DE102009051897A1 - Method for intraoperative recording of two dimensional x-ray image of e.g. organ of patient during positioning of intervertebral disk prosthesis, involves moving x-ray source to calculated target position, and recording image of organ - Google Patents

Abstract

The method involves determining a perspective position for recording an intraoperative two dimensional (2D) image of an organ of a patient (44), and intraoperative recording of the 2D image by an x-ray device (12). A target position of an x-ray source (36) is calculated such that the organ is illuminated from the determined perspective position by comparing the 2D image with a three dimensional (3D) image based on a geometrical ratio obtained by projecting the organ at an x-ray detector (38). The source is moved to the calculated target position, and the 2D image of the organ is recorded. An independent claim is also included for an x-ray system comprising an x-ray detector commonly movable with an x-ray source.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The invention relates to a method and an X-ray system for intraoperatively taking a 2D X-ray image of an organ from a desired perspective.

2. Description of the Related Art

Numerous surgical procedures today require an intraoperative recording of X-ray images. In most cases, an X-ray machine with a so-called C-arm is used, which carries an X-ray source at one end and an X-ray detector at the opposite end. Since the C-arm can be moved in a variety of ways, X-ray images of a patient's organ can usually be taken from different perspectives.

Often the choice of this perspective is crucial. The reason for this can be z. B. lie in the fact that only from a very specific perspective of the structure of interest on an X-ray image is recognizable. In other cases, the organ needs to be transilluminated from a particular perspective so that bones can be optimally aligned by means of screws or other aids. Even if the correct fit of an implant, z. B. an intervertebral disc prosthesis, to be checked, the implant must be transilluminated with the adjacent bone usually from a particular perspective.

So far, in such cases, the operator of the X-ray machine is positioned by the surgeon's instructions to position the X-ray source so that a first X-ray image is taken from a perspective that is believed to be quite close to the desired perspective. By intermittent or continuous readjustment and observation of the recorded X-ray image, the position of the X-ray source is then readjusted by means of the "try and error" until the desired perspective is set and the X-ray source is in its target position.

This way of approaching a desired target position of the X-ray source is not only time-consuming but, because of the numerous X-ray images that have to be taken for this purpose, results in a considerable radiation exposure of the patient and of the medical staff in the vicinity.

From the DE 103 22 739 A1 A method is known in which instruments guided by the surgeon, which are recorded intraoperatively in 2D X-ray images, are recorded in preoperatively generated 3D images of the relevant organ. In this way it is possible for the surgeon to follow the instrument on the 3D image, which is usually displayed with a higher resolution.

SUMMARY OF THE INVENTION

The object of the present invention is to improve a method and a system for intraoperatively taking a 2D image of an organ from a desired perspective so that the target position of the X-ray source can be approached in a shorter time. Furthermore, the hitherto unavoidable radiation exposure for the patient and the medical staff in his vicinity when finding the target position of the X-ray source to be reduced.

• a) Präoperatives Erzeugen eines 3D-Bildes des Organs;
• b) Festlegen einer Perspektive, von der aus ein intraoperatives 2D-Bild des Organs aufgenommen werden soll, unter Verwendung des 3D-Bildes;
• c) Intraoperatives Aufnehmen eines vorläufigen 2D-Bildes des Organs mit Hilfe des Röntgengeräts, wobei sich die Röntgenquelle in einer Ausgangsposition befindet;
• d) Berechnen einer vorzugsweise relativ zu der Ausgangsposition angegebenen Zielposition, welche die Röntgenquelle einnehmen muss, damit das Organ mit der in Schritt b) festgelegten Perspektive durchleuchtet werden kann, durch Abgleich des vorläufigen 2D-Bildes mit dem 3D-Bild unter Berücksichtigung der bei der Projektion des Organs auf den Röntgendetektor herrschenden geometrischen Verhältnisse;
• e) Verfahren der Röntgenquelle an die in Schritt d) berechnete Zielposition;
• f) Aufnehmen eines endgültigen 2D-Bildes des Organs.

