NOVEL AND COST-EFFICIENT MEANS OF MEASURING COLLIMATOR ROTATION ANGLES ON All THREE

Abstract

The invention relates to the field of radiation-based imaging. In particular, the invention relates to the field of X-ray collimation. In order to reduce the risk of an erroneous Amplimate chamber position that may lead to an additional dose to a patient, a rotation angle measurement device (10) for measuring a rotation angle of a rotatable X-ray collimator is provided. A rotation angle measuring device (10) includes a resistor strip (12) and a plunger (14). The resistive strip (12) comprises an elongate strip (15) attached to a first portion (60) of the rotatable X-ray collimator, and a longitudinal extent (LA) of the elongate strip (15) is arranged to bend about a rotational axis of the rotatable X-ray collimator. The plunger (12) is attached to the second portion (40) of the X-ray collimator. The first portion and the second portion are arranged to rotate relative to each other during rotation of the X-ray collimator. The plunger (12) is arranged in contact with the elongated strip (15) such that rotation of the rotatable X-ray collimator moves the elongated strip (15) relative to the plunger to produce an electrical signal indicative of a rotation angle of the rotatable X-ray collimator.

Description

Technical Field

[0001] The present invention relates to the field of radiation-based imaging, in particular to the field of X-ray collimation, and in particular to a rotation angle measurement device, a rotation angle measurement system, a rotation angle measurement method, a computer program element, and a computer-readable storage medium. Background Art

[0002] The collimator is a key subcomponent in an X-ray system. It adjusts the X-ray field to the limits required for actual exposure and enables the user to make these adjustments. The collimator provides a light simulation of the X-ray field. In clinical workflow scenarios, the user needs to rotate the collimator based on the patient's anatomy. Measuring the collimator rotation angle is crucial for achieving correct on-screen Amplimat Chamber visualization. Summary of the Invention

[0003] Therefore, a rotation angle measurement function may be required. The objects of the present invention are solved by the subject matter of the independent claims, with further embodiments being incorporated into the dependent claims. It should be understood that the following aspects of the present invention are equally applicable to the rotation angle measurement device, the rotation angle measurement system, the rotation angle measurement method, the computer program element, and the computer-readable storage medium. Therefore, any features, functions, steps, and / or elements described below with reference to one aspect of the present disclosure are equally applicable to any other aspect of the present disclosure.

[0004] According to a first aspect of the present invention, a rotation angle measuring device for measuring the rotation angle of a rotatable X-ray collimator is provided. The rotation angle measuring device includes a resistor bar and a plunger. The resistor bar includes an elongated strip attached to a first portion of the rotatable X-ray collimator. The longitudinal extent of the elongated strip is arranged to bend around the rotation axis of the rotatable X-ray collimator. The plunger is attached to a second portion of the X-ray collimator. The first portion and the second portion are arranged to rotate relative to each other during rotation of the X-ray collimator. The plunger is arranged to contact the elongated strip so that rotation of the rotatable X-ray collimator causes the elongated strip to move relative to the plunger to generate an electrical signal indicative of the rotation angle of the rotatable X-ray collimator.

[0005] Therefore, the present disclosure proposes a rotation angle measurement device, which includes a plunger and a resistor bar arranged on different parts (i.e., a first part and a second part) of a rotatable X-ray collimator. The first part and the second part are arranged to rotate relative to each other during the rotation of the X-ray collimator. For example, the first part moves, i.e., rotates, during the rotation of the rotatable X-ray collimator. The second part does not move, i.e., remains in its position. By pressing the plunger on the resistor bar, the resistor bar generates an electrical output, such as a voltage output. Depending on the rotational position of the plunger, the resistor bar outputs the result as a corresponding electrical signal indicating the rotation angle of the rotatable X-ray collimator. The proposed rotation angle measurement device can be combined with any X-ray system that requires automatic collimation with a rotation angle measurement feature. The proposed rotation angle measurement device can reduce the risk of incorrect amplimat chamber position that may result in additional dose to the patient. The proposed rotation angle measurement device can also help improve optimal collimation and reduce unnecessary radiation area.

[0006] This will be described in detail below, and specifically with respect to Figure 3A 、 3B , 4A and 4B are described. Figure 5A and an example of a resistor strip is shown in Figure 5B Shown in.

