Multi-energy x-ray imaging

Abstract

The invention relates to a method of multi-energy x-ray imaging for an examination object, comprising: - capturing a first x-ray image data record at a first spatial resolution, the first x-ray data record having been recorded with a first x-ray spectrum, - capturing a second x-ray image data record at a second spatial resolution, the second x-ray image data record having been recorded with a second x-ray spectrum, wherein the first and the second x-ray image data records image an at least partly shared examination region of the examination object, wherein the first and the second x-ray spectra differ, wherein the second spatial resolution is lower than the first spatial resolution, - adapting a spatial modulation of the second x-ray image data record on the basis of geometric and / or anatomical features of the examination object imaged in the first and the second x-ray image data records, - providing the adapted second x-ray image data record. The invention also relates to a medical x-ray device and a computer program product.

Description

[0001]202308105 1 Description Multi-energy X-ray imaging The invention relates to a method for multi-energy X-ray imaging of an examination subject, a medical X-ray device, and a computer program product. To distinguish between materials with different absorption properties, for example, to distinguish between iodine and / or calcium, multi-energy X-ray images of an examination subject can be acquired. In multi-energy X-ray imaging, for example, multi-energy computed tomography (CT) and / or multi-energy fluoroscopy or multi-energy radiography, multiple X-ray image data sets can be acquired with different X-ray spectra, in particular X-ray spectra with different spectral distributions.In dual-energy X-ray imaging, a special case of multi-energy X-ray imaging, exactly two X-ray image datasets with different X-ray spectra, in particular with different maximum energies, can be acquired. For example, in dual-energy X-ray imaging, a low-energy spectrum and a high-energy spectrum can be used, which can be generated by applying different tube voltages to the X-ray source. The different X-ray spectra, which in particular have different maximum energies, can be generated by a single X-ray source, especially when acquired at different times. Alternatively, two dedicated X-ray sources can be used to simultaneously acquire the X-ray image datasets with the different X-ray spectra.For example, iodine staining and / or bleeding can be derived from a combination of X-ray image datasets, for example, based on material decomposition techniques. Often, one of the two X-ray spectra is power-limited due to limitations of the X-ray source and / or filtering and / or high absorption of the object under examination. This can disadvantageously lead to insufficient signal strength at an X-ray detector. If a specified image quality is not met, for example, voltage modulation can be performed on the X-ray tube. This can disadvantageously impair the homogeneity of the detected X-ray image datasets. Furthermore, spectral separability between the low-energy spectrum and the high-energy spectrum can be impaired. Both effects can lead to lower sensitivity in material decomposition.It is therefore the object of the present invention to enable x-ray dose-efficient multi-energy x-ray imaging of an examination subject. This object is achieved according to the invention by the subject matter of the independent claims. Advantageous embodiments with expedient further developments are the subject matter of the subclaims. Regardless of the grammatical gender of a particular term, persons with male, female or other gender identity are also included. In a first aspect, the invention relates to a method, in particular a computer-implemented method, for multi-energy x-ray imaging of an examination subject. In a first step, a first x-ray image data set having a first spatial resolution is acquired. Furthermore, the first x-ray image data set is recorded with a first x-ray spectrum. In a further step, a second x-ray image data set having a second spatial resolution is acquired.The second X-ray image data set is recorded with a second X-ray spectrum. The first and second X-ray image data sets depict an at least partially common examination region of the examination object. The first and second X-ray spectra are different. Furthermore, the second spatial resolution is smaller than the first spatial resolution. In a further step, a 202308105 3 spatial modulation of the second X-ray image data set is adapted based on geometric and / or anatomical features of the examination object that are depicted in the first and second X-ray image data sets. The adapted second X-ray image data set is then provided. The steps of the proposed method described above can be carried out at least partially simultaneously or sequentially.The examination object can, for example, be a human and / or animal patient and / or a human and / or animal patient and / or an examination phantom. The acquisition of the first and second x-ray image data sets can each comprise receiving and / or recording the respective x-ray image data set. The receipt of the first and / or second x-ray image data sets can, in particular, comprise acquisition and / or reading from a computer-readable data storage device and / or receiving from a data storage unit, for example a database. Furthermore, the first and / or second x-ray image data sets can be provided by a provision unit of a medical imaging device. Alternatively or additionally, the first and second x-ray image data sets can be recorded using a common medical x-ray device or different medical x-ray devices.Advantageously, the first x-ray image dataset can have a two-dimensional (2D) and / or three-dimensional (3D) spatially