Method for operating an imaging X-ray device and imaging X-ray device

Abstract

The invention relates to a method for operating an imaging X-ray device (1) comprising an X-ray source (3) for emitting an X-ray field (9), to which a light fan device (7) for emitting a light fan (15) whose extent corresponds to that of the X-ray field (9) is associated, wherein, in order to determine and / or display a scatter radiation distribution resulting from the X-ray field (9) whose extent is set for an examination, an object of examination, in particular a patient (17), which is to be exposed to the X-ray field (9) for imaging, is covered with a covering material (16) which, on the side facing the X-ray source (3), is designed to diffusely reflect at least part of the light of the light fan (15), and the light fan device (7) is activated.

Description

[0001] The invention relates to a method for operating an X-ray imaging device having an X-ray emitter for emitting an X-ray field, to which a light fan device for emitting a light fan whose extent corresponds to that of the X-ray field is assigned. The invention also relates to an X-ray imaging device.

[0002] X-ray equipment, particularly in medical technology, uses X-ray radiation, which can have an ionizing effect. Therefore, the X-ray field used for imaging examinations is usually limited to the minimum necessary to avoid unnecessary exposure to the patient. Suitable beam-shaping devices, such as collimators and / or other aperture devices, are known for this purpose.

[0003] To visually determine the extent of the X-ray field, it has already been proposed in the prior art to combine light fan devices with the X-ray tube. In this case, an X-ray-transparent mirror is inserted into the beam path on the X-ray tube side, which deflects light incident on it from the side in the direction of the X-rays, thus creating a light fan that is congruent with the X-ray field. This optically indicates the extent of the X-ray field on the object under examination.

[0004] Strictly speaking, such a light fan is not a fan, since a fan has a flat extension, whereas the X-ray beam is basically conical or pyramidal. Therefore, such a light fan has the shape of a cone, a truncated cone, or a pyramid or a truncated pyramid. For the sake of simplicity, however, the term "light fan" will be used here and in the following.

[0005] Since significant scattered radiation can occur during X-ray examinations, personnel in the vicinity of the X-ray facility must also be protected, as scattered radiation poses a serious hazard. In fact, a large portion of scattered radiation is emitted by the object being examined, especially the patient.

[0006] Since X-rays are invisible to the human eye, it is challenging to provide adequate protective measures for staff at all times. During X-ray imaging examinations, staff focus is on patient care. Since scattered radiation has no immediate short-term negative effects, scattered radiation protection often takes a back seat.

[0007] It is known in the prior art that during the imaging examination with the X-ray device, for example when personnel remains in the room due to a medical intervention, radiation protection devices, such as radiation protection walls or other shielding components, are used, which, however, must be adjusted to the current setting of the X-ray device. This is particularly the case when a large number of possible orientations of the X-ray beam field are possible, as is the case with X-ray devices having imaging arrangements of X-ray emitter and X-ray detector that are adjustable in many degrees of freedom in the space. An example of this is an X-ray device with a C-arm, as is frequently used in an angiography system.In general, it can be said that, for example, radiation protection, made of lead, that is adequately positioned for anterior-posterior projections does not necessarily provide equally suitable scattered radiation protection for lateral projections.

[0008] To address this problem, regular training and exercises for staff are known to be effective, but these do not necessarily produce the desired results. In particular, success depends heavily on individual compliance.

[0009] Furthermore, the prior art has proposed calculating the scattered radiation distribution through complex computational processes using a computer and displaying the results to personnel, for example, on a monitor. However, this option is time-consuming and expensive due to the necessary calculations, and it is difficult to correlate displayed results with actual protective measures.

[0010] The invention is therefore based on the object of providing a possibility for the low-effort, time-efficient, in particular intuitively understandable and / or automatically realizable, adequate adaptation of scattered radiation protection measures.

[0011] To achieve this object, the invention provides a method having the features of claim 1 and an X-ray device having the features of claim 14. Advantageous embodiments emerge from the subclaims.

