DE102008049038A1 - Position-defined X-ray projections producing device for use during examination of patient, has X-ray optical marks formed during acquisition of image and transforming measured positions of radiator and detector in fixed coordinate system - Google Patents

Abstract

The device has a measuring system for determining position of a radiator (3) and a detector (4) that is fastened to an imaging unit of a X-ray diagnostic device. The measuring system is moved during movement of the imaging unit. Additional X-ray optical marks (7) applied in an optical path are formed during acquisition of X-ray image, and transform the measured positions of the radiator and the detector in a fixed coordinate system. The X-ray diagnostic device is a C-arm device or a computer tomography mechanism i.e. micro computer tomography. An independent claim is also included for a method for determining position of a radiator-detector unit of a X-ray diagnostic unit.

Description

The The invention relates to an apparatus and a method for determination the image pickup device, comprising at least one radiation source and at least one radiation detector of an X-ray diagnostic device, based on a common coordinate system parallel to the X-ray image data acquisition for the further processing of the position-determined X-ray image data.

modern X-ray diagnostic facilities are known in the Lage, by a rotation of the image pickup device a variety record individual X-ray projections and by means of an image processing device to a displayable reconstruction image, usually to process a 3D reconstruction image. The quality The reconstruction image depends on it known decisive for the accuracy of the position measurement the image pickup device for each projection image.

Next the long established computed tomography devices mobile and stationary systems in which the emitter-detector unit arranged on a C-arm, known. Unlike the ring-shaped Computed tomography devices show the C-arm systems greater instabilities, causing the Position of the image acquisition unit not with the accuracy as in Computed tomography systems can be detected.

State of the art

For determining the position of X-ray diagnostic devices, two basic approaches can be distinguished. In the so-called offline or non-simultaneous calibration method, a known calibration phantom constructed from X-ray optical marks is detected by the image recording device. From the X-ray image data, the position of the emitter-detector unit is calculated and stored as a reference value. When examining a patient, the position reference values for further processing are linked to the now recorded X-ray image data and supplied to the image processing unit. Procedures of this kind are in US Pat. No. 7,147,373 . US Pat. No. 6,044,132 . US Pat. No. 6,382,835 and DE 198 07 884 described. Disadvantage of the method presented therein is that only reproducible position values can be measured accurately. Dynamic, non-reproducible errors due to mechanical instabilities can not be detected. Position references must be recorded for every possible trajectory. Especially with freely positionable, multi-axis C-arm-holding systems, as they are made DE 199 58 864 but in principle any number of trajectories can be traversed.

On-line Calibration methods use additional, external sensors, to the position of the image pickup device during the X-ray image capture.

Out US 6,206,566 a system is known in which a spatially fixed camera system measures the position of the emitter-detector unit. The reference coordinate system is formed in this system by an optical measuring camera. The disadvantage of this system is that the measuring camera must remain fixed in space during the recording. Furthermore, the field of view of the camera must not be obscured or exceeded.

In EP 0 910 990 introduces a system that captures the position of the emitter-detector assembly with ultrasound or electromagnetically based measurement systems attached to the instrument base. While the C-arm mobile system shown in this system can improve the concealment problem, the measurement systems shown here are heavily dependent on environmental parameters such As temperature, metal objects dependent. The stationary coordinate system is formed on the mobile base, movements of the device base can not be detected.

Out US Pat. No. 7,125,165 For example, a system is known in which an optical measuring camera is attached to the C-arm of an X-ray diagnostic device. By optical measuring marks on the radiator and the detector of the image pickup device, the position of these components in the reference coordinate system of the camera is measured. If the measuring camera attached to the C-arm is also moved by the movement of further axes, the coordinate system of the camera, which is no longer fixed in space, is detected by another stationary camera via measuring marks attached to the first camera. This second camera may be attached to the base of the C-arm or in space. Above all, the solution described offers the advantage that the optical measuring marks can not be covered by the patient. Disadvantage of this solution is the need for a second measuring camera with extended movements to form a reference coordinate system. Especially with fixed cameras, visibility problems can occur, especially in multi-axis systems with extended trajectories.

task

The invention is based on the object, the position of the image pickup unit of an X-ray diagnostic device with high accuracy simultaneously with the X-ray image recording in a fixed Coordinate system to determine.