According to the invention, this object is achieved by a method using an x-ray device which has an x-ray source and an x-ray detector which can be moved jointly with the x-ray source, the method comprising the following steps:

• a) Preoperatively generating a 3D image of the organ;
• b) determining a perspective from which to record an intraoperative 2D image of the organ using the 3D image;
• c) intraoperatively taking a preliminary 2D image of the organ by means of the X-ray apparatus, wherein the X-ray source is in a starting position;
• d) calculating a target position, preferably relative to the starting position, which the X-ray source must occupy, so that the organ can be transilluminated with the perspective determined in step b), by matching the preliminary 2D image with the 3D image, taking into account that in the Projection of the organ on the X-ray detector prevailing geometric relationships;
• e) moving the X-ray source to the target position calculated in step d);
• f) taking a final 2D image of the organ.

The inventor has recognized that one can also computationally determine the target position at which the X-ray source must be in order to be able to record the X-ray image from the desired perspective. The prerequisite for this is that the form of the institution concerned is known. For this purpose, a 3D image of the organ is generated preoperatively, for example using high-resolution imaging techniques such as Magnetic resonance imaging (MRI). Furthermore, a preliminary 2D image of the organ must be taken intraoperatively using the X-ray machine. This 2D image is correlated with the preoperatively acquired 3D image to calculate the target position, taking into account the geometric relationships prevailing in the projection of the organ on the X-ray detector, preferably relative to the starting position from which the preliminary 2D Picture was taken. The X-ray source can then be moved manually or by motor to the calculated target position in order to record therefrom the final 3D image of the organ from the desired perspective.

The acquisition of a 2D image of the organ from the desired perspective thus requires only a single additional intraoperative 2D X-ray image, referred to herein as a "preliminary 2D image". The "try and error" method, which has hitherto been used for finding the target position of the X-ray source, is replaced according to the invention by a direct approach of a previously calculated target position.

This not only saves a considerable amount of time but, above all, a considerable reduction in radiation exposure for the patient and the medical staff. Where hitherto often 10, 20 or occasionally more intraoperative radiographs were required to find the target position of the X-ray source from which the organ can be picked from the desired perspective, only two X-ray images are sufficient when using the method according to the invention. The preoperatively generated 3D image which is likewise required in the method according to the invention is usually required in any case within the scope of the diagnosis or preparation of the operation. Therefore, this 3D image does not really increase the effort, nor is it regularly associated with additional radiation exposure, taking into account the diagnosis and preparation of the operation.

An additional factor is that starting up the desired target position no longer requires the involvement of the surgeon as in the prior art. So far, he had to determine with the help of his anatomical knowledge, how the X-ray source must be moved so that you can take a picture from the desired perspective. Given the multitude of possible movement axes of a modern X-ray machine, these findings, which usually had to be made in large numbers in the course of an operation, require a lot of experience and maximum concentration from the surgeon. When using the method according to the invention, however, the surgeon or a member of the non-medical personnel at rest before or during surgery on the basis of preoperatively recorded 3D image set the desired perspective and leave the non-medical personnel the next steps.

An X-ray machine suitable for carrying out the method typically has a C-arm, which makes it possible to move the X-ray source in a variety of ways together with the X-ray detector which is arranged at the opposite end of the C-arm. This makes it possible to illuminate the patient's organs from a variety of different perspectives. As organs in this context, all functional units of the organism are referred to, for example, bones, vessels, skin or organs in the strict sense, such as stomach or kidney.

In the present context, the term "perspective" generally describes how a three-dimensional organ is imaged onto a two-dimensional surface. Since the position of the X-ray detector relative to the X-ray source is immutable, the perspective is determined solely by the location of the X-ray source relative to the organ and the directions at which the X-ray source emits X-rays. In many X-ray sources, the angle spectrum of the X-radiation is fixed or at best dimmable at its edges, so that the target position describes only the location of the X-ray source and its three-dimensional orientation in space. If the x-ray device not only allows the position and orientation of the x-ray source to be changed, but also changes the angular spectrum, then the method according to the invention can also be extended such that an angle spectrum is calculated in step d), in the course of which the 2D image taken later is calculated. Picture appears in the desired perspective. An adjustable angle spectrum of the X-ray source makes it possible to increase the number of perspectives from which a 2D image can be taken by the organ in question.

