JP4692326B2 - X-ray imaging device - Google Patents

Description

  According to the present invention, a high-energy X-ray image obtained when an object is irradiated with an X-ray beam having a high energy and a low-energy X-ray image obtained when an X-ray beam having a low energy is irradiated to an object are image subtracted. The present invention relates to an energy subtraction type X-ray imaging apparatus that obtains a subtraction image by processing, and particularly relates to a technique for acquiring an energy subtraction image with good image quality.

  The conventional energy subtraction type X-ray imaging apparatus is a low energy obtained when a high-energy X-ray image obtained by irradiating a subject with a high-energy X-ray beam and a low-energy X-ray beam applied to the subject. The energy X-ray image is subjected to image subtraction processing for subtracting the images according to the weighting set for the high energy X-ray image and the low energy X-ray image, thereby obtaining one energy subtraction image.

  Normally, the energy of the X-ray beam is switched by switching the tube voltage of an X-ray tube that irradiates the subject with X-rays. In the case of a high-energy X-ray beam with high energy, for example, the tube voltage of the X-ray tube is 140 kV, and in the case of a low-energy X-ray beam with low energy, for example, the tube voltage of the X-ray tube is 60 kV. In the case of energy subtraction, there is an image difference between the high-energy X-ray image and the low-energy X-ray image due to the difference in energy absorption characteristics of the bone or soft tissue of the subject. By subtracting the images according to the weighting set for the low energy X-ray image, an energy subtraction image that has a different aspect from the high energy X-ray image and the low energy X-ray image can be obtained.

  Furthermore, the image quality of the energy subtraction image can be adjusted by changing the weighting of the high energy X-ray image and the low energy X-ray image, or the region of interest extracted in the energy subtraction image can be changed. By changing the weighting of the high-energy X-ray image and the low-energy X-ray image, for example, an energy subtraction image in which the soft tissue is erased and the bone portion is extracted as a target region can be obtained, or conversely, the bone portion is An energy subtraction image is obtained in which the soft tissue is extracted as a site of interest after being erased (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-188024 (page 6, column 9, FIG. 1)

However, the conventional X-ray imaging apparatus often has a problem that it is not possible to quickly obtain an energy subtraction image with an appropriate image quality.
There is a certain limit in adjusting the image quality of the energy subtraction image by changing the weighting of the high energy X-ray image and the low energy X-ray image. That is, when the energy of the X-ray beam at the time of obtaining the X-ray image is originally out of the range where the appropriate image quality of the energy subtraction image can be generated, the operation of changing the energy of the X-ray beam is performed. Therefore, another X-ray image having an appropriate image difference needs to be taken again by executing X-ray imaging again.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an X-ray imaging apparatus capable of quickly acquiring an energy subtraction image with an appropriate image quality.

In order to achieve such an object, the invention of claim 1 has the following configuration.
That is, the X-ray imaging apparatus according to the first aspect of the present invention includes (A) an X-ray tube that irradiates an X-ray beam to a subject to be imaged and an object that is generated by irradiation of the X-ray beam to the subject. X-ray imaging means provided with a two-dimensional X-ray detector for detecting a transmitted X-ray image, and (B) a higher energy side and a lower energy side of the X-ray beam irradiated to the subject. X-ray energy switching control means for performing energy switching control on the X-ray tube while changing at least the higher energy side with respect to the X-ray tube, and (C) high energy X-ray with high energy In accordance with the X-ray detection signal output from the two-dimensional X-ray detector with the irradiation of the beam, a high energy X-ray image is acquired for each stage of the energy of the X-ray beam and the energy X-ray imaging image acquisition means for acquiring a low-energy X-ray imaging image in accordance with an X-ray detection signal output from the two-dimensional X-ray detector upon irradiation with a low-energy X-ray beam; and (D) high energy X Image weight setting means for setting weights for radiographic images and low energy X-ray images, and (E) high energy X-ray images and low energy X-ray images according to weighting by the image weight setting means. Image subtraction means for obtaining an energy subtraction image by performing image subtraction processing for each of at least two or more combinations of a photographed image and a low energy X-ray photographed image, and (F) an image for displaying the energy subtraction image obtained by the image subtraction means Display means And it is characterized in and.