These Task is achieved by a device according to the Claim 1 and a method according to the claim 16 solved. Advantageous embodiments of the present Invention are given in the subclaims.

Presentation of the invention

at that indicated in independent claims 1 and 16 Embodiment of the present invention is the position of the image pickup device an X-ray diagnostic device by one of the X-ray diagnostic device mitbewegten measuring camera recorded and by additional, in introduced the beam path of image acquisition, fixed X-ray optical Measuring marks in a fixed position defined by these measuring marks Coordinate system determined.

The X-ray optical measuring marks are in a known arrangement integrated into the operating table or an operating table top or over a detachably fixed connection attached to the operating table or the patient. The arrangement of the marks is designed in such a way that on the basis of the relative Position each other even in a projection image each mark clearly can be identified. It can be identified from at least three Marks are formed a stationary coordinate system.

Special Advantages of the invention result from the combination of two different measuring systems, the disadvantages of each method through the combination the advantages of this are eliminated.

The at the X-ray diagnostic device permanently mounted measuring camera allows simultaneous X-ray imaging Position detection, without causing any obstruction of the line of sight between Camera and measuring marks can come. In addition, you can by suitable mathematical methods, the measuring marks with high Accuracy can be detected, as there are only small, relative position changes comes.

in the Contrary to a pure X - ray optical survey of the Positions of the emitter-detector unit may be as described herein combined procedures, the number of necessary brands on one Minimum be reduced. By the already of the optical measuring system known relative position between radiator and detector, projection geometry only three X-ray optical marks are necessary a stationary reference coordinate system from the known relative arrangement of the brands. As a result, those produced by the brands Minimized picture interference. In addition, the Complexity of the calculation and thus the algorithmic Cost significantly reduced, which made the calculation online can be.

The preferably optical measuring system can also be used for position detection other components are used. That's the way it is possible the position of a patient stored on the table also while capturing the image, thereby enabling the generated position-determined X-ray image data also used for surgical navigation. It is with the invention Design also possible, the sensor of another To capture position measuring system during image acquisition. This position measuring system can, for. B. for position determination surgical instruments. Again, the X-ray image data set and thus also the reconstructed 3D image data set by the X-ray optics certain fixed coordinate system according to the invention implicitly in the coordinate system of the other position measuring system known.

Farther it is implicitly possible to have multiple 3D reconstructed records of the same object spatially to each other or Link 3D data sets with X-ray projection images in a location-specific manner. The movement paths during the X-ray image recording need not be known before, in particular, too non-circular movements z. B. elliptical, spiral or linear movements possible.

The method according to the invention is suitable for any X-ray diagnostic device suitable for 3D reconstruction to calibrate.

embodiments

The The present invention will be described below with reference to preferred embodiments with reference to the accompanying drawings explains in which show:

1 a representation of an X-ray diagnostic device with inventive design of a position measuring system for determining the position of the image pickup device.

2 X-ray optical markers in point or spherical design, which are inserted in the operating table or operating table support.

3 X-ray optical markers in a cruciform design, placed in the operating table or operating table support.

4 X-ray optical markers in linear form introduced into the operating table or operating table support ger version with integrated coding.

5 the spatial arrangement of the X-ray-optical markers in line-shaped design with coding inserted into the operating table or operating table support.

6 the operating table top with detachably fixed reference body with introduced X-ray-optical marks, arranged in a clear pattern.

7 the projection of the X-ray optical marks to determine the reference coordinate system.

8th the data flow plan for determining the position of the image pickup device.

