Method for operating an X-ray imaging system, method for generating a database, and regulating device

Abstract

The present invention relates to a method for operating an X-ray imaging system (1), the method comprising the steps of: outputting a first X-ray radiation (4) from an X-ray source (3) to an X-ray detector (6) to acquire a first X-ray image (7) of an examination object (9), wherein the examination object (9) is arranged between the X-ray source (3) and the X-ray detector (6) and is penetrated by the first X-ray radiation (4); - acquiring, by the X-ray detector (6), the incident dose (18) of the first X-ray radiation (4) after passing through the examination object (9); - determining, by a control device (2) of the X-ray imaging system (1), a parameter value (17) of at least one parameter (16), the parameter being used for outputting a second X-ray radiation (5) from the X-ray source (3) to acquire a second X-ray image (8) of the examination object (9). It is stipulated that the parameter value (17) is determined by the control device (2) according to the foreground material (11) of the foreground object (10), the background material (13) of the background object (12) and the incident dose (18) according to a preset determination method.

Description

Field of the Invention

[0001] The present invention relates to a method for operating an X-ray imaging system, a method for generating a database, a regulating device, an X-ray imaging system, a control device, a computer program, and an electronically readable data carrier. Background Art

[0002] According to the prior art, medical X-ray imaging systems typically include a point-like X-ray source that outputs X-ray radiation in the direction of an examination object to be examined. The examination object can be a patient, for example. The X-ray radiation passes through the examination object and is partially absorbed by the examination object. A line-shaped and / or planar spatially resolved detector is arranged behind the examination object, and the detector can collect the X-ray radiation.

[0003] The X-ray radiation images the cross-section of the examination object. Depending on the absorption of the X-ray along the corresponding path, the locally collected X-rays have different intensities due to anatomy.

[0004] According to the prior art, medical X-ray systems are typically equipped with an automatic exposure control device. In these devices, the actual dose is measured at the detector input during irradiation of the examination object. Then this value is compared with a predetermined dose. The irradiation parameters are adapted based on the difference between the actual dose and the predetermined dose in order to further irradiate the examination object. The irradiation parameters include, for example, tube voltage, tube current, exposure time, and / or pre-filtering of the X-ray radiation for the next examination. Here, the irradiation parameters are adapted for the next measurement so that the predetermined dose is reached at the detector input in the next measurement.

[0005] The dynamic performance of new detectors has been significantly improved. Therefore, according to the prior art, the dose at the detector input no longer needs to be kept constant, but can be adapted at any time according to the requirements of image quality and patient dose.

[0006] However, different materials respond differently to the energy of the X-ray spectrum because the absorption of X-ray radiation by a material depends on the energy of the X-ray radiation.

[0007] In order to better show a foreground object in an X-ray image of a foreground material, the parameter values of the irradiation parameters are adjusted such that the contrast-noise gap, which is related to the difference between a first signal intensity value in an X-ray image of a first X-ray beam that only passes through a background object in the examination object and a second signal intensity value in an X-ray image of a second X-ray beam that passes through the background object and the foreground object, is as large as possible.

[0008] Although the prior art provides different solutions to optimize the contrast of foreground objects in X-ray images for foreground objects that may consist of different foreground materials, the background material in which the foreground objects are arranged is always the same. The background material is a preset intermediate mixture for describing human tissues. Therefore, only the foreground material is considered according to the prior art.

[0009] So far, the adjustment of the dose and quality of X-ray radiation has been optimized according to the contrast-noise ratio between the foreground material to be examined and human soft tissues. Special problems occur during high-demanding projections. High-demanding projections occur when the foreground object to be examined is arranged in front of or behind a background object, and the background object consists of the same or similar background material as the foreground object. In this case, the second X-ray beam that passes through the background object and does not pass through the foreground object passes through the same material as the first X-ray beam that passes through both the background object and the foreground object.

[0010] These situations may involve, for example, crossed coils in aneurysms, bone cement on thick bones, fillings in teeth, implants in bone structures, or ultrasound probes on the spine, and the prior art has not specifically addressed these problems. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to increase the contrast-noise gap for different combinations of the foreground material of the foreground object and the background material of the background object in X-ray images. The technical problem to be solved by the present invention is also to increase the contrast-noise gap in the presence of background material that is the same as the foreground material.

[0012] This technical problem is solved by a method for operating an X-ray imaging system, a method for generating a database, a regulating device, an X-ray imaging system, a control device, a computer program, and an electronically readable data carrier.

[0013] The first aspect of the present invention relates to a method for operating an X-ray imaging system.

[0014] It is stipulated that the operation mode of the X-ray imaging system is such that a preset contrast-noise gap of the foreground object in front of the background object is provided in the X-ray image.

[0015] The foreground object includes foreground material. The background object includes background material. In other words, it is stipulated that the foreground object should be imaged in the X-ray image by the X-ray imaging system, and the foreground object is located in front of and / or behind the background object with reference to the X-ray radiation direction (or the X-ray beam direction). The purpose of the method is to achieve a preset contrast-noise gap in the X-ray image. In other words, it is stipulated that the intensity of the foreground object is different from that of the background object, so that there is a preset contrast-noise gap. The background material and / or the foreground material can be provided to the X-ray imaging system according to user input.

