JP7524791B2 - X-ray imaging device and X-ray imaging method - Google Patents

Description

The present invention relates to an X-ray imaging device and an X-ray imaging method, and in particular to an X-ray imaging device and an X-ray imaging method that detects X-ray photons.

The photon-counting CT device disclosed in Patent Document 1 is configured to detect X-ray photons that are generated from an X-ray generating unit and have passed through a subject, and to collect count data representing the number of detected X-ray photons for a plurality of predetermined energy ranges. In addition, this photon-counting CT device is configured to reconstruct a photon-counting CT image (energy range image) relating to the energy range of the imaging target out of a plurality of predetermined energy ranges.

JP 2015-131028 A

However, in the photon-counting CT device of Patent Document 1, multiple energy ranges for imaging are predetermined, so while the number of X-ray photons may be sufficient in one energy range, the number of X-ray photons may be low in another energy range, resulting in a relatively large noise component. In this case, there is a problem that the image quality of the energy range image is degraded. Furthermore, although not stated explicitly in Patent Document 1, in a photon-counting CT device such as that described in Patent Document 1, material decomposition may be performed based on the energy range image. In this case, there is also a problem that the material decomposition ability (the ability to distinguish materials) based on the energy range image is degraded due to the relatively large noise component.

This invention has been made to solve the above problems, and one object of the invention is to provide an X-ray imaging device and an X-ray imaging method that can suppress deterioration in the image quality of the energy range image and suppress deterioration in the material decomposition ability based on the energy range image.

In order to achieve the above-mentioned object, an X-ray imaging apparatus in a first aspect of the present invention comprises an X-ray source, an X-ray detection unit that detects X-ray photons irradiated from the X-ray source and transmitted through a subject, and a processing unit that processes the output of the X-ray detection unit, wherein the processing unit is configured to perform a process of acquiring the number of X-ray photons counted based on the detection result of the X-ray photons detected by the X-ray detection unit, a process of setting a plurality of energy ranges based on the acquired number of X-ray photon counts, and a process of acquiring image data corresponding to each of the plurality of energy ranges based on the set plurality of energy ranges, and the processing unit is configured to acquire and set a start point and an end point of each of the plurality of energy ranges so that the variation in the number of X-ray photons counted in the plurality of energy ranges is within a predetermined variation range .

In addition, in order to achieve the above-mentioned object, an X-ray imaging method in a second aspect of the present invention includes the steps of detecting X-ray photons that have passed through a subject, acquiring the number of X-ray photon counts based on the detection results of the X-ray photons, setting a plurality of energy ranges based on the number of X-ray photon counts, and acquiring image data corresponding to each of the plurality of energy ranges based on the plurality of energy ranges, wherein the step of setting the plurality of energy ranges includes the step of acquiring and setting a start point and an end point of each of the plurality of energy ranges so that the variation in the number of X-ray photon counts in the plurality of energy ranges is within a predetermined variation range .

In the X-ray imaging device according to the first aspect and the X-ray imaging method according to the second aspect, the X-ray photon count is obtained based on the detection result of the X-ray photons, and multiple energy ranges for imaging are set based on the X-ray photon count, and image data corresponding to each of the multiple energy ranges is obtained based on the multiple energy ranges. As a result, unlike the case where multiple predetermined energy ranges are set, the multiple energy ranges are set based on the actual X-ray photon count, so that the energy range can be set so as to prevent the X-ray photon count from decreasing in a certain energy range and the noise component from becoming relatively large. As a result, it is possible to prevent the image quality of the energy range image from deteriorating due to the noise component being relatively large, and it is possible to prevent the material decomposition ability based on the energy range image from deteriorating. In addition, since the multiple energy ranges are automatically set based on the actual X-ray photon count, it is possible to set an appropriate energy range regardless of the specifications of the X-ray source and the X-ray detection unit, and it is possible to set an appropriate energy range regardless of the material and size of the subject.

