JP7130406B2 - Image processing device, X-ray diagnostic device and image processing program - Google Patents

Description

TECHNICAL FIELD Embodiments of the present invention relate to an image processing apparatus, an X-ray diagnostic apparatus, and an image processing program.

2. Description of the Related Art Conventionally, in an examination using an X-ray diagnostic apparatus, there are cases where a region of interest is observed with high resolution while observing a wide area of a subject from a bird's-eye view. In recent years, as an X-ray diagnostic apparatus used for such examination, for example, a first detector having a large field of view and a smaller field of view and higher resolution than the first detector (fine pixel pitch) An X-ray diagnostic apparatus is known that has an X-ray detector that also has two detectors.

In such an X-ray diagnostic apparatus, for example, the first detector and the second detector are switched and used depending on the application, and the X-ray image based on the signal output by the first detector and the , to display one of the X-ray images based on the signals output by the second detector. Moreover, in such an X-ray diagnostic apparatus, each X-ray image can be displayed in an overlapping manner. Such image display is expected to improve the accuracy of difficult procedures such as stent placement and coil embolization.

JP 2016-097296 A

A problem to be solved by the present invention is to suppress an increase in exposure dose while displaying a high-definition image.

An image processing apparatus according to an embodiment includes an acquisition unit, a generation unit, and a processing unit. The acquisition unit sequentially acquires first X-ray images obtained by imaging a subject using X-rays. The generation unit generates a second X-ray image captured with a higher X-ray dose than the first X-ray image at a time before the first X-ray image, and the first X-ray image. A combined composite image is generated in parallel with the acquisition of the first X-ray image. The processing unit adds pixel values based on the first X-ray image to positions of pixels corresponding to at least the second X-ray image in the combined image, based on temporal changes in the first X-ray image. Reflect information.

FIG. 1 is a diagram showing an example of the configuration of an X-ray diagnostic apparatus according to the first embodiment. 2A is a diagram illustrating an example of the configuration of an X-ray detector according to the first embodiment; FIG. 2B is a diagram illustrating an example of the configuration of the X-ray detector according to the first embodiment; FIG. FIG. 3 is a diagram for explaining an example of processing by a generation function according to the first embodiment; FIG. 4 is a diagram for explaining an example of processing by a generation function according to the first embodiment; FIG. 5 is a diagram for explaining an example of processing by the image processing function according to the first embodiment; FIG. 6 is a flow chart showing the processing procedure of the X-ray diagnostic apparatus according to the first embodiment. FIG. 7 is a diagram for explaining an example of processing by a processing circuit according to the second embodiment; FIG. 8 is a flow chart showing the processing procedure of the X-ray diagnostic apparatus according to the second embodiment. FIG. 9 is a flow chart showing the processing procedure of the X-ray diagnostic apparatus according to the second embodiment. FIG. 10 is a diagram showing an example of a synthesized image according to the third embodiment. FIG. 11 is a diagram illustrating an example of the configuration of an X-ray detector according to the third embodiment; FIG. 12 is a diagram illustrating an example configuration of an image processing apparatus according to the third embodiment.

Hereinafter, embodiments of an image processing apparatus, an X-ray diagnostic apparatus, and an image processing program will be described in detail with reference to the accompanying drawings. Note that the image processing apparatus, X-ray diagnostic apparatus, and image processing program according to the present application are not limited to the embodiments described below.

(First embodiment)
First, the overall configuration of the X-ray diagnostic apparatus according to the first embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of an X-ray diagnostic apparatus 100 according to the first embodiment. As shown in FIG. 1, an X-ray diagnostic apparatus 100 according to the first embodiment includes an X-ray high voltage device 11, an X-ray tube 12, an X-ray diaphragm 13, a top plate 14, and a C-arm 15. , an X-ray detector 16, a C-arm rotation/movement mechanism 17, a top plate movement mechanism 18, a C-arm/top plate mechanism control circuit 19, an aperture control circuit 20, a processing circuit 21, and an input interface 22. , a display 23 , an image data generation circuit 24 and a storage circuit 25 .

In the X-ray diagnostic apparatus 100 shown in FIG. 1, each processing function is stored in the storage circuit 25 in the form of a computer-executable program. The C-arm/top plate mechanism control circuit 19, the diaphragm control circuit 20, the processing circuit 21, and the image data generation circuit 24 are processors that implement functions corresponding to each program by reading and executing programs from the storage circuit 25. is. In other words, each circuit with each program read has a function corresponding to the read program.

