WO2009149991A1 - Procédé et dispositif de génération d'une image radiographique complète composée d’images partielles - Google Patents

Procédé et dispositif de génération d'une image radiographique complète composée d’images partielles Download PDF

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Publication number
WO2009149991A1
WO2009149991A1 PCT/EP2009/055293 EP2009055293W WO2009149991A1 WO 2009149991 A1 WO2009149991 A1 WO 2009149991A1 EP 2009055293 W EP2009055293 W EP 2009055293W WO 2009149991 A1 WO2009149991 A1 WO 2009149991A1
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WO
WIPO (PCT)
Prior art keywords
ray
movement
detector
ray source
positions
Prior art date
Application number
PCT/EP2009/055293
Other languages
German (de)
English (en)
Inventor
Andrea Zandegiacomo
Thomas Pohl
Helmuth Schramm
Original Assignee
Siemens Ag Österreich
Siemens Aktiengesellschaft
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Siemens Ag Österreich, Siemens Aktiengesellschaft filed Critical Siemens Ag Österreich
Publication of WO2009149991A1 publication Critical patent/WO2009149991A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/44—Constructional features of apparatus for radiation diagnosis
    • A61B6/4429—Constructional features of apparatus for radiation diagnosis related to the mounting of source units and detector units
    • A61B6/4435—Constructional features of apparatus for radiation diagnosis related to the mounting of source units and detector units the source unit and the detector unit being coupled by a rigid structure
    • A61B6/4441—Constructional features of apparatus for radiation diagnosis related to the mounting of source units and detector units the source unit and the detector unit being coupled by a rigid structure the rigid structure being a C-arm or U-arm
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/40—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis
    • A61B6/4021—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis involving movement of the focal spot
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/44—Constructional features of apparatus for radiation diagnosis
    • A61B6/4476—Constructional features of apparatus for radiation diagnosis related to motor-assisted motion of the source unit
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/52—Devices using data or image processing specially adapted for radiation diagnosis
    • A61B6/5211—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data
    • A61B6/5229—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data combining image data of a patient, e.g. combining a functional image with an anatomical image
    • A61B6/5235—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data combining image data of a patient, e.g. combining a functional image with an anatomical image combining images from the same or different ionising radiation imaging techniques, e.g. PET and CT
    • A61B6/5241—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data combining image data of a patient, e.g. combining a functional image with an anatomical image combining images from the same or different ionising radiation imaging techniques, e.g. PET and CT combining overlapping images of the same imaging modality, e.g. by stitching