[0007] According to an exemplary embodiment of the first aspect of the present invention, the plunger includes one of a spring-loaded plunger and a pressure-loaded plunger.

[0008] This will be described in detail below, and specifically with respect to Figure 5A The example shown is described.

[0009] According to an exemplary embodiment of the first aspect of the present invention, the second part comprises a source alignment flange arranged to couple the X-ray collimator to the X-ray source.

[0010] This will be described in detail below, and specifically with respect to Figure 3A 、 3B , 4A and 4B are described as examples.

[0011] According to an exemplary embodiment of the first aspect of the present invention, the first portion comprises a strip mounting bracket arranged opposite the source alignment flange.

[0012] This will be described in detail below, and specifically with respect to Figure 3A 、 3B , 4A and 4B are described as examples.

[0013] According to a second aspect of the present invention, a rotation angle measurement system is provided, which includes a rotation angle measurement device according to the first aspect and any associated examples, and a processing device configured to determine the rotation angle of a rotatable X-ray collimator based on an electrical signal generated by the rotation angle measurement device.

[0014] This will be described in detail below, and specifically with respect to Figure 6 The example shown is described.

[0015] According to an exemplary embodiment of the second aspect of the present invention, the processing device is further configured to perform a calibration of the rotation angle measuring device.

[0016] Thus, the correct angle of the collimator rotation feedback can be achieved. This will be described in detail below and specifically with respect to Figure 6 The example shown is described.

[0017] According to an exemplary embodiment of the second aspect of the present invention, the processing device is configured to perform a multi-point calibration of the rotation angle measuring device.

[0018] Multi-point calibration can include two-point calibration, three-point calibration, fourth-point calibration, etc.

[0019] According to an exemplary embodiment of the second aspect of the present invention, the multi-point calibration comprises a seven-point calibration, wherein the seven-point calibration comprises the following angular steps: -45°, -30°, -15°, 0°, 15°, 30° and 45°.

[0020] According to a third aspect of the present invention, there is provided an X-ray collimator comprising the rotation angle measurement device according to the first aspect and any related examples or the rotation angle measurement system according to the second aspect and any related examples.

[0021] According to a fourth aspect of the present invention, a rotation angle measurement method for measuring the rotation angle of a rotatable X-ray collimator is provided. The method comprises the following steps:

[0022] -Control the rotatable X-ray collimator to adjust the rotation position;

[0023] - obtaining an electrical signal from a rotation angle measuring device according to the first aspect and any associated examples, and

[0024] - determining a rotation angle of the rotatable X-ray collimator based on the electrical signal.

[0025] This will be described in detail below, and specifically with respect to Figure 7 The flowchart shown is described.

[0026] According to an exemplary embodiment of the fourth aspect of the present invention, the method further comprises the step of performing a calibration of the rotation angle measuring device.

[0027] According to an exemplary embodiment of the fourth aspect of the present invention, the step of performing calibration of the rotation angle measurement device includes performing multi-point calibration of the rotation angle measurement device.

[0028] According to an exemplary embodiment of the fourth aspect of the present invention, the multi-point calibration comprises a seven-point calibration, wherein the seven-point calibration comprises the following angular steps: -45°, -30°, -15°, 0°, 15°, 30° and 45°.

[0029] According to another aspect of the present invention, a computer program product is provided that includes instructions that, when executed by a processor, cause the processor to perform the steps of the method according to the fourth aspect and any related examples. The computer program may include instructions that, when executed by a computer, cause the computer to perform the method of any one of the embodiments described above. Therefore, a computer program element may be stored on a computer unit, which may also be part of an embodiment of the present invention. The computing unit may be suitable for performing or causing the steps of the above-described method to be performed. The computing unit may be suitable for automatic operation and / or execution of user commands. The computer program may be loaded into a working memory of a data processor. Therefore, a data processor may be equipped to perform the method of the present invention. This exemplary embodiment of the present invention covers both computer programs that use the present invention from scratch and computer programs that convert existing programs into programs that use the present invention. In addition, the computer program element may be able to provide all necessary steps to complete the process of the exemplary embodiment of the method described above.