resolved first image of the examination region of the examination object. The 2D spatially resolved first image can image the examination region as a 2D projection. In particular, the first image of the examination region can have a plurality of image points, in particular pixels and / or voxels, with image values, in particular attenuation values ​​and / or intensity values, which image, in particular represent, the 202308105 4 examination region. The first x-ray image dataset can also be time-resolved. In this case, the first x-ray image dataset can have a first spatial resolution. In particular, the first x-ray image dataset can image the examination region with the first spatial resolution.Advantageously, the second x-ray image data set can have a two-dimensional (2D) and / or three-dimensional (3D) spatially resolved second image of the examination region of the examination object. The 2D spatially resolved second image can image the examination region as a 2D projection. In particular, the second image of the examination region can have a plurality of image points, in particular pixels and / or voxels, with image values, in particular attenuation values ​​and / or intensity values, which image, in particular represent, the examination region. The second x-ray image data set can also be time-resolved. In this case, the second x-ray image data set can have a second spatial resolution. In particular, the second x-ray image data set can image the examination region with the second spatial resolution. The second spatial resolution is advantageously smaller than the first spatial resolution.In particular, the pixels of the second x-ray image dataset, which depict the at least partially common examination region, have a larger edge dimension, in particular a larger area and / or a larger volume, than the pixels of the first x-ray image dataset. The first and second x-ray spectra can comprise a low-energy spectrum and a high-energy spectrum. In particular, the first x-ray spectrum can comprise the low-energy spectrum and the second x-ray spectrum can comprise the high-energy spectrum. The first and second x-ray spectra can be generated by different applied tube voltages to an x-ray source. The different x-ray spectra, which in particular have different maximum energies, can be generated by a single x-ray source, in particular in the case of temporally staggered recordings.For example, the low-energy spectrum can be generated with a tube voltage of 70 kV and the high-energy spectrum with a tube voltage of 125 kV. For the high-energy spectrum, a filter, in particular comprising tin and / or molybdenum, is advantageously introduced into a beam path between the X-ray source and the X-ray detector in order to harden the high-energy spectrum and increase spectral separability. Advantageously, the first and second X-ray image data sets can depict the at least partially, in particular completely, common examination region of the examination object. The examination region can comprise a spatial region, in particular a three-dimensional region, of the examination object, in particular a volume.Advantageously, the examination region can comprise an anatomical and / or medical object of interest, for example, a tissue and / or an organ of the examination object and / or a diagnostic and / or surgical instrument and / or implant. Advantageously, the first and second x-ray image data sets can image the examination region with a substantially identical imaging geometry, for example, an imaging direction and / or an imaging region. Advantageously, the spatial modulation of the second x-ray image data set is adapted based on the geometric and / or anatomical features of the examination object that are imaged in the first and second x-ray image data sets. For example, a width and / or shape of edges in the first x-ray image data set can be determined.Furthermore, a width and / or shape of 202308105 6 corresponding edges in the second x-ray image data set can be adapted, in particular matched, based on the width and / or shape of the edges of the first x-ray image data set. For example, high-frequency components can be extracted from the first x-ray image data set and used in the second x-ray image data set to amplify high frequencies. For example, an edge image can be generated from the first x-ray image data set, in particular by means of gradients and / or Sobel filters and / or Canny edge detection, and the second x-ray image data set can be weighted therewith. Alternatively or additionally, the first x-ray image data set, in particular the edge image, can be used as a reference image, in particular a guidance image, in a common filter, for example a guided filter and / or a joint bilateral filter.The common geometric features of the examination object can include, for example, edges and / or contours and / or a marker structure and / or a contrast transition, which are imaged in the first and the second x-ray image data set. The common anatomical features can include, for example, a tissue boundary and / or a structure and / or an anatomical landmark, in particular an ostium, and / or an implant, which are imaged in the first and the second x-ray image data set. Advantageously, the result data set can include the adapted second result data set and / or a processing result based on the adapted second x-ray image data set. Providing the result data set can include storing it on a computer-readable storage medium and / or displaying it on a presentation unit and / or transmitting it to a provision unit.In particular, a 202308105 7 graphical representation of the result data set can be displayed by means of the display unit. Advantageously, this can avoid modulation of the tube voltage. Furthermore, an X-ray dose when acquiring the second X-ray image data set can advantageously