The method of the X-ray source to the target position calculated in step d) can be done manually. A display device of the X-ray device indicates to an operator in this case how the X-ray source has to be adjusted in order to transfer it to the target position. In many X-ray machines, scales with units of measure are assigned to the individual movement axes. The ad could then z. For example, only specify the relative changes, e.g. B. "-2 ° orbital motion; +2 units of horizontal movement ". Of course, however, absolute values can also be specified, for. B. "44 ° orbital angle, 13 cm horizontal distance".

The target position can be approached particularly quickly if the X-ray source can be moved by a motor. In this case, the X-ray machine points Actuators for the common method of the X-ray source and the X-ray detector and a control unit, by which the drives are controllable such that they move the X-ray source from the starting position to the target position.

In order to be able to specify the target position relative to the starting position in step d), in one embodiment of the invention both the starting position and the target position relative to the organ are indicated. Specifically, then, in a step d1), the home position of the X-ray source in which the preliminary 2D image is captured in step c) is given relative to the organ, the preliminary 2D image having the 3D image taking into account that in the Projection of the organ is matched to the X-ray detector prevailing geometrical relationships. Further, in a step d2), the target position which the x-ray source must occupy so that the organ can be transilluminated with the perspective determined in step b) is also indicated relative to the organ. Since the organ then represents a common reference for the initial and target positions, the target position can then be easily calculated relative to the starting position. The preliminary intraoperatively taken 2D image of the organ thus serves only to determine the location of the X-ray source relative to the organ. Since the target location of the x-ray source relative to the organ results directly from the desired perspective, it is then easy to deduce which path the x-ray source has to travel from the starting position to the target position.

In many cases, the starting position will only need to be slightly corrected to get to the target position. This may mean, for example, that the X-ray source is pivoted by a few degrees or translationally moved a few centimeters.

To simplify the comparison of the preliminary 2D image with the 3D image, edge images can be derived from these images. The algorithms required for this purpose are known in the prior art for the imaging methods.

• a) einer Röntgenquelle und einem gemeinsam mit der Röntgenquelle verfahrbaren Röntgendetektor,
• b) eine Anzeigeeinrichtung, auf der ein präoperativ erzeugtes 3D-Bild des Organs angezeigt werden kann,
• c) eine Eingabeeinrichtung, mit der ein Benutzer unter Verwendung des auf der Anzeigeeinrichtung angezeigten 3D-Bildes eine Perspektive festlegen kann, von der das 2D-Bild des Organs aufgenommen werden soll,
• d) eine Recheneinheit, die derart programmiert ist, dass sie eine vorzugsweise relativ zu der Ausgangsposition angegebene Zielposition berechnet, welche die Röntgenquelle einnehmen muss, damit das Organ mit der in Schritt b) festgelegten Perspektive durchleuchtet werden kann, wobei das vorläufige 2D-Bild mit dem 3D-Bild unter Berücksichtigung der bei der Projektion des Organs auf den Röntgendetektor herrschenden geometrischen Verhältnisse abgeglichen wird.

With regard to the X-ray system, the object mentioned at the beginning is solved by an X-ray system with:

• a) an X-ray source and an X-ray detector movable together with the X-ray source,
• b) a display device on which a preoperatively generated 3D image of the organ can be displayed,
• c) an input device with which a user can specify a perspective from which the 2D image of the organ is to be recorded, using the 3D image displayed on the display device,
• d) an arithmetic unit programmed to calculate a target position, preferably relative to the home position, which the X-ray source must occupy so that the organ can be transilluminated with the perspective determined in step b), the preliminary 2D image having the 3D image is adjusted taking into account the prevailing in the projection of the organ on the X-ray detector geometric relationships.

The advantages and advantageous developments mentioned above for the method according to the invention apply correspondingly to the X-ray system.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparent from the following description of an embodiment with reference to the drawings. Show:

1 a schematic representation of a system according to the invention;

2a to 2c a cube from different perspectives;

3 the projection of the into the 2a to 2c shown cube on a flat surface from a starting position;

4 the projection of the cube on the flat surface from the target position;

5 a flowchart for explaining essential steps of the method according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

