Phantom and method for registering a shape-capturing instrument

Abstract

The invention relates to a phantom and a method for the mutual registration of an X-ray system and a shape-capturing instrument. The phantom has an X-ray feature configured to enable registration of the phantom in the coordinate system of the X-ray system by means of X-ray images of the phantom taken by the X-ray system. The phantom has a shape feature configured to enable registration of the phantom in the coordinate system of the shape-capturing instrument by means of shape capture by the shape-capturing instrument. The shape feature is configured to allow the shape-capturing instrument to be inserted into it and thereby brought into a registration shape that extends in all three spatial directions. According to the method, the phantom is positioned in the recording area of ​​the X-ray system. Then, X-ray images of the phantom's X-ray feature are taken from different angles.Furthermore, the shape-capturing instrument is inserted into the phantom's shape feature. The shape of the inserted shape-capturing instrument is then captured by the phantom's position during this capture, with the instrument's position during the acquisition of the X-ray images corresponding to its position during the acquisition of the X-rays. Subsequently, the shape-capturing instrument and the X-ray system are mutually registered based on the X-ray images and the captured shape of the shape-capturing instrument.

Description

[0001] The invention relates to a phantom and a method for mutually registering the coordinate systems of an X-ray system and a shape-capturing instrument.

[0002] In minimally invasive procedures guided by X-ray imaging, for example with C-arm angiography systems, therapies and diagnoses are performed using instruments inserted into the body through small incisions, such as in the groin. X-ray imaging is used for navigation to a target located within the body, a blood vessel, or a hollow organ. Catheters and other instruments, as well as anatomical features, can be visualized using X-ray imaging. However, X-ray imaging has the disadvantage that both the patient and the medical personnel are exposed to a dose of radiation.

[0003] To overcome the disadvantage of radiation dose, shape-detection instruments are known to be used that enable the detection of one's own shape or position without the use of X-rays. Shape detection can be achieved, for example, by fiber-optic 3D shape scanning based on light guidance. Here, the modulation of the light guidance in the optical fiber is used to determine the shape. This technique is known to be used, for example, for the visualization of guide wires. Shape detection is performed without X-ray imaging and therefore without X-ray radiation dose. From the detected spatial shape, the spatial position within the fiber can also be derived if the position of the starting point of the optical fiber is known. Other X-ray-free approaches are known, for example, based on electromagnetic tracking, in which electromagnetic fields are used to determine the spatial position.The spatial shape of the tracked instrument can also be derived from the recorded position(s). In the following, the term "shape-capturing" is generally understood to mean that a spatial shape or position of an instrument can be captured without the use of X-rays.

[0004] Systems for determining shape and position typically use their own spatial coordinate system. For example, in fiber optic 3D shape scanning, it is known to anchor the coordinate system of the fiber optic system close to the relevant target location for position determination and in a suitable orientation relative to the target location. X-ray systems also typically use their own spatial coordinate system. The coordinate system of an X-ray system is usually anchored with respect to the X-ray source or X-ray detector. The shape and position information from non-X-ray shape-acquiring systems, such as fiber optic systems, should be usable within procedures under X-ray imaging. For this purpose, the definition of a common coordinate system for the shape-acquiring system and the X-ray system is necessary.The definition of a spatial transformation rule between the two coordinate systems. Such a transformation rule is also referred to as the registration of the two coordinate systems, or the registration of the X-ray system and the shape-capturing instrument. In the following, the terms transformation and registration will generally refer to spatial transformation and spatial registration, respectively. Similarly, the term registration will generally refer to the determination of a transformation rule between coordinate systems, the transformation of one coordinate system into another, or the transformation of coordinate systems into a single, common coordinate system.

[0005] The calibration and registration of an imaging system, such as a C-arm X-ray system, can be performed using a spiral phantom. A spiral phantom for X-ray registration can have a series of radiopaque markers. These markers can be arranged in or on the phantom in a non-linear or non-planar configuration, extending in all three spatial dimensions. The markers are often designed as radiopaque spheres. They are typically arranged asymmetrically and can differ from one another, allowing the position and orientation of the markers, and thus the phantom's position relative to the X-ray system, to be clearly determined from one or a few X-ray images.