1 is a schematic diagram showing a configuration of an X-ray imaging apparatus according to an embodiment; FIG. 2 is a schematic diagram illustrating sinogram image data according to an embodiment. 5 is a schematic diagram for explaining setting of an energy range by the X-ray imaging apparatus according to the embodiment. FIG. FIG. 13 is a schematic diagram for explaining setting of an energy range according to a comparative example. FIG. 11 is a schematic diagram for explaining a simulation result. 10 is a flowchart for explaining an X-ray imaging process performed by the X-ray imaging apparatus according to an embodiment. FIG. 13 is a schematic diagram for explaining setting of an energy range by an X-ray imaging apparatus according to a modified example of an embodiment.

An embodiment of the present invention will be described below with reference to the drawings.

(Configuration of X-ray imaging device)
The configuration of an X-ray imaging apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the X-ray imaging device 100 is a photon-counting type X-ray imaging device that uses X-ray photons that have passed through the subject 200 to generate an image of the inside of the subject 200. Specifically, the X-ray imaging device 100 is a PCCT (Photon Counting Computed Tomography) device. The X-ray imaging device 100 is also configured to be capable of performing material decomposition by utilizing the fact that the energy value characteristics of the X-ray photons that have passed through the subject 200 differ for each material.

The X-ray imaging device 100 includes an X-ray source 1, an X-ray detection unit 2, a rotating stage 3, and a control unit 4. The control unit 4 is an example of a "processing unit" in the claims.

The X-ray source 1 is configured to irradiate the subject 200 with X-rays. The X-ray source 1 includes an X-ray tube, and is configured to generate X-rays when a high voltage is applied, and to irradiate the generated X-rays toward the X-ray detection unit 2.

The X-ray detection unit 2 is a photon count type X-ray detection unit. The X-ray detection unit 2 is configured to detect X-ray photons that are irradiated from the X-ray source 1 and transmitted through the subject 200. The X-ray detection unit 2 is also configured to convert the detected X-ray photons into an electrical signal and output the converted electrical signal. Specifically, the X-ray detection unit 2 is configured to output an electrical signal corresponding to the X-ray photons so that the number of X-ray photons for each energy value can be counted. This makes it possible to count (count) the number of X-ray photons for each energy range (so-called bin). The X-ray detection unit 2 preferably has an energy resolution of 5 keV or less.

The X-ray detection unit 2 also includes a plurality of detection elements that convert X-ray photons into electrical signals. As the detection elements, for example, direct conversion type semiconductor elements that directly convert X-ray photons into electrical signals can be used. An example of such a semiconductor element is a cadmium telluride semiconductor element. As the detection elements, for example, indirect conversion type detection elements that include a scintillator that converts X-ray photons into light and a photodiode that converts light into an electrical signal and indirectly convert X-ray photons into an electrical signal may also be used.

The rotating stage 3 is configured to rotate the subject 200. The rotating stage 3 includes a platform for placing the subject 200, and a drive unit such as a motor that rotates the platform. Under the control of the control unit 4, the rotating stage 3 rotates the subject 200, thereby rotating the subject 200 relative to an imaging system including the X-ray source 1 and the X-ray detection unit 2. This allows X-ray imaging to be performed while changing the X-ray irradiation position on the subject 200.

The control unit 4 is configured to control each part of the X-ray imaging device 100. The control unit 4 includes a processor such as a CPU (Central Processing Unit) and a memory. The control unit 4 also functions as an image processing unit that processes data related to images. Specifically, the control unit 4 is configured to process the output of the X-ray detection unit 2. More specifically, the control unit 4 is configured to acquire energy range image data 5 (see FIG. 2) corresponding to multiple energy ranges for imaging based on the detection result of X-ray photons by the X-ray detection unit 2. The energy range image data 5 is an example of "image data" in the claims.

As shown in FIG. 2, the control unit 4 is configured to acquire each of the multiple energy range image data 5 based on the count number of X-ray photons in each of the multiple energy ranges. The energy range image data 5 is sinogram image data. The sinogram image data is image data in which the detection results of X-ray photons by the X-ray detection unit 2 are arranged two-dimensionally according to the numbers of the detection elements (detector numbers) and the rotation angles. The sinogram image data includes a subject region corresponding to the subject 200 and a non-subject region (air region outside the subject) corresponding to outside the subject 200.