1. X-ray system

In the 1 an inventive X-ray system is shown schematically and in total with 10 designated. The X-ray system 10 includes an X-ray machine 12 with a multi-adjustable C-arm 14 and a trolley 16 that by means of rollers 18 . 20 is movable on the floor. The equipment cart 16 takes a pillar 22 on, which is arranged perpendicular to the floor and adjustable in height in a manner not shown, which in the 1 by a double arrow 24 is indicated. A horizontal guide 26 is about a pendulum bearing 28 with the upper end of the column 22 connected. The pendulum bearing 28 allows a rotation of the Horizontal guide around a pendulum axle 30 , One end of the horizontal guide 26 is about a dump camp 32 with a holder 34 connected to the C-arm 14 holds. At one end of the C-arm 14 is an x-ray source 36 and at the other end, an X-ray detector 38 attached. The location of the x-ray source 36 relative to the x-ray detector 38 is not changeable, but fixed by the geometry of the C-arm 14 specified.

The C-arm 14 is movable along the circumference of the bracket 34 stored what is in the 1 by a double arrow 40 is indicated. Furthermore, the C-arm 14 with the help of the dump camp 32 around a tilt axis 42 be tilted, which is perpendicular to the pendulum axis 30 runs. In the illustrated embodiment, the pendulum axis is arranged perpendicular to the floor, so that the tilting axis 42 always in a horizontal plane.

With the C-arm 14 is it possible for a patient 44 also during an operation to illuminate and in this way an intraoperative radiograph of an organ of the patient 44 to win. The C-arm 14 encompasses an operating table 46 on which the patient 44 is stored. Due to the multiple displaceability of the C-arm 14 It is possible to record 2D X-ray images from different perspectives on most of the patient's organs.

In the illustrated embodiment, the C-arm 14 be adjusted by motor. For this purpose, the x-ray device has a plurality of drives, which are assigned to the different axes of motion and in the 1 are indicated by dashed rectangles. In detail, this is a drive 48a for the roles 18 . 20 , a drive 48b for a steering movement of the rollers 18 . 20 , a drive 48c for a vertical adjustment of the column 22 along the pendulum axis 30 , a drive 48d for a pendulum movement of the horizontal guide 26 around the pendulum axis 30 , a drive 48e for a horizontal movement of the holder 34 along the tilt axis 42 , a drive 48f for a tilting movement of the C-arm 14 around the tilt axis 42 and a drive 48g for an orbital movement of the C-arm 14 along its circumference in the holder 34 ,

A control unit 47 of the X-ray machine 12 which the drives 48 controls is with a computing unit 50 via a wired or wireless data connection 52 connected. Furthermore, the X-ray system has 10 a display device 54 and an input device 56 on, both with the arithmetic unit 50 can communicate via data connections. In the display device 54 In the simplest case, this is a screen, but projection devices (beamer) or head-up displays, for example, are also suitable. The input device 56 points in the in the 1 illustrated embodiment, a computer mouse 58 and a keyboard 60 However, other input devices such as mouse pads, touch-sensitive screens or voice-controlled input devices may also be considered.

The arithmetic unit 50 , the display device 54 and the input device 56 can be part of a per se conventional personal computer, as in the 1 is shown. In this case, only a software according to the invention is to be installed on the personal computer. In many cases, however, it will be necessary to resort to more specialized hardware, firstly optimized for use in operating theaters and secondly, allowing the surgeon to sit down at the operating table 46 from the comfortable of the display device 54 to capture displayed content and inputs via the input device 56 to be able to do.

2nd function

The function of the X-ray system 10 is explained in more detail below with reference to the remaining figures:
First, the surgeon determines from which organs of the patient 44 he during an operation to be performed later with the X-ray machine 12 Would like to record x-rays. For the sake of simplicity, it is assumed that this is only a single organ, for example a vortex. If x-ray images of several organs are to be taken intraoperatively, the following steps should be carried out accordingly for the other organs.

In a first step, a 3D image is taken preoperatively by the organ determined by the surgeon. A computer tomograph (CT), a magnetic resonance tomograph (MRT), an ultrasound machine or a positron emission tomograph (PET), for example, can be used for this purpose. The imaging method used should make it possible to obtain the 3D image of the organ with the highest possible resolution. A 3D image of an organ is characterized by containing data describing the three-dimensional shape of the organ in question. If such a 3D image is displayed two-dimensionally on a screen or a similar display device, then z. For example, the direction from which the organ is viewed may be changed (or, conversely, the organ rotated). The preoperatively recorded 3D image is in the arithmetic unit 50 saved; the preoperative part of the procedure is now complete.