Definitions

  • the present invention relates to a method and an apparatus for producing a sequence of partial images, which in an assembled form yield an overall X-ray image of an examination object, wherein a drive system moves an X-ray source stepwise into recording positions in order to emit in each case an X-ray beam , which is detected by a detector system as a radiation image after penetration of a sub-region of the examination subject.
  • the examination area is displayed stepwise, and the individual partial images are combined by means of a digital image processing system to form an X-ray overall image.
  • the quality of this calculated total X-ray image depends crucially on the receiving position in which the X-ray source is located when a partial image is taken.
  • Examined object is illuminated from different directions and is thus projected at different positions on the recording plane of the detector.
  • distortions i. a blurring at the seams of the individual partial images.
  • the distortion is the greater, the sharper the angle of entry of the X-rays is on the receiving plane, that is, the smaller the distance between the X-ray source and the detector.
  • this distortion can be computationally difficult to correct.
  • the X-ray source for taking the individual X-ray partial images is pivoted by a certain angle, but is fixed locally.
  • the disadvantage here is that the pivoting causes a slanting radiation, which again in particular in the edge regions of the beam cone, the objects lying one above the other in the examination object lying on the detector as lying side by side.
  • Projection error is again a distortion, which is the greater, the smaller the distance between the X-ray source and the recording plane.
  • Affect image quality of the overall X-ray image and represent a source of error that may lead to incorrect diagnostics.
  • the smallest possible distance between the radiation source and the detector is desirable, since the available room height in a treatment room is usually limited to less than 300 cm.
  • a drive system for the production of the individual partial recordings, respectively positions the X-ray source in recording positions, the positioning movement being composed of a linear movement and of a pivoting movement of the X-ray source.
  • the X-ray source is thus displaced laterally relative to the examination subject in several steps by a predeterminable distance and rotated by a predeterminable rotational or pivotal angle. This ensures that the parallax effect is less strong effect.
  • By suitably specifying the distance and the swivel angle it is possible to substantially reduce the distance between the X-ray source and the detector, without the quality of the overall X-ray image being greatly impaired. Ceiling mounting of the X-ray machine in conventional treatment rooms is possible.
  • the drive system automatically predefines the step size and the angle of rotation when the X-ray source moves into a pickup position. As a result, no manual actions for taking the sub-picture sequence are required.
  • the geometric dimensions of the examination object are taken into account when specifying the step size and the angle of rotation. This can for example be done so that the size of the area of interest to be examined is input to controls of the drive system.
  • the drive system then calculates from the distance between the X-ray source and the examination subject, as well as from the travel paths of the X-ray source and the detector, a favorable angle of rotation with regard to the quality of the overall image.
  • Short movement times can be achieved in particular if the linear movement and the rotational movement are performed simultaneously.
  • the linear movement takes place in the direction of a longitudinal axis, which is substantially parallel to a longitudinal axis of the examination subject.
  • the rotational movement about a pivot axis, which is arranged perpendicular to the longitudinal axis.
  • adjacent receiving positions each differ by an equal step size.
  • the specification of an equal step size is technically simple.
  • the distance between adjacent receiving positions is not equal but is set to a different size. This allows a particular area of interest, such as a particular portion of the spine, to be shifted out of a fuzzy interface area into a central area of a partial image. This can do that
  • the detector system has a flat detector which can be displaced by means of the drive system in a receiving plane.
  • the displacement in detector recording positions is carried out synchronously, ie simultaneously with the positioning movement of the x-ray source.
  • the movement of the flat detector takes place in such a way that the individual consecutive partial images overlap.
  • the overlap width is chosen so that the individual partial images can be merged to form an overall picture.
  • the drive device is given a driving profile that continuously rises or falls, so that the reaction torque during the acceleration phase or during the deceleration phase of the X-ray source is as low as possible ,
  • FIG. 1 shows a three-dimensional sketch of a first embodiment of the invention, in which the X-ray radiation directed onto an examination subject is shown.
  • Radiation source can be seen in three recording positions, each of these recording positions is approached by a positioning movement, which is composed of a linear movement and a rotational or pivotal movement of the X-ray source;
  • Figure 2 is a representation of the beam path of an X-ray source in four receiving positions, according to a second embodiment of the invention
  • Figure 3 is an illustration of the beam path of an X-ray source in four recording positions, wherein the recording positions are respectively occupied by a local displacement of the X-ray source, according to the prior art;
  • FIG. 4 shows a representation of the beam path of an X-ray source in four recording positions, wherein the recording positions are taken by a pivoting movement of a stationary X-ray source, wherein the distance between X-ray source and detector is 300 cm, according to the prior art;
  • Figure 5 is a view according to Figure 4, wherein the distance between the X-ray source and detector is 180 cm.
  • FIG. 1 shows an X-ray source 1 in three recording positions Pl, P2 and P3, in each of which a conical X-ray beam 4 is emitted.
  • the examination beam 2 is located in a receiving plane 12.
  • the X-ray source 1 is displaceable by means of an electric drive system 14 not shown here along the axis 6 (double arrow 8) and about the axis 5 pivotally mounted.
  • the axis 6 is approximately parallel to the longitudinal axis 9 of the examination subject 2 and passes through the focal point (focus) of the X-ray source 1.
  • the distance between the X-ray source 1 and the receiving plane 12 is indicated by the arrow SID.
  • the detector system 3 consists of a flat detector which is displaceable in the direction of the arrow 15.