The control unit 4 is configured to acquire reconstructed image data by performing reconstruction processing such as FBP (Filtered Back Projection) on the sinogram image data. Note that the reconstructed image data can be acquired for each sinogram image data. In other words, it is possible to acquire multiple reconstructed image data based on multiple sinogram image data. In addition, the multiple reconstructed image data also correspond to multiple energy ranges, and therefore can be said to be energy range images. In addition, the control unit 4 is configured to perform material decomposition of the subject 200 based on the multiple reconstructed image data.

(Average distribution of counts)
3 shows a graph (left graph in the figure) showing an example of the distribution of the X-ray photon counts with respect to the energy acquired by the X-ray detection unit 2, and a graph (right graph in the figure) showing the total number of counts (total value of the counts within the energy range) in each energy range of the graph on the left. In addition, in the two graphs shown in FIG. 3, the vertical axis indicates the X-ray photon counts, and the horizontal axis indicates the energy of the X-ray photons. Note that, for convenience, FIG. 3 shows an example in which four energy ranges E1 to E4 are set, but the number of energy ranges is not particularly limited.

In this embodiment, as shown in FIG. 3, the control unit 4 is configured to perform a process of acquiring the number of X-ray photons counted based on the detection result of the X-ray photons detected by the X-ray detection unit 2, a process of setting multiple energy ranges based on the acquired number of X-ray photon counts, and a process of acquiring energy range image data 5 corresponding to each of the multiple energy ranges based on the set multiple energy ranges.

Specifically, the control unit 4 is configured to obtain the number of X-ray photons counted for each energy value based on the detection result of X-ray photons detected by the X-ray detection unit 2 after imaging of the subject 200. At this time, the control unit 4 is configured to obtain the number of X-ray photons counted for each energy value in the entire energy range of the imaging target. In other words, the control unit 4 is configured to obtain the distribution of the number of X-ray photons counted in the entire energy range of the imaging target. Then, the control unit 4 is configured to set multiple energy ranges based on the number of X-ray photons counted for each energy value in the entire energy range of the imaging target.

In addition, in this embodiment, the control unit 4 is configured to set multiple energy ranges so that the variation in the count number of X-ray photons in the multiple energy ranges is within a predetermined variation range 6. Specifically, the control unit 4 is configured to set multiple energy ranges so that the count number of X-ray photons in the multiple energy ranges is within a predetermined value with respect to the average value (for example, the variation with respect to the average value is within 10%). In addition, the number of energy ranges to be set is predetermined. That is, the control unit 4 is configured to set multiple energy ranges so that the count number of X-ray photons is distributed evenly in a predetermined number of energy ranges (four in FIG. 3). Note that the average value is a value obtained by dividing the total number (total value) of the count number of X-ray photons in all energy ranges of the imaging target by the number of predetermined energy ranges. In addition, the number of energy ranges is preset, for example, by a user.

The variation from the average value of the X-ray photon count number in each energy range is determined by the energy resolution of the X-ray detection unit 2. In other words, the variation from the average value of the X-ray photon count number in each energy range is determined by how many keV X-ray photons can be counted based on the detection results of X-ray photons by the X-ray detection unit 2. Furthermore, the variation from the average value of the X-ray photon count number in each energy range becomes smaller as the unit energy at which X-ray photons can be counted becomes smaller, so from the viewpoint of reducing the variation, it is preferable to be able to count X-ray photons in units of 5 keV or less.

Here, an example of setting multiple energy ranges will be described with reference to Figure 3. In Figure 3, four energy ranges are set.

In this case, four energy ranges E1 to E4 are set based on the number of X-ray photons counted for each energy value in the entire energy range of the imaging target. At this time, the start and end of each of the four energy ranges E1 to E4 are obtained and set so that the number of X-ray photons counted in the multiple energy ranges falls within a predetermined value of the average value. As a result, the four energy ranges E1 to E4 are set to include the number of X-ray photons counted approximately equally, making it possible to prevent the number of X-ray photons from decreasing in a certain energy range.

On the other hand, when the count numbers are not averaged, the energy range is set as in the comparative example shown in FIG. 4. Specifically, in the example shown in FIG. 4, four energy ranges E1 to E4, which are equal divisions of the entire energy range of the imaging target, are set as predetermined energy ranges. In this case, the number of X-ray photon counts is small in the energy ranges E3 and E4, and the noise components become relatively large. As a result, the image quality of the energy range images corresponding to the energy ranges E3 and E4 is degraded, and the material decomposition ability is also degraded.