During surgery on the organ, the surgeon determines from which perspective using the X-ray machine 12 an intraoperative 2D image of the organ is to be recorded. For this purpose, the surgeon uses the display device 54 and the input device 56 , The procedure for this determination is in the 2a to 2c shown schematically:
For the sake of simplicity, it is assumed here that the organ to be transilluminated is a cube 62 is. Because in the arithmetic unit 50 the preoperatively taken 3D image and thus the complete three-dimensional shape of the cube 62 saved, the cube can 62 on the display device 54 be presented from any perspective.

The display device 54 shows the cube 62 first in a certain preset starting perspective, in which the cube appears as undistorted as possible. Here it is assumed that this is a parallel projection from diagonally above. This starting position can now be modified by the surgeon. Because the x-rays are the x-ray source 36 leave divergently, the organ (cube 62 ) in the manner of a central projection on the X-ray detector 38 projected. Because the type of projection thus by the X-ray system 12 is fixed, the display switches 54 directly to a representation in central projection around, as in the 2 B is recognizable. However, the surgeon can now change the direction of projection, ie determine from which side of the cube 62 should be represented. For this purpose, the surgeon z. B. a screen pointer 64 use it with the dice 62 until he turns off. a desired direction appears projected. From this direction, the intraoperatively recorded 2D X-ray image must be taken later.

Here, for the sake of simplicity, it is assumed that the surgeon wants to take a 2D X-ray image intraoperatively, in which the cube 62 appears from a central perspective, in which the vanishing point comes to lie at a certain point on a mid-perpendicular of a particular cube surface. Starting from the in the 2 B The surgeon can see the cube 62 so long with the help of the screen pointer 64 turn until this desired perspective is reached ( 2c ). This desired target perspective is confirmed by the surgeon with the aid of the input device 56 , whereby a corresponding record in the arithmetic unit 50 is stored.

The in the arithmetic unit 50 Software used for this purpose may be the representation of the cube 62 so control that only such perspectives from the display device 54 can be displayed, dealing with the X-ray machine 12 let realize. In particular, in the projection of the cube 62 on the x-ray detector 38 prevailing geometrical conditions are taken into account. These include, inter alia, in the 1 at 66 indicated angle spectrum with which the X-ray source 36 the X-rays emitted, and the distance between the X-ray source 36 and the X-ray detector 38 , For example, if the surgeon wants to pick a perspective that would bring the viewer closer to the cube 62 seems to be, than this in the 2c is shown, such a representation can be prevented, because yes, the X-ray source 36 can not be brought arbitrarily close to the organ.

In a next step is from the X-ray machine 12 a preliminary 2D image of the organ taken intraoperatively. For this purpose, the C-arm 14 with the help of the drives 48 to a home position, from which it is assumed that an X-ray image taken from there comes relatively close to the perspective that the surgeon previously determined using the preoperatively acquired 3D image. The 2D x-ray image taken from this starting position is now read by the arithmetic unit 50 used for this, a target position of the X-ray source indicated relative to the starting position 36 from which the organ can be screened just under the perspective previously determined by the surgeon. The steps to be performed will now be described with reference to FIGS 3 and 4 explains:
The 3 shows the geometric relationships that occur during fluoroscopy of the cube 62 in connection with the taking of the preliminary 2D image. How to get in the 3 can recognize is in the preliminary 2D image 68 , that of the starting position of the X-ray source determined only by experience 36 was taken out of the picture 70 of the cube 62 not with in the 2c shown perspective desired by the surgeon. The reason for this is that the position of the X-ray source 36 not exactly on the mid-perpendicular of the desired cube area 72 arranged, but is slightly offset to this. In the small front view of the cube 62 right in the 2 This is easily recognizable. This creates a distorted picture 70 of the cube 62 ,

Task of the arithmetic unit 50 it is now, starting from the starting position of the X-ray source 36 indicate a target position from which the intraoperatively acquired final 2D X-ray image appears to be taken exactly from the perspective previously set by the surgeon. For the representation right in the 2 This means that the location of the X-ray source 36 must be changed so that they are on the mid-perpendicular of the cube face 72 to come to rest, as is right in the 4 is shown.

