Method and apparatus for providing guidance data in an x-ray system

Abstract

The invention relates to a method for providing guidance data for positioning a region of interest, an X-ray source and an X-ray detector of a subject, the method comprising the steps of acquiring (S10) current positioning data of at least one tangible bony landmark of the region of interest from a measurement device, acquiring (S11) current positioning data of the X-ray source and the X-ray detector by a processor, determining (S12) guidance data for positioning the region of interest, the X-ray source and the X-ray detector by utilizing a parametric 3D model configured to describe a pose of the region of interest, determining the acquired current positioning data of the at least one tangible bony landmark of the X-ray source and the X-ray detector, and providing (S13) the guidance data by the processor.

Description

[Technical field]

[0001] The present invention relates to a method for providing guidance data for positioning a region of interest in a subject, an X-ray source and an X-ray detector, an apparatus for providing guidance data for positioning a region of interest in a subject, an X-ray source and an X-ray detector, a system for medical imaging, and a computer program element. [Background technology]

[0002] In medical imaging, X-ray imaging is a widely used medical imaging method. X-ray systems are state of the art and therefore well known. The quality of medical images obtained by such X-ray systems depends, among other things, on the quality of the preparation of the medical imaging process preceding the actual image acquisition, in particular the alignment of the subject relative to the X-ray system. If the quality of the medical image is insufficient, the medical image must be repeated, or even worse, an erroneous medical diagnosis may be derived from the medical image. In short, this may lead to increased costs for medical imaging, erroneous medical diagnoses, higher radiation exposure, and reduced image quality.

[0003] US 2016 / 0074004 A1 describes a positioning of an examination table relative to a medical technical imaging device, whereby a camera aligned with the examination table and a display and operation unit designed to output the camera image comprise a microprocessor, which is configured to cause the device to freeze the camera image on the display and operation unit in a manner that is time-dependent on a first user interaction, to define reference position information on the examination table in the frozen camera image based on a second user interaction, and to move the examination table or the medical technical imaging device by means of the positioning system, such that the reference position information coincides with the recording area of ​​the medical technical imaging device. US Patent Application Publication No. 2020 / 0375546 describes a medical imaging guidance system comprising a patient sensor configured to receive three-dimensional (3D) data associated with a patient and imaging hardware components configured to acquire image data of anatomical features associated with the patient, the imaging system comprising a hardware position sensor associated with the imaging hardware components and a processor configured to: generate a 3D surface map associated with the patient based on the 3D data; generate a 3D patient space from the 3D surface map associated with the patient; generate a 3D patient model by mapping an anatomical atlas to the 3D patient space, where the 3D patient model comprises one or more 3D representations of anatomical features of the human body within the 3D patient space; determine a desired position associated with the imaging hardware components to acquire image data of the anatomical features; determine a current position associated with the imaging hardware components from the hardware position sensor; and determine a desired movement associated with the imaging hardware components to position the imaging hardware components at the desired position. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there may be a need to provide guidance data in X-ray imaging, particularly in the preparation stages for the X-ray imaging. [Means for solving the problem]

[0005] The object of the present invention is solved by the subject matter of the independent claims, further embodiments are incorporated in the dependent claims.

[0006] According to a first aspect, there is provided a method for providing guidance data for positioning a region of interest, an x-ray source, and an x-ray detector of a subject. The method includes obtaining, by a processor, current positioning data of at least one tactile bony landmark of the region of interest from a measurement device, the current positioning data being derived from palpation of the at least one tactile bony landmark. The processor obtains the current positioning data of the x-ray source and the x-ray detector. The processor determines guidance data for positioning the region of interest, the x-ray source, and the x-ray detector by utilizing a parametric 3D model configured to describe a pose of the region of interest, the at least one tactile bony landmark of the x-ray source, and the x-ray detector, and the x-ray detector, and provides the guidance data by the processor.

[0007] The term "guidance data" as used herein should be understood broadly and relates to any information configured to guide the adaptation of the alignment of the region of interest, the X-ray source, and the X-ray detector from a current alignment to a desired alignment. The guidance data may include positioning data such as translational and rotational degrees of freedom of the region of interest, the X-ray source, and the X-ray detector. The guidance data may include degrees of freedom from the joint of the region of interest (e.g., the knee joint). The guidance data may include a shift value (e.g., shift x position in x direction of the X-ray detector 100 mm or shift knee joint angle -5°) from the current alignment to the desired alignment. The guidance information may be presented by a visual signal (e.g., a display) or an audio signal (e.g., a loudspeaker announcement). The guidance data may be intended for medical personnel such as a radiologist who operates, monitors, or the like, the imaging system. The guidance data may be intended as control information for the imaging system, the guidance data being configured to control the imaging system to automatically position the X-ray source and the X-ray detector. Furthermore, the imaging process itself may optionally be performed at least semi-automatically.

