JP6761642B2 - Motion artifact reduction method and dental X-ray CT device using it - Google Patents
Motion artifact reduction method and dental X-ray CT device using it Download PDFInfo
- Publication number
- JP6761642B2 JP6761642B2 JP2016025626A JP2016025626A JP6761642B2 JP 6761642 B2 JP6761642 B2 JP 6761642B2 JP 2016025626 A JP2016025626 A JP 2016025626A JP 2016025626 A JP2016025626 A JP 2016025626A JP 6761642 B2 JP6761642 B2 JP 6761642B2
- Authority
- JP
- Japan
- Prior art keywords
- subject
- ray
- dimensional position
- scan
- position data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims description 16
- 230000009467 reduction Effects 0.000 title description 4
- 238000002591 computed tomography Methods 0.000 claims description 49
- 238000003384 imaging method Methods 0.000 claims description 35
- 238000013170 computed tomography imaging Methods 0.000 claims description 12
- 230000008569 process Effects 0.000 claims description 6
- 230000008859 change Effects 0.000 description 5
- 230000001815 facial effect Effects 0.000 description 5
- 230000007246 mechanism Effects 0.000 description 4
- 238000003825 pressing Methods 0.000 description 3
- 230000002123 temporal effect Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Images
Landscapes
- Apparatus For Radiation Diagnosis (AREA)
Description
本発明はＸ線撮影時に生じるモーションアーチファクトを低減する方法およびこれを用いる歯科用Ｘ線ＣＴ装置に関するものである。 The present invention relates to a method for reducing motion artifacts generated during X-ray imaging and a dental X-ray CT apparatus using the method.
従来、ＣＴ撮影中、被検者の体動により、モーションアーチファクトが発生する。これを軽減するには特許４３１４２６０号に記載されているように、ＣＴ撮影装置に支持部と、該支持部に設けられ被検者の両側頭部を押さえる一対の側頭部押え部と、該側頭部押え部を被検者の側頭部に押当させ且つ押当を解除するように動作させる為の作動機構部と、該作動機構部を押当方向に付勢する付勢手段と、作動機構部を該付勢手段の付勢力に抗して押当解除方向に操作する為の操作部とを備え、被検者（被写体）の頭部をＣＴ撮影装置の撮影個所に剛固に緊締してブレをなくすようにした被検者頭部固定装置がある。 Conventionally, a motion artifact occurs due to the body movement of the subject during CT imaging. To alleviate this, as described in Japanese Patent No. 4314260, the CT imaging device has a support portion, a pair of temporal holding portions provided on the support portion to press both side heads of the subject, and the same. An actuating mechanism for pressing the temporal presser against the subject's temporal region and operating to release the press, and an urging means for urging the actuating mechanism in the pressing direction. The operating mechanism unit is provided with an operation unit for operating the operating mechanism unit in the pressing release direction against the urging force of the urging means, and the head of the subject (subject) is rigidly placed at the imaging location of the CT imaging device. There is a subject head fixing device that is tightened to eliminate blurring.
最近は、特許３７８５５７６号に記載されているように、Ｘ線発生器と、被写体保持手段に保持された被写体を挟んで前記Ｘ線発生器に対向配置されたＸ線撮像器とを備え、被写体のＸ線画像を得る医療用Ｘ線撮影装置で用いられる被写体ブレ補正手段であって、被検者(被写体)のブレを検出するセンサ手段を、前記被写体保持手段上の撮影目的位置の近傍に設置して、この被写体保持手段の基準位置に対する前記撮影目的位置の位置変化量を検出し、Ｘ線撮影中の前記センサ手段による位置変化量の検出情報に基づき前記Ｘ線撮像器で得られた画像のブレ補正を行うようにして被検者（被写体）を左程強く緊締することなく被検者（被写体）のブレを補正することが行われている。 Recently, as described in Patent No. 3785576, an X-ray generator and an X-ray imager arranged to face the X-ray generator with the subject held by the subject holding means sandwiched between the subject are provided. A sensor means for detecting blurring of a subject (subject), which is a subject blur correction means used in a medical X-ray imaging apparatus for obtaining an X-ray image of It was installed, detected the amount of change in the position of the target position for imaging with respect to the reference position of the subject holding means, and obtained by the X-ray imager based on the detection information of the amount of change in the position by the sensor means during X-ray photography. The blurring of the subject (subject) is corrected without tightening the subject (subject) as strongly as to the left by correcting the blur of the image.