If the cube 62 is provided with a marking whose position and orientation can be determined relative to a fixed reference frame by means of a locating system, and if so, the position and orientation of the X-ray source 36 can be determined with the aid of a locating system, it is easy to determine a target position for the X-ray source relative to the reference system 36 derived. In most cases, these conditions are not met. From the spatial arrangement of the C-arm 14 to the patient 44 can then be the location and orientation of the X-ray source 36 relative to the individual organs of the patient 44 do not determine the location of the patient 44 on the operating table 46 not exactly known. It is also not readily determinable where the organ to be screened is relative to a particular reference point of the patient.

However, since the exact shape of the organ from the preoperatively generated 3D image is as well known as that in the projection of the organ on the X-ray detector 38 prevailing geometrical conditions, the location of the X-ray source can be 36 derive mathematically from these data relative to the organ.

The example of the in the 3 Cube shown this can be done in such a way that one first computationally of a with the X-ray source 36 coincident vanishing rays emanate from the structures of the distorted image 70 of the cube 62 end up. Because the location of the x-ray source 36 relative to the x-ray detector 38 is fixed, this bundle of projection beams can be computed easily computationally. In this beam must the cube 62 now be inserted that on the structures of the image 70 ending projection rays through corresponding structures of the cube 62 run. The algorithms required for this purpose are known from image processing. Starting point for this calculation can be a position of the cube 62 as determined by the surgeon in establishing the perspective of the intraoperative 2D image. If the starting position is relatively close to the later target position, then relatively small translational and / or rotational movements of the cube are sufficient 62 until it computationally generates an image with the preliminary 2D image 70 matches. Once this match is achieved, the location of the x-ray source may be 36 relative to the organ (cube 62 ) are determined from the geometric relationships.

In many organs, it is not easy to associate structures on a 2D image obtained by projection with corresponding structures of the organ in a 3D image. It may be helpful in this context to derive edge images from the 2D image and the 3D image, for which suitable edge detection algorithms are known in the prior art. The above-described alignment of the structures is generally relatively easy for 2D and 3D edge images.

Now you have to consider the relative to the organ (cube 62 ) indicated target position, which is the X-ray source 36 in order for the organ to be screened with the surgeon's perspective. This information was already saved when the surgeon set the desired perspective. Namely in the 2c shown picture of the cube 62 The software needed to have a vanishing point for the projection relative to the cube 62 establish.

Now that both the starting position of the X-ray source 36 relative to the cube 62 as well as the target position relative to the cube 62 is known, it is easy to calculate the target position relative to the starting position. The control unit 47 now controls the drives 48 so on, that the x-ray source 36 from their starting position, from which they take the preliminary 2D image 70 of the cube 62 has taken, is moved to the target position. In the 4 is this process by small arrows 74 indicated. As the X-ray detector 38 always together with the X-ray source 36 is in the 4 also the location of the picture 68 ' relative to the cube 62 changed.

Note in this context that the travel path (unlike the 4 in general) not exclusively in a linear translational motion of the X-ray source 36 but additionally includes rotations about one or more axes, since the target position of the x-ray source 36 not only their location but also their orientation.

The essential steps of the method according to the invention are described below with reference to the in the 5 summarized flow chart summarized again:
In a first step S1 preoperatively a 3D image of the organ, here the cube 62 , generated.

In a second step S2, the surgeon defines a perspective from which an intraoperative 2D image of the organ is to be recorded.

In a third step S3, a preliminary 2D image of the organ with the aid of the X-ray device 12 recorded intraoperatively, with the X-ray source 36 is in a starting position.

In a fourth step S4, a target position, which is preferably indicated relative to the starting position, is calculated, which is the X-ray source 36 so that the organ can be screened with the perspective established in step b). In this case, the preliminary 2D image is compared with the 3D image, taking into account the geometric conditions prevailing during the projection of the organ onto the X-ray detector.

In a fifth step S5, the X-ray source 36 to the target position calculated in step S4.