be minimized. By modulating the second X-ray image data set, a higher spatial resolution can also be achieved. In a further advantageous embodiment of the proposed method, acquiring the second X-ray image data set can comprise binning pixels. Advantageously, acquiring the second X-ray image data set can comprise acquiring second raw X-ray image data. In addition to the second spatial resolution, the second raw X-ray image data can in particular have all the features and properties that were described in relation to the second X-ray image data set.The second raw x-ray image data can have a higher spatial resolution than the second spatial resolution, in particular the first spatial resolution. Advantageously, the second x-ray image data set can be provided by combining pixels of the second raw x-ray image data (binning). In this case, each pixel of the second x-ray image data set can be formed from several adjacent pixels of the second raw x-ray image data, for example by summing image values ​​of the pixels to be combined and / or applying a smoothing algorithm and / or averaging algorithm in the image space. The spatial resolution of the raw x-ray image data can comprise a digital resolution, for example by oversampling, and / or an in particular real, imaging resolution, in particular measured using a modulation transfer function (MTF).In particular, the second raw x-ray image data can have a higher spatial, in particular digital, resolution than the second spatial resolution if the second raw x-ray image data are recorded with a larger focal spot than the first x-ray image data set. In a further advantageous embodiment of the proposed method, the second x-ray image data set can be recorded with a larger focal spot than the first x-ray image data set. Advantageously, the first and second x-ray image data sets can be recorded using a medical x-ray device. The medical x-ray device can comprise an x-ray source and an x-ray detector. The x-ray source can be designed to emit x-rays to illuminate the object under examination, in particular the examination region.Furthermore, the X-ray detector can be designed to detect the X-rays, particularly after interaction with the examination region. In particular, the first and second X-ray image data sets can be recorded using a cone-beam computed tomography (CBCT) device. To emit the X-ray radiation, the X-ray source can comprise a cathode and an anode, with electrons being released from the cathode and accelerated under high voltage onto a region of the anode. The high voltage between the cathode and anode can also be referred to as the tube voltage of the X-ray tube. An area where the electrons strike the anode can be referred to as a focal spot.Advantageously, the second x-ray image data set can be acquired with a larger focal spot, in particular a larger spatial focal spot extent and / or a larger focal spot diameter, than the first x-ray image data set. This advantageously allows a higher tube voltage to be used to acquire the second x-ray image data set than to acquire the first x-ray image data set. This advantageously allows a shorter illumination duration to be used to acquire the second x-ray image data set. In a further advantageous embodiment of the proposed method, the first and second x-ray image data sets can be registered with one another. Registering the first and second x-ray image data sets can advantageously include applying a transformation rule to the first and / or second x-ray image data sets.Advantageously, the transformation rule can comprise an instruction for translating and / or rotating and / or scaling and / or deforming the first and / or second x-ray image data sets. Advantageously, the registration of the first and second x-ray image data sets can be based on the common geometric and / or anatomical features of the examination region that are depicted in the first and second x-ray image data sets. Advantageously, the registration of the first and second x-ray image data sets can comprise minimizing a deviation between the depictions of the common geometric and / or anatomical features in the first and second x-ray image data sets.This advantageously allows artifacts, for example motion artifacts, to be reduced, in particular when adapting the spatial modulation of the second x-ray image data set and / or when providing the result data set based on the first and second x-ray image data sets. In a further advantageous embodiment of the proposed method, acquiring the first x-ray image data set can comprise acquiring a plurality of first 202308105 10 x-ray projection images. The first x-ray image data set can be reconstructed from the plurality of first x-ray projection images. Furthermore, acquiring the second x-ray image data set can comprise acquiring a plurality of second x-ray projection images. The second x-ray image data set can be reconstructed from the plurality of second x-ray projection images.The first and second X-ray projection images can be recorded using one or different medical X-ray devices, in particular a medical C-arm X-ray device, along a 3D trajectory from different projection directions. In particular, the projection directions for recording the first and second X-ray projection directions can coincide in pairs. The projection directions, in particular angulations, can each describe a path of a beam, in particular a central and / or mid-beam, between the X-ray source and the X-ray detector, in particular a detector center point, of the X-ray device at the time the respective X-ray projection images are recorded.In particular, the projection directions can each describe an angulation of the X-ray device with respect to the examination object and / or an isocenter, in particular a center of rotation, of a defined arrangement of X-ray source and X-ray detector. The