更に、特許出願２０１４−１１１９６０号明細書に記載の従来のモーションアーチファクトを低減する方法は、被検者に向けてＸ線を照射するＸ線源と、被検者を通過したＸ線を検出するＸ線撮像手段と、被検者の周りに前記Ｘ線源およびＸ線撮像手段を対向して一体的に支持する旋回アームと、該旋回アームを旋回させるための旋回手段と、該旋回手段を支持する装置フレームとを備える歯科用Ｘ線撮影装置に、リアルタイムスキャン可能な３Ｄスキャナを設置する歯科用Ｘ線ＣＴ撮影装置において、撮影開始時に前記３Ｄスキャナで顔貌の３Ｄデータを取得する工程Ａと、Ｘ線によるＣＴスキャン中に常時３Ｄスキャナで顔貌の３Ｄデータを取得する工程Ｂと、３Ｄスキャナにより得られた前記工程Ａ及び前記工程Ｂから得られた情報から、顔貌の位置変化に応じて、Ｘ線ＣＴスキャンにより取得したプロジェクションデータの再構成演算の補正を行う工程とを設けるようにしている。 Further, the conventional method for reducing motion artifacts described in patent application 2014-111960 detects an X-ray source that irradiates an X-ray toward a subject and an X-ray that has passed through the subject. An X-ray imaging means, a swivel arm that integrally supports the X-ray source and the X-ray imaging means so as to face each other around the subject, a swivel means for swirling the swivel arm, and the swivel means. In a dental X-ray CT imaging device in which a 3D scanner capable of real-time scanning is installed in a dental X-ray imaging device provided with a supporting device frame, a step A of acquiring 3D data of a face with the 3D scanner at the start of imaging. , From the step B that constantly acquires 3D data of the face with a 3D scanner during the CT scan by X-ray, and the information obtained from the step A and the step B obtained by the 3D scanner, according to the position change of the face. , A step of correcting the reconstruction operation of the projection data acquired by the X-ray CT scan is provided.
斯様に、特許出願２０１４−１１１９６０号明細書に記載の従来のモーションアーチファクトを低減する方法は「撮影開始時に前記３Ｄスキャナで顔貌の３Ｄデータを取得する工程Ａ」を実施した後に、「Ｘ線によるＣＴスキャン中に常時３Ｄスキャナで顔貌の３Ｄデータを取得する工程Ｂ」を実施して、「３Ｄスキャナにより得られた前記工程Ａ及び前記工程Ｂから得られた情報から、顔貌の位置変化に応じて、Ｘ線ＣＴスキャンにより取得したプロジェクションデータの再構成演算の補正を行う工程を実施する」ようにしている。
従って、３Ｄスキャナは旋回アームに取付けられ旋回しながら顔貌の３Ｄデータを得る必要があるため、撮影開始時に顔貌の３Ｄデータを取得するためにはＸ線を照射しない状態で被検者の周りを一度旋回する必要があり、改善の余地があった。
Thus, the conventional method for reducing motion artifacts described in Patent Application No. 2014-111960 is "X-ray" after performing "step A of acquiring 3D data of facial features with the 3D scanner at the start of imaging". During the CT scan by the above, the step B of constantly acquiring the 3D data of the face with the 3D scanner is carried out, and the position of the face is changed from the information obtained from the step A and the step B obtained by the 3D scanner. Correspondingly, the step of correcting the reconstruction calculation of the projection data acquired by the X-ray CT scan is carried out. "
Therefore, since the 3D scanner needs to be attached to the swivel arm and obtain 3D data of the facial face while turning, in order to acquire the 3D data of the facial face at the start of shooting, the subject is surrounded by X-rays. It had to turn once and there was room for improvement.
本発明の目的は、上記従来の欠点に鑑みなされたもので、ＣＴ撮影中の被検者の体動による、モーションアーチファクトを軽減すると共に、被検者を強固に位置付けすることなく簡単に容易に撮影することのできるＣＴ撮影方法および装置を提供せんとするにある。 An object of the present invention has been made in view of the above-mentioned conventional drawbacks, and it is easy and easy to reduce motion artifacts caused by the body movement of the subject during CT imaging without firmly positioning the subject. It is intended to provide a CT imaging method and apparatus capable of imaging.