[0016] In the first step, it is stipulated that the X-ray source of the X-ray imaging system outputs or emits first X-ray radiation towards the X-ray detector to acquire a first X-ray image of the examination object. The examination object is arranged between the X-ray source and the X-ray detector. Thus, the examination object is penetrated by the first X-ray radiation.

[0017] In the second step, the X-ray detector acquires the incident dose of the first X-ray radiation after it has passed through the examination object. In other words, the first X-ray radiation emitted by the X-ray source is acquired by the X-ray detector. The X-ray detector determines the incident dose of the first X-ray radiation it has acquired. The incident dose can be described, for example, by the signal intensity value of the first X-ray radiation in a preset partial area of the first X-ray image or by the dose with reference to the entire first X-ray image. The incident dose can depend, for example, on the depth of the examination object and / or the materials present in the examination object.

[0018] In the third step, the incident dose is provided to the control device of the X-ray imaging system. In other words, the determined incident dose is transmitted to the control device of the X-ray imaging system so that the control device can control the X-ray imaging system according to the incident dose to generate a second X-ray image.

[0019] In the fourth step, the control device determines the parameter value of at least one parameter, and the parameter is used for the X-ray source to output second X-ray radiation to acquire a second X-ray image of the examination object. In other words, the control device determines the parameter value of at least one parameter. At least one parameter may be related to the output of the second X-ray radiation or the characteristics of the second X-ray radiation itself, and the second X-ray radiation is output by the X-ray source to take a second X-ray image of the examination object.

[0020] It is set that the control device determines the parameter value according to a preset determination method based on the foreground material, the background material, and the incident dose. In other words, the parameter value determined by the control device depends on the foreground material, the background material, and the acquired incident dose.

[0021] The parameter value of at least one parameter is given or parameterized by a regulating device according to a preset determination method, so that the expected contrast-noise gap between the first signal intensity value in the second X-ray image of the first X-ray beam passing through the background object in the inspection object and the second signal intensity value in the second X-ray image of the second X-ray beam passing through the background object and the foreground object is maximized. The determination method can include, for example, simulation performed by the regulating device using a model. The simulation can include, for example, Monte Carlo simulation. During the simulation, the parameter value can be changed in sub-steps. For the corresponding values, the resulting contrast-noise gap can be determined. The value of the parameter can be determined as the parameter value that produces the maximum contrast-noise gap. The determination can also be performed multidimensionally, where the values of multiple parameters are changed. The values of the parameters that produce the maximum contrast-noise gap can be determined as the parameter values of the parameters.

[0022] In a subsequent step, the regulating device can adjust the taking of the second X-ray image by using the parameter value of at least one parameter.

[0023] The advantage achieved by the present invention is that a high contrast-noise gap can be achieved for different preset combinations consisting of a foreground material and a background material.

[0024] An extended design of the present invention provides that the foreground material and the background material are the same. In other words, the background object can be composed of the same material as the foreground object, and / or the background object can have the same material as the foreground object. For example, it can be provided that the foreground object relates to an implant arranged in the inspection object, and this implant is arranged in front of a background object configured as another implant. The foreground object and the background object can both be made of titanium or have titanium, for example. Since the materials are the same, the parameter value of at least one parameter cannot be adjusted according to the different absorption characteristics of the materials. The advantage achieved by this extended design is that the contrast-noise gap can be improved even when the materials are the same.

[0025] An extended design of the present invention provides that a parameter value of at least one parameter is determined according to a predetermined determination method based on the foreground depth of the foreground object and the background depth of the background object. The foreground depth describes the path length of the second X-ray beam passing through the foreground object. The background depth describes the path lengths of the second X-ray beam and the first X-ray beam passing through the background object. The foreground depth may describe the geometric dimensions of the foreground object or a value range of the geometric dimensions, and this foreground depth may be preset or determined by measurement. Similarly, the background depth may describe the geometric dimensions of the background object or a value range of the geometric dimensions. For example, the foreground depth may describe the width of the foreground object preset as an implant along the direction from the X-ray source to the X-ray detector. The background object may describe the width of another implant along the direction from the X-ray source to the X-ray detector, and this other implant may be arranged behind the foreground object. For example, it may be desirable that the intersection region where the two implants cross in the second X-ray image is distinguished from the region where only the background object exists by different signal intensity values. The advantage resulting from this extended design is that the path lengths of the X-ray being absorbed only by the background object or being absorbed by both the background object and the foreground object can be taken into account for the determination of the parameter value.

[0026] An extended design of the present invention provides that the preset contrast-noise gap is described by the contrast-noise ratio. In other words, the preset contrast describes the difference in signal amplitude between the foreground object and the background object in the second X-ray image for a known background noise. For example, the background noise may be estimated, determined from the first X-ray image, or preset.

[0027] An extended design of the present invention provides that the foreground material and the background material are contrast agents. In other words, volumes enriched with the same contrast agent can be described by the foreground object and the background object. For example, it may be stipulated that the foreground object describes a first blood flow and the background object describes a second blood flow. The contrast agent may be iodine or contain iodine, for example.