[0030] According to another aspect of the present invention, a computer readable storage medium is provided on which a computer program product is stored. The computer program can be stored and / or distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with other hardware or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. However, the computer program can also be presented through a network like the World Wide Web and can be downloaded from such a network to the working memory of a data processor. The computer readable medium may include instructions that, when executed by a computer, cause the computer to perform the method of any one embodiment as described herein.

[0031] It should be noted that embodiments of the present invention are described with reference to different subject matter. In particular, some embodiments are described with reference to method-type claims, while other embodiments are described with reference to apparatus-type claims. However, those skilled in the art will appreciate from the above and following descriptions that, unless otherwise indicated, any combination of features relating to different subject matter, in addition to any combination of features belonging to one type of subject matter, is also considered disclosed herein. However, all features may be combined to provide synergistic effects that are greater than the simple sum of the individual features. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to the examples of embodiment.The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

[0033] Figure 1 An example of an X-ray collimator in an X-ray imager is shown.

[0034] Figure 2A The X-ray collimator is shown in a first angular position.

[0035] Figure 2B The X-ray collimator is shown in a second angular position.

[0036] Figure 3A A perspective view of an X-ray collimator is shown.

[0037] Figure 3B A top view of the X-ray collimator is shown.

[0038] Figure 4A The X-ray collimator is shown in a first angular position.

[0039] Figure 4B The X-ray collimator is shown in a second angular position.

[0040] Figure 5A An example of a plunger is shown.

[0041] Figure 5B An example of a resistor strip is shown.

[0042] Figure 6 An example of a rotation angle measurement system is shown.

[0043] Figure 7 A flow chart illustrating a method for measuring a rotation angle is shown.

[0044] List of reference numerals:

[0045] 10Rotation angle measurement equipment

[0046] 11 Spring

[0047] 12. Plunger

[0048] 14.Resistor strips

[0049] 15. Slim belt

[0050] 17. Active area

[0051] 19 electroporation channels

[0052] 20 collimator assembly

[0053] 30 adjustment knobs (multiple)

[0054] 40 Source Alignment Flange

[0055] 50 shutter

[0056] 60 mounting brackets

[0057] 70 processing equipment

[0058] 100 X-ray collimator

[0059] 110 X-ray source

[0060] 120 X-ray detectors

[0061] 130 shell

[0062] 140X-ray beam

[0063] 150 field of view

[0064] 160° rotation axis

[0065] 200X-ray imager

[0066] 300° rotation angle measurement method

[0067] LA Slim Range DETAILED DESCRIPTION

[0068] X-ray collimators are the main subcomponents in X-ray systems. Figure 1 1 shows an example of an X-ray collimator 100 in an X-ray imager 200. The X-ray imager 200 includes an X-ray source 110 and an X-ray detector 120. The X-ray source 110 and the X-ray collimator 100 are arranged in a housing 130. Figure 1As shown, before the collimator interaction, the X-ray beam 140 emitted from the X-ray source 110 is a diverging beam, so without the X-ray collimator 100, the cross-sectional size of the X-ray beam 140 when it reaches the X-ray detector 120 will be much larger than the area of ​​the desired region of interest (ROI) (such as the patient's lungs in a "chest X-ray"). The purpose of the X-ray collimator 100 is to limit the size of the cross-section of the beam to create a field of view 150 that matches the cross-section of the beam to the patient's ROI in size and shape.

[0069] For many examinations, such as lateral chest and orthopedic examinations, it is often necessary to rotate the collimator to reduce the unnecessary irradiation area. This can be done by the medical staff by manually rotating the collimator. Between the X-ray detector 120 and the object being examined, a dose measurement device can be positioned, which can be an arrangement of multiple measurement fields (for example five measurement fields). An example of a dose measurement device is an ionization chamber called an Amplimat chamber. Before starting irradiation with X-rays, the operator can select some (or all) of the measurement fields. Then, during subsequent irradiation of the object being examined with X-rays, only the selected group of measurement fields is used to measure the radiation dose during the actual irradiation with X-rays. The collimator rotation position input is crucial for proper visualization of the Amplimat chamber on the display screen. Figure 2A The X-ray collimator 100 is shown in an angular position of 0 degrees, which is the correct Amplimat chamber position. In the position shown, it is possible to measure the correct radiation dose during the actual irradiation with X-rays. However, if the X-ray collimator is in an angular position different from 0 degrees and the system has no input about this, the system can control all its functions where applicable by assuming that the collimator is at 0 degrees. For example, Figure 2B The X-ray collimator 100 is shown rotated 45 degrees about the rotation axis 160. This could lead to an erroneous Amplimat chamber position and thus to an erroneous radiation dose measurement, resulting in an excess dose to the examined patient.