上記目的を達成するために、本発明歯科用Ｘ線ＣＴ装置のモーションアーチファクト低減方法は、被検者に向けてＸ線を照射するＸ線源と、被検者を通過したＸ線を検出するＸ線撮像手段と、被検者の周りに前記Ｘ線源およびＸ線撮像手段を対向して一体的に支持する旋回アームと、該旋回アームを旋回させるための旋回手段と、該旋回手段を支持する装置フレームと、を備える歯科用Ｘ線ＣＴ撮影装置において、被検者に対して固定された位置から被検者の３次元位置データをリアルタイムに取得可能な３次元位置入力手段を具備し、前記３次元位置入力手段は、顔貌に帯状のレーザを発振し、顔の凹凸によって変化するレーザの縞パターンをＣＣＤカメラで撮影する手段であって、Ｘ線によるＣＴスキャン中に、同時に前記３次元位置入力手段によって被検者頭部の３次元位置データを取得する工程と、撮影終了後に、Ｘ線によるＣＴスキャン開始時の被検者の３次元位置データと、ＣＴスキャン中に得られた３次元位置データとを比較する工程と、比較した３次元位置データを基に、Ｘ線ＣＴスキャンにより取得したプロジェクションデータの再構成演算の補正を行う工程とを設け、前記被験者に対して固定された位置を、前記旋回手段を支持する装置フレームのＸ線源やＸ線撮像装置の旋回の邪魔にならない下方、或いは上方から患者の頭部を望むように配置した位置とし、前記補正を行う工程はＣＴスキャン中に得られた３次元位置データが変化した場合に、ＣＴスキャン開始時の被検者頭部の位置データにＸ線源からのＸ線を投影したかのように、Ｘ線ＣＴスキャンにより取得したプロジェクションデータを補正して、ＣＴ再構成時に、逆投影演算を行うことを特徴とする。 In order to achieve the above object, the motion artifact reduction method of the dental X-ray CT apparatus of the present invention detects an X-ray source that irradiates an X-ray toward a subject and an X-ray that has passed through the subject. The X-ray imaging means, the swivel arm that integrally supports the X-ray source and the X-ray imaging means so as to face each other around the subject, the swivel means for swirling the swivel arm, and the swivel means. A dental X-ray CT imaging apparatus including a supporting device frame includes a three-dimensional position input means capable of acquiring three-dimensional position data of the subject in real time from a position fixed to the subject. The three-dimensional position input means is a means for oscillating a band-shaped laser on the face and photographing a striped pattern of the laser that changes due to the unevenness of the face with a CCD camera, and at the same time during a CT scan using X-rays, the above 3 The process of acquiring the three-dimensional position data of the subject's head by the dimensional position input means, the three-dimensional position data of the subject at the start of CT scan by X-ray after the completion of imaging, and the three-dimensional position data obtained during the CT scan. A step of comparing with the three-dimensional position data and a step of correcting the reconstruction operation of the projection data acquired by the X-ray CT scan based on the compared three-dimensional position data are provided and fixed to the subject. The step of performing the correction by setting the position so as to view the patient's head from below or above so as not to interfere with the rotation of the X-ray source of the device frame supporting the rotation means or the rotation of the X-ray imaging device. X-ray CT as if X-rays from the X-ray source were projected onto the position data of the subject's head at the start of the CT scan when the three-dimensional position data obtained during the CT scan changed. It is characterized in that the projection data acquired by scanning is corrected and a back projection calculation is performed at the time of CT reconstruction.
又、本発明方法では、前記固定された位置を歯科用Ｘ線ＣＴ撮影装置の旋回手段を支持する装置フレーム、又は歯科用Ｘ線ＣＴ撮影装置外の被検者頭部を確認できる位置とすることを特徴とする。
前記補正を行う工程はＣＴスキャン中に得られた３次元位置データが変化した場合に、ＣＴスキャン開始時の被検者頭部の位置データにＸ線源からのＸ線を投影したかのように、Ｘ線ＣＴスキャンにより取得したプロジェクションデータを補正して、ＣＴ再構成時に、逆投影演算を行い得るようにする。
Further, in the method of the present invention, the fixed position is set to a position where the device frame supporting the turning means of the dental X-ray CT imaging device or the subject's head outside the dental X-ray CT imaging device can be confirmed. It is characterized by that.
The step of performing the correction is as if X-rays from the X-ray source were projected on the position data of the subject's head at the start of the CT scan when the three-dimensional position data obtained during the CT scan changed. In addition, the projection data acquired by the X-ray CT scan is corrected so that the back projection calculation can be performed at the time of CT reconstruction.