[0028] An extended design of the present invention provides that the foreground material and the background material are platinum. In other words, the foreground object and the background object are respectively composed of platinum or at least have platinum. The foreground object and the background object may be implants, for example.

[0029] An extended design of the present invention provides that the foreground material and the background material are iron. In other words, the foreground object and the background object are respectively composed of iron or at least have iron. The foreground object and the background object may be stents, for example.

[0030] An extended design of the present invention provides that the preset determination method includes calling the parameter values of at least one parameter from a database by means of a control device. In other words, the database is stored in the control device. The structure of the database can be designed such that the database assigns the parameter values of at least one parameter to the foreground material, the background material, and the incident dose. The database can include, for example, the following parameter values, which can be determined by the control device by means of the Monte Carlo method for the corresponding combinations of the background material, the foreground material, and the incident dose.

[0031] The parameter values of at least one parameter can advantageously be determined according to a preset Monte Carlo method.

[0032] The second aspect of the present invention relates to a method for generating a database by a control device. The method includes determining the incident dose for inspecting an object in a preset simulation method.

[0033] The inspection object used in the simulation method includes a foreground object composed of a foreground material and a background object composed of a background material. The incident dose is determined for the first X-ray radiation passing through the inspection object.

[0034] The second step includes determining the corresponding first signal intensity value of the first X-ray beam direction for the second X-ray radiation passing through the background object composed of the background material for the corresponding parameter values of at least one parameter of the second X-ray radiation.

[0035] The third step includes determining the corresponding second signal intensity value of the second X-ray beam direction for the second X-ray radiation passing through the background object composed of the background material and the foreground object composed of the foreground material for the corresponding values of the parameters of the second X-ray radiation.

[0036] The fourth step includes determining the parameter value of at least one parameter for which the contrast-to-noise ratio related to the difference between the first signal intensity value and the second signal intensity value has a maximum value for the corresponding incident dose.

[0037] The fifth step includes generating a database, wherein the database assigns parameter values to the parameters according to the foreground material, the background material, and the signal intensity values.

[0038] The database can be provided to the control device of the X-ray imaging system.

[0039] For application scenarios or application cases that can be obtained in the method and are not described in detail here, it can be provided that a fault report and / or a request for inputting user feedback and / or an adjustment of standard settings and / or a preset initial state are output according to the method.

[0040] A third aspect of the present invention relates to a control device. The control device is arranged to determine a parameter value of at least one parameter for outputting a second X-ray radiation by an X-ray source to acquire a second X-ray image of an examination object, and to adjust the parameter value of at least one parameter in the X-ray device. It is provided that the control device is arranged to determine the parameter value according to a preset determination method based on a foreground material, a background material, and an incident dose.

[0041] The determination method is designed to give a parameter value of at least one parameter such that the expected contrast-noise gap between a first signal intensity value in a second X-ray image of a first X-ray beam passing through a background object in the examination object and a second signal intensity value in a second X-ray image of a second X-ray beam passing through the background object and a foreground object in the examination object in the second X-ray radiation is maximized.

[0042] The control device may include at least one computing unit.

[0043] A fourth aspect designs an X-ray imaging system.

[0044] The X-ray imaging system has an X-ray source which is arranged to output a first X-ray radiation to an X-ray detector to acquire a first X-ray image of an examination object. The examination object is arranged between the X-ray source and the X-ray detector such that the examination object is penetrated by the first X-ray radiation.

[0045] The X-ray imaging system is arranged to determine an incident dose of the first X-ray radiation after passing through the examination object by the X-ray detector and to provide the incident dose to a control device of the X-ray imaging system.

[0046] The X-ray imaging system is arranged to determine a parameter value of at least one parameter for outputting a second X-ray radiation by the X-ray source to acquire a second X-ray image of the examination object by the control device according to a preset determination method. The determination method is designed to give a parameter value of at least one parameter such that the expected contrast-noise gap between a first signal intensity value in a second X-ray image of a first X-ray beam passing through a background object in the examination object and a second signal intensity value in a second X-ray image of a second X-ray beam passing through the background object and a foreground object in the examination object in the second X-ray radiation is maximized.

[0047] The advantages and refinements described above with respect to the method according to the first aspect of the present invention also apply substantially to the control device according to the present invention and to the X-ray imaging system according to the present invention. Therefore, the described method features of the control device and the X-ray imaging system should be regarded as functional features of the corresponding devices.

[0048] A fifth aspect of the present invention relates to a control device. The control device is arranged to determine the incident dose of a first X-ray radiation on an examination object, which examination object includes a foreground object made of a foreground material and a background object made of a background material.

[0049] The control device is arranged to determine, for a respective parameter value of a parameter of a second X-ray radiation, a respective first signal intensity value of a first X-ray beam direction of an X-ray beam of the second X-ray radiation passing through the background object made of the background material.

[0050] A third step includes determining, for a respective value of a parameter of the second X-ray radiation, a respective second signal intensity value of a second X-ray beam direction of the second X-ray radiation passing through the background object made of the background material and the foreground object made of the foreground material.