In addition, in this embodiment, as shown in Figs. 2 and 3, the control unit 4 is configured to acquire the X-ray photon count number of the subject region, which is the subject region corresponding to the subject 200, and the outside-subject region corresponding to the outside of the subject 200, and to set multiple energy ranges based on the acquired X-ray photon count number of the subject region. Specifically, the control unit 4 is configured to acquire the X-ray photon count number for each energy value of the subject region, and to set multiple energy ranges based on the acquired X-ray photon count number for each energy value of the subject region such that the X-ray photon count number in the multiple energy ranges falls within a predetermined value with respect to the average value.

In addition, in this embodiment, the control unit 4 is configured to acquire image data of the entire energy range (sinogram image data of the entire energy range) or image data of a specific energy range (sinogram image data of a specific energy range) based on the detection result of X-ray photons detected by the X-ray detection unit 2, and to identify the subject region based on the acquired image data of the entire energy range or image data of the specific energy range. For example, the control unit 4 acquires image data of the entire energy range corresponding to the entire energy range of the imaging target, compares the image data of the entire energy range with blank data captured in advance without the subject 200, and identifies the subject region and the non-subject region based on the comparison result between the image data of the entire energy range and the blank data captured in advance without the subject 200.

For example, the control unit 4 also acquires image data of a specific energy range that corresponds to a specific energy range out of the entire energy range of the imaging target, compares the image data of the specific energy range with blank data captured in advance without the subject 200, and identifies the subject region and the non-subject region based on the comparison result between the image data of the specific energy range and the blank data captured in advance without the subject 200. Note that when image data of a specific energy range is used, it is necessary to specify the specific energy range in advance.

(simulation result)
Next, the results of a simulation for confirming the improvement of material decomposition ability by the average distribution of the count numbers will be described with reference to Fig. 5. Note that in the actual simulation, grayscale images and color images were obtained based on the detection results of actual X-ray photons, but for convenience, Fig. 5 shows the actual grayscale images and color images as schematic diagrams.

In the simulation, the subject was a cylindrical body made of ASA (Acrylate Styrene Acrylonitrile) resin, with a cylindrical member made of PEI (Polyetherimide) resin and a cylindrical member made of ABS (Acrylonitrile Butadiene Styrene) resin embedded in it, creating a cylindrical hollow portion (air portion).

Figure 5 shows a reconstructed image of this subject (originally a grayscale image), an image showing the material decomposition results when the count numbers were not averaged (originally a color image), and an image showing the material decomposition results when the count numbers were averaged (originally a color image). In the image showing the material decomposition results, parts identified as the same material are shown in the same color (hatched or black in Figure 5).

In both the image showing the material decomposition results when the average distribution of counts was not performed and the image showing the material decomposition results when the average distribution of counts was performed, the number of energy ranges was set to 5. In the image showing the material decomposition results when the average distribution of counts was not performed, the five energy ranges were set as follows: E1 = 11 keV to 20 keV, E2 = 21 keV to 30 keV, E3 = 31 keV to 40 keV, E4 = 41 keV to 50 keV, and E5 = 51 keV to 60 keV. In addition, in the image showing the material decomposition results when the average distribution of count numbers was performed, the energy ranges were set as follows based on the detection results of the X-ray photons: E1 = 11 keV to 15 keV, E2 = 16 keV to 18 keV, E3 = 19 keV to 21 keV, E4 = 22 keV to 27 keV, and E5 = 28 keV to 60 keV.

In the image showing the material decomposition results when the average distribution of counts was not performed, the accuracy rate of material decomposition was 32%. On the other hand, in the image showing the material decomposition results when the average distribution of counts was performed, the accuracy rate of material decomposition was 80%. Therefore, the simulation results show that when the average distribution of counts was performed, the material decomposition ability was improved compared to when the average distribution of counts was not performed.

(X-ray photography processing)
Next, the X-ray imaging process performed by the X-ray imaging apparatus 100 of this embodiment will be described based on a flowchart in FIG.

As shown in FIG. 6, first, in step 101, the shooting conditions are accepted.

Then, in step 102, a scan is performed on the subject 200. In step 102, X-ray photography is performed by an imaging system including the X-ray source 1 and the X-ray detection unit 2 while the subject 200 is rotated by the rotating stage 3.