本発明歯科用Ｘ線ＣＴ装置は、被検者に向けてＸ線を照射するＸ線源と、被検者を通過したＸ線を検出するＸ線撮像手段と、被検者の周りに前記Ｘ線源およびＸ線撮像手段を対向して一体的に支持する旋回アームと、該旋回アームを旋回させるための旋回手段と、該旋回手段を支持する装置フレームとを備える歯科用Ｘ線ＣＴ撮影装置に於いて、被検者に対して固定された位置から被検者の３次元位置データをリアルタイムに取得可能な３次元位置入力手段を具備し、前記３次元位置入力手段は、顔貌に帯状のレーザを発振し、顔の凹凸によって変化するレーザの縞パターンをＣＣＤカメラで撮影する手段であって、Ｘ線によるＣＴスキャン中に、同時に前記３次元位置入力手段により被検者頭部の３次元位置データを取得する手段と、撮影終了後に、Ｘ線によるＣＴスキャン開始時の被検者の３次元位置データおよびＣＴスキャン中に得られた３次元位置データを比較する手段と、該比較した３次元位置データを基に、Ｘ線ＣＴスキャンにより取得したプロジェクションデータの再構成演算の補正を行う手段とを設けて被検者の動きによるモーションアーチファクトを軽減するようにし、前記被験者に対して固定された位置を、前記旋回手段を支持する装置フレームのＸ線源やＸ線撮像装置の旋回の邪魔にならない下方、或いは上方から患者の頭部を望むように配置した位置とすることにより構成したことを特徴とする The dental X-ray CT apparatus of the present invention includes an X-ray source that irradiates an X-ray toward a subject, an X-ray imaging means that detects X-rays that have passed through the subject, and the surroundings of the subject. Dental X-ray CT imaging including a swivel arm that integrally supports an X-ray source and an X-ray imaging means facing each other, a swivel means for swiveling the swivel arm, and a device frame that supports the swivel means. The apparatus includes a three-dimensional position input means capable of acquiring the three-dimensional position data of the subject in real time from a position fixed to the subject, and the three-dimensional position input means has a band shape on the face. It is a means for oscillating the laser of the above and photographing the stripe pattern of the laser that changes due to the unevenness of the face with a CCD camera, and at the same time during the CT scan by X-ray, the 3D position input means of the subject's head 3 The comparison was made between a means for acquiring the dimensional position data and a means for comparing the three-dimensional position data of the subject at the start of the CT scan with X-rays and the three-dimensional position data obtained during the CT scan after the end of imaging. Based on the three-dimensional position data, a means for correcting the reconstruction calculation of the projection data acquired by the X-ray CT scan is provided to reduce the motion artifact due to the movement of the subject, and the motion artifact is fixed to the subject. This position is configured by arranging the patient's head as desired from below or above so as not to interfere with the rotation of the X-ray source of the device frame supporting the turning means or the rotation of the X-ray imaging device. Characterized by
上述したように、本発明によれば、再構成画像からモーションアーチファクトを除去することが可能である。その上、本発明ではコーンビームＣＴの撮影中に被検者の体動を、固定位置からカメラなどを用いて撮影し、被検者の頭部の動きをＸ線撮影と同期して記録しておく。 As described above, according to the present invention, it is possible to remove motion artifacts from the reconstructed image. Further, in the present invention, the body movement of the subject is photographed from a fixed position using a camera or the like during the imaging of the cone beam CT, and the movement of the subject's head is recorded in synchronization with the X-ray imaging. Keep it.
被検者頭部の体動を、Ｘ線撮影された単純撮影画像と同期させ、被検者頭部の体動が生じた場合の被検者の体動後の位置を、Ｘ線によるＣＴスキャン開始時の被検者の位置（撮影時に位置付けされた位置）と比較して、ズレ分の角度・位置を把握して、補正パラメータとして加えて計算を行う。 The body movement of the subject's head is synchronized with the simple radiographed image, and the position after the body movement of the subject when the body movement of the subject's head occurs is CT by X-ray. Compared with the position of the subject at the start of scanning (the position positioned at the time of shooting), the angle and position of the deviation are grasped, and the calculation is performed by adding it as a correction parameter.
なお、被検者の体動後の位置は、被検者の体動前の位置と比較して相対的にズレ分の角度・位置を把握して、補正パラメータとして加えて計算を行ってもよい。
つまり、Ｘ線によるＣＴスキャン開始時の被検者の位置データ（体動前の位置データを含む）にＸ線源からのＸ線を投影したかのように、ＣＴスキャン中に取得されたＸ線の投影データを移動補正して逆投影処理を施し再構成演算を実施する。
It should be noted that the position of the subject after the body movement can be calculated by grasping the angle and position of the deviation relative to the position before the body movement of the subject and adding it as a correction parameter. Good.
That is, the X acquired during the CT scan is as if the X-ray from the X-ray source was projected onto the position data (including the position data before the body movement) of the subject at the start of the CT scan by X-ray. The line projection data is moved and corrected, back projection processing is performed, and a reconstruction operation is performed.