[0051] The control device is arranged to determine, as the parameter value of the parameter, the value that makes the contrast-noise gap have the maximum value, where the contrast noise gap describes the difference between the first signal intensity value and the second signal intensity value for a respective incident dose.

[0052] The control device is arranged to generate a database, wherein the database assigns the parameter values of at least one parameter to the parameter according to the foreground material, the background material, and the signal intensity value.

[0053] The control device may include at least one computing unit.

[0054] The advantages and refinements described above with respect to the method according to the second aspect of the invention also apply substantially to the control device according to the invention. Therefore, the method features of the control device should be regarded as functional features of the corresponding device.

[0055] According to the invention, the technical problem is also solved by a computer program which can be directly loaded into the memory of a regulating device of an X-ray imaging system, the computer program having program instructions for performing the steps of the above method according to the first aspect of the invention when the program is executed in the regulating device of the X-ray imaging system.

[0056] There may also be an electronically readable data carrier on which electronically readable control information is stored, which control information includes at least one of the computer programs (products) and is designed such that when the data carrier is used in a regulating device of an X-ray imaging system, the control information performs the method according to the first aspect of the invention.

[0057] The storage medium may include a storage unit.

[0058] A computing unit can in particular be understood as a data processing device comprising processing circuitry. The computing unit can in particular process data for performing computational operations. The computational operations can also include, if necessary, operations for performing retrieval access to data structures, such as look-up tables LUT (English: “look-up table”).

[0059] The computing unit can in particular include one or more computers, one or more microcontrollers and / or one or more integrated circuits, such as one or more application-specific integrated circuits ASIC (English: “application-specific integrated circuit”) and / or one or more field-programmable gate arrays FPGA and / or one or more system-on-a-chip SOC (English: “system on a chip”). The computing unit can also include one or more processors, such as one or more microprocessors, one or more central processing unit CPUs (English: “central processing unit”), one or more graphics processing unit GPUs (English: “graphics processing unit”) and / or one or more signal processors, in particular one or more digital signal processors DSP. The computing unit can also include a physical or virtual complex of computers or other mentioned units.

[0060] In different embodiments, the computing unit includes one or more hardware and / or software interfaces and / or one or more storage units.

[0061] The storage unit can be designed as a volatile data memory, such as a dynamic random access memory DRAM (English: “dynamic random access memory”) or a static random access memory SRAM (English: “static random access memory”), or as a non-volatile data memory, such as a read-only memory ROM (English: “read-only memory”), a programmable read-only memory PROM (English: “programmable read-only memory”), an erasable programmable read-only memory EPROM (English: “erasable programmable read-only memory”), an electrically erasable programmable read-only memory EEPROM (English: “electrically erasable programmable read-only memory”), a flash memory or a flash EEPROM, a ferroelectric random access memory FRAM (English: “ferroelectric random access memory”), a magnetoresistive random access memory MRAM (English: “magnetoresistive random access memory”) or a phase-change random access memory PCRAM (English: “phase-change random access memory”).

[0062] Regardless of the grammatical gender of a particular term, persons with a male or female gender identity are included.

[0063] Other features of the present invention result from the claims, the drawings and the description of the drawings. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned and / or shown in the following description of the drawings can be included in the present invention not only in the combinations given respectively, but also in other different combinations. In particular, embodiments and combinations of features that do not have all the features of the original claims can also be included in the present invention. In addition, embodiments and combinations of features that go beyond or deviate from the combinations of features set forth in the reference relationships of the claims can also be included in the present invention. Description of the Drawings

[0064] The present invention will be explained in more detail below with the aid of specific embodiments and the associated schematic diagrams. In the drawings, identical or functionally identical elements may be provided with the same reference numerals. If necessary, the same or functionally identical elements are not necessarily described repeatedly for different figures.

[0065] In the drawings:

[0066] Figure 1 Shows a schematic diagram of an X-ray imaging system;

[0067] Figure 2 Shows a schematic diagram of a foreground object;

[0068] Figure 3 Shows a schematic diagram of a foreground object and a background object;

[0069] Figure 4 Shows a schematic diagram of a curve showing the variation of a parameter value with the incident dose;

[0070] Figure 5 Shows a schematic diagram of a method for generating a database by a control device; and

[0071] Figure 6 Shows a schematic diagram of a method for operating an X-ray imaging system. Detailed implementation

[0072] Figure 1 Shows a schematic diagram of an X-ray imaging system.

[0073] The X-ray imaging system 1 may have a regulation device 2, which is configured to determine a parameter value 17 of at least one parameter 16 of the X-ray imaging system 1 for taking X-ray images 7, 8 of an examination object 9 and to adjust the parameter value in the X-ray imaging system 1. The X-ray imaging system 1 may have an X-ray source 3, which is arranged to output X-ray radiation 4, 5 in the direction of an X-ray detector 6 of the X-ray imaging system 1 for taking X-ray images 7, 8. The examination object 9 may be arranged between the X-ray source 3 and the X-ray detector 6. The examination object 9 may include a foreground object 10 made of a foreground material 11. The examination object 9 may also include a background object 12 made of a background material 13.