isocenter can describe a spatial point around which the defined arrangement of X-ray source and X-ray detector is movable, in particular rotatable, in particular during the acquisition of the first and / or second X-ray projection images. Advantageously, the various projection directions can each run through the isocenter, in particular a common isocenter. The 3D trajectory can describe a spatial path for arranging a reference point, for example a focal point, of the defined arrangement of X-ray source and X-ray detector.Advantageously, the plurality of first and second X-ray projection images can each image the examination object, 202308105 11 in particular the examination region, in a 2D spatially resolved manner. Advantageously, the first X-ray image dataset can be reconstructed from the plurality of first X-ray projection images, for example by means of a backprojection, in particular a filtered one. Advantageously, the second X-ray image dataset can be reconstructed from the plurality of second X-ray projection images, for example by means of a backprojection, in particular a filtered one. In this case, the first and the second X-ray image dataset can each have a 3D spatially resolved image of the examination region. The proposed embodiment can enable improved 3D multi-energy X-ray imaging of the examination object.In a further advantageous embodiment of the proposed method, adapting the spatial modulation of the second x-ray image data set can comprise transferring the first spatial resolution to the second x-ray image data set. The transfer of the first spatial resolution to the second x-ray image data set is described below using an advantageous exemplary embodiment, without limiting the inventive method to a specific adaptation of the spatial modulation. For example, the first and second x-ray image data sets can each image a tissue of the examination subject. In this case, at least one vessel, which is at least partially filled with a contrast agent, can lead through the tissue. The vessel can, for example, comprise an artery and / or vein. The vessel can have a comparatively small diameter.The contrast agent, for example iodine, can have a spectral dependence that differs from the surrounding soft tissue and / or blood. Advantageously, the arrangement of the contrast agent is essentially limited to the vessel. A spectral, in particular relative, change in X-ray absorption by the soft tissue can be obtained, for example, using lookup tables and / or calibration measurements. Due to the higher spatial resolution, the vessel can be resolved more precisely, in particular in more detail, in the first X-ray image data set than in the second X-ray image data set. For example, a first pixel, in particular a pixel or voxel, of the first X-ray image data set can image a part of the vessel, which can comprise an unknown mixture of soft tissue and / or blood and contrast agent. Furthermore, a second pixel of the first X-ray image data set can image only soft tissue.Using image segmentation, the pixels in the first X-ray image dataset can be identified that are at least partially attributable to a vessel (for example, the first pixel) or only to soft tissue (for example, the second pixel). An attenuation value ^^^^. 1,1 of the first pixel can have the following composition: where c is the concentration of the contrast agent in the vessel, ^^^^^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,1 the attenuation value of the contrast agent, and ^^^^^^^^ ^^^^ ^^^^ ^^^^,1 the attenuation value of the blood in the first X-ray spectrum. An attenuation value ^^^^ 2,1 of the second pixel can have the following composition: ^^^^ 2,1= ^^^^^^^^ ^^^^,1where ^^^^^^^^ ^^^^,1 describes the attenuation value of the soft tissue in the first X-ray spectrum. The second X-ray image dataset can have a lower spatial resolution than the first X-ray image dataset. In this case, one pixel, in particular one pixel or 202308105 13 voxels, of the second X-ray image dataset can completely image the examination region that is imaged in the first and second pixels of the first X-ray image dataset. Thus, the pixel of the second X-ray image dataset can have a signal with portions of the vessel, in particular blood and contrast agent, and soft tissue. The respective portions of the vessel ^^^^ 1,2 and soft tissue ^^^^ 2,2 in the pixel of the second X-ray image data set can be determined as: where ^^^^ 0,2 2 the attenuation value of the pixel of the second X-ray image data set, ^^^^^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,2 the attenuation value of the contrast agent, ^^^^^^^^ ^^^^ ^^^^ ^^^^,2 the attenuation value of the blood and ^^^^^^^^ ^^^^,2 the attenuation value of the soft tissue in the second X-ray spectrum. The arithmetic mean to determine ^^^^ 0,2 works in an approximation for low contrast agent concentrations c or for small differences between the attenuation values ​​^^^^^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^, ^^^^^^^^ ^^^^ ^^^^and ^^^^ ^^^^ ^^^^, which is used here for simplified notation. Otherwise, the correct averaging based on the linear detector count rates or corresponding exponential functions and logarithms according to the Beer-Lambert law must be assumed. ^^^^^^^^ ^^^^,2 can be determined, for example, from a known spectral X-ray absorption change of soft tissue from ^^^^^^^^ ^^^^,1= ^^^^ 2,1 can be determined. ^^^^^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,1, ^^^^^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,2, ^^^^^^^^ ^^^^ ^^^^ ^^^^,1 and ^^^^^^^^ ^^^^ ^^^^ ^^^^,2 can be used as known values ​​from previous calibration measurements and / or literature values. This gives: ^^^^1,2 = 2 ⋅ ^^^^0,2 − ^^^^2,2 = 2 ⋅ ^^^^0,2 − ^^^^ ^^^^ ^^^^,2 = ^^^^ ⋅ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,2 + ( 1 − ^^^^ ) ⋅ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,2 ^^^^ = 2 ⋅ ^^^^ 0,2 − ^^^^ ^^^^ ^^^^,2 − ^^^^^^^^ ^^^^ ^^^^ ^^^^,2^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,2 − ^^^^ ^^^^ ^^^^ ^^^^ ^^^^,2By exploiting known relationships and known, in particular spectral, absorption properties, the unknown contrast agent concentration c can be determined. In addition, the modulation of the second X-ray image data set can be adapted such that a consistently higher spatial resolution is achieved. In a further advantageous embodiment of the proposed method, the second X-ray image data set can depict a spatial intensity profile. The spatial modulation of the second X-ray image data set can be adapted such that amplitudes and / or integrals of the spatial intensity profile are retained.For example, adapting the spatial modulation of the second x-ray image data set can comprise adapting an increase in the spatial intensity profile, for example at an edge, wherein the amplitude and / or the integral of the spatial intensity profile is maintained. In particular, the adaptation can be carried out in such a way that upon a renewed, in particular simulated, reduction in the spatial modulation or the spatial resolution, in particular by simulated binning and / or simulated averaging and / or simulated downsampling, the second x-ray image data set, whose resolution has been "extrapolated," merges again, as unchanged as possible, into the original second x-ray image data set with reduced resolution. In a further advantageous embodiment of the proposed method, the first and second x-ray image data sets can depict a contrast agent arranged in the examination region.The geometric and / or anatomical features of the examination object can comprise a respective image of the contrast agent. Advantageously, the first and second X-ray image data sets can image the contrast agent, in particular the X-ray-opaque contrast agent, for example, a flowing movement and / or spreading movement of the contrast agent and / or a contrast agent bolus, in the examination object, in particular the examination region. Alternatively or additionally, the first and second X-ray image data sets can image stationary and / or quasi-stationary contrast agent deposits in the examination object, in particular the examination region. The contrast agent can be arranged in an organ, in particular a hollow organ, for example, a vascular section, and / or tissue of the examination object.Advantageously, the common geometric and / or anatomical features of the examination subject can comprise a respective image of the contrast agent in the first and second x-ray image data sets. The proposed embodiment can enable particularly reliable adaptation of the spatial modulation of the second x-ray image data set. In a further advantageous embodiment of the proposed method, the first and second x-ray image data sets can simultaneously image the at least partially common examination region. Advantageously, the first and second x-ray image data sets can be acquired substantially simultaneously. In particular, the first and second x-ray image data sets can comprise substantially identical acquisition times.If the acquisition of the first X-ray image dataset comprises the acquisition of a plurality of first X-ray projection images and the acquisition of the second X-ray image dataset comprises the acquisition of a plurality of second X-ray projection images, then a first and a second X-ray projection image can each image the examination region in pairs simultaneously, in particular from a matching projection direction. The proposed embodiment can enable improved multi-energy X-ray imaging of rapidly changing 202308105 16 processes, for example a movement, of the examination object. In a further advantageous embodiment of the proposed method, the result dataset can additionally be provided based on the first X-ray image dataset. Advantageously, the result dataset can be provided based on the first and the second X-ray image dataset.The provision of the result data set can comprise a multi-energy calculation, for example, filtering and / or segmentation and / or contrasting, based on the first and second x-ray image data sets. The proposed embodiment can enable precise material decomposition, in particular concentration determination. For example, the result data set can be provided comprising information on a material composition and / or material concentration, in particular a calcium and / or iodine concentration, in the examination region. In a further advantageous embodiment of the proposed method, the first and second x-ray image data sets can be recorded using a medical x-ray device. The medical x-ray device can comprise an x-ray source and an x-ray detector.The X-ray source can be designed to emit X-rays to illuminate the examination object, in particular the examination region. Furthermore, the X-ray detector can be designed to detect the X-rays, in particular after an interaction with the examination region. In particular, the first and second X-ray image data sets can be acquired using a multi-energy cone-beam computed tomography (CBCT), for example a dual-energy CBCT. The first and second X-ray image data sets can be acquired using the X-ray device sequentially or in a temporally interleaved manner. In a second aspect, the invention relates to a medical X-ray device designed to carry out a proposed method for multi-energy X-ray imaging of an examination object.The advantages of the X-ray device essentially correspond to the advantages of the proposed method for multi-energy X-ray imaging of an examination subject. Features, advantages, or alternative embodiments mentioned herein can also be applied to the other claimed subject matter, and vice versa. In a further advantageous embodiment of the proposed X-ray device, the