[0070] In order to solve the above problems, the present disclosure proposes a rotation angle measurement device to perform a collimator rotation angle measurement function. Figure 3A and 3B An exemplary arrangement of a rotation angle measuring device on an X-ray collimator is shown in As shown in these two figures, the rotation angle measuring device 10 includes a resistor bar 12 and a plunger 14 .

[0071] Figure 3A A perspective view of an X-ray collimator 100 is shown. The X-ray collimator 100 includes a collimator assembly 20 and one or more adjustment knobs 30 to adjust a shutter of the collimator assembly 20. Figure 3BA top view of the collimator assembly 20 is shown. In the illustrated example, the collimator assembly 20 includes a base 22 having an opening, a source alignment flange 40 for coupling the X-ray collimator to an X-ray source (e.g., an X-ray tube or tube assembly), and a shutter 50 that variably blocks X-ray radiation passing through the opening. In the illustrated example, the source alignment flange 40 is shown as a protrusion and a ring. In some other examples, the source alignment flange 40 may have another shape that can mate with or couple to the X-ray source 110. In the illustrated example, a bar mounting bracket 60 is provided and arranged on the base 22 of the collimator assembly 20. Although the bar mounting bracket 60 is shown as a protrusion and a semicircle, it should be understood that the source alignment flange 60 may have another shape. The bar mounting bracket 60 is arranged opposite the source alignment flange 40. The inner surface of the bar mounting bracket 60 faces the source alignment flange 40 and is curved about the rotation axis 160 of the rotatable X-ray collimator 100.

[0072] The X-ray collimator 100 can be rotated clockwise or counterclockwise. During the rotation of the X-ray collimator, the source alignment flange 40 and the bar mounting bracket 60 rotate relative to each other. For example, Figure 4A The X-ray collimator 100 is shown arranged in a first rotational position. In the first rotational position shown, the plunger 12 is in contact with the midpoint of the elongated strip of the resistor strip 14. This angular position may also be defined as the angular position of 0 degrees. Figure 4B The X-ray collimator 100 is shown moved to the second rotational position. Figure 4B As can be seen in the figure, only the plunger 12 attached to the source alignment flange 40 moves (i.e., rotates). The strip mounting bracket 60 does not move, i.e., remains in its position. Therefore, during rotation of the X-ray collimator 100, the source alignment flange 40 and the strip mounting bracket 60 rotate relative to each other. This relative movement causes a change in the rotational position of the plunger 12 on the resistance strip 14. The rotation angle measurement device 10 then outputs the result as an electrical signal, such as an analog voltage, which indicates the rotation angle of the rotatable X-ray collimator.

[0073] Figure 5A An example of a plunger 12 is shown. In this illustrated example, plunger 12 is a spring-loaded plunger including spring 11. However, it should be understood that plunger 12 can be of any type, such as a pressure-loaded plunger. Plunger 12 is a non-conductive mechanism. By pressing plunger 12 against resistor bar 14, resistor bar 14 generates the desired electrical output.

[0074] Figure 5BAn example of a resistor strip 14 is shown. In the example shown, resistor strip 14 includes an elongated strip 15 having an elongated extent LA. Resistive strip 14 includes an active region 17 made of a resistive material. Resistive strip 14 also includes electrical channels 19 configured to provide an electrical output. By way of example, electrical channels 19 may include two resistive output channels and one current collector channel. The two resistive circuits are separated by a spacer adhesive stack, and contact between the two circuits is achieved through pressure from a plunger on the top circuit, pushing downward until the top circuit connects with the bottom circuit, thereby generating a potential output in the form of a voltage divider.