[0074] The foreground object 10 and the background object 12 may be arranged in the examination object 9 in such a way that the X-ray radiation (or X-ray) passes through the foreground object 10 and the background object 12 or only through the background object 12 on the path from the X-ray source 3 to the X-ray detector 6.

[0075] The first X-ray beam path 20 may describe the path of the X-ray radiation 4, 5 passing through the background object 12.

[0076] The second X-ray beam path 21 may describe the path of the X-ray radiation 4, 5 passing through the background object 12 and the foreground object 10.

[0077] The X-ray radiation 4, 5 along the first X-ray beam path 20 can be acquired on the X-ray detector 6 with a first signal intensity value 14. The X-ray radiation along the second X-ray beam path 21 can have a second signal intensity value 15 on the X-ray detector 6.

[0078] Based on the difference between the signal intensity values 14, 15, a contrast-noise gap 19 can be determined, which describes a measure of the contrast for the foreground object 10 with the first signal intensity value 14 and the background object 12 with the second signal intensity value 15 in the X-ray images 7, 8. To make the foreground object 10 more visible in front of the background object 12, it may be desirable to achieve as large a contrast-noise gap 19 as possible. This can be achieved by adjusting the parameter value 17 of at least one parameter 16 of the X-ray radiation 4, 5. For this purpose, it may be necessary to determine the parameter value 17 of at least one parameter 16 by means of a regulation device 2 in order to increase the contrast-noise ratio 19 and to adjust it for the acquisition of the second X-ray image 8 achieved by means of the second X-ray radiation 5 in the X-ray imaging system 1. The at least one parameter 16 can relate to the output of the second X-ray radiation 8 or the second X-ray radiation 8 itself. The parameter 16 can include, for example, the output current, output voltage or pulse length of the second X-ray radiation 5.

[0079] The signal intensity values 14, 15 can depend on the absorption characteristics of the objects 10, 12 and the materials 11, 13 of the objects. The materials 11, 13 can in particular have spectral absorption characteristics, where the X-ray radiation 4, 5 is absorbed to different degrees depending on the photon energy of the X-ray radiation 4, 5.

[0080] To increase the signal difference, the X-ray imaging system 1 can have a regulation device 2 that is able to determine the parameter value 17 of at least one parameter 16 and adjust this parameter value in the X-ray imaging system 1.

[0081] To determine the parameter value 17 of at least one parameter 16, the X-ray imaging system 1 can be set to acquire two X-ray images 7, 8 of the examination object 9 successively in time. The regulation device 2 can be set to adjust a preset calibration value of the parameter 16 in order to output the first X-ray radiation 4. The X-ray imaging system 1 can be set to output, via the X-ray source 3, the first X-ray radiation 4 for acquiring the first X-ray image 7 of the examination object 9 in order to generate the first X-ray image 7. The X-ray detector 6 can be set to acquire the first X-ray radiation 4 and determine the incident dose 18 from the first X-ray image 7. The incident dose 18 can describe, for example, the signal intensity value within the area of the first X-ray image 7. The incident dose 18 can be described, for example, as water equivalent.

[0082] The regulating device 2 can be configured to determine, for the acquired incident dose 18, foreground material 11, and background material 13 of the first X-ray image 7 generated with the first X-ray radiation 4, at least one parameter value 17 of at least one parameter 16 for taking the second X-ray image 8 with the second X-ray radiation 5.

[0083] The parameter value 17 of at least one parameter 16 can be determined as follows such that the difference between the first signal intensity value 14 and the second signal intensity value 15 in the second X-ray image 8 is increased compared to the difference in the first X-ray image 7. Preferably, it relates to an optimal value that can maximize the difference between the signal intensity values 14, 15. The foreground material 11 and the background material 13 can be preset for the regulating device 2. Similarly, the foreground depth 22 of the foreground object 10 and the background depth 23 of the background object 12 can be preset for the regulating device 2. Thereby, the parameter value 17 of at least one parameter 16 can also be determined according to the foreground depth 22 of the foreground object 10 and / or the background depth 23 of the background object 12. The foreground depth 22 and the background depth 23 can describe the respective sizes of the objects 10, 12, and the foreground depth and the background depth can be acquired or preset. The background depth 23 and the foreground depth 22 can correspond to the path lengths of the X-ray radiations 4, 5 passing through the respective objects 10, 12 when passing through the examination object 9.

[0084] Other variables related to determining at least one parameter value 17 of at least one parameter 16 can include the densities of the foreground material 11 and the background material 13.

[0085] The regulating device 2 can be configured to determine the parameter value 17 of at least one parameter 16 according to a preset determination method. For example, the regulating device 2 can be configured to perform a simulation using the background material 13, the foreground material 11, and the incident dose 18 to determine the parameter value 17 of at least one parameter 16. The simulation can particularly include a Monte Carlo simulation.

[0086] Preferably, it can be stipulated that a database 25 is provided for the regulating device 2. The database 25 can be established by the control device 24, for example. The database 25 can output the parameter value 17 of at least one parameter 16 for the foreground material 11, the background material 13, and the incident dose 18.