[0006] The registration of the coordinate systems of an X-ray system and a shape-acquiring instrument is generally known in the art. To register the two coordinate systems, two X-ray images of the shape-acquiring instrument are typically taken. Based on these two X-ray images, the position of the instrument relative to the X-ray system is reconstructed. The reconstructed position is then registered along with the position information of the shape-acquiring instrument. This method requires taking two or more X-ray images and is therefore complex and time-consuming. The accuracy of this method depends on the precision with which the position of the instrument can be reconstructed from the X-ray images.

[0007] The purpose of the invention is to improve known methods.

[0008] The invention proposes a phantom and a method based on registration features that can be detected by both an X-ray system and a shape-capturing instrument. The invention thus provides a fast, precise, simple, and radiation-free or radiation-reduced method for registering the coordinate systems of an X-ray system and a shape-capturing instrument.

[0009] The phantom according to the invention for mutual registration of a shape-capturing instrument and an X-ray system has an X-ray feature configured to enable registration of the phantom in the coordinate system of the X-ray system by means of X-ray images of the phantom taken by the X-ray system. The phantom has a shape feature configured to enable registration of the phantom in the coordinate system of the shape-capturing instrument by means of shape capture by the shape-capturing instrument. The shape feature is configured to allow the shape-capturing instrument to be inserted into it and thereby brought into a registration shape that extends in all three spatial directions.

[0010] The X-ray feature can, for example, be an arrangement of X-ray markers known from calibration phantoms. The shape feature is designed such that it allows a shape-detecting instrument to be positioned within the spatial area of ​​the X-ray feature or in its immediate vicinity in a shape and position defined by the shape feature. The shape feature is designed to allow the shape-detecting instrument to be inserted into it and thereby brought into a registration shape that extends in all three spatial directions.

[0011] The phantom according to the invention can be considered a combined phantom that integrates the individual phantoms for both the X-ray system and the shape-capturing instrument. The relationship of the individual phantoms to each other is fixed by the phantom, thus enabling the registration of the coordinate systems of the X-ray system and the shape-capturing instrument relative to each other.

[0012] The phantom is a device that positions the shape-capturing instrument into a registration position and shape. The shape-capturing instrument can be, for example, a guide wire, a catheter, an endoscope, a laparoscope, or any other flexible, deformable instrument. The registration position is reached, for example, when the shape-capturing instrument is fully inserted into the shape feature. The registration position is the position of the instrument in which it can be correctly registered. The spatial relative position of the shape feature with respect to the radiographic feature of the phantom is structurally fixed by the phantom. The spatial relative position of the radiographic feature with respect to the radiographic system can be determined using one or more radiographs.The spatial relative position of the shape-detecting instrument inserted into the shape feature with respect to the X-ray system can be determined, for example, from one or more X-ray images. It can also be derived, for example, from the known spatial relative position of the shape feature with respect to the X-ray feature once the X-ray feature has been recorded.

[0013] The registration procedure can be performed on the X-ray system side or on the side of the image-capturing instrument, because both the X-ray system and the image-capturing instrument each have their own coordinate system. The X-ray system comprises a control unit and the image-capturing instrument a monitoring unit, each operating with its own coordinate system. Either or both of these units can perform the registration procedure.

[0014] The invention reduces the effort and time required for registering the coordinate systems, since the X-ray system and the shape-capturing instrument can be mutually registered by the phantom using the same one or more X-ray images. Furthermore, the phantom, in the form of its shape feature, provides a suitable three-dimensional registration shape for the shape-capturing instrument. The invention improves the precision of the registration because both systems can be registered using the same X-ray image(s), thus avoiding unwanted relative movements between the X-ray system and the shape-capturing instrument between registration X-ray images. The invention also reduces effort because no additional registration X-ray images are required for separate registration processes for the X-ray system and the shape-capturing instrument.

[0015] An advantageous embodiment of the invention provides that the phantom has an X-ray feature in the form of radiopaque markers arranged on or within the phantom, the arrangement of which extends in all three spatial directions. The registration of phantoms with radiopaque markers is known. Efficient registration methods are available that can be used for this purpose.