[0075] To measure the rotation angle of the X-ray collimator, a resistor strip 14 is attached to the inner surface of the strip mounting bracket 60, and the longitudinal extent LA of the elongated strip is arranged to bend around the rotation axis of the rotatable X-ray collimator 100. Additionally, a plunger 12 is arranged to contact the elongated strip such that rotation of the rotatable X-ray collimator causes the elongated strip to move relative to the plunger, thereby generating an electrical signal indicative of the rotation angle of the rotatable X-ray collimator. Based on the rotational position of the plunger, the resistor strip 14 outputs the result as an analog voltage as the output of the voltage divider described above. This analog voltage signal is converted to a digital value by an analog-to-digital converter located, for example, in the collimator microcontroller. Based on this digital voltage value, the equivalent collimator rotation angle is calculated, for example, in 0.1 degree steps, and transmitted to the system software.

[0076] Figure 6 The rotation angle measurement system includes the rotation angle measurement device 10 as described above and a processing device 70 configured to obtain an electrical signal from the rotation angle measurement device and determine the rotation angle of the rotatable X-ray collimator based on the electrical signal.

[0077] "Processor" is an example of a processing device 70 that uses one or more microprocessors that can be programmed using software (e.g., microcode) to perform the various functions described herein. The processing device can be implemented with or without a processor, and can also be implemented as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuits) to perform other functions. Examples of device components that can be used in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs). In various embodiments, the processor can be associated with one or more storage media (generally referred to herein as "memory," such as volatile and non-volatile computer memory). In some embodiments, the storage medium can be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform at least some of the functions described herein. Various storage media can be fixed within a computing device or can be transportable so that one or more programs stored thereon can be loaded into a computing device to implement various aspects of the present disclosure described herein. The terms "program" or "computer program" are used herein in a general sense to refer to any type of computer code (e.g., software or microcode) that can be used to program one or more processors. As an example, processing unit 70 or some of its components may reside in an operator console running as a software routine. The components may be programmed on a suitable scientific computing platform such as or ) and then converted to C++ or C routines maintained in the library and linked when called by the operator console.

[0078] To achieve the correct angle for the collimator rotation feedback, the processing device 70 can also be configured to perform calibration of the rotation angle measurement device, such as a multi-point calibration of the rotation angle measurement device. As an example, to achieve a + / - 0.5 degree rotation angle accuracy, the resistor strips 14 mounted on the collimator housing can be calibrated in seven steps, such as -45°, -30°, -15°, 0°, 15°, 30°, and 45°. At each of these angle steps, a corresponding digital value can be stored in the collimator microcontroller, and the result can be stored in a lookup table. The lookup table helps interpolate between angle values ​​with the required accuracy.

[0079] exist Figure 7A flow chart illustrating a rotation angle measurement method 300 for measuring the rotation angle of a rotatable X-ray collimator is shown in FIG. At block 310, the method 300 includes the step of controlling the rotatable X-ray collimator to adjust the rotational position. At block 320, the method 300 includes the step of obtaining an electrical signal from a rotation angle measurement device as described herein. At block 330, the method 300 also includes the step of determining the rotation angle of the rotatable X-ray collimator based on the electrical signal.

[0080] In some embodiments, method 300 may further include performing a step of calibrating the rotation angle measurement device, such as a multi-point calibration of the rotation angle measurement device. For example, the multi-point calibration includes a seven-point calibration, where the seven-point calibration includes the following angular steps: -45°, -30°, -15°, 0°, 15°, 30°, and 45°.

[0081] In a further exemplary embodiment of the present invention, a computer program or a computer program element is provided, which is characterized in that it is adapted to perform the method steps of the method according to one of the preceding embodiments on a suitable system.

[0082] Thus, a computer program element can be stored on a computer unit, which can also be part of an embodiment of the present invention. This computer unit can be adapted to perform or cause the steps of the method described above to be performed. Furthermore, it can be adapted to operate components of the apparatus described above. The computer unit can be adapted to automatically operate and / or execute user orders. The computer program can be loaded into the working memory of a data processor. Thus, the data processor can be equipped to perform the method of the present invention.

[0083] This exemplary embodiment of the invention covers both a computer program which uses the invention from scratch and a computer program which by an update turns an existing program into a program which uses the invention.

[0084] Furthermore, the computer program element may be able to provide all necessary steps to complete the procedures of an exemplary embodiment of the method as described above.

[0085] According to a further exemplary embodiment of the present invention, a computer-readable medium, for example a CD-ROM, is proposed, wherein the computer-readable medium has a computer program element stored thereon, the computer program element being described by the preceding section.