以下、本発明の実施の形態を図に基いて説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
図面を参照し本発明を説明する。図１および図２に示すように、被検者１に向けてＸ線を照射するＸ線源２と、被検者を通過したＸ線を検出するＸ線撮像手段３と、被検者の周りに前記Ｘ線源２およびＸ線撮像手段３を対向して一体的に支持する旋回アーム４aと、該旋回アームを旋回させるための旋回手段４と、該旋回手段４を支持する装置フレーム(図１には示さないが図２に２５で示す)とを備える歯科用Ｘ線撮影装置において、被検者１に対して固定された位置から被検者の３次元位置データをリアルタイムに取得可能な３次元位置入力手段１０を設け、Ｘ線によるＣＴスキャン中に、同時に前記３次元位置入力手段１０によって被検者頭部の３次元位置データを取得し、第１スイッチ２２又は第２スイッチ２３を経て３Ｄ（三次元）画像メモリ１１又は２４に記憶させ、撮影終了後に、Ｘ線によるＣＴスキャン開始時に第１スイッチ２２を経て３Ｄ画像メモリ１１に記憶した被検者の３次元位置データと、ＣＴスキャン中に第２スイッチ２３を経て３Ｄ画像メモリ２４に常時得られた３次元位置データとを比較手段２０にて比較し、該比較した３次元位置データを基に、補正手段８にてＸ線ＣＴスキャンにより取得したプロジェクションデータの再構成演算の補正を行うようにする。 The present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the X-ray source 2 that irradiates the subject 1 with X-rays, the X-ray imaging means 3 that detects the X-rays that have passed through the subject, and the subject's A swivel arm 4a that integrally supports the X-ray source 2 and the X-ray imaging means 3 so as to face each other, a swivel means 4 for swiveling the swivel arm, and a device frame that supports the swivel means 4 ( In a dental X-ray imaging device provided with (not shown in FIG. 1 but shown in FIG. 2), it is possible to acquire the three-dimensional position data of the subject in real time from a position fixed to the subject 1. The three-dimensional position input means 10 is provided, and at the same time, the three-dimensional position input means 10 acquires the three-dimensional position data of the subject's head during the CT scan by X-ray, and the first switch 22 or the second switch 23 The three-dimensional position data of the subject stored in the 3D (three-dimensional) image memory 11 or 24 through the above, and stored in the 3D image memory 11 via the first switch 22 at the start of CT scanning by X-ray after the completion of imaging. The three-dimensional position data constantly obtained in the 3D image memory 24 via the second switch 23 during the CT scan is compared by the comparison means 20, and based on the compared three-dimensional position data, the correction means 8 X. The reconstruction operation of the projection data acquired by the line CT scan is corrected.
即ち、この３次元位置入力手段１０によって被検者の３次元位置データを取得し、Ｘ線ＣＴスキャン開始直後に第１スイッチ２２をＯＮ状態にしてＸ線ＣＴスキャン開始直後の３次元位置データを３Ｄ画像メモリ１１に供給し、次いで比較手段２０に供給する。 That is, the three-dimensional position data of the subject is acquired by the three-dimensional position input means 10, the first switch 22 is turned on immediately after the start of the X-ray CT scan, and the three-dimensional position data immediately after the start of the X-ray CT scan is input. It is supplied to the 3D image memory 11 and then to the comparison means 20.
その後、第１スイッチ２２をオフ状態にし、第２スイッチ２３をオン状態にし、Ｘ線によるＣＴスキャンを行い、このＣＴスキャン中にも常時３次元位置入力手段１０によって被検者体動の３次元位置データを取得し、この３次元位置データは第２スイッチ２３を経て３Ｄ画像メモリ２４に供給し、次いで比較手段２０に供給する。比較手段２０では、３Ｄ画像メモリ１１と３Ｄ画像メモリ２４の位置データを比較し、角度や位置が異なる場合は角度や位置の違いを補正情報として補正手段８に供給し、補正手段８および再構成演算手段１６にてＸ線ＣＴスキャンにより取得したプロジェクションデータの再構成演算の補正を行うようにする。 After that, the first switch 22 is turned off, the second switch 23 is turned on, and a CT scan using X-rays is performed. Even during this CT scan, the three-dimensional position input means 10 constantly performs the three-dimensional movement of the subject. The position data is acquired, and the three-dimensional position data is supplied to the 3D image memory 24 via the second switch 23, and then to the comparison means 20. The comparison means 20 compares the position data of the 3D image memory 11 and the 3D image memory 24, and if the angles and positions are different, the difference in the angles and positions is supplied to the correction means 8 as correction information, and the correction means 8 and the reconstruction means 8 and the reconstruction means 8. The calculation means 16 corrects the reconstruction calculation of the projection data acquired by the X-ray CT scan.