  [Operation / Effect] When X-ray imaging is performed by the X-ray imaging apparatus according to the first aspect of the present invention, the X-ray tube provided in the X-ray imaging means follows the energy switching control received from the X-ray energy switching control means. The high energy X-ray beam and energy having high energy by switching the energy of the X-ray beam between a higher energy side and a lower energy side while changing at least the higher energy side in a plurality of stages. The object is irradiated with a low energy X-ray beam having a low intensity. The two-dimensional X-ray detector provided in the X-ray imaging means detects a transmitted X-ray image of a subject that is generated each time a high-energy X-ray beam or a low-energy X-ray beam is irradiated, and generates an X-ray detection signal. Convert and output.

  On the other hand, in the subsequent stage of the X-ray imaging unit, the X-ray imaging image acquisition unit generates a high-energy X-ray imaging image according to the X-ray detection signal output from the two-dimensional X-ray detection unit with the irradiation of the high-energy X-ray beam. Low energy X-ray imaging is acquired at each stage of the energy of the X-ray beam, and the low energy image acquisition means is in accordance with the X-ray detection signal output from the two-dimensional X-ray detection means as the low energy X-ray beam is irradiated. Get an image.

  On the other hand, the image subtraction means converts the high energy X-ray image and the low energy X-ray image into the high energy according to the weighting set for the high energy X-ray image and the low energy X-ray image by the image weight setting unit. Image subtraction processing is performed for each of at least two or more combinations of X-ray images and low-energy X-ray images to acquire energy subtraction images, and the acquired energy subtraction images are displayed by the image display means. The image quality of the energy subtraction image can be adjusted by changing the weighting by the image weighting setting means.

That is, in the case of the X-ray imaging apparatus according to the first aspect of the present invention, in one X-ray imaging, on the higher energy side of the X-ray beam irradiated by the X-ray tube provided in the X-ray imaging means. In addition to changing the energy over a plurality of stages, a high energy X-ray image is acquired for each stage of the energy of the X-ray beam by the X-ray image acquisition means.
On the higher X-ray beam energy side, the X-ray absorption aspect of the subject's bone changes considerably with changes in the X-ray beam energy. Therefore, high-energy X-ray imaging with different X-ray beam energy. There is a clear image difference between the images due to the energy difference of the X-ray beam.

Therefore, in the X-ray imaging apparatus according to the first aspect of the present invention, a plurality of high-energy X-rays having a clear image difference are obtained as high-energy X-ray images that are the basis of the energy subtraction image by only one X-ray image. Since the captured image is acquired, an energy subtraction image with an appropriate image quality can be reliably acquired by one X-ray imaging.
Therefore, according to the X-ray imaging apparatus of the first aspect of the present invention, an energy subtraction image with an appropriate image quality can be quickly acquired.

  According to a second aspect of the present invention, in the X-ray imaging apparatus according to the first aspect, the X-ray energy switching control means performs the energy switching control by executing an electrical control for switching the tube voltage of the X-ray tube. Is.

  [Operation / Effect] In the case of the X-ray imaging apparatus of the invention of claim 2, the X-ray energy switching control is performed by the X-ray energy switching control means executing the electrical control for switching the tube voltage of the X-ray tube. The energy of the beam is switched.

  According to a third aspect of the present invention, in the X-ray imaging apparatus according to the first or second aspect, the image subtraction means has a high energy level close to the center of the energy switching range among a plurality of high-energy X-ray images. Image subtraction processing is performed using energy X-ray images in order.

  [Operation / Effect] According to the X-ray imaging apparatus of the invention of claim 3, when the energy switching range is distributed around the most representative energy, the image subtraction means has a plurality of high energy X-rays. Since the image subtraction process is performed using the high-energy X-ray images close to the center of the energy switching range in order from the captured images, the energy subtraction image with an appropriate image quality can be acquired more quickly.