X-ray device can be designed as a multi-energy cone beam computed tomography (CBCT) device, in particular a dual-energy cone beam computed tomography device. This allows the first and second X-ray image data sets to be acquired using the same multi-energy CBCT.In a third aspect, the invention relates to a computer program product comprising a computer program that can be loaded directly into a memory of a provision unit, with program sections for executing all steps of a proposed method for multi-energy X-ray imaging of an examination object when the program sections are executed by the provision unit. The computer program product can comprise software with source code that still needs to be compiled and linked or that only needs to be interpreted, or executable software code that only needs to be loaded into the provision unit for execution. The computer program product enables the method for multi-energy X-ray imaging of an examination object to be executed quickly, identically repeatably, and robustly by the provision unit.The computer program product is configured such that it can carry out the method steps according to the invention by means of the provision unit. The computer program product is stored, for example, on a computer-readable storage medium or on a network or server, from where it can be loaded into the processor of a provision unit so that it can be directly connected to the provision unit or formed as part of the provision unit. Furthermore, control information of the computer program product can be stored on an electronically readable data carrier. The control information of the electronically readable data carrier can be designed such that it carries out a method according to the invention when the data carrier is used in a provision unit.Examples of electronically readable data carriers are a DVD, a magnetic tape, or a USB stick on which electronically readable information, in particular software, is stored. If this control information is read from the data carrier and stored in a provision unit, all inventive embodiments of the methods described above can be carried out. A largely software-based implementation has the advantage that previously used provision units can be easily retrofitted with a software update to operate in the inventive manner. In addition to the computer program, such a computer program product can optionally include additional components such as documentation and / or additional components, 202308105 19 as well as hardware components, such as hardware keys (dongles, etc.) for using the software.Embodiments of the invention are illustrated in the drawings and described in more detail below. In different figures, the same reference numerals are used for identical features. They show: Fig. 1 to 4 schematic representations of various embodiments of a proposed method for multi-energy X-ray imaging of an examination object, Fig. 5 a schematic representation of spatial intensity profiles of a first and second X-ray image data set and of a result data set, Fig. 6 a schematic representation of an advantageous embodiment of a proposed medical X-ray device. Fig. 1 shows a schematic representation of an advantageous embodiment of a proposed method for multi-energy X-ray imaging of an examination object. In this case, a first X-ray image data set RBD1, having a first spatial resolution, can be acquired CAP-RBD1.Advantageously, the first x-ray image data set RBD1 is recorded with a first x-ray spectrum. In a further step, a second x-ray image data set RBD2, having a second spatial resolution, can be acquired CAP-RBD2. In particular, the first and second x-ray image data sets RBD1 and RBD2 can be recorded using a medical x-ray device. In this case, the second x-ray image data set RBD2 can be recorded with a second x-ray spectrum. Furthermore, the first and second x-ray image data sets RBD1 and RBD2 can depict an at least partially common examination region of the examination subject. In addition, the first and second x-ray spectra can be different. The second spatial resolution can advantageously be smaller than the first spatial resolution.In a further step, a spatial modulation of the second x-ray image data set RBD2 can be adapted ADJ-RBD2 based on geometric and / or anatomical features of the examination object, which are mapped in the first and second x-ray image data sets RBD1 and RBD2. A result data set ED can then be provided PROV-ED based on the adapted second x-ray image data set RBD2.A. Advantageously, the result data set ED can additionally be provided PROV-ED based on the first x-ray image data set RBD1. Advantageously, the acquisition CAP-RBD2 of the second x-ray image data set RBD2 can comprise a binning of pixels. Advantageously, the second x-ray image data set RBD2 can be recorded with a larger focal spot than the first x-ray image data set RBD1.Advantageously, the first and second x-ray image data sets RBD1 and RBD2 can image a contrast agent arranged in the examination region. The geometric and / or anatomical features of the examination object can comprise a respective image of the contrast agent. Furthermore, the first and second x-ray image data sets RBD1 and RBD2 can simultaneously image the at least partially common examination region. Fig. 2 shows a schematic representation of a further advantageous embodiment of a proposed method for multi-energy x-ray imaging of an examination object. The first and second x-ray image data sets RBD1 and RBD2 can be registered with one another REG-RBD1-RBD2. 