[0087] The control device 24 can be configured to generate a database 25 by means of simulation, in particular Monte Carlo simulation. For example, in the simulation, a first signal strength value 14 and a second signal strength value 15 of different values of at least one parameter 16 can be determined, as well as an incident dose 18 for the second X-ray radiation 5. The values of the foreground material 11, the background material 13 and the parameter 16 can be changed in corresponding individual simulations. The control device 24 can be configured to store the parameter value 17 of at least one parameter 16 determined for the foreground material 11, the background material 13 and the incident dose 18 in the database 25.

[0088] The determination method can include querying the parameter value 17 from the database 25 by means of the regulation device 2. The advantage of providing the database 25 is that possible complex calculation - and / or simulation methods can be executed in advance by the control device 24. Thereby, the duration required for the determination by the regulation device 2 can be shortened. The database 25 can be stored for the regulation device 2. The database 25 can be stored on a central storage device outside the control device 24, the regulation device 2 or the X-ray imaging system 1, and can be accessed by the regulation device 2, for example, via a network or the like.

[0089] The regulation device 2 can be configured to, after determining the parameter value 17 of at least one parameter 16, adjust the parameter value 17 of at least one parameter 16 in the X-ray imaging system 1, and start the output of the second X-ray radiation by the X-ray source 3 to take a second X-ray image 8 of the examination object 9 by means of the X-ray imaging system 1.

[0090] Figure 2 A schematic diagram of a foreground object is shown.

[0091] Figure 2 A hypothesis for determining the parameter value 17 according to the prior art is shown. Shown is a foreground object 10, for example an implant, which has platinum 11 as the foreground material. It is assumed that the foreground object 10 is arranged in a background object 12 with soft tissue as the background material 13. Therefore, the parameter value 17 for increasing the contrast-noise gap 19 is determined according to the spectral absorption characteristics of the tissue and platinum.

[0092] Figure 3 A schematic diagram showing a foreground object and a background object is shown.

[0093] Figure 3 Shown is also Figure 2 shown in Figure 2In contrast to the situation shown, it is desired to increase the difference between two objects 10, 12 made of the same materials 11, 13. If the foreground object 10 is in front of the background object 12, which is, for example, a background object 12 made of platinum that has already been implanted, the visibility of the foreground object 10 made of platinum can be increased thereby. This can be a typical case of adding a coil to an existing coil group.

[0094] Figure 4 A schematic diagram showing a parameter value change curve in which the parameter value changes with the incident dose is shown.

[0095] In the first parameter value change curve 26 among the parameter value change curves 26, 27, the parameter value 17 of at least one parameter 16 changes with the incident dose 18 for platinum as the foreground material 11 and water or tissue as the background material 13. The first parameter value change curve 26 can correspond to Figure 2 the situation shown. The second parameter value change curve 27 shows the change of the parameter value 17 of at least one parameter 16 with the incident dose 18 for platinum as the foreground material 11 and platinum as the background material 13. The second change curve can correspond to Figure 3 the situation shown. The parameter 16 can be described by the optimal acceleration voltage in kV of the X-ray source 3, and the incident dose 18 can be described as the water equivalent in mm.

[0096] For the case of the first parameter value change curve 26, the foreground material 11 and the background material 13 are different from each other. For the case of the second parameter value change curve 27, the foreground material 11 and the background material 13 are the same.

[0097] A large jump position appears in the first parameter value curve 26. This jump position is caused by the K-edge of platinum at 78 keV. From this K-edge, the absorption becomes significantly better, and platinum stands out again relative to the background material 13 there.

[0098] If the background object 12 is also made of platinum, the foreground material 11 and the background material have the same spectral absorption characteristics. In other words, the advantage of increasing the difference can no longer be obtained from the K-edge of platinum, and the determined parameter value 17 of the acceleration voltage only continuously increases with the increase of the water equivalent.

[0099] Figure 5 A schematic diagram showing a method for generating a database by a control device is shown.

[0100] Step A1 includes determining the incident dose 18 for the inspection object 9 for the first X-ray radiation 4. The inspection object 9 includes a foreground object 10 made of the foreground material 11 and a background object 12 made of the background material 13.

[0101] Step A2 includes determining, for a respective value of at least one parameter 16 of the second X-ray radiation 5, a respective first signal intensity value 14 of a first X-ray beam direction 20 of one of the second X-ray radiations passing through a background object 12 composed of a background material 13.

[0102] Step A3 includes determining, for a respective value of the parameter 16 of the second X-ray radiation 5, a respective second signal intensity value 15 of a second X-ray beam direction 21 of one of the second X-ray radiations passing through a background object 12 composed of a background material 13 and a foreground object 10 composed of a foreground material 11.

[0103] Step A4 includes determining the following value of the parameter 16, which value causes the difference between the first signal intensity value 14 and the second signal intensity value 15 to have a maximum for a respective incident dose 18. The determined value is then determined as the parameter value 17.

[0104] Step A5 includes generating a database 25, wherein the database 25 assigns the parameter value 17 to the parameter 16 according to the foreground material 11, the background material 13, and the incident dose 18.