In the case of the X-ray imaging apparatus of the present invention, in one X-ray imaging, there is a plurality of energy on the higher energy side of the X-ray beam irradiated by the X-ray tube provided in the X-ray imaging means. In addition to being changed in stages, a high-energy X-ray image is acquired at each X-ray beam energy level by the X-ray image acquisition means.
On the higher X-ray beam energy side, the X-ray absorption aspect of the subject's bone changes considerably with changes in the X-ray beam energy. Therefore, high-energy X-ray imaging with different X-ray beam energy. There is a clear image difference between the images due to the energy difference of the X-ray beam.

Therefore, in the X-ray imaging apparatus of the present invention, a plurality of high-energy X-ray images having clear image differences are obtained as high-energy X-ray images that are the basis of the energy subtraction image by only one X-ray image. As a result, an energy subtraction image with appropriate image quality can be reliably acquired by one X-ray imaging.
Therefore, according to the X-ray imaging apparatus of the present invention, an energy subtraction image with appropriate image quality can be quickly acquired.

  An embodiment of the X-ray imaging apparatus of the present invention will be described. FIG. 1 is a block diagram illustrating the overall configuration of the X-ray imaging apparatus according to the embodiment.

As shown in FIG. 1, the X-ray imaging apparatus according to the embodiment includes an X-ray tube 1 that irradiates a subject M to be imaged with a cone-shaped X-ray beam and a subject that is generated by irradiation of the subject M with the X-ray beam. Standing X-ray imaging in which a flat panel X-ray detector (hereinafter abbreviated as “FPD” as appropriate) 2 as a two-dimensional X-ray detector for detecting a transmission X-ray image of the specimen M is provided. A mechanism 3 is provided.
The X-ray imaging mechanism 3 is installed with a traveling unit 5 that can move in the horizontal direction along a guide rail 4 installed on the ceiling U, and an orientation in which the upper end is fixed to the traveling unit 5 and the longitudinal direction is the vertical direction. A telescopic rod-like support arm 6 is provided, and the X-ray tube 1 is attached to the lower end of the support arm 6.

  By pushing the X-ray tube 1 together with the support arm 6 and manually moving the traveling unit 5 along the guide rail 4, the position of the X-ray tube 1 can be changed in the horizontal direction as indicated by an arrow RA. Further, by manually extending and retracting the support arm 6, the position of the X-ray tube 1 can be changed in the vertical direction as indicated by an arrow RB. In the apparatus according to the embodiment, the traveling unit 5 is moved and the support arm 6 is manually expanded or contracted. However, the traveling unit 5 may be moved or the support arm 6 may be electrically expanded and contracted.

  Further, the X-ray imaging mechanism 3 is provided with a support stand 7 standing on the floor F, and is installed to be slidable in the vertical direction with the FPD 2 standing vertically on the support stand 7. By manually sliding the FPD 2 in the vertical direction, the position of the FPD 2 can be changed in the vertical direction. In the apparatus according to the embodiment, the movement of the FPD 2 is manually performed, but the movement of the FPD 2 may be electrically performed.

  On the other hand, the X-ray tube 1 provided in the X-ray imaging mechanism 3 irradiates the X-ray beam XA every time a tube voltage is applied from the high voltage generator 8A of the X-ray tube power supply 8. The apparatus switches energy while changing the energy of the X-ray beam XA irradiated to the subject M between the higher energy side and the lower energy side while changing at least the higher energy side in five stages. An X-ray energy switching control unit 9 that controls the X-ray tube 1 is provided. In the case of the X-ray energy switching control unit 9, the energy switching control is performed by executing electrical control for switching the tube voltage of the X-ray tube 1 on the high voltage generation unit 8 </ b> A of the X-ray tube power source 8.

  Specifically, by the energy switching control by the X-ray energy switching control unit 9, on the higher energy side of the X-ray beam XA, the tube voltage of the X-ray tube 1 is 120 kV, 125 kV, 130 kV, 135 kV, 140 kV. It can be changed over 5 stages. On the lower energy side of the X-ray beam XA, the tube voltage of the X-ray tube 1 is fixed to one voltage of 60 kV and cannot be changed. That is, in the apparatus of the embodiment, the tube voltage of the X-ray tube 1 starts from 120 kV to 125 kV, 130 kV, 135 kV, 140 kV, and 60 kV as shown in FIG. 2 during one X-ray imaging. And can be changed in order.

