing complicated calculations such as simulation calculation of magnetic field generation and tomographic reconstruction. Functional information on the activity of the heart represented by isomagnetic field diagrams, arrow maps, isomagnetic field integral diagrams, current dipole position estimation results, etc., obtained from the magnetic field waveform obtained by the measurement, nuclear magnetic resonance (MRI) apparatus, 3 A composite image with a morphological image (tomographic image) substantially parallel to the chest surface obtained by a three-dimensional XCT apparatus or a transmission image such as a chest X-ray image obtained by an X-ray imaging apparatus can be easily obtained. Create and display composite images.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of the overall configuration of a biomagnetic field measurement apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram for explaining details of a configuration example of the biomagnetic field measurement apparatus according to the first embodiment of the present invention.
FIG. 3 is a schematic diagram showing an example of a procedure for placing an inspection object mounted on a bed on the lower surface of a dewar in the first embodiment of the present invention.
FIG. 4 is a diagram for explaining adjustment of irradiation directions of three lasers used when an inspection object mounted on a bed is arranged on the lower surface of a dewar in the first embodiment of the present invention.
FIG. 5 is an example of a display screen for information obtained by the biomagnetic field measurement apparatus according to the first embodiment of the present invention, and shows a display example of an image representing an estimated position of an active site.
FIG. 6 is a diagram showing an example of a display screen showing a position of a tomographic image by an MRI apparatus to be combined with an image showing an estimated position of an active site obtained by the biomagnetic field measurement apparatus in the first embodiment of the present invention.
FIG. 7 is a view showing a display example of a composite image of an image representing an estimated position of an active site obtained by the biomagnetic field measurement apparatus and a tomographic image obtained by the MRI apparatus in the first embodiment of the present invention.
FIG. 8 is a diagram showing a display example of a composite image of an isomagnetic field diagram obtained by a biomagnetic field measurement apparatus and a tomographic image by an MRI apparatus according to the second embodiment of the present invention.
FIG. 9 is a diagram showing a display example of a composite image of an arrow map obtained by a biomagnetic field measurement apparatus and a tomographic image by an MRI apparatus according to the second embodiment of the present invention.
FIG. 10 is a diagram showing a display example of a composite image of an isomagnetic field integral diagram obtained by a biomagnetic field measurement apparatus and a tomographic image by an MRI apparatus according to the second embodiment of the present invention.
FIG. 11 is a diagram showing a display example of a composite image of an activated region and isomagnetic field diagram obtained by a biomagnetic field measurement apparatus and a tomographic image by an MRI apparatus according to the second embodiment of the present invention.
FIG. 12 is a diagram showing a display example of a composite image of an isomagnetic field diagram and an arrow map obtained by a biomagnetic field measurement apparatus and a tomographic image by an MRI apparatus according to the second embodiment of the present invention.
FIG. 13 is a third embodiment of the present invention, and shows a display screen on a display device of a composite image of an isomagnetic field integral diagram measured for an actual patient by a biomagnetic field measurement device and a tomographic image by an MRI device. The figure which shows an example.
FIG. 14 is a fourth embodiment of the present invention, in a display device for a composite image of isomagnetic field diagrams and arrow maps actually measured for a patient by a biomagnetic field measurement apparatus and a tomographic image by an MRI apparatus; The figure which shows the example of a display screen.
FIG. 15 is a schematic diagram showing an example of a procedure for creating a composite image of a biological function image and a morphological image in each embodiment of the present invention.
FIG. 16 is a diagram for explaining an example of a conventional technique for specifying position coordinates of a head portion in biomagnetic field measurement for measuring a brain magnetic field.
FIG. 17 is a diagram for explaining an example of a conventional technique for specifying the position coordinates of a marker using an MRI image in order to synthesize a brain magnetic field measurement result and an MRI image of the head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Magnetic shield room, 6 ... Drive circuit, 7 ... Amplifier filter unit, 8 ... Computer, 11 ... Bottom of deure, 12 ... Detection coil, 13 ... Magnetic field generation coil, 21 ... MRI marker, 35 ... Test object, 31 ... Bed, 31-1 ... Bed holding stand, 31-2 ... Feed rail, 31-3 ... Left / right feed handle, 31-4 ... Hydraulic pump handle, 36 ... Dua (cold container), 36-1 ... xz label, 36 -2 ... yz label, 32 ... left-right direction (y-axis direction), 33 ... front-back direction (x-axis direction), 34 ... up-down direction (z-axis direction), 37, 38 ... reference point, 39 ... long axis direction of the bed , 40 ... Laser (second laser), 41 ... Laser oscillator (second laser light source), 41-1 ... Oscillator holder, 41-2 ... Pipe frame fixed to the bed holder, 42 ... Short axis of the bed Direction, 43 ... (First laser), 44 ... laser oscillator (first laser light source), 44-1 ... oscillator holder, 44-2 ... pipe frame fixed to the gantry, 45 ... measuring displacement of the bed from the floor. Ultrasonic displacement sensor, 46 ... gantry, 47 ... laser (third laser), 48 ... laser oscillator (third laser light source), 48-1 ... oscillator holder, 48-2 ... pipe frame fixed to the floor, 400 ... Sensor (SQUID magnetometer) arranged at a specific position, 400'-1 ... Enlarged white cross mark, 401 ... Measuring surface parallel to bed, 402 ... Multiple sensors (SQUID magnetometer), 403 ... a surface at a depth c parallel to the measurement surface, 404 ... a position of the xiphoid process, 405 ... a surface at a depth d parallel to the measurement surface, 406 ... a white arrow indicating an active site, 406 '... white Open arrow, 40 '-1 ... enlarged arrow, 405' ... pixel-corrected image, 407 ... tomographic image, 408 ... MRI marker, 408-1 ... white + mark, 408'-1 ... enlarged white ,..., Tomogram, 600... Measurement area, 602... Inactive site of myocardial activity, 410, 601, 701, 702, 703, 801.