[0086] The computer program may be stored and / or distributed on suitable media, such as optical storage media or solid-state media supplied together with or as part of other hardware, but the computer program may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0087] However, the computer program may also be presented over a network like the World Wide Web and can be downloaded from such a network into a working memory of a data processor. According to a further exemplary embodiment of the present invention, a medium for making a computer program element available for downloading is provided, which computer program element is arranged to perform a method according to one of the previously described embodiments of the invention.

[0088] It should be noted that embodiments of the present invention are described with reference to different subject matter. In particular, some embodiments are described with reference to method-type claims, while other embodiments are described with reference to apparatus-type claims. However, those skilled in the art will appreciate from the above and following descriptions that, unless otherwise indicated, any combination of features relating to different subject matter, in addition to any combination of features belonging to one type of subject matter, is also considered disclosed herein. However, all features may be combined to provide synergistic effects that exceed the simple sum of the features.

[0089] Although the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary rather than restrictive. The present invention is not limited to the disclosed embodiments. Other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention from a study of the drawings, the disclosure, and the appended claims.

[0090] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A rotation angle measuring device (10) for measuring the rotation angle of a rotatable X-ray collimator, the device comprising: - plunger (12); and - a resistance strip (14); wherein the resistive strip comprises an elongated strip attached to a first portion of the rotatable X-ray collimator, and wherein a longitudinal extent of the elongated strip is arranged to bend around an axis of rotation of the rotatable X-ray collimator; wherein the plunger is attached to a second portion of the X-ray collimator, wherein the first portion and the second portion are arranged to rotate relative to each other during rotation of the X-ray collimator; and The plunger is arranged to contact the elongated strip such that rotation of the rotatable X-ray collimator moves the elongated strip relative to the plunger to generate an electrical signal indicative of a rotation angle of the rotatable X-ray collimator.

2. The rotation angle measuring device according to claim 1, wherein The plunger includes one of the following: - a spring-loaded plunger; and -Pressure loaded plunger.

3. The rotation angle measuring device according to claim 1 or 2, wherein: The second portion comprises a source alignment flange (40) arranged to couple the X-ray collimator to an X-ray source.

4. The rotation angle measuring device according to claim 3, wherein The first portion includes a strip mounting bracket (60) disposed opposite the source alignment flange.

5. A rotation angle measurement system comprising: - A rotation angle measuring device (10) according to any one of the preceding claims; as well as - a processing device (70) configured to determine the rotation angle of the rotatable X-ray collimator based on the electrical signal generated by the rotation angle measurement device.

6. The rotation angle measurement system according to claim 5, wherein: The processing device is further configured to perform a calibration of the rotation angle measuring device.

7. The rotation angle measurement system according to claim 6, wherein: The processing device is configured to perform a multi-point calibration of the rotation angle measurement device.

8. The rotation angle measurement system according to claim 7, wherein: The multi-point calibration includes a seven-point calibration, wherein the seven-point calibration includes the following angular steps: -45°, -30°, -15°, 0°, 15°, 30°, and 45°.

9. An X-ray collimator (100), comprising: - A rotation angle measuring device according to any one of claims 1 to 4; or - A rotation angle measurement system according to any one of claims 5-8.

10. A rotation angle measurement method (300) for measuring the rotation angle of a rotatable X-ray collimator, the method comprising: - controlling (310) the rotatable X-ray collimator to adjust the rotational position; - obtaining (320) an electrical signal from a rotation angle measuring device according to any one of claims 1 to 4; and - determining (330) a rotation angle of the rotatable X-ray collimator based on the electrical signal.

11. The rotation angle measurement method according to claim 10, further comprising: - performing a calibration of the rotation angle measuring device.

12. The rotation angle measurement method according to claim 11, wherein: The step of performing calibration on the rotation angle measuring device comprises: - performing a multi-point calibration of the rotation angle measuring device.

13. The rotation angle measurement method according to claim 11, wherein: The multi-point calibration includes a seven-point calibration, wherein the seven-point calibration includes the following angular steps: -45°, -30°, -15°, 0°, 15°, 30°, and 45°.

14. A computer program element comprising instructions which, when executed by a processor, cause the processor to cause the steps of the method of any one of claims 10 to 13 to be performed.

15. A computer-readable storage medium having stored thereon the computer program product according to claim 14.

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