[0008] The term "subject" as used herein should be understood broadly and relates to any human or animal.

[0009] As used herein, the term region of interest should be understood broadly and relates to any part of an object. For example, the region of interest may be a bone, a joint, a hip joint, a bone arrangement of two or more bones and one or more joints (e.g., an ankle joint with a lower leg bone and a foot bone). The region of interest may also include the entire subject itself.

[0010] The X-ray source and the X-ray detector, as used herein, should be understood as the main elements of the X-ray system. The X-ray source and the X-ray detector may be arranged independently of each other. The position of the X-ray source and the X-ray detector can be known by the control of the X-ray system. The position of the X-ray source and the X-ray detector can be measured by a measuring device such as a range camera or a laser interferometer. The X-ray detector may be in the form of a digital cassette detector, which can be arranged in a non-restrictive manner within the field of view of the X-ray source. For example, the position of the X-ray source and / or the X-ray detector can be determined and / or indicated absolutely, for example by absolute coordinates in a correspondingly defined coordinate system, and / or for example relative to a commonly defined reference point or relative to each other.

[0011] As used herein, the term palpable bony landmark should be understood broadly and relates to bony landmarks that are typically hidden by the tissue and skin of a subject such that the palpable bony landmark cannot be directly detected, i.e., cannot be seen, for example, by a visual system (e.g., the human eye or a camera). A palpable bony landmark may be a suitable bone part, bone portion, etc., such as the ankle of the foot, which may be hidden by excess tissue in an overweight person. However, the ankle can nevertheless be palpated by a radiographer.

[0012] The term processor as used herein should be understood broadly and relates to any electronic data processing unit configured to perform the steps of the above-mentioned methods. The processor may be implemented in hardware and / or software. The processor may be a single entity or may be distributed over multiple entities.

[0013] The term positioning data as used herein relates to any spatial information configured to describe the position or alignment of the region of interest, the X-ray source, and the X-ray detector. The positioning data may include absolute and relative values ​​in a coordinate system (e.g., the coordinate system of the X-ray imaging system, or the coordinate system of the region of interest or object). The term "current" as used herein refers to positioning information that currently exists.

[0014] The term measurement device as used herein should be understood broadly and relates to any sensor or sensor arrangement configured to determine a position, i.e. one or more sensors. The measurement device may comprise one or more of an RGB camera, an RGB-D camera, a range camera, a laser interferometer, which is not limited herein. The measurement device may be positioned to be directed towards the area of ​​interest, for example above the area of ​​interest or to the side of the area of ​​interest. The measurement device may be in a wired (e.g., communication network such as Ethernet) or wireless (e.g., WIFI) connection to the processor.

[0015] As used herein, the term palpation should be understood broadly and relates to tactile sampling. Palpation may include palpation performed by a human (e.g., a radiographer) or a soft tissue robot. Palpation may also be performed by a human using an auxiliary tool such as a pointing device.

[0016] The term parametric 3D model as used herein should be understood broadly and relates to a model configured to describe the geometric alignment between the region of interest, the X-ray source, and the X-ray detector. The parametric 3D model may be further configured to describe the region of interest by parameters indicating dimensions or sizes of parts of the region of interest (e.g., bones) and one or more degrees of freedom of the region of interest (e.g., flexion angle of a knee joint). The parametric 3D model may be further configured to describe the pose of the region of interest, i.e., the spatial position of the region of interest, which may also be referred to as a combination of the position and orientation of a rigid body, such as the subject's body or the region of interest. In other words, the parametric 3D model generally describes the imaging alignment, and in particular describes one or more dimensions or sizes and one or more degrees of freedom of the region of interest. The parametric 3D model may, for example, take measured positioning data as input and may output a current alignment of the region of interest, the X-ray source, and the X-ray detector. The current alignment may be described using positioning data of one or more elements of the region of interest of the X-ray source and the X-ray detector.