The X-ray high-voltage device 11 is a high-voltage power supply that generates a high voltage under the control of the processing circuit 21 and supplies the generated high voltage to the X-ray tube 12 . The X-ray tube 12 uses a high voltage supplied from the X-ray high voltage device 11 to generate X-rays.

The X-ray diaphragm 13 narrows down the X-rays generated by the X-ray tube 12 so that the region of interest of the subject P is selectively irradiated under the control of the diaphragm control circuit 20 . For example, the X-ray diaphragm 13 has four slidable diaphragm blades. The X-ray diaphragm 13 arbitrarily changes the shape, size, and position of the aperture by sliding these diaphragm blades under the control of the diaphragm control circuit 20 . By adjusting the size and position of the aperture with the X-ray diaphragm 13 in this manner, the size and position of the X-ray irradiation area on the detection surface of the X-ray detector 16 are adjusted. That is, the X-rays generated by the X-ray tube 12 are focused by the opening of the X-ray diaphragm 13 and irradiated to the subject P. FIG. The diaphragm blades of the X-ray diaphragm 13 are slid so that, for example, only the ROI set by the operator is irradiated with X-rays. Also, the X-ray diaphragm 13 can be provided with additional filters for adjusting the radiation quality. Additional filters are set, for example, depending on the inspection.

The top plate 14 is a bed on which the subject P is placed, and is placed on a bed device (not shown). Note that the subject P is not included in the X-ray diagnostic apparatus 100 .

The X-ray detector 16 detects X-rays that have passed through the subject P. FIG. For example, the X-ray detector 16 has detection elements arranged in a matrix. Each detection element converts the X-rays that have passed through the subject P into an electric signal, accumulates the electric signal, and transmits the accumulated electric signal to the image data generation circuit 24 . Here, the X-ray detector 16 according to this embodiment has two detectors with different pixel pitches. 2A and 2B are diagrams showing an example of the configuration of the X-ray detector 16 according to the first embodiment. Here, FIG. 2A shows a longitudinal sectional view of the X-ray detector 16. FIG. 2B also shows a top view of the X-ray detector 16. FIG.

For example, the X-ray detector 16 has a first photodetector 16a, a second photodetector 16b, and a scintillator 16c, as shown in FIG. 2A. A first detector is composed of the first photodetector 16a and the scintillator 16c, and a second detector is composed of the second photodetector 16b and the scintillator 16c.

The scintillator 16c converts the X-rays emitted from the X-ray tube 12 into light. The first photodetector 16a includes, for example, a two-dimensional image sensor employing a TFT (Thin Film Transistor) array made of amorphous silicon, detects light converted by the scintillator 16c, and outputs an electrical signal. do. The second photodetector 16b includes, for example, a two-dimensional image sensor employing a CMOS (Complementary Metal Oxide Semiconductor) transistor, detects light converted by the scintillator 16c, and outputs an electrical signal. The electrical signal output by the first photodetector 16a is hereinafter referred to as the first electrical signal, and the electrical signal output by the second photodetector 16b is referred to as the second electrical signal.

Thus, the scintillator 16c is shared by the first photodetector 16a and the second photodetector 16b. In other words, the X-ray detector 16 shares the scintillator 16c that converts the X-rays emitted from the X-ray tube 12 into light, and detects the light converted by the scintillator 16c to output an electrical signal. It has a first photodetector 16a and a second photodetector 16b. Then, the first photodetector 16a and the second photodetector 16b output electric signals simultaneously detecting the light converted by the scintillator 16c. Note that the X-ray diagnostic apparatus 100 can also be controlled to output electrical signals from only one of the first photodetector 16a and the second photodetector 16b.

Also, as shown in FIG. 2A, the first photodetector 16a and the second photodetector 16b each have a plurality of elements that constitute a pixel unit. Each of these elements converts a fluorescent image obtained by incident X-rays into an electrical signal and accumulates it in a photodiode (PD). The example of FIG. 2A illustrates the case where the first photodetector 16a has eight elements in one row and the second photodetector 16b has eight elements in one row.

Here, the pixel pitch of each element of the second photodetector 16b is finer than the pixel pitch of each element of the first photodetector 16a. In the example shown in FIG. 2A, the pixel pitch of each element of the first photodetector 16a corresponds to the pixel pitch of two elements of the second photodetector 16b. That is, in the XY plane of the X-ray detector 16, one element of the first photodetector 16a corresponds to four elements of the second photodetector 16b. Therefore, the second photodetector 16b has higher resolution than the first photodetector 16a.