Then, in step 103, the subject region is identified. In step 103, the subject region is identified based on image data for the entire energy range or image data for a specific energy range.

Then, in step 104, the number of X-ray photons counted for each energy value in the subject region is obtained. In step 104, the distribution of the number of X-ray photon counts in the subject region across the entire energy range of the imaging target is obtained.

Then, in step 105, multiple energy ranges are set based on the number of X-ray photons counted for each energy value in the subject region. In step 105, multiple energy ranges are set so that the number of X-ray photons counted in the multiple energy ranges falls within a predetermined value relative to the average value.

Then, in step 106, image generation is performed based on the multiple energy ranges. In step 106, multiple sinogram image data (energy range image data 5) corresponding to the multiple energy ranges and multiple reconstructed image data corresponding to the multiple sinogram image data are generated.

Then, in step 107, image output and image storage are performed. In step 107, for example, the image is output to a display unit such as a monitor. Also, in step 107, for example, the image is stored in a storage device such as a HDD.

(Effects of this embodiment)
In this embodiment, the following effects can be obtained.

As described above, this embodiment includes an X-ray source 1, an X-ray detection unit 2 that detects X-ray photons irradiated from the X-ray source 1 and transmitted through the subject 200, and a control unit 4 that processes the output of the X-ray detection unit 2. The control unit 4 is configured to perform the following processes: acquire the number of X-ray photons counted based on the detection result of the X-ray photons detected by the X-ray detection unit 2; set multiple energy ranges based on the acquired number of X-ray photon counts; and acquire energy range image data 5 corresponding to each of the multiple energy ranges based on the set multiple energy ranges.

As a result, unlike the case where multiple predetermined energy ranges are set, multiple energy ranges are set based on the actual X-ray photon counts, so that the energy range can be set to prevent the X-ray photon counts from becoming small in a certain energy range, causing the noise components to become relatively large. As a result, it is possible to prevent the image quality of the energy range image from deteriorating due to the relatively large noise components, and to prevent the material decomposition ability based on the energy range image from deteriorating. In addition, since multiple energy ranges are automatically set based on the actual X-ray photon counts, an appropriate energy range can be set regardless of the specifications of the X-ray source 1 and the X-ray detection unit 2, and an appropriate energy range can be set regardless of the material and size of the subject 200.

In addition, the above embodiment has the following additional advantages:

In other words, in this embodiment, as described above, the control unit 4 is configured to set multiple energy ranges so that the variation in the count number of X-ray photons in the multiple energy ranges is within a predetermined variation range 6. This allows the count number of X-ray photons to be distributed so as to reduce the variation in the multiple energy ranges, and therefore it is possible to prevent the count number of X-ray photons from decreasing in the multiple energy ranges, causing noise components to become relatively large. As a result, it is possible to prevent the image quality of the multiple energy range images from deteriorating, and also to prevent the material decomposition ability based on the multiple energy range images from deteriorating.

In addition, in this embodiment, as described above, the control unit 4 is configured to set multiple energy ranges so that the count numbers of X-ray photons in the multiple energy ranges fall within a predetermined value relative to the average value. This makes it possible to easily distribute the count numbers of X-ray photons in the multiple energy ranges so as to reduce variation, and therefore makes it easy to prevent the count numbers of X-ray photons from decreasing in the multiple energy ranges, resulting in a relatively large noise component.

In addition, in this embodiment, as described above, the control unit 4 is configured to acquire the X-ray photon count number of the subject region, between the subject region corresponding to the subject 200 and the outside-subject region corresponding to the outside of the subject 200, and set multiple energy ranges based on the acquired X-ray photon count number of the subject region. In this way, multiple energy ranges are set based on the X-ray photon count number of the subject region where material decomposition is performed, so that the energy range can be set effectively. As a result, it is possible to effectively suppress a decrease in the material decomposition ability based on the energy range image. In addition, since it is not necessary to acquire the X-ray photon count number of the subject region in the outside-subject region, the processing load can be reduced compared to the case where the X-ray photon count numbers of both the subject region and the outside-subject region are acquired.