[0017] The invention is based on the finding that the quality of a medical image is important for the follow-up diagnosis of a medical image. The quality of a medical image depends on what the medical image should show. For example, a special gap between two bones in a special fluoroscopy, for example, the gap between the medial and lateral malleolus in a special direction of the radiation beam. In other words, the quality of the acquired medical image depends on the angle between the central beam of the X-ray imaging system and, for example, the joint axis of the patient's knee, the knee being the region of interest. The desired angle may be derived from guidelines for producing radiographs, etc. In order to obtain such a medical image with the desired angle between the central beam and the joint, the region of interest, the X-ray source and the X-ray detector must be aligned accordingly. Since the region of interest (for example, the gap between the medial and lateral malleolus or the knee joint) is hidden by the tissue and skin of the subject (i.e., the patient), it may not be obvious how the region of interest, the X-ray source and the X-ray detector must be positioned. In clinical practice, radiographers with a lot of experience feel palpable bony landmarks or palpable bony prominences and place the tactile impression in a three-dimensional context to position the region of interest, the X-ray source and the X-ray detector. However, this requires a great deal of experience from the radiographer. The present invention proposes to simplify this approach by detecting current positioning data of at least one palpable bony landmark, the X-ray source and the X-ray detector, and to provide the radiographer guidance data based on the current positioning data of how to position the region of interest, the X-ray source and the X-ray detector. In other words, the present invention assists the computer-aided radiographer in preparing the alignment of the region of interest, the X-ray source and the X-ray detector, so that a highly experienced radiographer is not required. This may be advantageous since it simplifies the imaging process, especially the preparation phase. This may be advantageous in terms of quality, cost and efficiency. This may be advantageous since a radiographer with a great deal of experience is not required for the imaging process. An important advantage is that a less experienced radiographer can easily adapt the positioning without the use of radiation (i.e. low dose pre-images or retakes).The positioning and / or alignment of the region of interest, the X-ray source and the X-ray detector can advantageously be performed before the X-ray imaging process. This is further advantageous for training inexperienced radiologists. A further advantage may be that the method does not require markers or the like.

[0018] According to one embodiment, obtaining current positioning data of the at least one tactile bone landmark may include measuring a spatial position of at least a fingertip of a radiographer or a soft tissue palpation robot, which palpates the at least one tactile bone landmark. The measured spatial position may be registered to a coordinate system (e.g., the coordinate system of the x-ray system). The underlying registration algorithm may include a weighting according to the expected accuracy of the measured positioning data. For example, the radiographer palpates the region of interest (e.g., ankle joint) and detects the lateral malleolus (i.e., the first tactile bone landmark) with one fingertip of the left hand and the medial malleolus (i.e., the second tactile bone landmark) with one fingertip of the right hand. The position of the visible fingertip indirectly reveals the position of the invisible tactile bone landmark. By measuring the spatial position of the fingertip, the spatial position of the tactile bone landmark can be easily determined. When the radiographer palpates the region of interest, a measuring device, such as a range camera, one or more cameras, may measure the spatial position. Alternatively, the radiographer may utilize auxiliary equipment, for example, wearing a tracking device (e.g., an electromagnetic tracking device, or a reflective marker for optical tracking) on ​​the hand, wrist, or finger. When the soft tissue robot palpates the region of interest, the positioning data of the tactile bony landmarks is determined by the control of the soft tissue robot, which continuously tracks the spatial position of the limbs of the soft tissue robot. The soft tissue robot may be equipped with touch sensors for palpation and / or patient positioning. This may be advantageous since the position to at least one tactile bony landmark is accurately determined. The radiographer may be equipped with touch sensors (e.g., gloves with touch sensors on the fingertips).

[0019] According to one embodiment, acquiring current positioning data of the at least one tactile bone landmark may include a trigger signal configured to indicate that the radiographer or at least one fingertip of the soft tissue palpation robot palpates the at least one tactile bone landmark. By measuring the trigger signal, synchronization of the palpation of the at least one bone landmark and the acquisition of its positioning data may be advantageously achieved. The trigger signal may be received by a measurement device (e.g., a microphone, a button, a camera, a pressure sensor, or a touch sensor) and transmitted to a processor to initiate the measurement of the spatial position of the at least one tactile bone landmark. This may be advantageous in terms of accuracy and efficiency, as it simplifies the process. This may be advantageous, as the moment when the radiographer finds the tactile bone landmark is not otherwise observable.

[0020] According to one embodiment, the trigger signal may be generated actively by the radiographer and / or passively by a touch sensor located on at least one fingertip of the radiographer or the soft tissue tactile robot. Examples for actively generating the trigger signal may include pressing a button, voice recognition, eye tracking, and gesture detection. For example, the radiographer may touch at least one tactile bony landmark and then touch a button with the other hand to generate the trigger signal. For example, the radiographer may touch at least one tactile bony landmark and then verbally command the device to generate a trigger signal, for example, by uttering "measure now", which command may be captured by a microphone. For example, the radiographer may touch at least one tactile bony landmark and then blink his eye twice to generate a trigger signal that may be captured by a camera. For example, the radiographer may touch at least one tactile bony landmark and then raise his other hand to generate a trigger signal that may be captured by a camera. The touch sensor may detect an increased pressure indicative of at least one tactile bony landmark. For example, the radiographer or the soft tactile robot can palpate at least one tactile bony landmark to generate a trigger signal, and the radiographer or the soft tactile robot can increase the tactile pressure. The post-processing unit can, for example, process the pressure pattern, detect the trigger signal, and send it to the processor to initiate measurement of the spatial position of the at least one tactile bony landmark. This can further improve accuracy, efficiency, and flexibility.