1 shows a per se known X-ray diagnostic device, on a multi-jointed robot arm ( 1 ) is a C-arm ( 2 ), at whose ends a radiator ( 3 ) and a detector ( 4 ) face each other. A preferably optical measuring camera ( 5 ) is with the C-arm ( 2 ) firmly connected. On the spotlight ( 3 ) are preferably optical measuring marks ( 6 ) appropriate. At the detector ( 4 ) are also preferably optical, of the measuring marks ( 6 ) distinguishable measuring marks ( 7 ) appropriate. The measuring field ( 11 ) of the measuring camera ( 5 ) covers the area of the markers ( 6 ) on the radiator ( 3 ) and the markers ( 7 ) at the detector ( 4 ). The in the cone of rays ( 10 ) operating table top ( 9 ) is about X-ray optical marks ( 8th ) extended according to the invention. The measuring camera ( 5 ) is via a data connection ( 12 ) with a data processing device ( 14 ) connected. The X-ray diagnostic device is connected via a data connection ( 13 ) also with the data processing device ( 14 ) connected. The data processing unit ( 15 ) is used for the 3D reconstruction of the position-measured X-ray image data and has a display device ( 16 ).

2 shows an example of the operating table top or operating table top ( 9 ) with integrated point-shaped X-ray optical measuring marks ( 8th ).

3 shows the example in the operating table top ( 9 ) integrated X-ray optical measuring marks ( 8th ) in a cruciform design.

4 shows the example in the operating table top ( 9 ) integrated X-ray optical measuring marks ( 8th ) in a linear design with clear position coding.

5 shows by way of example the three-dimensional arrangement of the line-shaped, X-ray-optical measuring marks ( 8th ) in the operating table top ( 9 ).

6 shows by way of example a reference body ( 26 ) with introduced X-ray optical measuring marks ( 8th ), which via releasably fixed connecting elements ( 27 ) on the operating table top ( 9 ) is attached.

7 shows the spotlight ( 3 ) and its coordinate system ( 20 ); in the beam path ( 10 ) are the X-ray optical marks ( 8th ) in a known reference coordinate system ( 18 ). On the detector ( 4 ), a projection image ( 21 ). The projection ( 17 ) of the X-ray optical marks ( 8th ) are in the coordinate system ( 19 ) of the detector ( 4 ) determinable.

8th shows the connection of the data processing processes. The process of calculating the coordinate systems for optical marks ( 22 ) is connected to the measuring camera ( 5 ) and the process for calculating the reference coordinate system ( 23 ). The X-ray detector ( 4 ) is connected via a data link to the process for identifying the X-ray optical measuring marks ( 24 ), which in turn is connected to the process of calculating the reference coordinate system ( 23 ), which has a data connection to the data fusion process ( 25 ) for linking the X-ray image data with the position data. The data processing device for further processing, preferably for 3D reconstruction ( 15 ) receives the data for further processing.

In order to generate position-specific X-ray projection images for further processing, the image displayed on the robot ( 1 ) fixed C-arm ( 2 ) to the operating table ( 9 ) so aligned that the body region of the patient to be examined by the beam cone ( 10 ) is detected. In the usual rotational motion around the patient for computed tomography X-rays from the radiator ( 3 ) and irradiate next to the patient and the operating table ( 9 ) with the X-ray optical measuring marks ( 8th ). These form in the detector ( 4 ) received X-ray projection image ( 21 ). Parallel to the X-ray image, the C-arm ( 2 ) and from the robot ( 1 ) moving measuring camera ( 5 ) the position and position of the radiator ( 3 ) with the measuring marks ( 6 ), as well as the position and position of the detector ( 4 ) with the measuring marks ( 7 ). The spatial relationship between the measuring marks ( 6 ) and the coordinate system ( 20 ) of the radiator ( 3 ) and between the measuring marks ( 7 ) and the image coordinate system ( 19 ) of the detector ( 4 ) is assumed to be known. It may be known for manufacturing reasons or measured by a calibration and stored in the data processing device ( 14 ) get saved.