Also, as shown in FIG. 2B, the first photodetector 16a has a wider field of view than the second photodetector 16b. That is, as shown in FIG. 2B, the second photodetector 16b has a size that partially overlaps the detection area of the first photodetector 16a. Accordingly, the second photodetector 16b collects high-resolution X-ray image data in the overlapping region with the first photodetector 16a. Here, in the X-ray diagnostic apparatus 100, the X-ray diaphragm 13 has four diaphragm blades, and under the control of the diaphragm control circuit 20, these diaphragm blades can be configured to be slidable. In such a case, for example, in the X-ray diagnostic apparatus 100, the X-ray diaphragm 13 has diaphragm blades 13a to 13d, as shown in FIG. 2B.

The aperture blade 13a is arranged parallel to one side of the first photodetector 16a and the second photodetector 16b, and is slid in the direction of the double arrow 51 to adjust the X-ray irradiation area. Further, the aperture blade 13b is arranged parallel to one side of the first photodetector 16a and the second photodetector 16b and parallel to the aperture blade 13a, and is slid in the direction of the double arrow 52. , to adjust the X-ray irradiation area. In addition, the aperture blade 13c is arranged in a direction parallel to one side of the first photodetector 16a and the second photodetector 16b and perpendicular to the aperture blade 13a and the aperture blade 13b. is slid to adjust the X-ray irradiation area. Further, the aperture blade 13d is arranged parallel to one side of the first photodetector 16a and the second photodetector 16b and parallel to the aperture blade 13c, and is slid in the direction of the double arrow 54. , to adjust the X-ray irradiation area.

Returning to FIG. 1 , C-arm 15 holds X-ray tube 12 , X-ray diaphragm 13 and X-ray detector 16 . The C-arms 15 are individually rotated on a plurality of axes by actuators such as motors provided on the supports.

The C-arm rotating/moving mechanism 17 is a mechanism for rotating and moving the C-arm 15 by driving a motor or the like provided on the support. The top plate moving mechanism 18 is a mechanism for moving the top plate 14 . For example, the tabletop moving mechanism 18 moves the tabletop 14 using power generated by an actuator.

The C-arm/top plate mechanism control circuit 19 controls the C-arm rotating/moving mechanism 17 and the top plate moving mechanism 18 under the control of the processing circuit 21, thereby rotating and moving the C-arm 15 and moving the top plate 14. Adjust movement. Under the control of the processing circuit 21, the aperture control circuit 20 adjusts the opening degree of the aperture blades of the X-ray aperture 13 to change the shape, size, and position of the aperture, and irradiate the subject P. Controls the irradiation range of X-rays.

The image data generation circuit 24 generates projection data using the electrical signals converted from the X-rays by the X-ray detector 16 and stores the generated projection data in the storage circuit 25 . Specifically, the image data generation circuit 24 generates the first projection data from the first electrical signal output by the first photodetector 16a, and the second projection data output by the second photodetector 16b. Second projection data is generated from the two electric signals, and each generated projection data is stored in the storage circuit 25 . For example, the image data generation circuit 24 converts the first electric signal and the second electric signal received from the X-ray detector 16 into current/voltage conversion, A (Analog)/D (Digital) conversion, parallel/ A serial conversion is respectively performed to generate first projection data based on the first electrical signal and second projection data based on the second electrical signal, respectively. The image data generation circuit 24 then stores the generated first projection data and second projection data in the storage circuit 25 .

The storage circuit 25 receives and stores the projection data generated by the image data generation circuit 24 . For example, the storage circuit 25 stores first projection data based on the first electrical signal and second projection data based on the second electrical signal. The storage circuit 25 also stores the X-ray image generated by the processing circuit 21, the volume data, and the synthesized image. Details of the composite image will be described later.

The storage circuit 25 also stores programs corresponding to various functions read and executed by each circuit shown in FIG. For example, the storage circuit 25 stores a program corresponding to the control function 211, a program corresponding to the generation function 212, and a program corresponding to the image processing function 213, which are read and executed by the processing circuit 21. FIG. In FIG. 1, the single storage circuit 25 stores the programs corresponding to each processing function, but a plurality of storage circuits are distributed and various circuits such as the processing circuit 21 are individually stored. A configuration in which the corresponding program is read from the storage circuit may be used.