[0021] In one embodiment, determining the guidance data may include determining a pose of the region of interest by utilizing a parametric 3D model and acquired current positioning data of at least one tactile bony landmark of the region of interest. The term "pose" as used herein relates to a spatial alignment of one or more elements (e.g., bones and joints) of the region of interest. The parametric 3D model may, for example, rely on at least one tactile bony landmark to estimate the pose of the region of interest. By determining the pose of the region of interest, the alignment within the region of interest may advantageously be determined. This may advantageously increase the accuracy of the guidance data. The parametric 3D model may further be used to determine the pose of the region of interest of one or more visible anatomical landmarks of the region of interest, for example measured by a measuring device. This may increase the accuracy of the guidance data.

[0022] In an embodiment, the guidance data may include a comparison of the pose of the region of interest, the positioning data of the region of interest, the positioning data of the X-ray source and the X-ray detector with the target alignment of the region of interest, the X-ray source and the X-ray detector. As used herein, the term target alignment of the region of interest, the X-ray source and the X-ray detector relates to an alignment obtained from a guideline for imaging the respective region of interest or from an expert input. The target alignment is described by the positioning data of the region of interest, the X-ray source and the X-ray detector. The target alignment may be stored, for example, in a table on a storage medium in communication with the processor. The comparison may include a calculation of a difference between the positioning data of the current alignment and the target alignment, which may be advantageously processed into guidance data provided to the radiographer.

[0023] In one embodiment, the parametric 3D model may include one or more anatomical parameters of the region of interest, the anatomical parameters may include at least one scale parameter of the region of interest and at least one degree of freedom of movement of the region of interest. The scale parameter may be the length, surface, volume of an element (e.g. bone) of the region of interest. The degree of freedom of movement may be the displacement of an element (e.g. bone) of the region of interest. The degree of freedom of movement may be the angle of a joint (e.g. knee joint) of the region of interest. The degree of freedom of movement may be the twist of the region of interest or an element of the region of interest. The parametric 3D model may be a general model, which may be adapted depending on the subject or region of interest to be imaged. For example, scale parameters such as the length of a bone are different for children and adults. The scale parameter may be adapted based on acquired anatomical landmarks of the region of interest. The parametric 3D model may be a multi-joint model. In other words, the parametric 3D model may relate to an adaptable multi-body model, where each single body and each degree of freedom of movement may be advantageously adjusted to describe the reality as accurately as possible.

[0024] In one embodiment, the method may further include receiving, by the processor, current positioning data of one or more anatomical landmarks of the region of interest from a measurement device, and updating, by the processor, the parametric 3D model based on the received current positioning data of one or more anatomical landmarks of the region of interest. The term anatomical landmark as used herein relates to a visible landmark configured to be measured by a measurement device. The measurement device may be an optical measurement device such as an RGB camera, a range camera, an RBG-D camera, etc. In contrast to tactile bone landmarks, the anatomical landmarks are visible and are not hidden by tissue and / or skin. The measured anatomical landmarks may be used to update the 3D parametric model. For example, the positioning data of two anatomical landmarks may be measured by a range camera, and the two anatomical landmarks indicate the length of the tibia. The parametric 3D model may then use the measured information to update the parametric 3D model of the lower leg (i.e., the region of interest in this example). This may be advantageous as it improves the accuracy of the parametric 3D model and therefore the accuracy of the guidance data. The measured spatial positions of the anatomical landmarks may be registered to a coordinate system (e.g., the coordinate system of the X-ray system or the region of interest). The underlying registration algorithm may include a weighting according to the expected accuracy of the measured positioning data. This may be advantageous in terms of outliers.

[0025] In one embodiment, the measurement device may be an optical measurement device, in particular a range camera. The optical measurement may be a stereo camera system including two or more cameras. The optical measurement device may be positioned above or to the side of the region of interest, the X-ray source, and / or the X-ray detector. The optical measurement device may be in wired or wireless communication with the processor. The optical measurement device may comprise one or more measurement sensors. The optical measurement device may be a single entity or may be distributed over multiple entities. The optical measurement device may comprise a communication interface.

[0026] According to one embodiment, the guidance data can be continuously determined and provided during positioning of the region of interest of the object, the X-ray source and the X-ray detector. In other words, the method is permanently implemented during the preparation phase, thus advantageously assisting, for example, the radiographer. This can increase the efficiency and quality of medical images. This is achieved by continuously executing the process steps of the method.