[0016] An advantageous embodiment of the invention provides that the shape feature is designed as a tube. The tube can, for example, have a round cross-section. Such a tube is well suited for the insertion of, for example, an endoscope, laparoscope, catheter, or guidewire. In particular, the shape of a tube with a round cross-section is similar to the basic shape of a blood vessel and is therefore especially well suited for the insertion of an intravascular instrument, such as a guidewire or catheter. Furthermore, a tube, especially one with a round cross-section, is easy to manufacture and easy to integrate into a phantom.

[0017] An advantageous embodiment of the invention provides that the phantom additionally possesses an optical feature by which it can be registered in the coordinate system of an optical camera arrangement. This enables additional optical registration, thereby increasing the accuracy of the registration. Furthermore, optical registration can also be performed instead of registration based on X-ray images, thus reducing the radiation dose and the overall effort required for X-ray imaging in the registration process. However, for this purpose, the optical feature must be registered in the coordinate system of the X-ray system. Therefore, savings in radiation dose and effort are particularly possible if the optical feature is not registered using X-ray images from the X-ray system, but, for example, also based on an optical image.For this purpose, the X-ray system could, for example, be equipped with an additional optical camera array that is permanently attached to the X-ray system and registered with it from the outset. Thus, if the X-ray system has an optical camera array that is registered with the system from the beginning, the optical feature of the phantom can be recorded without having to take X-ray images.

[0018] An advantageous embodiment of the invention provides that the phantom has a detection device that can recognize when the shape-capturing instrument is inserted into the phantom. When the detection device recognizes that the instrument has been inserted into the phantom, it generates a registration signal.

[0019] The detection device is designed to recognize when the instrument has been inserted to at least a certain position. This position is chosen to enable mutual registration of the shape-detection instrument and the X-ray system. When the detection device recognizes that the instrument has reached this position, it generates a registration signal. The detection device can be implemented, for example, as a touch sensor, a tactile sensor, or a capacitive or optical sensor. These can be conventional, commercially available sensors that are simple, reliable, and cost-effective. Following the generation of the registration signal, a computer-implemented registration process can be used to perform the mutual registration of the instrument and the X-ray system.

[0020] The registration process can be performed on the X-ray system or on the image-capturing instrument, because both the X-ray system and the image-capturing instrument each have a coordinate system. The X-ray system comprises a control unit, and the image-capturing instrument a monitoring unit. One of these units, or both simultaneously, can perform the registration process. The registration process can also be performed by a separate, unrelated computing unit. Accordingly, the registration signal is transmitted from the acquisition unit to the control unit of the X-ray system, to the monitoring unit of the image-capturing instrument, or to the other computing unit. As soon as the registration signal is received, the registration process is started in the receiving unit(s).

[0021] The invention's automatic initiation of the registration process reduces the effort and time required for registering the coordinate systems. By capturing the position of the shape-capturing instrument within the phantom that is suitable for mutual registration, the precision of the registration can be improved, since the exact relative position of the instrument in relation to the X-ray system is precisely known with the previously known suitable registration position.

[0022] According to the inventive method, a phantom is positioned within the imaging area of ​​the X-ray system. X-ray images of the phantom's shape feature are then acquired by the X-ray system from different angles. The phantom's position remains unchanged during the acquisition of the X-ray images. The shape-capturing instrument is also inserted into the phantom's shape feature. Preferably, the shape-capturing instrument is inserted into the phantom before the X-ray images are acquired so that it is depicted in the images and can thus provide additional information for the registration process. However, it is also possible to insert the shape-capturing instrument into the phantom only after the X-ray images have been acquired, or independently of the acquisition of the X-ray images, if no X-ray images of the shape-capturing instrument are required for the subsequent registration process.This is advantageous, for example, if the shape-capturing instrument is sensitive to X-rays. The shape of the inserted shape-capturing instrument is captured by the shape-capturing instrument, with the position of the phantom during shape capture corresponding to the position of the phantom during the acquisition of the X-ray images. Subsequently, the shape-capturing instrument and the X-ray system are mutually registered based on the X-ray images and the captured shape of the shape-capturing instrument.