In a sixth step S6, the final 2D image of the organ is recorded.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10322739 A1 [0006]

Claims (11)

Method for intraoperatively taking a 2D x-ray image of an organ ( 62 ) from a desired perspective and using an X-ray machine ( 12 ), which is an X-ray source ( 36 ) and one together with the X-ray source ( 36 ) movable X-ray detector ( 38 ), characterized by the following steps: a) preoperative generation of a 3D image of the organ; b) determining a perspective from which to record an intraoperative 2D image of the organ using the 3D image; c) Intraoperative acquisition of a preliminary 2D image of the organ with the aid of the X-ray apparatus ( 12 ), wherein the X-ray source ( 36 ) is in a home position; d) calculating a target position which the X-ray source ( 36 ), so that the organ can be transilluminated with the perspective determined in step b), by matching the preliminary 2D image with the 3D image, taking into account the projection of the organ onto the X-ray detector (FIG. 38 ) prevailing geometrical conditions; e) Method of X-ray source ( 36 ) to the target position calculated in step d); f) taking a final 2D image of the organ. Method according to Claim 1, characterized in that the step d) comprises the following further steps: d1) calculating a starting position of the X-ray source relative to the organ at which the preliminary 2D image is acquired in step c) by matching the preliminary 2D image with the 3D image taking into account the projection of the organ onto the X-ray detector prevailing geometrical conditions; d2) calculating a target position indicated relative to the organ which the X-ray source must occupy to allow the organ to be transilluminated with the perspective determined in step b); d3) calculating the target position relative to the home position. A method according to claim 1 or 2, characterized in that edge images are derived from the preliminary 2D image and the 3D image, and that the adjustment in step d) is performed on the basis of the edge images. Method according to one of the preceding claims, characterized in that the x-ray source is moved by motor to the target position calculated in step d). Method according to one of the preceding claims, characterized in that the geometric conditions prevailing in the projection of the organ on the X-ray detector, an angle spectrum, are emitted with the X-rays from the X-ray source, and the distance between the X-ray source and the X-ray detector. X-ray system for intraoperatively taking a 2D X-ray image of an organ from a desired perspective for producing intraoperative X-ray images, comprising: a) an X-ray source ( 36 ) and one together with the X-ray source ( 36 ) movable X-ray detector ( 38 ), b) a display device ( 54 ) on which a preoperatively generated 3D image of the organ can be displayed, c) an input device ( 56 ), by which a user is informed by means of the on the display device ( 54 ) can determine a perspective from which the 2D image of the organ is to be recorded, d) a computing unit ( 50 ) which is programmed to calculate a target position which the X-ray source ( 36 ), so that the organ can be transilluminated with the perspective determined in step b), whereby the preliminary 2D image is aligned with the 3D image, taking into account the geometric conditions prevailing in the projection of the organ on the X-ray detector. X-ray system according to claim 6, characterized in that the X-ray system ( 12 ) Drives ( 48 ) for the common method of the X-ray source ( 36 ) and the X-ray detector ( 38 ) and a control unit ( 47 ), by which the drives ( 48 ) are controllable such that they are the X-ray source ( 36 ) move from the starting position to the target position. X-ray system according to claim 6 or 7, characterized in that the arithmetic unit ( 50 ) is programmed to perform the following further steps: a) calculating a starting position of the X-ray source relative to the organ ( 36 ), in which the preliminary 2D image is captured, by matching the preliminary 2D image with the 3D image, taking into account the geometric relationships prevailing in the projection of the organ on the X-ray detector; b) calculating a target position indicated relative to the organ which the X-ray source ( 36 ), so that the organ can be examined with the specified perspective; c) calculating the target position relative to the home position. X-ray system according to one of claims 6 to 8, characterized in that the arithmetic unit ( 50 ) is programmed to derive edge images from the preliminary 2D image and the 3D image, and that the alignment of the preliminary 2D image with the 3D image is performed on the basis of the edge images. X-ray system according to one of claims 6 to 9, characterized in that it drives ( 48 ), which are adapted to the X-ray source ( 36 ) to move to the calculated target position by motor. X-ray system according to one of claims 6 to 10, characterized in that in the projection of the organ on the X-ray detector ( 38 ) geometric conditions an angle spectrum, with the X-rays from the X-ray source ( 36 ) and the distance between the X-ray source ( 36 ) and the X-ray detector ( 38 ).

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