202308105 21 Fig. 3 shows a schematic representation of a further advantageous embodiment of a proposed method for multi-energy x-ray imaging of an examination object.In this case, the acquisition CAP-RBD1 of the first x-ray image data set RBD1 can comprise an acquisition CAP-PD1 of a plurality of first x-ray projection images PD1. Furthermore, the first x-ray image data set RBD1 can be reconstructed from the plurality of first x-ray projection images PD1. Furthermore, the acquisition CAP-RBD2 of the second x-ray image data set can comprise an acquisition CAP-PD2 of a plurality of second x-ray projection images PD2. In this case, the second x-ray image data set RBD2 can be reconstructed from the plurality of second x-ray projection images PD2. Fig. 4 shows a schematic representation of a further advantageous embodiment of a proposed method for multi-energy x-ray imaging of an examination object. In this case, the result data set ED can additionally be provided based on the first x-ray image data set RBD1 PROV-ED. In Fig.5 schematically shows a spatial intensity profile IV1 of a first x-ray image data set RBD1 and a spatial intensity profile IV2 of a second x-ray image data set RBD2. A maximum height AH1 and AH2 of the respective intensity profiles IV1 and IV2, in particular an amplitude peak, can depend on an attenuation of the x-rays due to the interaction with the examination region, in particular the contrast agent, in the respective x-ray spectrum, in particular the first and second x-ray spectra. Furthermore, an edge width EW1 and EW2 of the respective intensity profiles IV1 and IV2 can depend on the respective spatial resolution of the first and second x-ray image data sets RBD1 and RBD2.Advantageously, adapting the spatial modulation, in particular the spatial intensity profile IV2, 202308105 22 of the second x-ray image data set RBD2 can comprise transferring the first spatial resolution to the second x-ray image data set RBD2. In this case, the spatial modulation of the second x-ray image data set RBD2 can be adapted such that amplitudes and / or integrals of the spatial intensity profile IV2 are retained. The intensity profile IV2.A of the adapted second x-ray image data set RBD2.A can, for example, have the edge width EW1 of the first x-ray image data set and the amplitude peak AH2 and / or the integral of the intensity profile IV2 of the second x-ray image data set RBD2. Fig. 6 shows a schematic representation of an advantageous embodiment of a proposed medical x-ray device.6 shows, by way of example for a proposed X-ray device, a schematic representation of a medical C-arm X-ray device 37, comprising a provision unit PRVS, a display unit 41, and an input unit 42. The medical C-arm X-ray device 37 can advantageously have an X-ray detector 34 and an X-ray source 33, which are arranged in a defined arrangement on a C-arm 38. The C-arm 38 of the C-arm X-ray device 37 can be mounted so as to be movable about one or more axes. Furthermore, the C-arm X-ray device 37 can comprise a movement unit 39, for example a wheel system and / or a robot arm and / or a rail system, which enables movement of the C-arm X-ray device in space. The C-arm X-ray device 37 shown schematically in Fig. 6 can advantageously be designed as a multi-energy CBCT.To record the first and second x-ray image data sets RBD1 and RBD2, in particular the first and second x-ray projection images PD1 and PD2, of the examination object 31 positioned on a patient support device 32, the provision unit PRVS can send a signal 24 to the x-ray source 33. The x-ray source 33 can then emit an x-ray beam. When the x-ray beam strikes a surface of the detector 34 after interacting with the examination object 31, the detector 34 can send a signal 21 to the provision unit PRVS. The provision unit PRVS can use the signal 21 to acquire the first and second x-ray image data sets RBD1 and RBD2, in particular the first and second x-ray projection images PD1 and PD2.The input unit 42 can, for example, comprise a keyboard and / or a pointing device and / or a detection unit, for example a speech detection unit and / or gesture detection unit. Furthermore, the presentation unit 41 can, for example, comprise a monitor and / or a display and / or a projector. The input unit 42 can preferably be integrated into the presentation unit 41, for example in the case of a capacitive and / or resistive input display. The input unit 42 can advantageously be designed to detect a user input. For this purpose, the input unit 42 can, for example, send a signal 26 to the provision unit PRVS. The provision unit PRVS can be designed to control the recording of the first and second x-ray image data sets RBD1 and RBD2, in particular the first and second x-ray projection images PD1 and PD2, based on the user input.The display unit 41 can advantageously be designed to display a graphical representation of the result data set. For this purpose, the provision unit PRVS can send a signal 25 to the display unit 41. The schematic representations contained in the described figures do not represent any scale or size relationships. Finally, it is pointed out once again that the methods described in detail above and the devices shown are merely exemplary embodiments which can be modified in a variety of ways by a person skilled in the art without departing from the scope of the invention. Furthermore, the use of the indefinite articles "a" or "an" does not exclude the possibility that the features in question may be present multiple times.Likewise, the terms "unit" and "element" do not exclude the possibility that the components in question consist of several interacting subcomponents, which may also be spatially distributed. In the context of the present application, the expression "based on" can be understood in particular in the sense of the expression "using". In particular, a formulation according to which a first feature is generated (alternatively: determined, determined, etc.) based on a second feature does not exclude the possibility that the first feature can be generated (alternatively: determined, determined, etc.) based on a third feature.