In addition, in this embodiment, as described above, the control unit 4 is configured to acquire image data of the entire energy range or image data of a specific energy range based on the detection result of X-ray photons detected by the X-ray detection unit 2, and to identify the subject area based on the acquired image data of the entire energy range or image data of the specific energy range. This makes it possible to easily identify the subject area, and therefore to easily set multiple energy ranges based on the count number of X-ray photons in the identified subject area.

[Modification]
It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

For example, in the above embodiment, an example was shown in which the present invention is applied to an X-ray imaging device as a CT device, but the present invention is not limited to this. The present invention may be applied to an X-ray imaging device other than a CT device. For example, the present invention may be applied to an X-ray imaging device that performs fluoroscopic imaging or an X-ray imaging device that performs tomosynthesis imaging.

In the above embodiment, an example is shown in which the subject is rotated relative to the imaging system including the X-ray source and the X-ray detection unit, but the present invention is not limited to this. In the present invention, X-ray imaging may be performed while changing the X-ray irradiation position on the subject by rotating the imaging system including the X-ray source and the X-ray detection unit relative to the subject.

In the above embodiment, an example was shown in which the control unit functions as an image processing unit, but the present invention is not limited to this. In the present invention, an image processing unit including a processor such as a GPU (Graphics Processing Unit) may be provided separately and independently from the control unit. In this case, the image processing unit may function as the "processing unit" of the present invention.

In addition, in the above embodiment, an example is shown in which multiple energy ranges are set so that the variation in the count number of X-ray photons in the multiple energy ranges falls within a predetermined variation range, but the present invention is not limited to this. For example, in the modified example shown in FIG. 7, multiple energy ranges are set so that the count number of X-ray photons in a predetermined energy range (energy range E2 in FIG. 7) among the multiple energy ranges is larger than in the other energy ranges. That is, in the modified example shown in FIG. 7, multiple energy ranges are configured to be set so that the count number of X-ray photons is distributed according to the weighting of the multiple energy ranges.

The graph shown in FIG. 7 shows the change in the linear attenuation coefficient of a material with respect to energy. In addition, in the graph shown in FIG. 7, the vertical axis is the linear attenuation coefficient, and the horizontal axis is the energy of the X-ray photon. In the graph shown in FIG. 7, a spectrum corresponding to the K absorption edge of the material is present. In addition, the weight of the energy range E2 corresponding to the K absorption edge of the material is set to be larger than the energy ranges E1, E3, and E4. In other words, the four energy ranges E1 to E4 are set so that the count number of X-ray photons in the energy range E2 is larger than the energy ranges E1, E3, and E4. In this case, since the count number of X-ray photons in the energy range E2 corresponding to the K absorption edge of the material can be increased, an image in which the K absorption edge is emphasized can be obtained.

In the above embodiment, the X-ray photon count number of the subject region corresponding to the subject and the outside-subject region corresponding to the outside of the subject is obtained, and multiple energy ranges are set based on the X-ray photon count number of the obtained subject region, but the present invention is not limited to this. In the present invention, the X-ray photon count number of the entire field of view including both the subject region corresponding to the subject and the outside-subject region corresponding to the outside of the subject may be obtained, and multiple energy ranges may be set based on the X-ray photon count number of the entire field of view obtained. Also, the X-ray photon count number at the center of the field of view may be obtained, and multiple energy ranges may be set based on the X-ray photon count number at the center of the field of view obtained. Since the subject is usually captured at the center of the field of view, the X-ray photon count number corresponding to the subject region can be easily obtained by obtaining the X-ray photon count number at the center of the field of view.

[Aspects]
It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

(Item 1)
An X-ray source;
an X-ray detection unit that detects X-ray photons irradiated from the X-ray source and transmitted through an object;
a processing unit that processes an output of the X-ray detection unit,
The processing unit includes:
A process of acquiring the count number of the X-ray photons based on a detection result of the X-ray photons detected by the X-ray detection unit;
A process of setting a plurality of energy ranges based on the acquired count number of the X-ray photons; and
An X-ray imaging apparatus configured to perform processing for acquiring image data corresponding to each of the plurality of energy ranges based on the plurality of set energy ranges.

(Item 2)
2. The X-ray imaging apparatus according to claim 1, wherein the processing unit is configured to set the plurality of energy ranges such that a variation in the count number of the X-ray photons in the plurality of energy ranges falls within a predetermined variation range.