[0105] Figure 6 A schematic diagram showing a method for operating an X-ray imaging system 1 is shown.

[0106] Step B1 includes outputting, by an X-ray source 3, a first X-ray radiation to an X-ray detector 6 to acquire a first X-ray image 7 of an examination object 9, wherein the examination object 9 is arranged between the X-ray source 3 and the X-ray detector 6 and is penetrated by the first X-ray radiation.

[0107] Step B2 includes acquiring, by the X-ray detector 6, the incident dose 18 of the first X-ray radiation after passing through the examination object 9. Step B2 further includes providing the incident dose 18 to a regulating device 2 of the X-ray imaging system 1.

[0108] Step B3 includes determining, by the regulating device 2, a parameter value 17 of at least one parameter 16 for outputting a second X-ray radiation by the X-ray source 3 to acquire a second X-ray image 8 of the examination object 9, wherein the parameter value 17 is determined by the regulating device 2 according to a preset determination method according to the foreground material 11, the background material 13, and the incident dose 18, and wherein the parameter value 17 increases the contrast-noise gap 19 in which the foreground object 10 and the background object 12 form a contrast in the second X-ray image 8.

[0109] Before the visibility of the determined contrast is further optimized in the image processing device, it is important to optimize the corresponding contrast-to-noise ratio by appropriate setting of physical parameters such as voltage, current, filtering, and pulse width. The X-ray image is the input data for the image processing device and must have the best contrast-to-noise ratio for the relevant contrast.

[0110] The problem of high-demand projections can be solved by optimizing the physical parameters of the dose regulation so that they are adapted to the contrast-to-noise ratio of the corresponding contrast to be enhanced. This is a generalization of the scheme of the contrast-to-noise ratio of the contrast in front of the background of human soft tissue.

[0111] In the case where the coils are projected overlapping each other in an aneurysm, the aim can be to improve the contrast of the coil crossings relative to the individual coils. In this case, it is advantageous to optimize with platinum on platinum as the relevant contrast instead of projecting platinum onto human soft tissue as the background material.

[0112] By means of simulations, such as Monte Carlo simulations, the optimal given parameters of the physical image chain can be found, which generate X-rays for the desired visual contrast. For high-demand projections, the background material of human soft tissue can be replaced by other materials. The results of the (Monte Carlo) simulations can be stored in a database that can be accessed in real time.

Claims

1. A method for operating an X-ray imaging system (1), the method comprising the following steps: - outputting first X-ray radiation (4) from the X-ray source (3) to the X-ray detector (6) in order to acquire a first X-ray image (7) of an examination object (9), wherein the examination object (9) is arranged between the X-ray source (3) and the X-ray detector (6) and is penetrated by the first X-ray radiation (4); - detecting an incident dose (18) of the first X-ray radiation (4) after passing through the examination object (9) by means of an X-ray detector (6); - determining, by means of a control device (2) of the X-ray imaging system (1), a parameter value (17) of at least one parameter (16) for outputting a second X-ray radiation (5) from the X-ray source (3) for acquiring a second X-ray image (8) of the examination object (9), It is characterized in that - determining a parameter value (17) by means of a control device (2) according to a preset determination method based on a foreground material (11) of a foreground object (10) arranged in the object to be examined (9), a background material (13) of a background object (12) arranged in the object to be examined (9), and an incident dose (18), - wherein the determination method gives a parameter value (17) of at least one parameter (16) such that an expected contrast-to-noise gap (19) between a first signal intensity value (14) in a second X-ray image (8) of a first X-ray beam trajectory (20) of a second X-ray radiation (5) and a second signal intensity value (15) in a second X-ray image (8) of a second X-ray beam trajectory (21) is maximized, wherein the first X-ray beam trajectory (20) passes through a background object (12) in an object to be examined (9) and the second X-ray beam trajectory (21) passes through the background object (12) and a foreground object (10).

2. The method according to claim 1, wherein: The foreground material (11) and the background material (13) are the same.

3. The method according to claim 1 or 2, wherein: According to a predetermined determination method, a parameter value (17) of at least one parameter (16) is determined based on a foreground depth (22) of a foreground object (10) and a background depth (23) of a background object (12), wherein: The foreground depth (22) describes the path length of the second X-ray beam path (21) through the foreground object (10), and The background depth (23) describes the path length of the second x-ray beam course (21) and the first x-ray beam course (20) through the background object (12).

4. The method according to any one of the preceding claims, wherein: The contrast-to-noise gap (19) is described by the contrast-to-noise ratio.

5. The method according to any one of the preceding claims, wherein: The foreground material (11) and the background material (13) are contrast agents.

6. The method according to any one of the preceding claims, wherein: The foreground material (11) and the background material (13) are platinum.

7. The method according to any one of the preceding claims, wherein: The foreground material (11) and the background material (13) are iron.

8. The method according to any one of the preceding claims, wherein: The preset determination method comprises calling a parameter value (17) of at least one parameter (16) from a database (25) by means of a control device (2).

9. The method according to any one of the preceding claims, wherein: The control device (2) determines a parameter value (17) of the at least one parameter (16) according to a predetermined Monte Carlo method.