[0012] In a method of the type mentioned at the outset, the invention provides that, in order to determine and / or display a scattered radiation distribution which is created by the X-ray field, an examination object which is to be exposed to the X-ray field for imaging is covered with a covering means which, on the side facing the X-ray emitter, is designed to at least partially diffusely reflect the light of the light fan, and the light fan device is activated to emit a light fan whose extent corresponds to that of the X-ray field.

[0013] The X-ray field is generally first adjusted to the desired extent for the examination using at least one beam-shaping device, in particular a collimator and / or a diaphragm device. If the light fan device, which can in particular comprise a mirror arranged in the beam path of the X-ray radiation such that at least a relevant portion of the at least one beam-shaping device acts on the light reflected by the mirror, is then activated, the light from the light fan that strikes the cover means is diffusely reflected and therefore simulates the scattered radiation effect that occurs for the X-ray field due to the object under examination, in particular a patient. Studies have shown that the scattered radiation distribution of the X-ray radiation is comparable to such a diffuse reflection of light.

[0014] Since the covering means advantageously adapts at least partially to the shape of the examination object in the covered area, it also images the shape of the examination object, which further contributes to simulating the behavior of the scattered radiation due to the diffusely reflected light of the light fan. In this case, at least the area of ​​the examination object facing the X-ray tube must be covered, in particular in a shape-adapted manner. In particular, it can be provided to completely cover the examination object along at least one examination region intended for imaging, so that the examination object is enclosed by the covering means, for example a patient blanket or film. The scattered radiation can then be reproduced for any position of the X-ray tube (not covered by a non-optically transparent patient support means).This is particularly useful with regard to lateral positions of the X-ray tube, especially to the side of a patient positioned on a patient table, as may occur, for example, when using a C-arm.

[0015] It is therefore proposed to use a diffusely reflecting examination object cover, in particular a patient cover, whose scattering properties for the light of the light fan are particularly comparable to the scattering properties of the examination object, for example, a human body, for X-rays. This makes it possible to qualitatively visualize or detect the scattered radiation in the room of the X-ray device, which can, for example, form part of an angiography system for minimally invasive medical procedures, without the need to use actually dangerous radiation, in particular X-rays.

[0016] In particular, it can be provided that the fan-shaped light device is activated before an examination using the X-ray field when the X-ray source is switched off. As explained, the X-ray device is already set to generate the X-ray field in the desired extent. The light of the fan-shaped light device can thus be triggered independently of the X-ray radiation in order to check the scattered radiation distribution before the X-ray radiation is used, for example, to appropriately adapt protective measures and / or modify the X-ray field.

[0017] The light fan device is used to make the scattered radiation distribution visible and / or detectable in a harmless manner. No complex calculations are required; instead, a suitable drape with diffuse reflection on the side facing the X-ray tube simply needs to be placed over the patient. Drapes are often used in X-ray examinations anyway, for example, for sterile draping. Therefore, if such drapes are designed to be diffusely reflective, no additional work step is required; if the diffusely reflective drape is also provided, it can still be placed quickly and easily over the examination subject, especially the patient.

[0018] The control system of the X-ray device can be designed to be less complex, since complex algorithms for estimating the scattered radiation distribution are no longer necessary.

[0019] An advantageous development of the invention can provide that the light-emitting device emits visible light. In this case, the scattered radiation is made qualitatively visible in the space for people, so that directly irradiated objects or persons are immediately visible. In this way, it is possible to intuitively and visually assess whether the current measures for scattered radiation protection are sufficient, in particular whether radiation protection devices are correctly arranged. In this way, without complex calculations, estimation processes and the like, a directly understandable and accessible visualization of the scattered radiation distribution is possible.

[0020] Alternatively or additionally, within the scope of the present invention, it can be particularly advantageously provided that, by means of at least one light sensor arranged at a measuring position outside the X-ray field, sensor data describing the light of the light fan reflected by the covering means is recorded and evaluated by an evaluation unit to determine scattered radiation estimation information. Such a configuration can be particularly useful when the light reflected by the covering means is too weak for sufficiently clear optical visibility by a person, in particular due to residual illumination of the room, or even when light outside the visible spectrum is used, which is possible within the scope of the present invention.For example, infrared light can be used instead of or in addition to light in the visible range and measured by the light sensors. In particular, a wavelength range can be specifically selected in which there is as little stray light as possible in the room. In principle, it is advisable to select the wavelength range measured by the at least one light sensor to correspond to the wavelength range of the light in the light fan.

[0021] A measurement is useful because it allows an objective assessment of the quantitative distribution of the light of the light fan reflected by the covering means and thus of the qualitative scattered radiation distribution. This can be used directly, in particular, for control measures, for example, to reduce scattered radiation in areas where people are located and / or to protect against scattered radiation and / or to warn and / or inform people, which will be discussed in more detail below. The scattered radiation estimation information therefore describes, in particular, the estimated qualitative scattered radiation distribution derived from the quantitative measurement of the light of the light fan reflected by the covering means. For this purpose, multiple measuring positions are preferably used, thus employing multiple light sensors.

[0022] For example, it can be provided that an optoelectronic sensor and / or a camera is used as the at least one light sensor. However, other types of light sensors, such as simple photocells, can also be used within the scope of the present invention.

[0023] The evaluation unit can preferably be part of a control unit of the X-ray device. The control unit can also control the operation of the light fan device and, for example, the X-ray tube, using a recording unit. Upon activation of the light fan device, the control unit can also start recording the sensor data from the light sensors.

[0024] In a particularly expedient embodiment, it can be provided that a first light sensor of a light sensor arrangement that can be worn by a person, in particular worn around the neck, is used as at least one of the at least one light sensor. If at least one first light sensor is attached to a person, it can be checked whether relevant scattered radiation intensities occur at their position. In particular, several first light sensors can be arranged on a person. The person can move with the light fan device switched on in order to check the exposure to scattered radiation at different positions. For example, the at least one first light sensor can be arranged on a person by means of a carrier, for example a piece of clothing, a lanyard or the like, of the light sensor arrangement.In exemplary embodiments, an arrangement of first light sensors can also be used, for example, over the person's front torso. A head-mounted light sensor arrangement is also conceivable.

[0025] Alternatively or additionally, it can also be provided that a second light sensor is used as at least one of the at least one light sensor, which is or will be fastened, in particular detachably, to a position intended for the possible presence of a person. For example, such second light sensors can have a fastening means, for example for magnetic or other adhesion to other surfaces. The fastening means can be detachably designed, but it is of course also possible to provide a fixed arrangement of at least one second light sensor, in particular a plurality of second light sensors, at positions where people are usually present.

[0026] Preferably, a control unit can check at least one action condition that evaluates the scattered radiation estimation information. If this condition is met, at least one scattered radiation protection and / or scattered radiation reduction measure associated with the action condition and / or at least one notification output measure is executed by the control unit. The control unit can also be part of the control device of the X-ray device and also serve other purposes, for example, the general control of components. Action conditions allow for the automation of measures based on the automatic measurement of the scattered radiation distribution, in particular while the light fan device and the acquisition of sensor data remain active or when further activation of the light fan device and the measurement can follow automatically.In this way, the impact of the measures, in particular the scattered radiation protection and / or scattered radiation reduction measures, can also be checked.

[0027] Specifically, it can be provided that the scattered radiation protection and / or scattered radiation reduction measure comprises the positioning of a radiation protection device, in particular a protective plate, and / or an adjustment of at least one radiation generation parameter of the X-ray tube and / or an adjustment of the extent of the X-ray field and / or that the information output measure comprises the acoustic and / or visual output of a warning and / or the output of a suggestion for a procedure for scattered radiation protection and / or scattered radiation reduction. For example, radiation protection walls are known whose extent, in particular in height, is adjustable and whose actuators can be controlled accordingly. In another specific example, it is conceivable to adjust parameters of the X-ray tube, for example the tube voltage, a filter, but also a position and / or orientation of the X-ray tube.Finally, it is also possible to specifically alert people to the existing danger by issuing a notification, for example, a warning. Additionally or alternatively, particularly if automatic control is not possible or desired, a suggestion for a procedure for scattered radiation protection and / or scattered radiation reduction can be issued. This can be done in the form of a confirmation request, after which at least one scattered radiation protection and / or scattered radiation reduction measure can be automatically implemented for controllable components in accordance with the suggestion.

[0028] In a specific development of the invention, it can be provided that the covering means used is a covering means which at least partially has a reflective coating on the side facing away from the examination object and / or in which at least one reflective material is integrated, in particular woven, into the covering means. For example, the coating and / or the material can comprise a metal or a metal alloy. In another embodiment, it can be provided that the coating comprises a reflective powder and / or this is introduced as a material into the covering means. In the case of an at least partially textile covering means, it can also be expedient to use threads made of, in particular, diffusely reflective material, for example with metal fibers, to produce the covering means or to integrate them into it.It is evident that a large number of variants for designing the covering means to reflect diffusely, which are basically known for other applications, can also be used within the scope of the present invention.

[0029] A useful further development can provide for the reflective design to be realized by a pattern of diffusely reflecting partial surfaces on the side facing the X-ray tube. In this case, a covering means is used as the covering means which is not completely diffusely reflective in the area exposed to the light fan, but only to the extent that sufficient reflection occurs for sufficient visibility and / or sufficient measurability. In this way, disruptive light effects can be avoided in visible light. Furthermore, it can be ensured that the coverage of the X-ray field represented by the light fan remains clearly and easily visible on the object under examination.

[0030] Specifically, for example, the pattern may be formed from intersecting diffusely reflecting stripes, particularly as a diamond pattern. Other patterns that provide sufficiently good or dense area coverage, such as dot patterns, check patterns, and the like, may also be used.

[0031] In general, various materials can be used to achieve diffuse reflectivity. Suitable materials for achieving diffuse reflection include, for example, barium sulfate, optical PTFE-based materials, ODM98, glass reflector films, and the like.

[0032] A film and / or a patient blanket can be used as the covering means. It is preferred to provide the diffusely reflective property on a covering means, such as a patient blanket, that is already in use and can be provided in a form-fitting manner at various locations or wrapping the entire patient. However, another covering means, for example, implemented as a film, is also possible, which proves particularly useful when the patient is to be completely enclosed in the examination area (as a section of their length).

[0033] In exemplary embodiments, the covering means can be stretched at least partially over the examination object and diffusely reflect the light of the light fan on a smooth portion of the side facing the X-ray tube. In such a configuration, diffusely reflecting, smooth surfaces can be used, and uneven surfaces do not have to be used to produce the diffuse reflection. In particular, the covering means nevertheless continues to adapt at least roughly, for example sufficiently approximately, to the shape of the examination object. For example, the covering means can be placed over the torso of a patient, depicting an approximately elliptical cylindrical shape.

[0034] In many cases, the X-ray field is adjusted so that it only hits the object under examination. In this way, not only is the area in which image data is actually desired irradiated, thus reducing scattered radiation from the outset, but excessive contrast differences that could impair image quality are also avoided. If, however, a portion of the X-ray field does not hit the object under examination or the opaque material, it can be provided that, for an area distant from the object under examination, not covered by the opaque material, and illuminated by the X-ray field, another diffusely reflecting reflective material can be used for this area, particularly one that reflects in the same way as the opaque material. If the material onto which the portion impinges has different scattering properties, the reflective properties can also be adjusted accordingly.

[0035] In addition to the method, the invention also relates to an imaging X-ray device, comprising an X-ray emitter for emitting an X-ray field and a light fan device assigned to the X-ray emitter for emitting a light fan, the extent of which corresponds to that of the X-ray field, wherein the X-ray device additionally has a covering means for covering an examination object to be examined with the X-ray field, which is designed to reflect at least partially the light of the light fan on the side facing the X-ray emitter in a diffusely reflecting manner for determining and / or displaying a scattered radiation distribution which is created by the X-ray field whose extent is adjusted for an examination.All statements regarding the method according to the invention can be transferred analogously to the X-ray device according to the invention and vice versa, so that the advantages already mentioned can also be obtained with the X-ray device.

[0036] In particular, the X-ray device has at least one beam-shaping device assigned to the X-ray tube for adjusting the extent of the X-ray field. The X-ray tube can form part of a recording arrangement that also includes an X-ray tube. The recording arrangement can be movable with respect to at least one degree of freedom, so that the X-ray field also changes its position and / or orientation in space. In this case, the light fan device and the beam-shaping device expediently form an X-ray tube arrangement with the X-ray tube, in particular a structural unit that is moved together. Such an X-ray tube arrangement can also have at least one filter device for optionally introducing at least one filter into the beam path of the X-ray field. In particular, the X-ray device can have at least one light sensor.

[0037] Overall, the X-ray device can be a radiography device. The X-ray device can also be part of an angiography system and preferably comprise a C-arm on which the X-ray source and an X-ray detector(s) are arranged opposite each other.

[0038] Particularly preferably, the X-ray device can comprise a control device configured to carry out automatically executed steps of the method according to the invention and comprising at least one processor and at least one memory device. The control device can, for example, comprise functional units formed by software and / or hardware. In particular, in addition to a recording unit for controlling the recording operation, the following can be provided: - an adjustment unit for adjusting the extent of the X-ray field, in particular by controlling the beam shaping device, and / or - a control unit designed to control at least the light fan device, and / or - an evaluation unit for evaluating sensor data from the at least one light sensor.

[0039] The control unit can then also be configured to evaluate the at least one action condition and to control corresponding components to carry out the associated action.

[0040] Further advantages and details of the present invention will become apparent from the exemplary embodiments described below and from the drawings. Fig. 1 a schematic diagram of an X-ray device according to the invention, Fig. 2 schematically shows an X-ray tube arrangement of the X-ray device, Fig. 3 schematically shows the functional principle of a covering agent, Fig. 4 a schematic sketch of a person behind a radiation protection device before carrying out a measure, Fig. 5 a schematic sketch of the person behind the radiation protection device after the measure has been carried out, Fig. 6 a flow chart of an embodiment of the method according to the invention, Fig. 7 the functional structure of a control device of the X-ray device, and Fig. 8 a possible diffusely reflecting pattern on a covering agent.

[0041] Fig. Figure 1 shows a schematic diagram of an X-ray device 1 according to the invention. The X-ray device 1 comprises an X-ray emitter arrangement 2 with an X-ray emitter 3 and an X-ray detector 4. The X-ray emitter 3 and the X-ray detector 4 form a recording arrangement, which can be arranged, for example, on a C-arm 5 (shown only schematically here). The recording arrangement can be movable relative to a patient placed on a patient table (not shown) of the X-ray device 1 as the examination subject.

[0042] In addition to the X-ray source 3, the X-ray source arrangement 2 also comprises, assigned to the X-ray source and initially shown only schematically here, at least one beam-shaping device 6, for example a collimator and / or a diaphragm device, as well as a light fan device 7. By means of the beam-shaping device 6, the extent of an X-ray field generated by the X-ray source 3 and emitted to the X-ray detector 4 can be adjusted. The light fan device 7 allows the generation of a light fan whose extent corresponds to the X-ray field and which can thus indicate the area exposed to the X-rays on the examination object.

[0043] A concrete design is exemplified in Fig. 2. For the sake of clarity, only the rotating anode 8 and the adjacent X-ray exit window of the X-ray source 3, which is embodied as an X-ray tube in this case, are shown. The X-rays of the X-ray field 9 exit the X-ray source 3 through the X-ray exit window, with extrafocal radiation being intercepted by depth diaphragms 10. The beam-shaping device 6 in this case comprises additional diaphragms 12 that can be moved according to the arrows shown. It should be noted that, in addition to the beam-shaping device 6, a filter device (not shown in detail here) can also be provided.

[0044] The light fan device 7 in this case comprises a light source 13 arranged in a common housing with the beam-shaping device 6 and an X-ray-transparent mirror 14 arranged in the X-ray field 9. The light reflected by the mirror 14 in the direction of the X-ray radiation is also influenced at least partially by the beam-shaping device 6, so that the light exits the X-ray emitter arrangement 2 congruent with the X-ray field 9, thus being able to indicate the extent of the X-ray field 9 as a light fan 15.

[0045] Returning to Fig. 1, the X-ray device 1 also comprises a covering means 16 which, at least on one side facing the X-ray tube 3, at least in an area indicated here by dashed lines, is designed to diffusely reflect the light from the light fan device 7. The covering means 16 is flexible and can thus adapt to the shape of the examination object, here the patient, and in particular can even be wrapped around the patient, i.e., enclose the patient, for example, for lateral positions of the X-ray tube 3. The covering means 16 can be, for example, a patient blanket or a film, which can in particular be provided in addition to the patient blanket.

[0046] The diffusely reflective design can be achieved in various ways. For example, a film can be made entirely of a diffusely reflective material, such as ODM98. Alternatively, coatings can also be used and / or diffusely reflective threads, which can comprise, for example, fibers made of metal or other reflective material, can be woven into the film.

[0047] The use of the covering means 16 for visualising and / or determining the scattered radiation distribution that can arise from the X-ray field 9 is explained Fig. More precisely. There, the examination object, here the patient 17, is schematically shown as being surrounded by the covering means 16. Starting from the X-ray emitter arrangement 2, which is in a lateral position here, the light fan 15, the extent of which corresponds to that of the X-ray field 9, is shown. Here, the light fan device 7 has already been activated before the use of the X-ray field 9 for imaging, so that the light fan 15 exists independently of any possibly harmful X-rays. When the light of the light fan 15 strikes the diffusely reflecting covering means 16, it is diffusely reflected, similar to the scattered radiation of the X-ray field 9 that occurs by scattering of the X-rays in the patient 17. The diffusely illuminated area 18 is schematically indicated.

[0048] If visible light is generated by the light source 13, the area 18 and thus the scattered radiation distribution are visualized. A person 19 can thus determine the extent to which they or other persons 19 are illuminated, which applies accordingly to objects.

[0049] However, it is also possible to carry out a qualitative measurement of the scattered radiation distribution by measuring diffusely reflected light of the light fan 15, here schematically indicated by arrows 20, for which purpose Fig. 1 can be used. In exemplary embodiments, non-visible light, such as infrared light, can also be used for the measurement, which can be used in addition to or as an alternative to the visible light.

[0050] First light sensors 21 are provided for detachable arrangement on a person 19 and can be part of a light sensor arrangement 22, which can comprise, for example, a piece of clothing, a lanyard, or the like on which the first light sensors 21 are arranged. Thus, the light sensors 21 can be used to measure at various locations on a person 19 whether relevant scattered radiation is to be expected there.

[0051] Second light sensors 22, of which only one is shown here as an example, can be attached, in particular again detachably, at various locations in the room in which the X-ray device 1 is arranged, for example at locations where persons 19 can be positioned during an imaging examination. Even if only one second light sensor 22 is shown here, several second light sensors 22 can expediently be used to record the scattered radiation distribution as comprehensively as possible. Of course, more than three first light sensors 21 can also be used.

[0052] The sensor data from the light sensors 21, 22 can be evaluated by a control device 23 of the X-ray device 1 to determine scattered radiation estimation information describing the scattered radiation distribution. This, in turn, can be evaluated using various action conditions, each of which is assigned to a specific action. Such measures can include scattered radiation protection measures, scattered radiation mitigation measures, and / or warning measures. Warning measures can warn persons 19 or alert them to scattered radiation. Scattered radiation mitigation measures can reduce scattered radiation, for example, by adjusting the radiation generation parameters of the X-ray tube 3.

[0053] An example of a scattered radiation protection measure is the Fig. 4 and Fig. 5 explained in more detail. In Fig. 4 shows the situation before the measure is carried out. A person 19 is partially covered by a radiation protection device 24, here a radiation protection wall 25, beside the patient 17. Nevertheless, the area 18 extends beyond the upper end of the radiation protection wall 25, so that a first light sensor 21 on the person 19 misses light and relevant scattered radiation is qualitatively present there according to the scattered radiation estimation information. A measure condition is fulfilled, which is assigned as a scattered radiation protection measure to the raising of the radiation protection wall 25, which is controllable accordingly.

[0054] Fig. Figure 5 shows the situation after this measure has been implemented by the control device 23. The radiation protection wall 25 is now higher and covers the entire area 18 relative to the person 19, so that the first light sensor 21 no longer measures any light. Further measures are no longer necessary before the X-ray radiation of the X-ray field 9 can actually be triggered for imaging.

[0055] Fig. 6 shows a flowchart of an embodiment of the method according to the invention, in which such a measurement also takes place. In a step S1, the desired extent of the X-ray field 9 is first set, for example, using the light fan 15, in particular by controlling the beam-shaping device 6 by the control device 23. The covering means 16 can already be arranged on the patient 17 or can be arranged thereafter.

[0056] Before the X-ray radiation from the X-ray field 9 is actually emitted, the light fan device 7 is activated by the control device 23 in step S2. Therefore, in step S3, the scattered radiation distribution can be measured qualitatively in the form of the diffusely reflected light from the light fan 15 using the light sensors 21, 22.

[0057] In the control device 23, the scattered radiation estimation information is determined from the sensor data of the light sensors 21, 22 in step S4. This information can be evaluated in step S5 using the action conditions. If at least one action condition is met, the corresponding, assigned at least one action is executed in step S6.

[0058] As already mentioned, the control device 23 controls the operation of the X-ray device 1. The execution of the method, insofar as it can be automated, can also be carried out by means of the control device 23. Fig. 7 shows the functional structure of the control device 23.

[0059] In addition to a storage means 30 and a recording unit 26 for controlling the recording operation itself, this has an adjustment unit 27 for adjusting an extent of the X-ray field 9 according to step S1. Furthermore, a control unit 28 is provided, which is designed to control at least the light fan device 7, for example, to activate it according to step S2. The light sensors 21, 22 can also be subsequently controlled accordingly by the control unit 28 for measurement. The sensor data from the light sensors 21, 22 can then be evaluated in an evaluation unit 29 according to step S4. The action conditions according to step S5 can then in turn be evaluated by the control unit 28, which controls corresponding components of the X-ray device 1 to carry out the assigned measures when fulfilled.

[0060] Fig. Finally, Figure 8 shows an exemplary embodiment in which the side facing the X-ray source 2 is not completely diffusely reflective, but a pattern of diffusely reflective partial surfaces 31, here stripes, is formed, in the present case, for example, a diamond pattern.

[0061] It should also be noted that, particularly if it is possible that part of the X-ray field 9 does not hit the object under examination (and also the covering means 16), an additional reflection means can also be used.

[0062] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited to the disclosed examples and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention.

[0063] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identity are included.

Claims

[1] Method for operating an X-ray imaging device (1) having an X-ray emitter (3) for emitting an X-ray field (9), to which a light fan device (7) for emitting a light fan (15) whose extent corresponds to that of the X-ray field (9) is assigned, characterized by in that, in order to determine and / or display a scattered radiation distribution which is created by the X-ray field (9), an examination object which is to be exposed to the X-ray field (9) for imaging, in particular a patient (17), is covered with a covering means (16) which, on the side facing the X-ray emitter (3), is designed to at least partially diffusely reflect the light of the light fan (15), and the light fan device (7) is activated. [2] Method according to claim 1, characterized bythat the light fan device (7) is activated before an examination using the X-ray field (9) when the X-ray source (3) is switched off. [3] Method according to claim 1 or 2, characterized by that the light fan device (7) emits visible light. [4] Method according to one of the preceding claims, characterized by that by means of at least one light sensor (21, 22) which is arranged at a measuring position outside the X-ray field (9), sensor data which describe light of the light fan (15) reflected by the covering means (16) is recorded and evaluated by means of an evaluation unit (29) to determine scattered radiation estimation information. [5] Method according to claim 4, characterized by that a first light sensor (21) of a light sensor arrangement (22) that can be worn, in particular worn, by a person (19) is used as at least one of the at least one light sensor (21, 22). [6] Method according to claim 4 or 5, characterized by that as at least one of the at least one light sensor (21, 22) a second light sensor (22) is used, which is or will be fastened, in particular detachably, to a position intended for the possible presence of a person (19). [7] Method according to one of claims 4 to 6, characterized by that a control unit (28) checks at least one action condition which evaluates the scattered radiation estimation information, upon the fulfillment of which at least one scattered radiation protection measure and / or scattered radiation reduction measure and / or at least one notification output measure associated with the action condition is carried out by the control unit (28). [8] Method according to claim 7, characterized bythat the scattered radiation protection measure and / or scattered radiation reduction measure comprises a positioning of a radiation protection device (24), in particular a protective plate, and / or an adjustment of at least one radiation generation parameter of the X-ray source (3) and / or an adjustment of the extent of the X-ray field (9) and / or that the information output measure comprises the acoustic and / or visual output of a warning and / or the output of a suggestion for a procedure for scattered radiation protection and / or for scattered radiation reduction. [9] Method according to one of the preceding claims, characterized by that the covering means (16) at least partially has a reflective coating on the side facing away from the examination object and / or at least one reflective material is integrated, in particular woven, into the covering means (16). [10] Method according to one of the preceding claims, characterized bythat the reflective formation is realized by a pattern of diffusely reflecting partial surfaces (31) on the side facing the X-ray source (3). [11] Method according to one of the preceding claims, characterized by that a film and / or a patient blanket is used as the covering means (16). [12] Method according to one of the preceding claims, characterized by that the covering means (16) is stretched at least partially over the object to be examined and diffusely reflects the light of the light fan (15) on a smooth portion of the side facing the X-ray emitter (3). [13] Method according to one of the preceding claims, characterized bythat in the case of an area illuminated by the X-ray field (9) which is remote from the object to be examined and not covered by the covering means (16), a further diffusely reflecting reflection means is used for this area, in particular in the same way as the covering means (16). [14] X-ray imaging device (1), comprising an X-ray emitter (3) for emitting an X-ray field (9) and a light fan device (7) associated with the X-ray emitter (3) for emitting a light fan (15), the extent of which corresponds to that of the X-ray field (9), characterized bya covering means (16) for covering an examination object to be examined with the X-ray field (9), which is designed to reflect at least partially the light of the light fan (15) diffusely on the side facing the X-ray emitter (3) in order to determine and / or display a scattered radiation distribution which is created by the X-ray field (9) whose extent is adjusted for an examination.

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