The input interface 22 includes a trackball, a switch button, a mouse, a keyboard, a touch pad for performing input operations by touching the operation surface, and a display screen for setting a predetermined area (for example, ROI in partial perspective). It is realized by a touch screen integrated with a touch pad, a non-contact input circuit using an optical sensor, an audio input circuit, a foot switch for X-ray irradiation, and the like.

The input interface 22 is connected to the processing circuit 21 , converts an input operation received from an operator into an electric signal, and outputs the electric signal to the processing circuit 21 . In this specification, the input interface 22 is not limited to having physical operation parts such as a mouse and a keyboard. For example, an example of an input interface includes a processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs this electrical signal to a control circuit.

The display 23 displays a GUI (Graphical User Interface) for receiving instructions from the operator and various images generated by the processing circuit 21 . Also, the display 23 displays various processing results by the processing circuit 21 .

The processing circuit 21 controls the overall operation of the X-ray diagnostic apparatus 100 by executing a control function 211 , a generation function 212 and an image processing function 213 . Specifically, the processing circuit 21 performs various processes by reading out from the storage circuit 25 and executing a program corresponding to the control function 211 for controlling the entire apparatus. For example, the control function 211 controls the X-ray high-voltage device 11 according to an operator's instruction transferred from the input interface 22, adjusts the voltage supplied to the X-ray tube 12, and irradiates the subject P. control the amount of X-rays applied and ON/OFF. Further, for example, the control function 211 controls the C-arm/top plate mechanism control circuit 19 according to the operator's instructions, and adjusts the rotation and movement of the C-arm 15 and the movement of the top plate 14 .

Further, for example, the control function 211 controls the diaphragm control circuit 20 according to an operator's instruction, and adjusts the opening degrees of the diaphragm blades 13a to 13d of the X-ray diaphragm 13, thereby irradiating the subject P. Controls the irradiation range of X-rays.

Further, the control function 211 controls projection data generation processing by the image data generation circuit 24 in accordance with an operator's instruction. The control function 211 also controls image processing, analysis processing, and the like for projection data. For example, the control function 211 generates an X-ray image by performing various image processing on projection data (first projection data and second projection data) stored in the storage circuit 25 . Alternatively, the control function 211 directly acquires the projection data (the first projection data and the second projection data) from the image data generation circuit 24, and the acquired projection data (the first projection data and the second projection data). An X-ray image is generated by performing various image processing on the .

Note that the control function 211 can also store the processed X-ray image in the storage circuit 25 . For example, the control function 211 can perform various processes using image processing filters such as moving average (smoothing) filters, Gaussian filters, median filters, recursive filters, and bandpass filters.

In addition, the control function 211 reconstructs reconstruction data (volume data) using the projection data (first projection data and second projection data) acquired by rotational imaging, and generates the reconstructed volume data. It can also be stored in the memory circuit 25 . Furthermore, the image processing circuit 26 can also generate a three-dimensional image from the volume data.

The control function 211 also controls the display 23 to display a GUI for receiving an operator's instruction, an image stored in the storage circuit 25, a processing result by the processing circuit 21, and the like.

A generation function 212 generates a composite image. Also, the image processing function 213 executes image processing on the synthesized image. Note that the generation function 212 and the image processing function 213 will be detailed later. Here, the control function 211 is an example of an imaging unit in the claims. Also, the generation function 212 is an example of a generation unit in the scope of claims. Also, the image processing function 213 is an example of a processing unit in the claims.

The overall configuration of the X-ray diagnostic apparatus 100 has been described above. With such a configuration, the X-ray diagnostic apparatus 100 according to the present embodiment suppresses an increase in exposure dose while displaying high-definition images. As described above, the X-ray diagnostic apparatus 100 includes the high-resolution second photodetector 16b and can display a higher-definition X-ray image. However, since the second photodetector 16b has a narrow field of view, when the X-ray image based on the second projection data detected by the second photodetector 16b is displayed on a large display, a higher dose is required. X-ray images acquired at are obtained. As a result, when performing a procedure while observing a high-resolution X-ray image, the exposure dose of the subject increases.