[0023] According to the invention, the mutual registration of the shape-capturing instrument and the X-ray system, or the mutual registration of their coordinate systems, is achieved using a single phantom. This saves time and effort, as only one phantom is required and only needs to be positioned once. Furthermore, the fact that only one phantom is used in a consistent position allows the shape of the shape-capturing instrument and the position of the phantom to be captured simultaneously by the shape-capturing instrument and the position of the phantom by the X-ray system. Advantageously, the shape of the shape-capturing instrument can also be captured simultaneously by the X-ray system if the shape-capturing instrument is already inserted into the phantom at the time of the X-ray exposure(s).This avoids the need to reposition the phantom or to perform the two shape-capture steps separately.

[0024] According to an advantageous embodiment of the method, at least two X-ray images of the shape-capturing instrument are taken at angles that differ by at least 30 degrees and are preferably orthogonal to each other. The position of the phantom and the shape-capturing instrument remains unchanged during the X-ray acquisition. The shape of the shape-capturing instrument is then reconstructed from the at least two X-ray images. Reconstruction based on a small number of X-ray images allows at least the determination of the position and course of the shape-capturing instrument, although not a complete three-dimensional reconstruction. The shape-capturing instrument and the X-ray system, or their coordinate systems, are then mutually registered using the reconstructed and the captured shape of the shape-capturing instrument.

[0025] By using X-ray images to capture both the phantom's radiographic features and the shape of the shape-capturing instrument, a particularly reliable registration with respect to the X-ray system can be achieved. Furthermore, the radiographic features and the shape of the shape-capturing instrument can be captured using the same X-ray images, thus saving time and effort by eliminating the need for additional X-rays. Combined with the shape captured by the shape-capturing instrument itself, this provides two different pieces of information regarding the shape of the shape for the registration process, thereby increasing the accuracy and robustness of the procedure.

[0026] According to an advantageous further development of the method, a phantom model is received, which comprises a spatial shape model of the shape feature. The model can be based on common modeling systems; for example, it can be a 3D mesh model. The shape model of the shape feature encompassed by the phantom model is provided by reading, extracting, or retrieving it from the phantom model. Then, the shape-capturing instrument and the X-ray system, or rather their coordinate systems, are mutually registered based on the shape of the shape model and the shape captured by the shape-capturing instrument.

[0027] The shape of the form feature, including its position and course, is known with high accuracy due to the predetermined design of the phantom. Consequently, the shape of the form-capturing instrument inserted into the form feature, which is imprinted by the form feature's shape, is also known with high accuracy and is not subject to inaccuracies from shape reconstruction, which could, for example, be performed using X-ray images. This increases the accuracy of the registration process. Furthermore, additional process steps, effort, and radiation dose required to reconstruct the shape of the form-capturing instrument using X-ray images can be avoided. This reduces the complexity of the registration process, allowing it to be carried out more quickly and with greater accuracy.

[0028] Further features and advantages will become apparent from the dependent patent claims and from the following description of exemplary embodiments with reference to figures.

[0029] The figures show: Fig. 1 X-ray system and shape-capturing instrument with phantom Fig. 2 Phantom according to the invention Fig. 3 Phantom according to the invention in another view Fig. 4 Phantom according to the invention in top view Fig. 5 Phantom according to the invention with optical marker Fig. 6 Phantom according to the invention with instrument capture

[0030] In Fig. Figure 1 is a schematic representation of an X-ray system 1. The X-ray system 1 is controlled by a control unit 21. A patient table 2 is assigned to the X-ray system 1. Objects or patients positioned on the patient table 2 can be imaged with the X-ray system 1.

[0031] The figure also schematically depicts a shape-sensing instrument 6. The shape-sensing instrument 6 is controlled by a control unit 7 to generate and evaluate sensor data. The shape-sensing instrument 6 can, for example, be an instrument that incorporates an optical shape-sensing fiber. Such fibers are known and allow the shape and path of the fiber, and thus of the shape-sensing instrument 6, to be detected. By evaluating the sensor data generated by the shape-sensing fiber, the control unit 7 can determine the current shape and path of the fiber, and thus of the shape-sensing instrument 6.