図１および図２を参照し明らかなように、比較手段２０では、Ｘ線ＣＴスキャン開始直後に取得され、第１スイッチ２２を経て３Ｄ画像メモリ１１に記憶された被検者の３次元位置データと、第２スイッチ２３を経、且つ３Ｄ画像メモリ２４に常時供給されてＸ線ＣＴスキャン中に常時得られた被検者の３次元位置データとを比較し、被検者体動の位置変化を監視する。 As is clear with reference to FIGS. 1 and 2, in the comparison means 20, the three-dimensional position data of the subject acquired immediately after the start of the X-ray CT scan and stored in the 3D image memory 11 via the first switch 22. And the 3D position data of the subject, which is constantly supplied to the 3D image memory 24 through the second switch 23 and constantly obtained during the X-ray CT scan, and the position change of the subject's body movement. To monitor.
この際、図２（ａ），（ｂ），（ｃ）に示すように、Ｘ線ＣＴスキャン開始直後に取得した被検者の動きの３次元位置データと、Ｘ線ＣＴスキャン中に取得した被検者の動きの３次元位置データとの角度・位置情報に違いがある場合は以下に示すように処理する。
ａ：被検者の動きに応じ、補正手段８で、被検者の動きに対するＸ線の入射角および位置を三角測距の原理を用いて算出する。被検者の位置がＸ線ＣＴスキャン開始時の被検者の位置と異なる場合は、入射角・位置関係の差分を補正するように再構成演算手段１６にてＣＴスキャンによって取得したプロジェクションデータに逆投影処理を施して再構成演算を実施する。
すなわち、あたかもＸ線ＣＴスキャン開始直後に取得した位置データにＸ線源からのＸ線を投影したかのように、ＣＴスキャン中に取得したＸ線投影データを入射角度差分だけ移動補正して逆投影処理を施して再構成演算を実施する。その際プロジェクションデータに周波数窓関数によるフィルタリング処理を行なえば適宜ボケ部を削除することができる。
ｂ：ａの方式において補正不能な顔貌の位置変化が生じた場合には、ＣＴスキャンを即座に停止することもできる。
At this time, as shown in FIGS. 2A, 2B, and 2C, the three-dimensional position data of the movement of the subject acquired immediately after the start of the X-ray CT scan and the three-dimensional position data acquired during the X-ray CT scan. If there is a difference in the angle / position information from the three-dimensional position data of the movement of the subject, it is processed as shown below.
a: According to the movement of the subject, the correction means 8 calculates the incident angle and position of the X-ray with respect to the movement of the subject by using the principle of triangular ranging. If the position of the subject is different from the position of the subject at the start of the X-ray CT scan, the projection data acquired by the CT scan by the reconstruction calculation means 16 is used to correct the difference in the incident angle / positional relationship. The back projection process is performed and the reconstruction operation is performed.
That is, the X-ray projection data acquired during the CT scan is moved and corrected by the incident angle difference, as if the X-rays from the X-ray source were projected onto the position data acquired immediately after the start of the X-ray CT scan. The reconstruction process is performed by performing the projection process. At that time, if the projection data is filtered by the frequency window function, the blurred portion can be appropriately deleted.
b: When an uncorrectable facial position change occurs in the method a, the CT scan can be stopped immediately.
図１を参照し、Ｘ線ＣＴスキャンによって得られたコーンビームＣＴ画像の処理は、以下のように行う。
本発明では、Ｘ線撮像手段３からＡ／Ｄ変換手段５を経て大容量フレーム画像記憶手段６に記憶されたＸ線撮影データは、比較手段２０からの補正情報がない場合は、補正手段では何もせず、大容量フレーム画像記憶手段６からのフレーム画像の逆投影処理を行って再構成演算手段１６に供給し、更には処理画像記憶手段１７に供給し再構成画像を記憶する。
ここで比較手段２０からの補正情報がある場合は、補正手段８によって補正されたフレーム画像の逆投影処理を再構成演算手段１６で行って、処理画像記憶手段１７に供給し、再構成した画像を記憶する。記憶された再構成画像は画像表示記憶手段１８を経て処理された画像を表示記憶し、出力手段１９に供給し、表示手段(図示なし)に所望のコーンビームＣＴ画像を得るようにしている。
With reference to FIG. 1, the processing of the cone beam CT image obtained by the X-ray CT scan is performed as follows.
In the present invention, the X-ray imaging data stored in the large-capacity frame image storage means 6 from the X-ray imaging means 3 via the A / D conversion means 5 is a correction means when there is no correction information from the comparison means 20. Without doing anything, the frame image is back-projected from the large-capacity frame image storage means 6 and supplied to the reconstruction calculation means 16, and further supplied to the processed image storage means 17 to store the reconstructed image.