  On the other hand, the FPD 2 provided in the X-ray imaging mechanism 3 is irradiated with a high-energy X-ray beam having a high energy of the X-ray beam XA or a low-energy X-ray beam having a low energy of the X-ray beam XA. A transmission X-ray image of the specimen M is detected, converted into an X-ray detection signal, and output. The X-ray image acquisition unit 10 in the subsequent stage of the FPD 2 converts the high-energy X-ray image for each stage of the energy of the X-ray beam according to the X-ray detection signal output from the FPD 2 with the irradiation of the high-energy X-ray beam. And a low-energy X-ray image is acquired in accordance with an X-ray detection signal output from the FPD 2 when the low-energy X-ray beam is irradiated. The high-energy X-ray image and the low-energy X-ray image acquired by the X-ray image acquisition unit 10 can be displayed on the screen of the display monitor 11 at the subsequent stage.

  Since the tube voltage of the X-ray tube 1 is switched as described above during one X-ray imaging, the high-energy X-ray imaging image acquired by the X-ray imaging image acquisition unit 10 in one X-ray imaging and the low voltage are reduced. The energy X-ray images are five high energy X-ray images shown in the following (A) to (E) and one low energy X-ray image shown in (F) below.

(A) A high energy X-ray image when the tube voltage of the X-ray tube 1 is 120 kV.
(B) High energy X-ray image when the tube voltage of the X-ray tube 1 is 125 kV.
(C) A high energy X-ray image when the tube voltage of the X-ray tube 1 is 130 kV.
(D) A high energy X-ray image when the tube voltage of the X-ray tube 1 is 135 kV.
(E) A high energy X-ray image when the tube voltage of the X-ray tube 1 is 140 kV.
(F) Low energy X-ray image when the tube voltage of the X-ray tube 1 is 60 kV.

  In the case of the apparatus of the embodiment, the operation panel 12 for inputting X-ray imaging condition data of the tube voltage and tube current of the X-ray tube 1 or an X-ray imaging start command, a computer and its operation program are mainly configured. In addition, an imaging control unit 13 is provided that performs a general function by sending necessary data and commands to each unit according to the progress of data and commands input from the operation panel 12 or X-ray imaging. In addition, an operation menu necessary for execution of X-ray imaging is also displayed on the screen of the display monitor 11, and the display monitor 11, the operation panel 12, and the imaging control unit 13 are workstations for acquiring X-ray imaging images. Is created.

  Further, the high energy X-ray image acquired by the X-ray image acquisition unit 10 is sent to and stored in the high energy image memory 14 and the low energy X-ray image acquired by the X-ray image acquisition unit 10 is stored. Are sent to the low energy image memory 15 for storage. During one X-ray imaging, the high energy image memory 14 stores the five high energy X-ray imaging images shown in the above (A) to (E), and the low energy image memory 14 stores the above-described images. One low-energy X-ray image shown in (F) is stored.

  Further, the apparatus according to the embodiment includes an image weight setting unit 16 that sets weights for a high energy X-ray image and a low energy X-ray image stored in the high energy image memory 14 and the low energy image memory 15, and an image According to the weighting by the weight setting unit 16, the high energy X-ray image and the low energy X-ray image are subjected to image subtraction processing for all combinations of the high energy X-ray image and the low energy X-ray image, and the energy subtraction image is obtained. An image subtraction unit 17 is provided.

  Specifically, the image weighting setting unit 16 sets a coefficient a for a high energy X-ray image and a coefficient b for a low energy X-ray image. Further, the image subtraction unit 17 performs an operation of subtracting an image of a × log (pixel signal of a high energy X-ray image) −b × log (pixel signal of a low energy X-ray image). Therefore, by appropriately setting the coefficient a and the coefficient b by the image weighting setting unit 16, for example, an image in which only bone portions such as the ribs and the spine are substantially captured is acquired as a subtraction image, or conversely, In particular, an image showing only the soft tissue can be acquired as a subtraction image.