[0027] In one embodiment, providing guidance data may include visual and / or audio representations. The visual representation may be a display showing a schematic representation of the current alignment of the region of interest, the X-ray source, the X-ray detector, and the target alignment. The visual representation may be shown in virtual reality glasses or augmented reality glasses. The audio representation may be provided to the radiographer through a loudspeaker or earphones, and may include direct positioning instructions of the region of interest, the X-ray source, and the X-ray detector. The audio guidance may comprise acoustic tones using tone frequencies and / or repetition intervals to indicate rotation or translation of the patient or the X-ray source or the X-ray detector.

[0028] According to an embodiment, determining the guidance data of the region of interest, the X-ray source and the X-ray detector may include the calculation of a pseudo X-ray image by utilizing a parametric 3D model. The pseudo X-ray image is a schematic representation of the projection resulting from a current alignment of the region of interest, the X-ray source and the X-ray detector. The pseudo X-ray image may help to evaluate whether the current alignment is sufficient. This may be advantageous in terms of efficiency and quality.

[0029] Further aspects relate to an apparatus, an X-ray source, and an X-ray detector for providing guidance data for positioning a region of interest of a subject. The apparatus comprises a processor configured to acquire current positioning data of at least one tactile bony landmark of the region of interest from a measurement device, the current positioning data being derived from palpation of the at least one tactile bony landmark, the processor further configured to acquire current positioning data of the X-ray source and the X-ray detector, the processor further configured to determine guidance data for positioning the region of interest, the X-ray source, and the X-ray detector by utilizing the parametric 3D model and the acquired current positioning data of the at least one tactile bony landmark, the X-ray source, and the X-ray detector, the processor further configured to provide the guidance data. The processor can be a CPU, a workstation, a controller, or a node of a data center. The processor may be a single entity or distributed over multiple entities.

[0030] A further aspect relates to a system for medical imaging, comprising an apparatus as described above and an X-ray system, the X-ray system comprising an X-ray source and an X-ray detector.

[0031] A final aspect relates to a computer program element configured to execute the steps of the above-mentioned method when executed by a processor. The processor may be part of the medical imaging system or may be provided separately in another computing device. The computer program element may be stored in a computing unit that may be part of the embodiment. This computing unit may be configured to execute or trigger the execution of the steps of the above-mentioned method. It may also be configured to operate each component of the above-mentioned device. The computing unit may be configured to operate automatically and / or to execute a user's order. The computer program may be loaded into a working memory of a data processor. The data processor may thus be equipped to execute a method according to one of the above-mentioned embodiments. This exemplary embodiment of the invention encompasses both a computer program that uses the invention from the beginning and a computer program that transforms an existing program into a program that uses the invention by updating. Furthermore, the computer program element may provide all the steps necessary to fulfill the procedure of the exemplary embodiment of the procedure described above. According to a further exemplary embodiment of the invention, a computer readable medium such as a CDROM, a USB stick, etc. is presented, the computer readable medium having stored thereon a computer program element, which computer program element is described by the previous section. The computer program may be stored and / or distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless communication systems, however, the computer program may also be presented over a network, such as the World Wide Web, and downloaded from such a network into the working memory of a data processor.According to a further exemplary embodiment of the invention, a medium is provided for making available a computer program element for downloading, the computer program element being configured to perform a method according to one of the aforementioned embodiments of the invention.

[0032] It should be noted that the above-described embodiments may be combined with each other regardless of the aspects they relate to. Thus, the methods may be combined with structural features of devices and / or systems of other aspects, and similarly, the devices and systems may be combined with features of each other and with features discussed above with respect to the methods.

[0033] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Brief description of the drawings]

[0035] [Figure 1] 1 shows a schematic diagram of an apparatus according to a first embodiment of the present disclosure. [Diagram 2] A schematic diagram of the palpation of two palpable bony landmarks of the region of interest is shown. [Diagram 3] 1 shows a visual representation of guidance data. [Figure 4] 13 illustrates a visual representation of guidance data according to a further embodiment. [Diagram 5] FIG. 1 shows a schematic diagram of a system according to one embodiment of the present disclosure. [Figure 6] 1 shows a flowchart of a method according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] 1 shows a schematic diagram of an apparatus 10 according to a first embodiment of the present disclosure, the apparatus 10 being configured to provide guidance data for positioning a region of interest in a subject, an X-ray source, and an X-ray detector.