The measuring data of the measuring camera ( 5 ) are sent via the data connection ( 12 ) to the data processing device ( 14 ) Posted. At the same time emp the data processing device ( 14 ) the X-ray projection image ( 21 ) via the data connection line ( 13 ) from the detector ( 4 ). The X-ray projection image ( 21 ) may be previously processed by the data processing system of the imaging unit yet z. B. filtered.

The X-ray optical measuring marks ( 8th ) are arranged to be in a reference coordinate system ( 18 ) are clearly known. An embodiment of the measuring marks ( 8th ) is in 2 given, the individual beads are so three-dimensional integrated in the operating table top that they can be clearly identified by mapping the pattern in conjunction with the already known projection geometry. A further advantageous embodiment of the X-ray optical marks ( 8th ) is in 3 shown. Here are the brands realized as crosses, which can be two- or three-dimensionally designed. Even the crosses are clearly identifiable to each other. Another embodiment is in 4 and 5 shown here are the X-ray optical marks ( 8th ) designed in a linear design. The lines are three-dimensional in the operating table top ( 9 ) arranged. By the pattern of the linear design, on the one hand, each line can be uniquely identified, on the other hand, the pattern of a line is designed so that unique positions on the line can be identified.

In 6 a favorable embodiment of the X-ray optical measuring marks is shown. Here are the measuring marks ( 8th ) in a reference body ( 26 ) and can be connected via detachably fixed connections ( 27 ) z. B. in the form of screws clamps or other holding systems with the operating table top ( 9 ) get connected. It is advantageous here that the device can be removed during normal fluoroscopy operation.

In the data processing system ( 14 ), the incoming data will be sent according to the in 8th processed data flow plan processed. From the preferably optical measuring system ( 5 ) determined positions of the measuring marks ( 6 ) and ( 7 ), the coordinate system ( 20 ) of the radiator ( 3 ) and the coordinate system ( 19 ) of the detector ( 4 ) generated X-ray projection image ( 21 ). The data processing process ( 22 ) uses the previously stored geometric information on the position of the measuring marks relative to the radiator or to the detector. Through this process step, the position of the radiator coordinate system as well as the position of the detector coordinate system in the non-stationary coordinate system of the measuring camera at the time of the X-ray image recording are known. The projection image simultaneously recorded for the measurement process ( 21 ) is used in the data processing process ( 24 ) and the position of the image ( 17 ) of the X-ray optical marks ( 8th ) in the detector coordinate system ( 19 ) and to the data processing process ( 23 ) forwarded. The position of the reference coordinate system ( 18 ) is now made by combining the data processing process ( 22 ) known projection geometry, the clearly arranged X-ray optical marks ( 8th ) and the data processing process ( 24 ) identified position of the projection ( 17 ) of the brands ( 8th ). This processing step is possible because the X-ray optical marks ( 8th ) are arranged clearly to each other. The coordinate system ( 20 ) of the radiator ( 3 ) and the coordinate system ( 19 ) of the detector ( 4 ) can be used in the fixed coordinate system ( 18 ). In the data processing process ( 25 ), the X-ray image information ( 21 ) with the coordinate systems ( 19 ) and ( 20 ) is linked to a data packet and sent to the data processing unit ( 15 ) for further processing, preferably the 3D reconstruction.