Therefore, in the X-ray diagnostic apparatus 100 according to the first embodiment, a first X-ray image acquired with a normal dose and a second X-ray image acquired with a dose higher than that of the first X-ray image By applying image processing to a synthesized image obtained by synthesizing an image, an increase in exposure dose is suppressed while a high-definition image is displayed. For example, by using the above-described composite image for image display when a procedure such as stent placement or coil embolization is performed in the X-ray diagnostic apparatus 100, the procedure can be performed while observing a high-definition image, and An increase in exposure dose can be suppressed. Here, the first X-ray image in this embodiment is an image acquired with a normal dose when performing a procedure, for example, a fluoroscopic image acquired by the first photodetector 16a. be. Further, the second X-ray image in the present embodiment is an image acquired with a higher dose than the first X-ray image, for example, an X-ray image acquired by the second photodetector 16b, , captured images collected by the first photodetector 16a, and the like. In addition, below, a 2nd X-ray image is also described as a reference image.

Details of the X-ray diagnostic apparatus 100 will be described below. The control function 211 in the X-ray diagnostic apparatus 100 captures the subject with X-rays and sequentially acquires first X-ray images. Further, the control function 211 acquires a second X-ray image by imaging the subject with an X-ray dose higher than that of the first X-ray image at a time before the first X-ray image. For example, the control function 211 controls the acquisition of the second X-ray image and the subsequent acquisition of the first X-ray image according to the operation by the operator. Here, in this embodiment, the first X-ray image is a fluoroscopic image collected by the first photodetector 16a, and the second X-ray image is an X-ray image collected by the second photodetector 16b. A line image will be described as an example.

In such a case, the control function 211 first controls the X-ray high-voltage device 11, the diaphragm control circuit 20, the C-arm/top plate mechanism control circuit 19, and the image data generation circuit 24 according to the operation by the operator. to acquire a second X-ray image from the second photodetector 16b. After that, the control function 211 controls the X-ray high-voltage device 11, the aperture control circuit 20, the C-arm/top plate mechanism control circuit 19, and the image data generation circuit 24 so that the first photodetector 16a to the first X-ray images (fluoroscopic images) are acquired sequentially.

The generation function 212 combined the first X-ray image with a second X-ray image captured at a time earlier than the first X-ray image with a higher X-ray dose than the first X-ray image. A composite image is generated in parallel with the acquisition of the first X-ray image. Specifically, the generation function 212 synthesizes the second X-ray images acquired under the control of the control function 211 with the plurality of first X-ray images (fluoroscopic images) that are sequentially acquired. Generate multiple composite images. Here, the generation function 212 sequentially generates composite images in accordance with, for example, the sequential acquisition of the first X-ray images. An example of processing by the generation function 212 will be described below with reference to FIGS. 3 and 4. FIG. 3 and 4 are diagrams for explaining an example of processing by the generation function 212 according to the first embodiment.

For example, generation function 212 generates the composite image shown in FIG. 3 each time a first x-ray image is acquired. For example, the generating function 212 generates a composite image by combining the first X-ray image I1 and the second X-ray image I2 as shown in FIG. That is, the generation function 212 generates a composite image by combining the second X-ray image I2 acquired in advance with the first X-ray image that is sequentially generated. For example, the generating function 212 generates a composite image by combining the first X-ray image I11 and the second X-ray image I2, as shown in FIG. The generation function 212 then generates a composite image by combining the first X-ray image I12 acquired after the first X-ray image I11 and the second X-ray image I2. In this way, the generation function 212 sequentially synthesizes the sequentially acquired first X-ray image and the second X-ray image acquired before the first X-ray image, thereby producing a plurality of Synthetic images are generated sequentially.

That is, the generation function 212 generates a plurality of synthesized images by sequentially synthesizing normal X-ray images with one high-definition X-ray image. Here, the composite image generated by the generating function 212 may be an image obtained by replacing a region corresponding to the second X-ray image in the first X-ray image with the second X-ray image, or It may be an image in which the second X-ray image is superimposed on the first X-ray image. For example, the generation function 212 generates a composite image by replacing the region corresponding to the second X-ray image I2 in the first X-ray image I11 with the second X-ray image I2. Alternatively, the generation function 212 generates a composite image superimposed on the second X-ray image I2 in the region corresponding to the second X-ray image I2 in the first X-ray image I11.

Here, the generating function 212 aligns the first X-ray image and the second X-ray image prior to generating the composite image. For example, the generation function 212 first determines whether there is a positional shift between the first X-ray image and the second X-ray image based on anatomical feature points in the images. However, if there is a positional deviation, alignment between the images is executed. Then, the generation function 212 determines the positional deviation between the successive images in chronological order for the plurality of first X-ray images acquired over time, and performs alignment according to the determination result.