[0037] The apparatus 10 comprises a processor 11 configured to obtain current positioning data of at least one tactile bony landmark of the region of interest from a measurement device, the current positioning data originating from palpation of the at least one tactile bony landmark. The processor 11 is in this example a CPU of a workstation. The region of interest is for example the ankle of the foot and the at least one tactile bony landmark is the medial malleolus. The positioning data may be transmitted from the measurement device to the processor via a communication interface. The measurement device is in this example a range camera capable of providing 3D positioning data. The processor 11 is further configured to obtain current positioning data of the X-ray source and the X-ray detector. The positioning data of the X-ray source and the X-ray detector are also measured in this example by the measurement device (i.e. the range camera). Alternatively, the positioning data may be provided from a control of the X-ray system. The processor 11 is further configured to determine guidance data for positioning the region of interest, the X-ray source and the X-ray detector by utilizing the parametric 3D model and the obtained current positioning data of the at least one tactile bony landmark, the X-ray source and the X-ray detector. The parametric 3D model is then stored in a storage medium of the device 10. Alternatively, the parametric 3D model can be stored on a server in a data center, and there can be communication (e.g., Ethernet) between the processor and the server. The processor 11 is further configured to provide guidance data. The processor 11 has, for example, a communication interface connected to a display configured to present the guidance data.

[0038] 2 shows a schematic diagram of palpation of two tactile bony landmarks of a region of interest 20. The region of interest 20 is the ankle of the foot. The ankle is placed on an X-ray detector 21, in this example a digital cassette X-ray detector. The radiographer palpates the region of interest 20 with hands 22 and 23. The radiographer palpates fingertip 24 of the left hand 22, the lateral malleolus, and fingertip 25 of the right hand 23, the medial malleolus of the ankle. For example, by voice recognition, the radiographer generates a trigger signal to trigger a measuring device (e.g. a range camera (not shown)) to measure the spatial positions of both fingertips 24 and 25 in order to obtain position information of the tactile bony landmarks.

[0039] FIG. 3 shows a visual representation of the guidance data corresponding to the palpation shown in FIG. 2. The guidance data 30 is used to position the region of interest, the X-ray source and the X-ray detector. The guidance data 30 shows a skeletal model of the ankle of the foot (i.e. the region of interest 31) and two palpable bony landmarks 32 and 33. The guidance data 30 includes a schematic diagram of an ideal X-ray detector 34 and the central beam 35 of the X-ray source. The guidance data 30 further includes a representation of the current central beam 36 and an arrow 37 with a displacement value that guides the radiography device to adapt the X-ray source by 100 mm in this direction. The guidance data 30 assists the radiography device to adapt the position of the X-ray source and the X-ray detector in this example. The radiographer was shown the guidance information by augmented reality glasses. Alternatively, the guidance data is shown on a display in the examination room. The guidance data can further include different views of the region of interest.

[0040] Fig. 4 shows a visual representation of guidance data 40 according to a further embodiment. The guidance data 40 comprises a pseudo-X-ray image of a region of interest 41, in this example the ankle of Fig. 1. The pseudo-X-ray image is calculated using a parametric 3D model. The pseudo-X-ray image is a schematic illustration of the projection resulting from the current alignment of the region of interest, the X-ray source and the X-ray detector. The pseudo-X-ray image is presented to the radiographer by means of augmented reality glasses.

[0041] FIG. 5 shows a schematic diagram of a system 50 for medical imaging. The system 50 comprises a device 51 for providing guidance data for positioning the region of interest of the object, the X-ray source, and the X-ray detector, as described in FIG. 1. The system 50 further comprises an X-ray system, which comprises an X-ray source 52 and an X-ray detector 53. The subject 54 lies on a support 55. The region of interest 56 is the ankle, which in this example is located above the X-ray detector 53, a digital cassette X-ray detector. Alternatively, any other X-ray detector can be used. A radiographer 57 prepares the positioning of the region of interest 56, the X-ray source 52, and the X-ray detector 53. A measuring device 58 is located on the ceiling above the X-ray imaging device 57 and the region of interest 56. The measuring device 58 is an RGB-D camera, which in this example is configured to measure the spatial position of the radiographer's fingertips palpating the region of interest. The measuring device 58 is further configured to measure positioning data of one or more anatomical landmarks of the region of interest, such as the ends of the foot and the knee joint. The measuring device 58 is further configured to measure positioning data from the X-ray detector 53. In this example, the position of the X-ray source is obtained by a control (not shown) of the X-ray system. The radiographer wears augmented reality glasses 59 configured to show guidance data for positioning the region of interest, the X-ray source and the X-ray detector. The X-ray system, the measuring device 58, the augmented reality glasses 59 and the control of the device 51 are wirelessly connected by WIFI, Bluetooth, etc.