Claims

202308105 25 claims 1. A method for multi-energy X-ray imaging of an examination object (31), comprising: - capturing (CAP-RBD1) a first X-ray image data set (RBD1) having a first spatial resolution, wherein the first X-ray image data set (RBD1) is recorded with a first X-ray spectrum, - capturing (CAP-RBD2) a second X-ray image data set (RBD2) having a second spatial resolution, wherein the second X-ray image data set (RBD2) is recorded with a second X-ray spectrum, wherein the first and the second X-ray image data sets (RBD1, RBD2) image an at least partially common examination region of the examination object (31), wherein the first and the second X-ray spectra are different, wherein the second spatial resolution is smaller than the first spatial resolution,- adapting (ADJ-RBD2) a spatial modulation of the second x-ray image data set (RBD2) based on geometric and / or anatomical features of the examination subject (31) that are imaged in the first and second x-ray image data sets (RBD1, RBD2); - providing (PROV-ED) a result data set (ED) based on the adapted second x-ray image data set (RBD2.A).

2. The method according to claim 1, wherein the acquisition (CAP-RBD2) of the second x-ray image data set (RBD2) comprises binning pixels.

3. The method according to claim 1 or 2, wherein the second x-ray image data set (RBD2) is recorded with a larger focal spot than the first x-ray image data set (RBD1).

4. The method according to one of the preceding claims, 202308105 26 wherein the first and second x-ray image data sets (RBD1, RBD2) are registered with each other (REG-RBD1-RBD2).

5. The method according to one of the preceding claims, wherein the acquisition (CAP-RBD1) of the first x-ray image data set (RBD1) comprises the acquisition (CAP-PD1) of a plurality of first x-ray projection images (PD1), wherein the first x-ray image data set (RBD1) is reconstructed (RECO-RBD1) from the plurality of first x-ray projection images (PD1), wherein the acquisition (CAP-RBD2) of the second x-ray image data set (RBD2) comprises the acquisition (CAP-PD2) of a plurality of second x-ray projection images (PD2), wherein the second x-ray image data set (RBD2) is reconstructed (RECO-RBD2) from the plurality of second x-ray projection images (PD2). 6.Method according to one of the preceding claims, wherein the adaptation (ADJ-RBD2) of the spatial modulation of the second x-ray image data set (RBD2) comprises transferring the first spatial resolution to the second x-ray image data set (RBD2).

7. Method according to one of the preceding claims, wherein the second x-ray image data set (RBD2) maps a spatial intensity profile, wherein the spatial modulation of the second x-ray image data set (RBD2) is adapted (ADJ-RBD2) such that amplitudes and / or integrals of the spatial intensity profile are retained.

8. Method according to one of the preceding claims, wherein the first and second x-ray image data sets (RBD1, RBD2) map a contrast agent arranged in the examination region, wherein the geometric and / or anatomical features of the examination object (31) comprise a respective image of the contrast agent. 202308105 27 9. The method according to one of the preceding claims, wherein the first and second x-ray image data sets (RBD1, RBD2) simultaneously image the at least partially common examination region.

10. The method according to one of the preceding claims, wherein the result data set (ED) is additionally provided (PROV-ED) based on the first x-ray image data set (RBD1).

11. The method according to one of the preceding claims, wherein the first and second x-ray image data sets (RBD1, RBD2) are acquired using a medical x-ray device.

12. A medical x-ray device configured to carry out a method according to one of the preceding claims.

13. The medical x-ray device according to claim 12, wherein the x-ray device is configured as a multi-energy cone beam computed tomography device. 14.Computer program product with a computer program which can be loaded directly into a memory of a provision unit (PRVS), with program sections to carry out all steps of a method according to one of claims 1 to 11 when the program sections are executed by the provision unit (PRVS).

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