Claims

A plurality of SQUID magnetometers that detect a magnetic field generated from the heart to be examined, and are arranged in a two-dimensional manner; a cryogenic container that cools the plurality of SQUID magnetometers; and a gantry that is fixed to a floor and holds the cryocontainer A bed having an upper surface parallel to the bottom surface of the cryogenic container holding the inspection object and a coordinate system (x, y, z) having a measurement surface by the plurality of SQUID magnetometers as an xy plane; Is performed in the x, y, and z directions, a drive circuit for driving the plurality of SQUID magnetometers, and a magnetic field waveform signal detected by the plurality of SQUID magnetometers. An arithmetic processing means, a display means for displaying the result of the arithmetic processing, and a first fan-shaped laser that radiates an xz label that extends in a fan shape within the xz plane and is marked on the outer peripheral surface of the bottom surface of the cryogenic container are generated. A first laser source, a second laser source that generates a second fan-shaped laser that radiates a yz label that extends in a fan shape within the yz plane and is marked on the outer peripheral surface of the bottom surface of the cryogenic vessel; And a third laser source that generates a linear laser beam that irradiates the upper surface of the bed from an oblique direction so as to cross the second fan-shaped laser, and a first laser source that fixes the first laser source to the gantry. 1 frame, a second frame for fixing the second laser source to a holding base for holding the bed, and a third frame for fixing the third laser source to the floor or ceiling. And the second fan-shaped laser has a first reference point indicated by a first marker disposed on a body surface of a first point of the chest to be examined, and a second reference point of the chest to be examined. indicated by a second marker disposed on the body surface of the point The second laser source is moved in the x direction so as to pass through two reference points, and a line connecting the first reference point and the second reference point is the center of the plurality of SQUID magnetometers. The chest to be inspected is arranged at the lower part of the bottom surface of the cryogenic container so as to coincide with or parallel to one direction of arrangement, the position of the inspection object is adjusted, and the first fan-shaped laser is in the first direction. The bed is moved in the y direction so that it passes through the reference point, the bed is moved in the x direction so that the second fan-shaped laser coincides with the yz plane, and the linear laser beam is moved in the first direction. The bed is moved in the z direction until it coincides with one reference point, and the computing means (1) creates an image representing functional information related to the activity of the heart to be examined from the signal of the magnetic field waveform. (2) the first marker is the first marker The pixel size of the image representing the functional information is made to coincide with the pixel size of the morphological image including the heart to be examined, which is arranged at the reference point and photographed by the imaging device. A process of creating a functional image having pixels of the same size as the size; (3) the position of the first reference point in the functional image, and the position of the first reference point in the morphological image. And (4) a process of creating a composite image of the functional image and the morphological image, and the composite image is displayed on the display means Measuring device.

2. The biomagnetic field measurement apparatus according to claim 1, wherein the first point is a sword-like projection to be inspected, and the second point is a neck notch to be inspected. Biomagnetic field measurement device.