[0032] On the patient table 2, a phantom 3 according to the invention is positioned within the imaging area of ​​the X-ray system 1. The phantom 3 comprises, as a form feature, a tube 4 into which the shape-capturing instrument 6 is fully inserted. "Fully inserted" means that the shape-capturing instrument 6 is inserted to the end of the tube 4, the end of which limits further advancement and insertion of the shape-capturing instrument 6. The phantom 3 also has a series of X-ray features, which are designed as X-ray markers 5. The X-ray markers 5, like the tube 4, are arranged within the phantom 3 extending in all three spatial directions. The X-ray markers 5 can also be of different sizes and have different levels of transparency to X-rays in order to enable differentiation in X-ray images.The arrangement and visibility of the X-ray markers 5 facilitate the recording of the positions of the X-ray markers 5 in X-ray images and thereby facilitate or improve the determination of the respective three-dimensional position in space.

[0033] Phantom 3 is conventionally designed with respect to the X-ray markers 5. Such phantoms are known and allow for precise registration between the X-ray system and the phantom. Additionally, Phantom 3 features tube 4, which is used to position the shape-capturing instrument 6 in a three-dimensional shape. Since tube 4 is located within the imaging area of ​​the X-ray system 1, mutual registration of the X-ray system 1 and the shape-capturing instrument 6 is enabled.

[0034] For mutual registration, one or more X-ray images of the phantom 3, including the shape-capturing instrument 6, are taken. If multiple X-ray images are taken, they may differ in their angle of view. If the angles of view differ by at least 30 degrees, the spatial positions of the depicted objects can be reconstructed from the X-ray images. A particularly accurate reconstruction is possible with a difference of 90 degrees. Using the X-ray markers 5, the X-ray system 1 with the phantom 3 is registered from the X-ray image(s). This provides a registration for the X-ray system 1 and the imaging area.

[0035] Simultaneously, the shape-capturing instrument 6 can be reconstructed, or at least symbolically reconstructed, from several of the X-ray images whose angles differ by at least 30 degrees. Symbolic reconstruction refers to a reconstruction of the position and trajectory of the shape-capturing instrument 6, but it is not a complete three-dimensional representation of the shape-capturing instrument 6. With this reconstruction, the position and trajectory of the shape-capturing instrument 6 are defined within the coordinate system of the X-ray system 1.

[0036] Alternatively or additionally, the position and path of the shape-capturing instrument 6 within the coordinate system of the X-ray system 1 can also be determined from the previously known construction of the phantom 3. The shape-capturing instrument 6 assumes the position and path of the tube 4, which is determined by its design and structurally fixed. The position and path of the tube 4 within the phantom 3 can be assumed to be known beforehand. Therefore, the position and path of the tube 4 with respect to the X-ray markers 5 can also be assumed to be known beforehand. Consequently, the position and path of the shape-capturing instrument 6 inserted into the tube 4 with respect to the X-ray markers 5, and thus indirectly with respect to the X-ray system 1, are also known.

[0037] For mutual registration, the position and trajectory of the shape-capturing instrument 6 must be determined not only in the coordinate system of the X-ray system 1 but also in the coordinate system of the shape-capturing instrument 6. For this purpose, the position and trajectory of the shape-capturing instrument 6 are determined by the control unit 7. The determination of the position and trajectory of the shape-capturing instrument 6 can, for example, be performed simultaneously with the X-ray images taken by the phantom 3 for registration purposes. Alternatively, the determination can be performed at a different time. In this case, it is only necessary to ensure that the position of the phantom 3, including its orientation, remains unchanged. To ensure that the phantom 3 does not move, it can, for example, be firmly attached to the patient table 2 using a holder.

[0038] Mutual registration can then be performed based on the position and trajectory of the shape-capturing instrument 6 in the coordinate system of the X-ray system 1 and in the coordinate system of the shape-capturing instrument 6. For this purpose, information about the captured shape can be transmitted from the control unit 7 to the control unit 21, or conversely, information about the captured shape can be transmitted from the control unit 21 to the control unit 7, or information about the respective captured shape can be transmitted from the control unit 7 and the control unit 21 to a separate computer. The registration can then be carried out by the control unit 7, the control unit 21, or the separate computer using known registration procedures.