10. A method for generating a database (25), the method comprising the following steps to be performed by a control device (24) in a preset simulation method: - for a first X-ray radiation (4), determining an irradiation dose (18) for an object to be examined (9), the object to be examined comprising a foreground object (10) consisting of a foreground material (11) and a background object (12) consisting of a background material (13); - for a corresponding parameter value (17) of a parameter (16) of the second X-ray radiation (5), determining a corresponding first signal intensity value (14) for a first X-ray beam course (20) of the second X-ray radiation passing through a background object (12) consisting of a background material (13); - for a corresponding parameter value (17) of a parameter (16) of the second X-ray radiation (5), determining a corresponding second signal intensity value (15) for a second X-ray beam course (21) of the second X-ray radiation passing through a background object (12) formed by a background material (13) and a foreground object (10) formed by a foreground material (11); - determining a parameter value (17) for which a contrast-to-noise gap describing the difference between the first signal intensity value (14) and the second signal intensity value (15) has a maximum value for the corresponding incident dose (18); and - generating a database (25) in which: The database (25) assigns parameter values ​​(17) to parameters (16) based on foreground material (11), background material (13) and incident dose (18).

11. A control device (2), in, The control device (2) is configured to: - determining a parameter value (17) of at least one parameter (16) according to a predetermined determination method, the parameter being used for outputting a second X-ray radiation from the X-ray source (3) to acquire a second X-ray image (8) of the examination object (9); and - adjusting a parameter value (17) of at least one parameter (16) in the X-ray device; It is characterized in that The control device (2) is configured to: determining the parameter value (17) according to a preset determination method based on the foreground material (11), the background material (13) and the incident dose (18), The determination method specifies a parameter value (17) of at least one parameter (16) so as to maximize an expected contrast-noise gap (19) between a first signal intensity value (14) in a second X-ray image (8) of a first X-ray beam of a second X-ray radiation passing through a background object (12) in an object under examination (9) and a second signal intensity value (15) in a second X-ray image (8) of a second X-ray beam passing through the background object (12) and a foreground object (10).

12. An X-ray imaging system (1), in, The X-ray imaging system (1) is configured to: - outputting first X-ray radiation from the X-ray source (3) to the X-ray detector (6) in order to acquire a first X-ray image (7) of the examination object (9), wherein the examination object (9) is arranged between the X-ray source (3) and the X-ray detector (6) and is penetrated by the first X-ray radiation; - determining an incident dose (18) of the first X-ray radiation after passing through the examination object (9) by means of an X-ray detector (6); - a control device (2) for providing the incident dose (18) to the X-ray imaging system (1); - determining, by means of the control device (2), a parameter value (17) for at least one parameter (16) for the output of a second X-ray radiation by the X-ray source (3) in order to acquire a second X-ray image (8) of the examination object (9); It is characterized in that The control device (2) is configured to: determining the parameter value (17) according to a preset determination method based on the foreground material (11), the background material (13) and the incident dose (18), The determination method specifies a parameter value (17) of at least one parameter (16) so as to maximize an expected contrast-noise gap (19) between a first signal intensity value (14) in a second X-ray image (8) of a first X-ray beam of a second X-ray radiation passing through a background object (12) in an object under examination (9) and a second signal intensity value (15) in a second X-ray image (8) of a second X-ray beam passing through the background object (12) and a foreground object (10).

13. A control device (24), in, The control device (24) is configured to, in a predetermined simulation method, - for a first X-ray radiation (4), determining an irradiation dose (18) for an object to be examined (9), the object to be examined comprising a foreground object (10) consisting of a foreground material (11) and a background object (12) consisting of a background material (13); - for a corresponding parameter value (17) of a parameter (16) of the second X-ray radiation (5), determining a corresponding first signal intensity value (14) for a first X-ray beam course of the second X-ray radiation passing through a background object (12) consisting of a background material (13); - for a corresponding parameter value (17) of a parameter (16) of the second X-ray radiation (5), determining a corresponding second signal intensity value (15) for a second X-ray beam course of the second X-ray radiation passing through a background object (12) consisting of a background material (13) and a foreground object (10) consisting of a foreground material (11); - determining a parameter value (17) for which a contrast-to-noise difference (19) describing the difference between the first signal intensity value (14) and the second signal intensity value (15) has a maximum value for the corresponding incident dose (18); and - generating a database (25), wherein the database (25) assigns parameter values ​​(17) of at least one parameter (16) to the parameter (16) as a function of the foreground material (11), the background material (13) and the incident dose (18).

14. A computer program that can be directly loaded into the memory of the control device (2) of the X-ray imaging system (1) according to claim 12, and the computer program has program instructions so that when the program is executed in the control device (2) of the X-ray imaging system (1), the steps of the method according to one of claims 1 to 10 are executed.

15. An electronically readable data carrier having electronically readable control information stored thereon, the control information comprising at least one computer program according to claim 14 and arranged to be executed when the data carrier is used. The method according to one of claims 1 to 10 is performed in a control device (2) of an X-ray imaging system (1) according to claim 12.

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