For example, the generation function 212 compares changes in pixel values (e.g., differences in pixel values) of pixels at corresponding positions (same positions) in the first X-ray images that occur in chronological order with a threshold, Based on the number of pixels whose change in pixel value exceeds the threshold, it is determined whether or not there is a positional shift between the first X-ray images successive in time series. For example, when a position shift occurs due to body movement of the subject, a change in pixel value occurs in a large number of pixels between the first X-ray images that precede and follow each other in time series. Therefore, the generation function 212 determines that a positional shift has occurred when the number of pixels whose change in pixel value exceeds the threshold exceeds the threshold. Then, the generating function 212 synthesizes the first X-ray image after alignment and the second X-ray image after performing the alignment of the first X-ray image when there is a positional deviation. do. In other words, the generating function 212 generates the first X-ray image and the second X-ray image when the number of pixels whose pixel values have changed exceeds the threshold in the first X-ray images that are sequentially acquired. A composite image is generated after executing the alignment process of . The generation function 212 stores the generated synthetic image in the storage circuit 25 .

The control function 211 causes the display 23 to display the synthesized image generated by the generation function 212 . For example, the control function 211 receives a composite image from the generation function 212 and causes the display 23 to display the received composite image. Alternatively, the control function 211 reads the composite image stored in the storage circuit 25 and causes the display 23 to display it.

The image processing function 213 adds pixel value information based on the first X-ray image to positions of pixels corresponding to at least the second X-ray image in the combined image based on temporal changes in the first X-ray image. To reflect. Specifically, the image processing function 213 changes the pixel values of the pixels included in the region of the first X-ray image corresponding to the second X-ray image after the change of the first X-ray image. is reflected in the corresponding position of the second X-ray image. For example, the image processing function 213 replaces the pixel value of the pixel at the corresponding position in the second X-ray image with the changed pixel value in the first X-ray image.

As described above, in the X-ray diagnostic apparatus 100, a composite image is used for image display when a procedure such as stent placement or coil embolization is performed, so that the procedure can be performed while observing a high-definition image. and to prevent an increase in exposure dose. That is, in the X-ray diagnostic apparatus 100, a high-definition image (second X-ray image) is acquired of a region of interest such as a stent placement position or an aneurysm position, and a wider field of view is acquired by normal fluoroscopy. While acquiring images (first X-ray images), a composite image is generated and displayed. Then, in the X-ray diagnostic apparatus 100, changes in pixel values in a region (region of interest) of the second X-ray image are reflected on the second X-ray image, so that a high-definition image of the region of interest can be obtained. Allows observation of changes (eg device intrusion into the region of interest, etc.). Here, since the acquired image during observation is a normal fluoroscopic image, it is possible to suppress an increase in exposure dose.

For example, the image processing function 213 detects changes in pixel values of the first X-ray image generated by the control function 211, and reflects pixel value information in the second X-ray image according to the detection result. . As an example, the image processing function 213 detects whether or not a pixel value change has occurred in a region of the first X-ray image corresponding to the second X-ray image. Here, the image processing function 213 identifies a region in the first X-ray image corresponding to the second X-ray image based on the registration information from the generation function 212 .

An example of the processing of the image processing function 213 will be described below with reference to FIG. FIG. 5 is a diagram for explaining an example of processing by the image processing function 213 according to the first embodiment. Here, in FIG. 5, a synthesized image is generated by synthesizing the second X-ray image I2 with the first X-ray images “I11, I12, I13, . . . ” acquired over time. case. For example, the image processing function 213 performs subtraction between successively acquired first X-ray images in chronological order, and detects pixels whose values after subtraction exceed a threshold value as pixels whose pixel values have changed. I judge. The image processing function 213 performs the above determination each time the first X-ray image is generated, and further determines whether or not the pixel value has changed in the region corresponding to the second X-ray image I2.

Here, for example, as shown in the lower part of the left diagram of FIG. It is detected that the pixel value has changed in the region corresponding to the X-ray image I2 of No. 2. Then, the image processing function 213 reflects the pixel values corresponding to the detected device D1 in the corresponding positions of the second X-ray image, as shown in the lower part of the right diagram of FIG. For example, the image processing function 213 replaces the pixel values at the positions corresponding to the device D1 in the second X-ray image I2 with the pixel values corresponding to the device D1 in the first X-ray image I13.