  In the apparatus according to the embodiment, the image weighting setting unit 16 collectively sets one weighting coefficient a for five high-energy X-ray images. The configuration may be such that weighting coefficients are set separately for each of the five high-energy X-ray images.

  The combinations of the high-energy X-ray image and the low-energy X-ray image that are subjected to the image subtraction process by the image subtraction unit 17 are all five as shown in the following (a) to (e). Therefore, the number of image subtraction units 17 acquired by subtraction images in one X-ray imaging is 5.

(A) A combination of a high energy X-ray image when the tube voltage of the X-ray tube 1 is 120 kV and a low energy X-ray image when the tube voltage of the X-ray tube 1 is 60 kV.
(B) A combination of a high energy X-ray image when the tube voltage of the X-ray tube 1 is 125 kV and a low energy X-ray image when the tube voltage of the X-ray tube 1 is 60 kV.
(C) A combination of a high energy X-ray image when the tube voltage of the X-ray tube 1 is 130 kV and a low energy X-ray image when the tube voltage of the X-ray tube 1 is 60 kV.
(D) A combination of a high energy X-ray image when the tube voltage of the X-ray tube 1 is 135 kV and a low energy X-ray image when the tube voltage of the X-ray tube 1 is 60 kV.
(E) A combination of a high energy X-ray image when the tube voltage of the X-ray tube 1 is 140 kV and a low energy X-ray image when the tube voltage of the X-ray tube 1 is 60 kV.

  According to the five combinations shown in the above (a) to (e), the tube voltage of the X-ray tube 1 becomes a voltage in the range of 110 kV or higher on the higher energy side of the X-ray beam XA. The energy of the X-ray beam XA when acquiring an energy X-ray image is always in an appropriate high level region. Further, since the tube voltage of the X-ray tube 1 is in the range of 70 kV or less on the lower energy side of the X-ray beam XA, the energy of the X-ray beam XA when acquiring a low energy X-ray image is always appropriate. It is in the low level range. As a result, a sufficient image difference is reliably attached between the high energy X-ray image and the low energy X-ray image.

  The five subtraction images acquired by the image subtraction unit 17 are stored in the subtraction image memory 18, read out from the subtraction image memory 18 at an appropriate time, and displayed on the screen of the display monitor 19. The five subtraction images may be displayed side by side on the screen of the display monitor 19 or may be displayed in order on the screen of the display monitor 19.

  In the case of the apparatus of the embodiment, an operation board 20 for inputting data or commands necessary for executing image subtraction processing such as weighting values for high-energy X-ray images and low-energy X-ray images, a computer and its operation program And a subtraction control unit 21 that performs a general function by sending necessary data and commands to each unit in accordance with the progress of data and commands input by the operation board 20 or image subtraction processing. . The display monitor 19 is also configured to display an operation menu for inputting a numerical value for weighting the high-energy X-ray image and the low-energy X-ray image. The display monitor 19, the operation board 20, and the subtraction are displayed. The control unit 21 creates a workstation for acquiring a subtraction image.

  Next, an X-ray imaging image acquisition process by the X-ray imaging apparatus according to the embodiment having the above-described configuration will be described with reference to the drawings. FIG. 3 is a flowchart showing an X-ray image acquisition process by the apparatus of the embodiment.

  [Step S1] X-ray imaging is started as the operator performs an input operation for commanding start of the X-ray imaging apparatus on the operation panel 12.

  [Step S2] The tube voltage of the X-ray tube 1 is set to 120 kV.

  [Step S3] As the tube voltage is applied to the X-ray tube 1, the subject is irradiated with a high-energy X-ray beam.

  [Step S4] In accordance with the X-ray detection signal output from the FPD 2, a high-energy X-ray image is acquired by the X-ray image acquisition unit 10 and stored in the high-energy image memory 14.

  [Step S5] If a tube voltage of 140 kV has already been applied to the X-ray tube 1, the process jumps to Step S7. If a tube voltage of 140 kV has not yet been applied to the X-ray tube 1, the process proceeds to the next step S6.