  • the step size of the detector system 3 is in this example the same size with the step size of the linear displacement of the X-ray source 1 ( ⁇ sl or ⁇ s2).
  • the sequence of partial images can be recorded according to the arrow 8 from left to right or from right to left.
  • the displacement of the X-ray source 1 between adjacent pick-up positions, eg between Pl and P2, or between P2 and P3 involves a translation and a rotation.
  • This type of stepwise displacement of the X-ray source 1 combines, so to speak, the movement processes of the above-mentioned known methods, in which either only one translation or only one rotation of the X-ray source 1 is performed.
  • Pickup position P2 shifts (linear movement according to the arrow 8 to the right). This displacement takes place by the drive system 14. The distance traveled in this translation is the step size ⁇ sl. A rotary movement comes to this linear movement: the X-ray source 1 is rotated by the angle ⁇ l clockwise. The longitudinal movement and the rotational movement preferably occur simultaneously during the positioning process; however, the two movements can also be performed one behind the other. As soon as the X-ray source 1 is in the position P2, a cone-shaped X-ray beam 4 is emitted again for the purpose of taking a second partial image. This X-ray beam 4 is now directed to a central sub-area of the examination object 2.
  • the X-ray source 1 is shifted from the pickup position P2 to the pickup position P3.
  • the X-ray emitter 1 again covers a linear movement with the step size ⁇ s2 and the emitter 1 with respect to the rotational position in P2 by the angle of rotation ⁇ 2 in FIG Pivoted clockwise.
  • the X-ray source 1 is tilted by the angle ⁇ l + ⁇ 2.
  • the angle between the longitudinal axis 6 and the axis 7 (central ray) of the radiation beam 4 is shown in FIG. 1 with ⁇ 1, ⁇ 2, ⁇ 3.
  • Adjacent recording positions are laterally offset by the step size .DELTA.sl or .DELTA.s2 and rotated by the rotational angle .DELTA..phi..sub.1 or .DELTA..phi.2.
  • the detector system 3 detects the individual partial images 11 of the examination object 2.
  • the image information provided by the detector system 3 is generated in a conventional manner by means of an image processing device, not shown here, an overall X-ray image 13 (see FIG. 2) of the examination subject 2 created.
  • the reconstruction of a two-dimensional overall image from a sequence of overlapping two-dimensional partial images takes place digitally. Both methods and devices of the digital image composition are well known and need not be further explained here for the understanding of the present invention.
  • the technical design of the detector system 3 may be different, for example, a sheet-shaped solid state detector (scintillator), which is slidably mounted in the plane 12 and synchronously with the
  • the detector system 3 can also comprise a DLR cassette, an X-ray storage film, a conventional X-ray film, or another suitable sheet-like recording medium.
  • the step size and angle of rotation can vary from one position to another. Is advantageous in particular an adaptation to the size of the examination subject 2, or to areas of particular anatomical interest, which can be done by corresponding input to controls not shown here, the drive system 14.
  • FIG. 2 shows a representation of the beam path of an X-ray source in four recording positions Pl, P2, P3, P4, according to a second embodiment of the invention.
  • FIG. 3, FIG. 4 and FIG. 5 each show a representation of the beam path according to the prior art.
  • the specified dimensions correspond to the real geometry.
  • OS thickness
  • OS length
  • OS 120 cm
  • At the top and at the bottom of the object 2 distinctive points are marked (on the top of the X-ray beam 1 lying with the sign " ⁇ ", on the side facing the table 10 bottom with the character "D").
  • the projection ("shadow") of these marking points in the recording plane 12 will be explained in more detail below.
  • the detector system 3 consists essentially of a planar detector, which is displaceable in the direction of the recording plane 12, that is, in the present example for recording the partial images in four recording positions einmul. This retraction into the recording positions is effected synchronously with the displacement of the x-ray source 1 shown above into the respective recording positions Pl, P2, P3, P4. By way of illustration, these four sub-images below the representation of the beam path are shown offset again with each other. In the lowermost illustration, the composite X-ray overall image 13 is shown after composing. (Under the examination object 2, a table 10 is drawn, whose position is irrelevant for the representation of the beam path.)
  • FIG. 2 shows four receiving positions P1, P2, P3, P4 of the X-ray source 1 which, according to the present invention, are respectively approached by a translation and a rotation.
  • the maximum angle of incidence (max rad. Angle) is 11.31 °; the parallax effect is 0.91 cm.
  • FIG. 3 shows the beam path of a prior art recording method in which the X-ray source 1 moves sideways but is not pivoted. X-ray source 1 and detector 3 are moved parallel to each other. However, due to the lateral movement of the X-ray source 1, the already mentioned undesired parallax effect occurs, that is, an object is illuminated from different directions and thus projected onto the detector at different positions. For example, superposed marking points ( ⁇ and D) in the center of the examination object 2 in FIG. 3 interchange their position, depending on whether they lie on the right or on the left edge of the two detector positions. This leads in the composite
  • the parallax effect (parallax offset) is 1.61 cm.
  • FIG. 2 If one compares the result of the invention (FIG. 2) with the first method known from the prior art, the lateral "displacement of the radiation source" (FIG. 3), the advantage of the invention can be clearly seen: FIG Parallax effect, which alienates the composite part recordings by a blur that is difficult to correct computationally, is reduced by half: 0.91 cm according to the invention in Figure 2 (compared with 1.61 cm according to the prior art in FIG 3). The maximum incidence of 11.31 ° in FIG. 2 (invention) has increased compared with FIG. 3 (prior art), but is still within an acceptable range.
  • the X-ray device fits in treatment rooms conventional height.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Medical Informatics (AREA)
  • Radiology & Medical Imaging (AREA)
  • Molecular Biology (AREA)
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  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
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  • Physics & Mathematics (AREA)
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  • Heart & Thoracic Surgery (AREA)
  • High Energy & Nuclear Physics (AREA)
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  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
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  • Apparatus For Radiation Diagnosis (AREA)