[0042] FIG. 6 shows a flowchart of a method according to a further embodiment of the present disclosure. The method is used to provide guidance data for positioning a region of interest, an X-ray source, and an X-ray detector of a subject. The method includes the following steps: In step S10, current positioning data of at least one tactile bony landmark of the region of interest from a measurement device is obtained by a processor, the current positioning data being derived from palpation of the at least one tactile bony landmark. The current positioning data of the at least one tactile bony landmark may be obtained by measuring a spatial position of at least a fingertip of the radiographer or the soft tissue palpation robot palpating the at least one tactile bony landmark. The measurement of the spatial position of the at least one fingertip may be initiated by a trigger signal configured to indicate that at least one fingertip of the radiographer or the soft tissue palpation robot palpates the at least one tactile bony landmark. The trigger signal may be actively generated by the radiographer and / or passively generated by a touch sensor disposed on at least one fingertip of the radiographer or the soft tissue palpation robot. The trigger signal can be generated by a button pressed by the radiographer or by an increase in pressure on a touch sensor. The spatial position of the fingertip can be measured using a range camera.

[0043] In step S20, current positioning data of the X-ray source and the X-ray detector is acquired by the processor. The positioning data of the X-ray source and the X-ray detector can be measured using a range camera. Alternatively, the positioning data may be received from the control of the X-ray system or from another measuring device, for example an RGB-D camera. The measured positioning data is sent to the processor.

[0044] Step S30 includes determining, by the processor, guidance data for positioning the region of interest, the X-ray source, and the X-ray detector by utilizing the parametric 3D model and the acquired current positioning data of at least one tactile bony landmark, the X-ray source, and the X-ray detector. The parametric 3D model may include anatomical parameters of the region of interest. The anatomical parameters may include at least one scale parameter of the region of interest and at least one degree of freedom of movement of the region of interest. Optionally, the processor may further receive current positioning data of one or more anatomical landmarks of the region of interest from a measurement device (e.g., a range camera). Optionally, the processor may further update the parametric 3D model based on the received current positioning data of one or more anatomical landmarks of the region of interest. Optionally, the processor may further determine a pose of the region of interest by utilizing the parametric 3D model and the acquired current positioning data of at least one tactile bony landmark of the region of interest. Optionally, the processor may further determine a comparison of the pose of the region of interest, the positioning data of the region of interest, the positioning data of the X-ray source and the X-ray detector with the target alignment of the region of interest, the X-ray source and the X-ray detector. The guidance data may be determined continuously. Optionally, the guidance data may include a pseudo X-ray, and the pseudo X-ray image may be calculated by utilizing a parametric 3D model.

[0045] Step S40 includes providing, by the processor, guidance data. The guidance information may be provided by means of a visual representation and / or by an audio representation. Optionally, the guidance data may be provided continuously.

[0046] In another exemplary embodiment, a computer program or a computer program element is provided, characterized in that it is configured to execute, on a suitable system, the method steps of the method according to one of the previous embodiments.

[0047] Thus, the computer program element may be stored in a data processing unit which may be part of the embodiments. This data processing unit may be configured to execute or trigger the execution of the steps of the above-mentioned method. Furthermore, it may be configured to operate the components of the above-mentioned device and / or system. The computing unit may be configured to operate automatically and / or to execute user orders. The computer program may be loaded into the working memory of the data processor. The data processor may thus be equipped to execute the method according to one of the above-mentioned embodiments.

[0048] Moreover, the computer program element may provide all the steps required to fulfill the steps of the exemplary embodiments of the procedures described above.

[0049] According to a further exemplary embodiment of the present invention, a computer readable medium such as a CDROM, a USB stick or the like is presented, the computer readable medium having stored thereon a computer program element, which computer program element is described by the previous section.

[0050] The computer program may be stored and / or distributed on a suitable medium, such as an optical storage medium or a solid-state medium, provided together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless communication systems.

[0051] However, the computer program may also be presented via a network such as the World Wide Web and downloaded from such a network into the working memory of a data processor. According to a further exemplary embodiment of the invention, a medium for making available a computer program element for downloading is provided, this computer program element being configured to perform a method according to one of the aforementioned embodiments of the invention.

[0052] It should be noted that the embodiments of the present invention are described with reference to different subject matters. In particular, some embodiments are described with reference to method type claims, and other embodiments are described with reference to device type claims. However, a person skilled in the art will gather from the above and following description that, unless otherwise notified, any combination of features belonging to one type of subject matter, as well as any combination between features related to different subject matters, are considered to be disclosed in this application. However, all features can be combined to provide synergistic effects that are more than the simple sum of the features.

[0053] While the invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered as illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the dependent claims.