Here, if there is correction information from the comparison means 20, the back projection process of the frame image corrected by the correction means 8 is performed by the reconstruction calculation means 16, and the image is supplied to the processed image storage means 17 and reconstructed. Remember. The stored reconstructed image displays and stores an image processed through the image display storage means 18, supplies the output means 19, and causes the display means (not shown) to obtain a desired cone beam CT image.
上述した例では、被検者の頭部位置を表示するのに、３次元位置入力手段は３次元スキャナを使用して構成できるが、本発明において、特に３次元位置入力手段としては、顔貌に帯状のレーザを発振し、顔の凹凸によって変化するレーザの縞パターンをＣＣＤカメラで撮影することで三次元データが得られる三次元レジストレータ又はステレオカメラを用いるのが好適である。 In the above example, the three-dimensional position input means can be configured by using a three-dimensional scanner to display the head position of the subject, but in the present invention , particularly as the three- dimensional position input means, the facial appearance It is preferable to use a three-dimensional resister or a stereo camera that can obtain three-dimensional data by oscillating a band-shaped laser and photographing the stripe pattern of the laser that changes depending on the unevenness of the face with a CCD camera.
１ 被検者
２ Ｘ線源
３ Ｘ線撮像手段
４ 旋回手段
４ａ 旋回アーム
５ Ａ／Ｄ変換器
６ 大容量フレーム画像記憶手段
８ 補正手段
９ 補綴物
１０ ３次元位置入力手段
１１ ３Ｄ画像メモリ
１６ 再構成演算手段
１７ 処理画像記憶手段
１８ 画像表示記憶手段
１９ 出力手段
２０ 比較手段
２２ 第１スイッチ
２３ 第２スイッチ
２４ ３Ｄ画像メモリ
２５ 装置フレーム
1 Subject 2 X-ray source 3 X-ray imaging means 4 Swivel means 4a Swivel arm 5 A / D converter 6 Large-capacity frame image storage means 8 Correction means 9
Claims (2)
前記被験者に対して固定された位置を、前記旋回手段を支持する装置フレームのＸ線源やＸ線撮像装置の旋回の邪魔にならない下方、或いは上方から患者の頭部を望むように配置した位置とし、前記補正を行う工程はＣＴスキャン中に得られた３次元位置データが変化した場合に、ＣＴスキャン開始時の被検者頭部の位置データにＸ線源からのＸ線を投影したかのように、Ｘ線ＣＴスキャンにより取得したプロジェクションデータを補正して、ＣＴ再構成時に、逆投影演算を行うことを特徴とする歯科用Ｘ線ＣＴ装置のモーションアーチファクト低減方法。 An X-ray source that irradiates an X-ray toward a subject, an X-ray imaging means that detects X-rays that have passed through the subject, and the X-ray source and the X-ray imaging means facing each other around the subject. In a dental X-ray CT imaging device including a swivel arm that integrally supports the swivel arm, a swivel means for swiveling the swivel arm, and a device frame that supports the swivel means, the subject is A three-dimensional position input means capable of acquiring three-dimensional position data of a subject in real time from a fixed position is provided, and the three-dimensional position input means oscillates a band-shaped laser on the face and changes depending on the unevenness of the face. It is a means for photographing the fringe pattern of the laser to be performed with a CCD camera, and is a step of simultaneously acquiring the three-dimensional position data of the subject's head by the three-dimensional position input means during CT scanning by X-ray, and the end of imaging. Later, based on the step of comparing the three-dimensional position data of the subject at the start of the CT scan with X-rays and the three-dimensional position data obtained during the CT scan, and the compared three-dimensional position data, X-rays are taken. A process for correcting the reconstruction operation of the projection data acquired by CT scan is provided .
A position fixed to the subject so as to view the patient's head from below or above so as not to interfere with the rotation of the X-ray source of the device frame supporting the turning means or the rotation of the X-ray imaging device. Then, in the step of performing the correction, when the three-dimensional position data obtained during the CT scan changes, is the X-ray from the X-ray source projected onto the position data of the subject's head at the start of the CT scan? A method for reducing motion artifacts in a dental X-ray CT apparatus, which comprises correcting projection data acquired by an X-ray CT scan and performing a back-projection calculation at the time of CT reconstruction.