[0039] In Fig. Figure 2 shows a schematic representation of the phantom 3 according to the invention. The X-ray markers 5 are of different sizes, making them distinguishable from one another. They are arranged in a spiral pattern around the outer surface of the phantom 3. The arrangement and size of the X-ray markers 5 allow the position and orientation of the phantom 3 to be determined using two or more X-ray images. For this purpose, the X-ray images are taken at angles that differ by at least 30 degrees.

[0040] The Phantom 3 also features a tube 4 into which a shape-capturing instrument 6 can be inserted. The tube 4 is designed to accommodate the shape-capturing instrument 6, for example, by having a suitable cross-section and diameter. Since the tube 4 is elongated and tubular in shape, it can accommodate an elongated, tube-like shape-capturing instrument 6. The shape of the shape-capturing instrument 6 is similar to that of the tube 4 in terms of its position and shape. "Similar" in this context means that the shape of the shape-capturing instrument 6, when inserted into the tube 4, approximately matches the shape of the tube 4.

[0041] The accuracy of the match depends essentially on the clearance between the shape-detecting instrument 6 and the tube 4. This clearance should allow for easy and resistance-free insertion of the instrument 6. In particular, if the known shape of the tube 4 is to be used for registering the shape-detecting instrument 6, the clearance should be as small as possible to ensure high accuracy. In this case, the accuracy of the shape detection by the instrument could be taken into account when setting the clearance; if the instrument allows shape detection with millimeter accuracy, the clearance should also be set in the millimeter range. Conversely, if the shape of the tube 4 is not to be used for registering the shape-detecting instrument 6, the diameter of the tube 4 could be chosen to be relatively large in order to accommodate a wide variety of instruments 6.

[0042] In Fig. Figure 3 schematically depicts the phantom 3 according to the invention from a different perspective. In this altered perspective, the tube 4 appears different. The illustration serves to demonstrate the three-dimensional extent, particularly of the tube 4.

[0043] In Fig. Figure 4 schematically depicts the phantom 3 according to the invention from yet another perspective, namely a top view. This figure serves to illustrate the arrangement of the X-ray markers 5 in the outer region of the phantom 3 and the spatial extent of the tube 4.

[0044] In Fig. Figure 5 schematically depicts a phantom 10 according to the invention, which has an additional optical feature in the form of an optical marker device 8. Reference is made to the preceding description regarding the X-ray markers 5 and the tube 4. The additional marker device 8 comprises a series of optical markers 11 and is fixedly mounted on the phantom 10. The optical markers 11 of the additional marker device 8 can be detected by an optical camera system 9. The camera system 9 can, for example, be based on a conventional optical camera or on a depth camera. The optical markers 11 of the marker device 8 are spatially arranged such that the spatial position and orientation of the marker device 8 can be determined from the images captured by the camera.In this respect, the optical marker device 8 together with camera system 9 represents a known optical tracking system and the detection of position and orientation is carried out according to known methods.

[0045] The optical marker device 8 can be permanently attached to the Phantom 10 or be removable. The only essential requirement is that it remains in the same position on the Phantom 10 during the X-ray imaging 8 and camera acquisition. Instead of or in addition to the optical marker device 8, optical markers can also be arranged directly on the Phantom 10. Common designs can be used for this purpose, such as circles, crosshairs, or checkerboard patterns.

[0046] The optical marker device 8, or the optical tracking of the phantom 10, allows its position and orientation to be determined within the coordinate system of the optical tracking system. To determine the position and orientation of the phantom 10 within the coordinate system of the X-ray system 1, the optical tracking system can also determine its position and orientation using corresponding optical markers on the X-ray system 1. This allows for a mutual registration of the phantom 10 and the X-ray system 1 based on the position and orientation determined by the tracking system. Using the known position and path of the tube 4 within the phantom 10, the position and path of a shape-capturing instrument inserted into the tube 4 can then also be determined within the coordinate system of the optical tracking system and registered with the coordinate system of the X-ray system 1.