[0054] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope. [Explanation of symbols]

[0055] 10, 51 equipment 11 Processors 20, 31, 41, 56 Area of ​​interest 21, 34, 53 X-ray detector 22, 23 Hands 24, 25 fingertips 30, 41 Guidance Data 32, 33 Palpable bony landmarks 35 Ideal central beam X-ray source 36 Current central beam X-ray source 37 Arrow 50 Systems 52 X-ray source 54 Subject 55 Support 57 X-Ray Photographer 58 Measuring Equipment 59 Augmented Reality Glasses S10 Acquire current positioning data of palpable bony landmarks S20 Acquisition of current position data of X-ray source and X-ray detector S30 Guidance data determination S40 Guidance data provision

Claims

1. A method for providing guidance data for positioning a region of interest of a subject, an X-ray source, and an X-ray detector, comprising: obtaining, by a processor, current positioning data of at least one palpable bone landmark of the region of interest from a measuring device, wherein the current positioning data is derived from palpation of the at least one palpable bone landmark; obtaining, by the processor, current positioning data of the X-ray source and the X-ray detector; determining, by the processor, guidance data for positioning the region of interest, the X-ray source, and the X-ray detector by using a parametric 3D model configured to describe a pose of the region of interest and the obtained current positioning data of the at least one palpable bone landmark, the X-ray source, and the X-ray detector; providing, by the processor, the guidance data; and having: The step of obtaining the current positioning data of the at least one palpable bone landmark includes: measuring a spatial position of at least one fingertip of a soft tissue palpation robot that palpates the at least one palpable bone landmark, and / or receiving a trigger signal configured to indicate that at least one fingertip of the soft tissue palpation robot palpates the at least one palpable bone landmark. having: Method.

2. The method according to claim 1, wherein the trigger signal is actively generated by the X-ray photographer and / or passively generated by a touch sensor disposed on at least one fingertip of the soft tissue palpation robot.

3. The method according to claim 1, wherein the step of determining the guidance data comprises determining a pose of the region of interest by using the parametric 3D model and the obtained current positioning data of at least one palpable bone landmark of the region of interest.

4. The method according to claim 3, wherein the step of determining the guidance data includes comparing a pose of the region of interest, positioning data of the region of interest, positioning data of the X-ray source and the X-ray detector, and a target alignment of the region of interest, the X-ray source, and the X-ray detector. **Claim 5**: The parametric 3D model has anatomical parameters of the region of interest, wherein the anatomical parameters have at least one scale parameter of the region of interest and at least one degree of freedom of movement of the region of interest. The method according to claim 1. **Claim 6**: The method according to claim 1, further comprising: receiving, by the processor, current positioning data of one or more anatomical landmarks of the region of interest from the measuring device; updating, by the processor, the parametric 3D model based on the received current positioning data of one or more anatomical landmarks of the region of interest. The method according to claim 1, further comprising the above. **Claim 7**: The method according to claim 1, wherein the measuring device is an optical measuring device, in particular a range camera. **Claim 8**: The method according to claim 1, wherein the guidance data is continuously determined and provided during positioning of the region of interest of the subject, the X-ray source, and the X-ray detector. **Claim 9**: The step of providing the guidance data has a visual representation, and / or an audio representation The method according to claim 1. **Claim 10**: The method according to claim 1, wherein the step of determining the guidance data of the region of interest, the X-ray source, and the X-ray detector includes calculating a virtual X-ray image by using the parametric 3D model. **Claim 11**: An apparatus for providing guidance data for positioning a region of interest of a subject, an X-ray source, and an X-ray detector, the apparatus comprising: a soft tissue palpation robot, and a processor configured to acquire current positioning data of at least one palpable bone landmark of the region of interest from a measuring device wherein the current positioning data is derived from palpation of the at least one palpable bone landmark; the processor is further configured to acquire current positioning data of the X-ray source and the X-ray detector; the processor is further configured to determine guidance data for positioning the region of interest, the X-ray source, and the X-ray detector by using the parametric 3D model describing the pose of the region of interest and the acquired current positioning data of the at least one palpable bone landmark, the X-ray source, and the X-ray detector. ​ The processor is further configured to provide the guidance data, The step of obtaining current positioning data of the at least one tangible bone landmark comprises, the measuring device measuring the spatial position of at least one fingertip of a soft tissue palpation robot that palpates the at least one tangible bone landmark and transmitting it to the processor, and / or the processor receiving a trigger signal configured to indicate that at least one fingertip of the soft tissue palpation robot palpates the at least one tangible bone landmark and has, an apparatus. **Claim 12**: A system for medical imaging, comprising the apparatus according to claim 11, an X-ray system and has a system. **Claim 13**: A computer program element configured to execute the steps of the method according to any one of claims 1 to 10 when executed by a processor of the apparatus according to claim 11.

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