1

robot

2

C-arm

3

spotlight

4

detector

5

Measuring camera, preferably optically

6

measuring mark spotlight

7

measuring mark detector

8th

X-ray optics measuring marks

9

Operating table top or operating table pad

10

ray cone

11

optical measuring field

12

Data Connection optical measurement data

13

Data Connection X-ray image data

14

Data processing device for position determination

15

Data processing device for 3D reconstruction

16

display

17

projective Illustration of the X-ray optical measuring marks

18

Reference coordinate system

19

Detector coordinate system

20

Spotlights coordinate system

21

projection image

22

Data processing process for the calculation of the coordinate systems of optical measuring marks

23

Data processing process for calculating the position of the image acquisition unit in the reference coordinate system

24

Data processing process for the identification of the X-ray optical measuring marks the X-ray projection image

25

Data processing process for fusing X-ray image and position data

26

reference body for the acquisition of X-ray optical measuring marks

27

solvable fixed fasteners (eg screws)

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 7147373 [0004]
• - US 6044132 [0004]
• - US 6382835 [0004]
• - DE 19807884 [0004]
• - DE 19958864 [0004]
• US 6206566 [0006]
• - EP 0910990 [0007]
• - US 7125165 [0008]

Claims (24)

Device for generating position-determined X-ray projections, characterized in that attached to the imaging unit of the X-ray diagnostic device is a measuring system for determining the position of the radiator and detector, which is moved during a movement of the imaging unit and additional, introduced in the beam path X-ray optical marks are imaged during X-ray image recording and allow the to transform measured positions of emitter and detector into a stationary coordinate system. Device according to claim 1, characterized characterized in that the X-ray diagnostic device for Generation of 3D reconstructions is suitable. Device according to claim 1 characterized characterized in that the X-ray diagnostic device a C-arm device is. Device according to claim 1 characterized characterized in that the X-ray diagnostic device free is positionable and via advanced trajectories features. Device according to one of the preceding claims characterized in that the imaging unit with at least a radiator and at least one detector in the form of a C-arm a support arm is mounted in the manner of a robot arm. Device according to claim 1 characterized characterized in that the X-ray optical marks detachable firmly connected to the operating table. Device according to claim 1 characterized characterized in that the X-ray optical marks detachable firmly connected to the patient. Device according to claim 1 characterized characterized in that the X-ray optical marks in a Operating table support are integrated. Device according to claim 1 characterized characterized in that the X-ray optical marks in the Operating table are integrated. Device according to claim 1 characterized characterized in that the X-ray optical marks in a clearly identifiable patterns are arranged. Device according to one of the claims 1 and 6 to 10, characterized in that the X-ray optical Marks point, ball, cross or linear formed are. Device according to the previous Claim characterized in that the linear, X-ray marks by interrupting the lines Both are clearly identifiable as well as unique positions define on the line. Device according to claim 1 characterized characterized in that the measuring system is optical, electromagnetic or Ultrasound-based works. Device according to one of the claims 1 to 13, characterized in that a data processing device the data is automatically processed. Device according to one of the claims 1 and 14, characterized in that the data processing in parallel takes place for image acquisition. Method for determining the position of the emitter-detector unit an X-ray diagnostic unit, characterized in that with a first measuring system, the position of the radiator and the detector in a dynamic coordinate system simultaneously with image acquisition be measured and represented by the image data stationary Marks is transformed into a fixed coordinate system. A method according to claim 16 characterized characterized in that for calculating the fixed coordinate system the relative positions of emitters determined by the first measuring system and detector are used. A method according to claim 16 characterized characterized in that the at least three fixed marks their arrangement can be clearly identified in the projection image can. Method according to one of the claims 16 to 18, characterized in that the position data for further processing be linked with the image data. Method according to one of the previous Claims characterized in that the determined Position data for the registration of the X-ray image data for the navigation of surgical instruments is used. Method according to one of the previous Claims characterized in that the position of Measuring system of a surgical navigation system during the image acquisition is recorded. Method according to one of the claims 16 to 19, characterized in that the position information for spatial arrangement for a plurality of 3D reconstructions, which map the same object, is used. Method according to one of the claims 16 to 19, characterized in that the position information for the spatial arrangement of X-ray projection images and 3D reconstructions are used. Method according to one of the previous Claims characterized in that the X-ray diagnostic device a computed tomography device, e.g. B. is a micro-CT.