Abstract

L’invention concerne un procédé de génération d'une série d’images partielles qui, assemblées, donnent une image radiographique complète d’un objet examiné (2). Un système d’entraînement déplace une source de rayons X (1) en l'amenant progressivement dans des positions d’enregistrement (P1, P2, P3, P4) successives pour respectivement émettre un faisceau de rayons X (4) qui, après avoir traversé une région partielle de l’objet examiné, est détecté par un système de détecteurs (3) sous forme d'image de rayonnement (11). L’invention est caractérisée en ce qu’un mouvement linéaire et un mouvement rotatif sont exécutés lorsque la source de rayons X (1) est amenée dans une position d’enregistrement.
PCT/EP2009/055293 2008-06-09 2009-04-30 Procédé et dispositif de génération d'une image radiographique complète composée d’images partielles WO2009149991A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008027476.3 2008-06-09
DE102008027476 2008-06-09

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WO2009149991A1 true WO2009149991A1 (fr) 2009-12-17

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109674484A (zh) * 2017-10-19 2019-04-26 西门子保健有限责任公司 断层合成方法和x射线拍摄装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020159564A1 (en) * 2001-04-30 2002-10-31 Eastman Kodak Company Mothod for acquiring a radiation image of a long body part using direct digital x-ray detectors
US20050185755A1 (en) * 2004-02-25 2005-08-25 Shimadzu Corporation Radiographic apparatus and radiation detection signal processing method
DE102006013024A1 (de) * 2005-03-22 2006-09-28 General Electric Co. System und Verfahren zur Bewegungs-und Angulationsprofilberücksichtigung bei der Tomosynthese
DE102007052572A1 (de) * 2006-11-06 2008-05-08 General Electric Company Verfahren und Vorrichtung zum Definieren mindestens eines Akquisitions- und Bearbeitungs-Parameter in einer Tomosynthesevorrichtung
US20080152088A1 (en) * 2006-12-20 2008-06-26 Xiaohui Wang Long length imaging using digital radiography

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020159564A1 (en) * 2001-04-30 2002-10-31 Eastman Kodak Company Mothod for acquiring a radiation image of a long body part using direct digital x-ray detectors
US20050185755A1 (en) * 2004-02-25 2005-08-25 Shimadzu Corporation Radiographic apparatus and radiation detection signal processing method
DE102006013024A1 (de) * 2005-03-22 2006-09-28 General Electric Co. System und Verfahren zur Bewegungs-und Angulationsprofilberücksichtigung bei der Tomosynthese
DE102007052572A1 (de) * 2006-11-06 2008-05-08 General Electric Company Verfahren und Vorrichtung zum Definieren mindestens eines Akquisitions- und Bearbeitungs-Parameter in einer Tomosynthesevorrichtung
US20080152088A1 (en) * 2006-12-20 2008-06-26 Xiaohui Wang Long length imaging using digital radiography

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109674484A (zh) * 2017-10-19 2019-04-26 西门子保健有限责任公司 断层合成方法和x射线拍摄装置

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