A plurality of SQUID magnetometers that detect a magnetic field generated from the heart to be examined, and are arranged in a two-dimensional manner; a cryogenic container that cools the plurality of SQUID magnetometers; and a gantry that is fixed to a floor and holds the cryocontainer A bed having an upper surface parallel to the bottom surface of the cryogenic container holding the inspection object and a coordinate system (x, y, z) having a measurement surface by the plurality of SQUID magnetometers as an xy plane; Is performed in the x, y, and z directions, a drive circuit for driving the plurality of SQUID magnetometers, and a magnetic field waveform signal detected by the plurality of SQUID magnetometers. An arithmetic processing means, a display means for displaying the result of the arithmetic processing, and a first fan-shaped laser that radiates an xz label that extends in a fan shape within the xz plane and is marked on the outer peripheral surface of the bottom surface of the cryogenic container are generated. A first laser source, a second laser source that generates a second fan-shaped laser that radiates a yz label that extends in a fan shape within the yz plane and is marked on the outer peripheral surface of the bottom surface of the cryogenic vessel; And a third laser source that generates a linear laser beam that irradiates the upper surface of the bed from an oblique direction so as to cross the second fan-shaped laser, and the second fan-shaped laser includes the inspection A first reference point indicated by a first marker placed on the body surface of the first point of the subject's chest and a second marker placed on the body surface of the second point of the subject's chest The second laser source is moved in the x direction so as to pass through the second reference point indicated by, and a line connecting the first reference point and the second reference point is the plurality of SQUID magnetic fluxes. The inspection object so that the center of the meter coincides with or is parallel to one direction of arrangement. A chest is disposed below the bottom of the cryocontainer, the position of the inspection target is adjusted, and the bed is moved in the y direction so that the first fan-shaped laser passes through the first reference point; The bed is moved in the x direction so that the second fan-shaped laser coincides with the yz plane, and the bed is moved in the z direction until the linear laser beam coincides with the first reference point. A biomagnetic field measuring apparatus characterized by that.

4. The biomagnetic field measurement apparatus according to claim 3, wherein the first point is a sword-like projection to be inspected, and the second point is a neck notch to be inspected. Biomagnetic field measurement device.

A plurality of SQUID magnetometers that detect a magnetic field generated from the heart to be examined, and are arranged in a two-dimensional manner; a cryogenic container that cools the plurality of SQUID magnetometers; and a gantry that is fixed to a floor and holds the cryocontainer A bed having an upper surface parallel to the bottom surface of the cryogenic container holding the inspection object and a coordinate system (x, y, z) having a measurement surface by the plurality of SQUID magnetometers as an xy plane; Is performed in the x, y, and z directions, a drive circuit for driving the plurality of SQUID magnetometers, and a magnetic field waveform signal detected by the plurality of SQUID magnetometers. An arithmetic processing means, a display means for displaying the result of the arithmetic processing, and a first fan-shaped laser that radiates an xz label that extends in a fan shape within the xz plane and is marked on the outer peripheral surface of the bottom surface of the cryogenic container are generated. A first laser source, a second laser source that generates a second fan-shaped laser that radiates a yz label that extends in a fan shape within the yz plane and is marked on the outer peripheral surface of the bottom surface of the cryogenic vessel; And a third laser source that generates a linear laser beam that irradiates the upper surface of the bed from an oblique direction so as to cross the second fan-shaped laser, and the second fan-shaped laser includes the inspection A first reference point indicated by a first marker placed on the body surface of the first point of the subject's chest and a second marker placed on the body surface of the second point of the subject's chest The second laser source is moved in the x direction so as to pass through the second reference point indicated by, and a line connecting the first reference point and the second reference point is the plurality of SQUID magnetic fluxes. The inspection object so that the center of the meter coincides with or is parallel to one direction of arrangement. A chest is disposed below the bottom of the cryocontainer, the position of the inspection target is adjusted, and the bed is moved in the y direction so that the first fan-shaped laser passes through the first reference point; The bed is moved in the x direction so that the second fan-shaped laser coincides with the yz plane, and the bed is moved in the z direction until the linear laser beam coincides with the first reference point. And (1) a process of creating an image representing functional information related to the activity of the heart to be examined from the signal of the magnetic field waveform, and (2) the first marker at the first reference point. The pixel size of the image representing the functional information is matched with the pixel size of the morphological image including the heart to be examined, which is arranged and photographed by the imaging device, and is the same as the pixel size of the morphological image Functional image with size pixels A process of creating an image, (3) a process of making the position of the first reference point in the functional image the same as the position of the first reference point in the morphological image, and ( 4) A biomagnetic field measurement apparatus characterized by executing a process of creating a composite image of the functional image and the morphological image, and displaying the composite image on the display means.

6. The biomagnetic field measurement apparatus according to claim 5, wherein the first point is a sword-like projection to be inspected and the second point is a neck notch to be inspected. Biomagnetic field measurement device.