[0047] In Fig.Figure 6 schematically depicts a phantom 12 according to the invention with a detection device 13. Reference is made to the preceding description regarding the X-ray markers 5 and the tube 4. The detection device 13 can detect whether an instrument has been fully inserted into the tube 4. Once the instrument is fully inserted into the tube 4, it has assumed a position and shape suitable for registering the coordinate system of the instrument with that of the X-ray system 1. When the detection device 13 detects that an instrument has been fully inserted into the tube 4, i.e., has assumed a position and shape suitable for registration, it generates a registration signal. The detection device 13 can, for example, comprise a contact sensor or touch sensor arranged in the tube 4, which reacts when an instrument touches the end of the tube 4.The detection device 13 can, for example, also include an optical sensor that makes it possible to optically detect when an instrument is advanced into the end region of the tube 4.

[0048] The registration signal is transmitted to the computing unit or units that execute the registration procedure. The registration signal is thus transmitted to the control unit 21, the monitoring unit 7, or to a separate computing unit. As soon as the relevant computing unit or units receive the registration signal, the execution of the registration procedure is initiated. To carry out the registration procedure, the relevant computing unit or units receive the position and trajectory of the instrument in the coordinate system of the X-ray system 1 as well as in the coordinate system of the instrument itself. Based on this information, mutual registration can be carried out in a known manner. The acquisition unit 13 thus enables the registration procedure to be started automatically as soon as the instrument is inserted into the tube 4 of the phantom 12.

[0049] The preceding description is intended to include persons of male, female or other gender identities, regardless of the grammatical gender of a particular term.

Claims

[1] Phantom for mutual registration of a shape-capturing instrument and an X-ray system, wherein the phantom has an X-ray feature which is set up to enable registration of the phantom in the coordinate system of the X-ray system by means of X-ray images of the phantom by the X-ray system, characterized by , that the phantom has a shape feature that is designed to enable the phantom to be registered in the coordinate system of the shape-capturing instrument by means of shape capture by the shape-capturing instrument, the form feature is designed to introduce the form-capturing instrument into it and thereby bring it into a registration form that extends in all three spatial directions. [2] Phantom according to claim 1, wherein the X-ray feature is designed as X-ray visible markers arranged on or in the phantom, the arrangement of which extends in all three spatial directions. [3] Phantom according to one of the preceding claims, wherein the shape feature is designed as a tube. [4] Phantom according to one of the preceding claims, which additionally has an optical feature configured to enable the phantom to be registered in the coordinate system of an optical camera arrangement. [5] Phantom according to any one of the preceding claims, which has a detection device designed to recognize when the shape-capturing instrument has been inserted into the phantom, wherein a registration signal can be generated by means of the detection device when it detects that the shape-capturing instrument has been inserted into the phantom. [6] Method for mutually registering a shape-capturing instrument and an X-ray system, comprising the steps - Positioning a phantom according to one of the preceding device claims in the recording area of ​​the X-ray system, - Taking X-ray images of the phantom's X-ray feature using the X-ray system at different angles, while the phantom's position remains unchanged during the X-ray exposures, - Introducing the shape-capturing instrument into the shape feature of the phantom, - Capturing the shape of the shape-capturing instrument by the shape-capturing instrument, wherein the position of the phantom corresponds to the position during the X-ray images, - Mutual registration of the shape-capturing instrument and the X-ray system based on the X-ray images and the captured shape of the shape-capturing instrument. [7] Procedure according to the preceding procedure claim, comprising the steps - Taking at least two X-ray images of the shape-capturing instrument, the angles of which differ by at least 30 degrees and are preferably orthogonal to each other, whereby the position of the phantom and the shape-capturing instrument remains unchanged during the X-ray imaging, - Reconstructing the shape of the shape-capturing instrument from at least two X-ray images, - Mutual registration of the shape-capturing instrument and the X-ray system based on the reconstructed shape of the shape-capturing instrument and the captured shape of the shape-capturing instrument. [8] A method according to any of the preceding method claims, comprising the steps - Receiving a phantom model that includes a spatial shape model of the shape feature, - Providing the form model, - Mutual registration of the shape-capturing instrument and the X-ray system based on the shape of the shape model and the captured shape of the shape-capturing instrument.

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