  [Step S6] The tube voltage setting of the X-ray tube 1 is increased by 5 kV, and then the process returns to Step S3.

  [Step S7] The tube voltage setting of the X-ray tube 1 is lowered to 60 kV.

  [Step S8] As the tube voltage is applied to the X-ray tube 1, the subject is irradiated with a low-energy X-ray beam.

  [Step S9] When a low energy X-ray image is acquired by the X-ray image acquisition unit 10 according to the X-ray detection signal output from the FPD 2 and stored in the low energy image memory 15, all the X-ray images are stored. It will be acquired.

Next, a subtraction image acquisition process by the X-ray imaging apparatus of the embodiment having the above-described configuration will be described with reference to the drawings. FIG. 4 is a flowchart showing a subtraction image acquisition process by the apparatus of the embodiment.
In the following, it is assumed that the setting of the weighting coefficient for the high energy X-ray image and the low energy X-ray image is completed.

  [Step T1] A low-energy X-ray image is read from the low-energy image memory 15 and set in the image subtraction unit 17.

  [Step T2] One unread high-energy X-ray image is read from the high-energy image memory 14 and set in the image subtraction unit 17.

  [Step T3] The image subtraction unit 17 obtains a subtraction image by performing image subtraction processing on the high energy X-ray image and the low energy X-ray image according to the weighting by the image weight setting unit 16.

  [Step T4] The subtraction image acquired by the image subtraction unit 17 is stored in the subtraction image memory 18.

[Step T5] If the number of acquired subtraction images has reached 5, all the subtraction images have been acquired, and the subtraction image acquisition process is completed. If the number of acquired subtraction images is less than 5, the process returns to step T2.
The subtraction image stored in the subtraction image memory 18 is read out and displayed in parallel with the above process, or promptly after the above process ends. The operator can quickly select one image with the optimum image quality from the five subtraction images displayed on the display monitor 19.

  As described in detail above, in the case of the apparatus of the embodiment, the one having the higher energy of the X-ray beam XA irradiated by the X-ray tube 1 provided in the X-ray imaging mechanism 3 in one X-ray imaging. In addition to the fact that the energy is changed over five stages, the X-ray imaging image acquisition unit 10 acquires a high-energy X-ray imaging image for each stage of the energy of the X-ray beam XA. On the higher energy side of the X-ray beam XA, the aspect of X-ray absorption in the bone of the subject M changes considerably with the change in the energy of the X-ray beam XA. There is a clear image difference between the X-ray images due to the energy difference of the X-ray beam XA.

Therefore, in the apparatus of the embodiment, five high-energy X-ray images having a clear image difference are acquired as high-energy X-ray images based on the energy subtraction image by only one X-ray image. Therefore, an energy subtraction image with an appropriate image quality can be reliably acquired by one X-ray imaging.
Therefore, according to the X-ray imaging apparatus of the embodiment, an energy subtraction image with an appropriate image quality can be quickly acquired.

The present invention is not limited to the above embodiment, and can be modified as follows.
(1) In the apparatus of the embodiment, an apparatus having the same configuration as that of the embodiment can be given as a modified example except that the energy of the X-ray beam is changed over a plurality of stages on the lower energy side.
In the case of the apparatus of this modification, a plurality of low-energy X-ray images having image differences are acquired as low-energy X-ray images that are the basis of energy subtraction images by only one X-ray image. An energy subtraction image with an appropriate image quality can be obtained more reliably by one X-ray imaging.

  (2) In the case of the apparatus of the embodiment, the configuration is such that one low energy X-ray image is captured with respect to five high energy X-ray images, but one high energy X-ray image is obtained. An apparatus having the same configuration as that of the embodiment can be cited as a modified example, except that five low-energy X-ray images are acquired one by one immediately before or after obtaining the image, and five low-energy X-ray images are acquired. . However, in the case of the apparatus of this modification, the X-ray exposure dose of the subject increases by the amount of imaging of four low-energy X-ray images as compared with the apparatus of the example.