前記被験者に対して固定された位置を、前記旋回手段を支持する装置フレームのＸ線源やＸ線撮像装置の旋回の邪魔にならない下方、或いは上方から患者の頭部を望むように配置した位置とすることにより構成したことを特徴とする歯科用Ｘ線ＣＴ装置。 An X-ray source that irradiates an X-ray toward a subject, an X-ray imaging means that detects X-rays that have passed through the subject, and the X-ray source and the X-ray imaging means facing each other around the subject. In a dental X-ray CT imaging device provided with a swivel arm that integrally supports the swivel arm, a swivel means for swiveling the swivel arm, and a device frame that supports the swivel means, the subject is The three-dimensional position input means capable of acquiring the three-dimensional position data of the subject in real time from the fixed position is provided, and the three-dimensional position input means oscillates a band-shaped laser on the face and causes the unevenness of the face. A means for photographing a changing laser stripe pattern with a CCD camera, and a means for simultaneously acquiring three-dimensional position data of the subject's head by the three-dimensional position input means during a CT scan using X-rays, and an image After the end, X-rays are based on the means for comparing the three-dimensional position data of the subject at the start of the CT scan by X-ray and the three-dimensional position data obtained during the CT scan, and the compared three-dimensional position data. A means for correcting the reconstruction operation of the projection data acquired by CT scan is provided to reduce motion artifacts due to the movement of the subject .
A position fixed to the subject so as to view the patient's head from below or above so as not to interfere with the rotation of the X-ray source of the device frame supporting the rotation means or the rotation of the X-ray imaging device. A dental X-ray CT apparatus characterized by the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016025626A JP6761642B2 (en) | 2016-02-15 | 2016-02-15 | Motion artifact reduction method and dental X-ray CT device using it |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016025626A JP6761642B2 (en) | 2016-02-15 | 2016-02-15 | Motion artifact reduction method and dental X-ray CT device using it |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2017143873A JP2017143873A (en) | 2017-08-24 |
| JP6761642B2 true JP6761642B2 (en) | 2020-09-30 |
Family
ID=59680996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2016025626A Active JP6761642B2 (en) | 2016-02-15 | 2016-02-15 | Motion artifact reduction method and dental X-ray CT device using it |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6761642B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20230149128A1 (en) * | 2021-11-18 | 2023-05-18 | Orca Dental AI Ltd. | Method for Simulating Dental Images that Include Tooth Roots |
| CN115005860B (en) * | 2022-08-03 | 2022-11-15 | 有方（合肥）医疗科技有限公司 | Method and device for reducing oral and maxillofacial CBCT imaging motion artifacts |
-
2016
- 2016-02-15 JP JP2016025626A patent/JP6761642B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2017143873A (en) | 2017-08-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5019879B2 (en) | X-ray CT apparatus, image processing program, and image processing method | |
| WO2013005833A1 (en) | X-ray imaging device and calibration method therefor | |
| JP6363016B2 (en) | X-ray equipment | |
| JP4594783B2 (en) | Cone beam X-ray CT imaging system | |
| JP2002219127A (en) | Panoramic x-ray ct photographing device | |
| JP6761642B2 (en) | Motion artifact reduction method and dental X-ray CT device using it | |
| JP3540916B2 (en) | 3D X-ray CT system | |
| JP5379998B2 (en) | X-ray CT apparatus and object positioning method in X-ray CT apparatus | |
| JP2006204329A (en) | X-ray tomographic equipment | |
| JP4861037B2 (en) | Measuring device | |
| JP2006034579A (en) | Method and device for controlling radiation irradiation, and program | |
| JP2008253569A (en) | Apparatus and method for detecting abnormal body movement | |
| US20100171822A1 (en) | Tomographic image capturing apparatus and tomographic image capturing method | |
| KR102180602B1 (en) | Cephalo X-ray image acquisition device capable of obtaining 3D facial optical images and cephalo X-ray images | |
| JP6401498B2 (en) | Dental X-ray CT imaging method | |
| JP2010158299A (en) | Tomographic image capturing apparatus and tomographic image capturing method | |
| JP7245783B2 (en) | Computed tomography and positioning of the imaged volume | |
| JP2006130060A (en) | X-ray ct apparatus | |
| JP6401499B2 (en) | Motion artifact reduction method in dental tomography apparatus | |
| US20180322665A1 (en) | Dynamic Image Data Treatment in Dental Imaging Devices | |
| US20220101570A1 (en) | Method and apparatus for generating x-ray image and computer-readable recording medium | |
| JP5415885B2 (en) | Radiation CT apparatus and image processing apparatus | |
| KR20170105753A (en) | null | |
| KR102203610B1 (en) | Method and Apparatus for generating panoramic image, computer-readable recording medium | |
| JP6760510B2 (en) | Radiation imaging device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20190111 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20191016 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20191126 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20200115 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20200317 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20200413 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20200902 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20200907 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6761642 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |