Method for scattered radiation correction and device

Abstract

For a particularly fast and effective scattered radiation correction of 2D X-ray images, in particular a series of X-ray images, a method for scattered radiation correction in a (2D) X-ray image or a series of X-ray images which can be recorded by means of a recording system having an X-ray source, an X-ray detector and a collimator forming the primary X-ray radiation is provided, comprising the following steps: Providing the X-ray image which was recorded at a first setting of the collimator in which the object to be examined is displayed, Providing an auxiliary X-ray image which was recorded at a second setting of the collimator, in which second setting in particular exclusively one or more partial areas of the X-ray detector are displayed, each with an area which is very small compared to the total area of ​​the X-ray detector,Subtracting the auxiliary X-ray image from the X-ray image, determining a scattered radiation correction using image data of the X-ray detector obtained from the subtraction at least in the area of ​​the partial areas, and correcting the X-ray image using the determined scattered radiation correction.

Description

[0001] The invention relates to a method for correcting scattered radiation in a (2D) X-ray image or a series of X-ray images according to patent claim 1, a method for correcting scattered radiation in a (2D) X-ray image or a series of X-ray images according to patent claim 9 and a device for carrying out such a method according to patent claim 10.

[0002] Scattered radiation is a well-known and common problem in medical X-ray imaging that impairs image quality. In 3D imaging for and during interventional procedures and examinations, e.g., DynaCT, scatter correction is mandatory to achieve adequate image quality. But scatter also has a negative effect on the perceived and quantitative image quality in 2D imaging during surgical procedures, such as fluoroscopy or digital subtraction angiography (DSA). First, the low-frequency component of the scattered signal acts as an offset to the image intensity, impairs log normalization, and generally reduces contrast in native imaging. Second, scatter violates the assumptions normally used for DSA or roadmap imaging, which in turn can lead to artifacts in the contrasted vessels (i.e., vessels appear white instead of black in DSA).

[0003] Besides the use of anti-scatter grids to block scattered radiation, special scatter correction is rarely used in 2D imaging. Possible approaches generally have significant drawbacks. When using scatter kernels (as in 3D imaging), significant effort is required to extend from 3D to 2D, as the parameter space (SID, tube voltage, collimation, etc.) is much larger. Supervised training of an AI is also complex; primary modulation requires an additional primary modulator, which must be located in the beam path, and unsharp masking can produce significant errors.

[0004] From the unpublished EP 23215901.2, it is known to estimate and interpolate scattered radiation in X-ray-based medical imaging using image data acquired outside the collimator shadow. However, this approach only works if the collimator shadow is sufficiently large.

[0005] It is an object of the present invention to provide a method for scattered radiation correction in a (2D) X-ray image, which enables rapid and low-cost scattered radiation correction even for series of X-ray images. Furthermore, it is an object of the invention to provide an X-ray device suitable for carrying out the method.

[0006] The object is achieved according to the invention by a method for correcting scattered radiation in a (2D) X-ray image or a series of X-ray images according to patent claim 1 and patent claim 9 and by a device according to patent claim 10. Advantageous embodiments of the invention are the subject of the respective subclaims.

[0007] A method according to the invention for correcting scattered radiation in an X-ray image or a series of X-ray images of an examination subject, which can be recorded by means of a recording system comprising an X-ray source, an X-ray detector, and a collimator that forms the primary X-ray radiation, comprises the following steps: providing the X-ray image that was recorded at a first setting of the collimator, in which an examination subject is superimposed; providing an auxiliary X-ray image that was recorded at a second setting of the collimator, in which second setting exclusively one or more partial areas of the X-ray detector, each with a very small area compared to the total area of ​​the X-ray detector, are superimposed; at least partially subtracting the image data of the auxiliary X-ray image from the image data of the X-ray image,Determination of a scatter correction using image data from the X-ray detector obtained from the subtraction, at least in the range of the partial areas, and correction of the X-ray image using the determined scatter correction. The object under examination can, for example, contain an organ, part of an organ or body part, or a structure to be imaged; in the case of interventional procedures, it can also contain an instrument inserted into the body. The X-ray image(s) of the method are, in particular, two-dimensional projection images. During subtraction, the image data recorded by corresponding or identical image pixels of the X-ray detector are subtracted from one another, whereby an appropriate adjustment to X-ray parameters such as the X-ray dose can be made beforehand.

[0008] A further method according to the invention for correcting scattered radiation in a (2D) X-ray image or a series of X-ray images comprises the following steps: setting a second setting of the collimator such that one or more partial areas of the X-ray detector are displayed, each with an area that is very small compared to the total area of ​​the X-ray detector, and recording an auxiliary X-ray image, setting a first setting of the collimator such that an examination object is displayed, and recording an X-ray image, at least partially subtracting the image data of the auxiliary X-ray image from the image data of the X-ray image, determining a scattered radiation correction using image data of the X-ray detector obtained from the subtraction at least in the area of ​​the partial areas, and correcting the X-ray image using the determined scattered radiation correction.

[0009] This method(s) makes it possible, particularly for 2D imaging and for series of 2D X-ray images, to create and perform precise, effective, and rapid scatter correction. This scatter correction can also be quickly and effortlessly adapted to changes (e.g., in angulation or the examination area). Scatter correction requires no additional hardware and can be performed with a very low additional X-ray dose. The computational effort also remains low. The method can, for example, be inserted very quickly between two X-ray images in live X-ray imaging by performing a quick, "artificial" collimation and de-collimation and acquisition of the auxiliary X-ray image. This can even be performed so quickly between two fluoroscopy X-ray images that the medical staff do not even notice it. The method does not place any additional strain on the patient.The quality of X-ray images can be significantly improved, thereby improving both the diagnosis and the performance of interventional procedures under X-ray guidance (e.g. fluoroscopy).

[0010] According to one embodiment of the invention, the auxiliary X-ray image is pre-corrected for scattered radiation prior to subtraction using image data from the X-ray detector obtained in the collimator shadow. By combining the original method with further image quality improvements, e.g., the scattered radiation correction from the unpublished EP 23215901.2, particularly high image quality is possible. In EP 23215901.2, data from at least one region of the X-ray image shaded by the collimator (collimator shadow), frequently in peripheral regions of the X-ray image, is used to determine a scattered radiation correction, since no image data from direct X-ray radiation can occur in the collimator shadow.

[0011] According to a further embodiment of the invention, when the auxiliary X-ray image is recorded, a large number of partial areas are displayed, each with an area that is very small compared to the total area of ​​the X-ray detector. Instead of just one very small area, a large number of small areas are displayed, in particular partial areas distributed over the entire area of ​​the X-ray detector, for example evenly distributed in the manner of a matrix. In this way, after subtraction, an even better determination of the scattered radiation distribution over the entire X-ray image can be carried out. From the scattered radiation distribution determined by subtraction in the partial areas, the scattered radiation can then be estimated or calculated, for example by averaging or interpolation, in the areas that were not directly exposed in the auxiliary X-ray image. Algorithms or machine learning methods can be used for this purpose.

[0012] According to a further embodiment of the invention, the maximum area of ​​individual sub-regions is each at most 1 / 50, in particular at most 1 / 100, of the total area of ​​the X-ray detector. The very small area of ​​the sub-regions can in particular be much smaller than these values. The sub-regions can also be designed as very narrow strips, similar to slot scan technology, for example only a maximum of a few millimeters wide. With such a small area, due to the tight collimation in the sub-region illuminated by the primary beam, virtually no image data is generated by scattered radiation, so that subtracting the image data of the exposed sub-region of the auxiliary X-ray image from the image data of the X-ray image results in a very exact representation of the scattered radiation component of the X-ray image.Should a small amount of scattered radiation nevertheless occur in the exposed area, this can be removed before subtraction by alternative scatter corrections.

[0013] According to a further embodiment of the invention, the X-ray dose when taking the auxiliary X-ray image is a maximum of 1 / 10 or less of the X-ray dose when taking the X-ray image. This results in only a negligible radiation exposure for the patient, for example, a maximum of 1 / 500 of a normal X-ray image (1 / 50 x 1 / 10).

[0014] According to a further embodiment of the invention, a series of X-ray images are acquired in succession and corrected using the method. For example, several or many X-ray images can be corrected using the scattered radiation correction determined by the method. This can be carried out, for example, when no change (in the X-ray parameters or movement of the object under examination) occurs. If numerous or regular changes occur, a new auxiliary X-ray image can be acquired each time, thus repeating the method. Since this results in little additional X-ray dose and the method can be carried out very quickly (only a brief collimation and de-collimation with image acquisition), this creates negligible disruption to the process.

[0015] According to a further embodiment of the invention, at least one intermediate auxiliary X-ray image is provided, which was recorded at a third setting of the collimator. At this third setting, one or more partial regions are superimposed, each with an area size between the total area of ​​the first setting and the very small area of ​​the second setting. The intermediate auxiliary X-ray image is used to specify the determined scattered radiation correction. By means of such an intermediate auxiliary X-ray image, whose area exposed to the primary radiation is larger than the very small area, e.g., 2 times or 4 times, but smaller than the area of ​​the normal X-ray image, further information about the scattered radiation can be determined and used.While the contribution of scattered radiation to the image data on the area struck by the primary beam is negligible for the very small area, it will be greater for the intermediate auxiliary X-ray image, so that here, for example, data can be used to interpolate the scattered radiation contribution. If additional intermediate auxiliary X-ray images are provided, which were acquired with additional collimator settings, in which additional settings partial areas with an area size between the total area of ​​the first setting and the very small area of ​​the second setting are displayed, and used to more precisely determine the scattered radiation, such interpolation or estimation can be improved even further. For example, the partial areas struck by the primary radiation can be enlarged and several intermediate auxiliary X-ray images can be acquired, e.g. 2x, 4x, 8x, 16x, etc.The influence of scattered radiation can then be determined (e.g., calculated, interpolated, extrapolated, or simulated) from the corresponding intermediate X-ray images and the auxiliary X-ray image. The accuracy of the scattered radiation estimate can also be improved by observing the path of the scattered radiation in the decreasing collimator shadow and the change in intensity of the equally irradiated area.

[0016] The invention further comprises a medical X-ray device for carrying out a method described above, comprising a recording system for recording X-ray images with an X-ray detector, an X-ray source for emitting primary X-ray radiation, and a beam-shaping collimator designed to display partial areas with a very small area, a control unit for controlling the X-ray device, and a processing unit for subtracting the auxiliary X-ray image from the X-ray image, for determining a scattered radiation correction using image data obtained from the subtraction at least in the area of ​​the partial areas, and for carrying out the scattered radiation correction of X-ray images. The X-ray device can be, for example, a C-arm X-ray device, wherein the X-ray detector and the X-ray source are arranged on an adjustable C-arm. The collimator is, for example,arranged in the area of ​​the X-ray source in such a way that it can shape the primary X-ray beam with respect to the illuminated area using one or more apertures or slats.

[0017] The invention and further advantageous embodiments according to the features of the dependent claims are explained in more detail below with reference to schematically illustrated embodiments in the drawings, without thereby limiting the invention to these embodiments. They show: Fig. 1 shows a sequence of steps of a method for correcting scattered radiation in a 2D X-ray image; Fig. 2 shows a further sequence of steps of a method for correcting scattered radiation in a 2D X-ray image; Fig. 3 an x-ray image; Fig. 4 an auxiliary X-ray image; Fig. 5 another auxiliary X-ray image; Fig. 6 shows a further sequence of steps of a method for correcting scattered radiation in a 2D X-ray image; Fig. 7 an X-ray machine for carrying out the procedure; and Fig. 8 a sequence of a method for scattered radiation correction.

[0018] In the Fig. 1 and Fig. Figure 2 shows steps of methods for scatter correction in a (2D) X-ray image or a series of X-ray images, which methods represent a fast and low-cost option for scatter correction of 2D X-ray images, even during interventional procedures under X-ray monitoring. In a first step 10 ( Fig. 1) an auxiliary X-ray image is provided. The auxiliary X-ray image is taken at a second collimator setting, in which one (or more) partial areas T of the X-ray detector are superimposed, each with a very small area compared to the total area of ​​the X-ray detector. Fig. 4 shows a corresponding schematic recorded auxiliary X-ray image 20, which displays a partial area T (here arranged, for example, in the center of the X-ray detector) with a very small area, so that in the partial area T hit by the primary radiation, no or hardly any scattered radiation contributes to the recorded image data and only a primary radiation component P of the image data is present (this is known, for example, from the slot scan method). The partial area T has, for example, an area of ​​a maximum of 1 / 50 of the total area of ​​the X-ray detector, in particular also significantly smaller, e.g., with a width of a few pixels or a few millimeters. Two or more (non-contiguous) partial areas T, for example, a plurality of partial areas, can also be displayed - see, for example, based on a further schematic recorded auxiliary X-ray image 22 with a matrix of partial areas T distributed over the detector area with (e.g.,(same) very small areas. As an alternative method to the one described in . Fig. 1, in a sixth step 15 a second adjustment of the collimator is carried out and an auxiliary X-ray image 20 is taken directly - see Fig. 2. The X-ray dose for taking the auxiliary X-ray image is generally only a fraction of the X-ray dose of a conventional X-ray image, for example 1 / 10 or less, in order to ensure the lowest possible radiation exposure to the object being examined.

[0019] In a second step 11, an X-ray image 21 of the object under examination is provided ( Fig. 1). Alternatively, in a seventh step 16, a first adjustment of the collimator is carried out and the X-ray image is taken directly ( Fig. 2). The X-ray image is or was acquired with a first adjustment of the collimator in such a way that an examination object is superimposed, for example, an organ, part of an organ, body part, or an instrument arranged in a hollow organ. The 2D X-ray image can also be part of a series of X-ray images, which are acquired sequentially, for example, to monitor an interventional procedure or an examination, e.g., in the context of fluoroscopy. The first adjustment of the collimator when acquiring the 2D X-ray image 21 generally superimposes an examination area O - see Fig. 3. The displayed examination area O generally represents a significant portion of the total area of ​​the X-ray detector, for example, at least 1 / 5 or 1 / 4 of the total area of ​​the X-ray detector. The first setting thus displays a significantly larger area of ​​primary radiation than the second collimator setting. The image data of an X-ray image acquired in this way contains, in addition to the imaging component P generated by the primary radiation, a (generally disturbing) scattered radiation component S. The image data is therefore composed of the primary radiation component + scattered radiation component P+S.

[0020] Switching between the first and second collimator settings and back can be done very quickly. This is done as quickly as possible to minimize interruptions to X-ray image acquisition, for example, during live fluoroscopy. The order of the first and second steps (10 and 11) or the sixth and seventh steps (15 and 16) can be selected depending on the application.

[0021] In a third step 12, the image data of the auxiliary X-ray image 20 is then subtracted from the image data of the 2D X-ray image 21, wherein beforehand, in particular, a corresponding adjustment to X-ray parameters such as the X-ray dose can be carried out (e.g., if the X-ray dose of the X-ray image is 10 times higher than that of the X-ray image, 10 times the value is subtracted). The subtraction is carried out, in particular, pixel-by-pixel using known methods. Only a partial subtraction can also be carried out, e.g., without the image data in the region of the collimator shadow. In the region of the partial area T with the very small area, only the scattered radiation component S results from the calculation P+SP=S.If a further (i.e. alternative) auxiliary X-ray image 22 is used in which a large number of very small areas are superimposed distributed over the entire area, a corresponding distribution of the scattered radiation S over the X-ray detector can be seen in the area of ​​the many partial areas T.

[0022] From this image data of the scattered radiation, a scattered radiation correction for the 2D X-ray image or for other similar 2D X-ray images (e.g. in a series of X-ray images) can then be determined in a fourth step 13. The simplest possibility for this can simply consist of subtracting the scattered radiation component S of the partial area determined from the subtraction from the image data of the acquired X-ray image (and / or other X-ray images in the series), e.g. the same scattered radiation component S for each pixel. In such a case, the scattered radiation correction would therefore be the subtraction of an artificially generated subtraction mask, which subtracts the scattered radiation component S for each pixel of the X-ray image (or at least each pixel of the X-ray image in the directly exposed image area). Such a scattered radiation correction can, for example, be accurate if the partial area T in the auxiliary X-ray image used is located in the center of the X-ray detector.

[0023] A more complex scattered radiation correction can also be determined using an algorithm based on the scattered radiation determined from the subtraction (third step 12), which takes other factors such as the X-ray dose, the material composition of the object under examination or angulation into account. In the case of a further auxiliary X-ray image which has a large number of partial areas distributed over the X-ray detector, the scattered radiation correction can be determined as a subtraction mask according to the determined scattered radiation distribution. Areas between the partial areas can be determined by interpolation or averaging or other methods. Image data from the collimator shadow can also be used to determine the scattered radiation correction. A method such as that from EP 23215901.2 can also be used in addition. Machine learning algorithms can also be used to determine a scattered radiation correction.

[0024] In a fifth step 14, the X-ray image is then corrected using the determined scatter correction, for example, by subtracting the subtraction mask or applying a determined correction algorithm. Multiple X-ray images or even a series of X-ray images can also be corrected using the determined scatter correction.

[0025] As soon as a (significant) change in X-ray parameters such as X-ray dose, angulation, movement of the object under examination, etc. occurs, the procedure can be repeated and the scatter correction thus obtained can be applied to the current and / or further X-ray images in the series.

[0026] In the event that the scattered radiation in the area hit by the primary radiation is not completely zero, but only very small, even in the auxiliary X-ray image, an additional scattered radiation correction can be carried out before the third step 12. This is described in the Fig. 6. Here, after the acquisition / provision of the auxiliary X-ray image, in which the image data in the partial area is composed of the primary radiation component P and a very small scattered radiation component s, i.e., R+s, an additional scattered radiation correction is performed in an eighth step 17. This scattered radiation correction can, for example, be performed as in EP 23215901.2 on the basis of image data measured in the collimator shadow (which are based exclusively on scattered radiation and, in the case of the auxiliary X-ray image, are small), e.g., using interpolation.

[0027] Furthermore, intermediate auxiliary X-ray images can also be provided and / or acquired, which were acquired at a third and / or further collimator setting(s). The corresponding partial area(s) have an area that is larger than the very small area of ​​the auxiliary X-ray image, but smaller than the area displayed in the X-ray image. Several intermediate auxiliary X-ray images can also be acquired and / or provided here, with the partial areas increasing or decreasing in size (e.g., doubled in each case or through gradual changes). With this approach, an increase in the proportion of scattered radiation can be expected with an increase in the exposed area, which can be used to determine a scattered radiation correction. Appropriate estimates, simulations, or results obtained using machine learning algorithms, for example, can be incorporated here.The accuracy of the scattered radiation estimate can also be improved by varying the intensity of the different-sized sub-areas irradiated with the same X-ray parameters using different intermediate X-ray images. Using the intermediate X-ray images, a more precise scattered radiation correction can then be determined.

[0028] Further information about the scattered radiation may also be determined and used. For example, the influence of the scattered radiation can be determined (e.g., calculated, interpolated, extrapolated, or simulated) from the corresponding intermediate X-ray images and the auxiliary X-ray image. The accuracy of the scattered radiation estimate can also be improved based on the pattern of the scattered radiation in, for example, the shrinking collimator shadow, as well as the change in intensity of the area being irradiated at the same time.

[0029] In the Fig. Figure 8 shows the sequence of the procedure based on the respective X-ray images. On the one hand, the acquired X-ray image 21 with the image data from primary radiation P and scattered radiation S is shown, and on the other hand, the acquired auxiliary X-ray image 20 (either with image data without scattered radiation or with low scattered radiation s, the former can also be achieved through additional correction). Subtraction results in a subtracted image 35; after performing the scattered radiation correction, a corrected X-ray image 34 results.

[0030] In the Fig.7 shows an X-ray device 33 for carrying out the method for scattered radiation correction. The X-ray device 33 has a recording system for recording X-ray images, with an X-ray detector 26, an X-ray source 25 for emitting primary X-ray radiation, and a collimator 27. The collimator is designed to shape the primary X-ray radiation and thus to blend in partial areas, in particular with a multitude of conceivable sizes and positions, in particular even with very small areas. The collimator 27 can, for example, have many adjustable blades and / or diaphragm elements for this purpose. A complex collimator with a multitude of asymmetrically arranged diaphragm elements can be used, in particular to create auxiliary X-ray images with a multitude or matrix of partial areas.The X-ray device 33 is controlled by a control unit 28, for example, for acquiring X-ray images and adjusting the collimator to a first and second setting. The X-ray device also has a processing unit 29, which is designed for image processing and, in particular, for subtracting image data of the auxiliary X-ray image from the image data of the X-ray image. Subtraction methods are generally known. Furthermore, the processing unit 29 and / or an additional calculation unit are designed to determine a scattered radiation correction using image data obtained from the subtraction, at least in the area of ​​the partial regions, and to perform the scattered radiation correction of X-ray images.

[0031] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

[0032] The invention can be briefly summarized as follows: For a particularly fast and effective scattered radiation correction of 2D X-ray images, in particular a series of X-ray images, a method for scattered radiation correction in a (2D) X-ray image or a series of X-ray images which can be recorded by means of a recording system having an X-ray source, an X-ray detector and a collimator forming the primary X-ray radiation is provided, comprising the following steps: Providing the X-ray image which was recorded at a first setting of the collimator in which the object to be examined is displayed, Providing an auxiliary X-ray image which was recorded at a second setting of the collimator,in which second setting, in particular, only one or more partial areas of the X-ray detector are displayed, each with a very small area compared to the total area of ​​the X-ray detector, subtraction of the auxiliary X-ray image from the X-ray image, determination of a scattered radiation correction using image data of the X-ray detector obtained from the subtraction at least in the area of ​​the partial areas, and correction of the X-ray image using the determined scattered radiation correction.

[0033] At the beginning of an X-ray scene, tight collimation is used to create a single auxiliary X-ray image with a low dose. Due to the tight collimation, this auxiliary X-ray image is then virtually free of scattered radiation. Subsequent expansion of the collimator to the desired size results in scattered radiation being added to the image signal. By forming the difference, a very accurate estimate of the level of scattered radiation in the tightly collimated section is then obtained. In addition, image information behind the collimator can still be used. The tight collimation can be repeated as needed, e.g., if something has changed in the acquisition situation (e.g., patient movement, change in angulation). This process can be repeated at any granularity.

Claims

[1] Method for correcting scattered radiation in a (2D) X-ray image or a series of X-ray images of an object to be examined, which can be recorded by means of a recording system comprising an X-ray source, an X-ray detector and a collimator forming the primary X-ray radiation, comprising the following steps: • Provision of the X-ray image taken during a first collimator setting with the object to be examined displayed, • Provision of an auxiliary X-ray image which was recorded at a second setting of the collimator, at which second setting (in particular exclusively) one or more partial areas of the X-ray detector are displayed, each with a very small area compared to the total area of ​​the X-ray detector, • Subtraction of at least part of the auxiliary X-ray image from the X-ray image, • Determination of a scattered radiation correction using image data of the X-ray detector obtained from the subtraction at least in the area of ​​the partial areas, and • Correction of the X-ray image using the determined scatter correction. [2] The method according to claim 1, wherein the auxiliary X-ray image is pre-corrected for scattered radiation before the subtraction using image data of the X-ray detector obtained in the collimator shadow. [3] Method according to one of the preceding claims, wherein, when the auxiliary X-ray image is recorded, a plurality of partial areas are displayed, each having a very small area compared to the total area of ​​the X-ray detector. [4] Method according to one of the preceding claims, wherein the maximum area of ​​the partial areas is in each case 1 / 50, in particular 1 / 100, of the total area. [5] Method according to one of the preceding claims, wherein an X-ray dose when taking the auxiliary X-ray image is at most 1 / 10 of the X-ray dose when taking the X-ray image. [6] Method according to one of the preceding claims, wherein a series of X-ray images are taken in succession and corrected by means of the method. [7] Method according to one of the preceding claims, wherein at least one intermediate auxiliary X-ray image is provided which was taken at a third setting of the collimator, at which third setting one or more partial areas each having a size of the area between the total area of ​​the first setting and the very small area of ​​the second setting are displayed, and wherein the intermediate auxiliary X-ray image is used to specify the determined scattered radiation correction. [8] Method according to claim 7, wherein further intermediate auxiliary X-ray images which were taken at further settings of the collimator, at which further settings partial areas with further area sizes between the total area of ​​the first setting and the very small area of ​​the second setting are displayed, are provided and used for a more precise determination of the scattered beam correction. [9] Method for correcting scattered radiation in a (2D) X-ray image or a series of X-ray images which can be recorded by means of a recording system comprising an X-ray source, an X-ray detector and a collimator forming the primary X-ray radiation, comprising the following steps: • Setting a second setting of the collimator in such a way that only one or more partial areas of the X-ray detector are displayed, each with a very small area compared to the total area of ​​the X-ray detector, and recording an auxiliary X-ray image, • Setting a first setting of the collimator so that an object to be examined is displayed and taking an X-ray image, • Subtraction of at least part of the auxiliary X-ray image from the X-ray image, • Determination of a scattered radiation correction using image data of the X-ray detector obtained from the subtraction at least in the area of ​​the partial areas, and • Correction of the X-ray image using the determined scatter correction. [10] Medical X-ray device for carrying out a method according to one of claims 1 to 9, comprising • A recording system for recording X-ray images with an X-ray detector, an X-ray source for emitting primary X-ray radiation and a collimator which is designed to display partial areas, in particular with a very small area, • a control unit for controlling the X-ray device, • a processing unit for subtracting the auxiliary X-ray image from the X-ray image, for determining a scattered radiation correction using image data obtained from the subtraction at least in the area of ​​the partial areas and for carrying out the scattered radiation correction of X-ray images.

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