(Item 3)
2. The X-ray imaging apparatus according to claim 1, wherein the processing unit is configured to set the plurality of energy ranges such that the count number of the X-ray photons in the plurality of energy ranges falls within a predetermined value with respect to an average value.

(Item 4)
4. The X-ray imaging device according to any one of items 1 to 3, wherein the processing unit is configured to acquire the count number of the X-ray photons in a subject region corresponding to the subject and an outside-subject region corresponding to outside the subject, and to set the plurality of energy ranges based on the acquired count number of the X-ray photons in the subject region.

(Item 5)
5. The X-ray imaging device according to claim 4, wherein the processing unit is configured to acquire image data of the entire energy range or image data of a specific energy range based on a detection result of the X-ray photons detected by the X-ray detection unit, and to identify the subject region based on the acquired image data of the entire energy range or image data of the specific energy range.

(Item 6)
detecting X-ray photons transmitted through the object;
acquiring a count number of the X-ray photons based on a detection result of the X-ray photons;
setting a plurality of energy ranges based on the count number of the X-ray photons;
and acquiring image data corresponding to each of the plurality of energy ranges based on the plurality of energy ranges.

(Item 7)
7. The X-ray imaging method according to claim 6, wherein the step of setting a plurality of energy ranges includes a step of setting the plurality of energy ranges such that a variation in the count number of the X-ray photons in the plurality of energy ranges falls within a predetermined variation range.

(Item 8)
7. The X-ray imaging method according to claim 6, wherein the step of setting the plurality of energy ranges includes a step of setting the plurality of energy ranges such that the count number of the X-ray photons in the plurality of energy ranges falls within a predetermined value with respect to an average value.

1 X-ray source 2 X-ray detection unit 4 Control unit (processing unit)
5 Energy range image data (image data)
6 Predetermined variation range 100 X-ray imaging device 200 Subject E1 to E4 Energy range

Claims (6)

An X-ray source;
an X-ray detection unit that detects X-ray photons irradiated from the X-ray source and transmitted through an object;
a processing unit that processes an output of the X-ray detection unit,
The processing unit includes:
A process of acquiring the count number of the X-ray photons based on a detection result of the X-ray photons detected by the X-ray detection unit;
A process of setting a plurality of energy ranges based on the acquired count number of the X-ray photons; and
The method is configured to perform a process of acquiring image data corresponding to each of the plurality of energy ranges based on the plurality of energy ranges that have been set ,
The processing unit is configured to acquire and set a start point and an end point of each of the multiple energy ranges so that a variation in the count number of the X-ray photons in the multiple energy ranges falls within a predetermined variation range. The X-ray imaging device according to claim 1, wherein the processing unit is configured to set the plurality of energy ranges so that the count number of the X-ray photons in the plurality of energy ranges falls within a predetermined value relative to the average value. 3. The X-ray imaging device according to claim 1, wherein the processing unit is configured to acquire the count number of the X-ray photons in a subject region corresponding to the subject and an outside-subject region corresponding to outside the subject, and to set the plurality of energy ranges based on the count number of the X-ray photons in the acquired subject region. 4. The X-ray imaging device according to claim 3, wherein the processing unit is configured to acquire image data of the entire energy range or image data of a specific energy range based on a detection result of the X-ray photons detected by the X-ray detection unit, and to identify the subject region based on the acquired image data of the entire energy range or image data of the specific energy range. detecting X-ray photons transmitted through the object;
acquiring a count number of the X-ray photons based on a detection result of the X-ray photons;
setting a plurality of energy ranges based on the count number of the X-ray photons;
acquiring image data corresponding to the plurality of energy ranges based on the plurality of energy ranges ;
An X-ray imaging method, wherein the step of setting the multiple energy ranges includes a step of obtaining and setting a start point and an end point of each of the multiple energy ranges so that a variation in the count number of the X-ray photons in the multiple energy ranges is within a predetermined variation range . 6. The X-ray imaging method according to claim 5, wherein the step of setting the plurality of energy ranges includes a step of setting the plurality of energy ranges such that the count number of the X-ray photons in the plurality of energy ranges falls within a predetermined value with respect to an average value.

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