  (3) In the case of the apparatus of the embodiment, the X-ray imaging mechanism 3 is a standing imaging type. However, the present invention is not limited to an apparatus including a standing imaging type X-ray imaging mechanism. The present invention can also be applied to an apparatus provided with an X-ray imaging mechanism other than the position photographing type.

  (4) In the apparatus of the embodiment, the two-dimensional X-ray detection means is an FPD, but the two-dimensional X-ray detection means is not limited to the FPD, and may be an image intensifier, for example.

  (5) In the case of the apparatus of the example, energy subtraction images were obtained for all combinations of five high-energy X-ray images and one low-energy X-ray image. It is not necessary to perform image subtraction processing for the combination. For example, when the high energy switching range is assigned with the most representative energy as the center, first, two high energy X-ray images close to the center of the energy switching range are selected from the high energy X-ray images. An image is selected, and an image subtraction process is performed on the combination of these two high-energy X-ray images and one low-energy X-ray image and displayed on the screen. Since the two high-energy X-ray images used first are representative energies, energy subtraction images with appropriate image quality are often obtained. If one of the two displayed energy subtraction images is an appropriate image, that image is adopted, and the remaining high-energy X-ray image can be omitted to improve processing efficiency by omitting image subtraction processing. it can. If the two displayed energy subtraction images are of inappropriate image quality, image subtraction processing may be performed on the remaining high energy X-ray images.

It is a block diagram which shows the whole structure of the X-ray imaging device of an Example. It is a graph which shows the time-dependent change of the tube voltage of the X-ray tube of the X-ray imaging device of an Example. It is a flowchart which shows the X-ray imaging image acquisition process of the X-ray imaging device of an Example. It is a flowchart which shows the subtraction image acquisition process of the X-ray imaging device of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... X-ray tube 2 ... FPD (two-dimensional X-ray detector)
3 ... X-ray imaging mechanism (X-ray imaging means)
9 ... X-ray energy switching control unit (X-ray energy switching control means)
10: X-ray imaging image acquisition unit (X-ray imaging image acquisition means)
16 ... Image weight setting unit (image weight setting means)
17 Image subtraction unit (image subtraction means)
19 ... Display monitor (image display means)
M ... Subject XA ... X-ray beam

Claims (3)

  (A) An X-ray tube that irradiates a subject to be imaged with an X-ray beam and a two-dimensional X-ray detector that detects a transmitted X-ray image of the subject that is generated when the subject is irradiated with the X-ray beam are provided. The X-ray imaging means, and (B) the energy of the X-ray beam irradiated to the subject between the higher energy side and the lower energy side at least on the higher energy side in a plurality of stages. X-ray energy switching control means for performing energy switching control for changing the X-ray tube while changing, and (C) an X-ray output from a two-dimensional X-ray detector upon irradiation with a high-energy X-ray beam having high energy A high-energy X-ray image is acquired at each stage of the energy of the X-ray beam according to the X-ray detection signal, and two-dimensional X-ray inspection is performed along with the irradiation of the low-energy X-ray beam with low energy. X-ray imaging image acquisition means for acquiring a low-energy X-ray imaging image in accordance with an X-ray detection signal output from the instrument; and (D) an image for setting weights for the high-energy X-ray imaging image and the low-energy X-ray imaging image A combination of at least two of a high-energy X-ray image and a low-energy X-ray image with a high-energy X-ray image and a low-energy X-ray image according to weighting by weighting setting means and (E) image weight setting means. An X-ray imaging apparatus comprising: image subtraction means for obtaining an energy subtraction image by performing image subtraction processing; and (F) an image display means for displaying the energy subtraction image obtained by the image subtraction means. .   2. The X-ray imaging apparatus according to claim 1, wherein the X-ray energy switching control means performs energy switching control by executing electrical control for switching a tube voltage of the X-ray tube. 3. The X-ray imaging apparatus according to claim 1, wherein the image subtraction unit sequentially uses a plurality of high-energy X-ray images from a high-energy X-ray image close to the center of the energy switching range. X-ray imaging apparatus that performs image subtraction processing.

Images