As a result, the synthesized image displayed by the display 23 is an image in which the device D1 is shown on the second X-ray image I2, as shown in the upper right part of FIG. Note that the synthesized image before the pixel values are reflected is an image in which the device D1 is not shown on the second X-ray image I2, as shown in the upper left part of FIG.

In this way, the image processing function 213 detects a change in the pixel value of the region corresponding to the second X-ray image in the first X-ray image, and outputs the changed pixel value information to the second X-ray image. is reflected in the corresponding position of For example, when the device D1 moves in the region corresponding to the second X-ray image I2, the image processing function 213 detects changes in pixel values due to movement of the device D1 in the first X-ray image collected over time. , and the pixel value information is reflected in the corresponding position of the second X-ray image I2 in each synthesized image. This allows the operator to observe the motion of the device D1 in the high-definition second X-ray image I2.

Here, in the above example, the example of replacing the pixel values of the second X-ray image with the pixel values of the first X-ray image has been described. The method includes a composite image in which a region corresponding to the second X-ray image in the first X-ray image is replaced with the second X-ray image, and a second X-ray image on the first X-ray image. can be applied in any case of a composite image on which is superimposed. In addition, in the case of a composite image obtained by superimposing the second X-ray image on the first X-ray image, by changing the opacity of the second X-ray image in addition to replacing the pixel values, , the pixel value information of the first X-ray image can be reflected in the corresponding position of the second X-ray image.

In such a case, the generation function 212 generates a composite image by superimposing the second X-ray image on the first X-ray image. The image processing function 213 reduces the opacity of the second X-ray image so that the pixel value information after the change of the first X-ray image is transferred to the corresponding position of the second X-ray image. To reflect. For example, when the image processing function 213 detects a change in the pixel value of the region corresponding to the second X-ray image in the first X-ray image I13, the opacity of the entire second X-ray image I2 is By decreasing, the pixel values of the first X-ray image I13 are reflected on the second X-ray image I2. To give an example, the image processing function 213, of the first X-ray image and the second X-ray image displayed in different layers, opacifies the layer displaying the second X-ray image. Decreasing the intensity reduces the overall opacity of the second X-ray image I2.

Alternatively, when the image processing function 213 detects a change in the pixel value of the region corresponding to the second X-ray image in the first X-ray image I13, the pixel at the corresponding position in the second X-ray image I2 By lowering the opacity of , the pixel values of the first X-ray image I13 are reflected on the second X-ray image I2. For example, the image processing function 213 uses a layer mask that reduces the opacity of positions on the second X-ray image I2 that correspond to positions where pixel values have changed in the first X-ray image. The pixels at the corresponding locations in the second X-ray image I2 are made less opaque.

As described above, in the X-ray diagnostic apparatus 100, while acquiring the first X-ray image (perspective image) in a wide field of view, the first X-ray image and the previously acquired high-definition second X-ray image are acquired. When a pixel value change occurs in a position corresponding to the second X-ray image in the sequentially acquired first X-ray image, information on the changed pixel value is displayed. Reflected on the second X-ray image. That is, except for the region corresponding to the second X-ray image in the first X-ray image with a wide field of view, the image is updated in real time, and the pixel values on the second X-ray image are changed according to the changes in the pixel values. It will be updated.

Next, processing of the X-ray diagnostic apparatus 100 according to the first embodiment will be described using FIG. FIG. 6 is a flow chart showing the processing procedure of the X-ray diagnostic apparatus 100 according to the first embodiment. Steps S101 to S103, 106, and 107 shown in FIG. 6 are steps in which the processing circuit 21 reads a program corresponding to the control function 211 from the storage circuit 25 and executes it. Steps S103 to S105 and S109 are steps in which the processing circuit 21 reads out a program corresponding to the generation function 212 from the storage circuit 25 and executes it. Steps S104 and S108 are steps in which the processing circuit 21 reads out a program corresponding to the image processing function 213 from the storage circuit 25 and executes it.

For example, as shown in FIG. 6, processing circuitry 21 acquires a reference image (step S101) and then acquires fluoroscopic images over time (step S102). Next, the processing circuit 21 sequentially generates and displays synthesized images while acquiring fluoroscopic images (step S103). Here, the processing circuit 21 appropriately aligns the reference image and the fluoroscopic image.

Then, the processing circuit 21 determines whether or not the pixel values of the region corresponding to the reference image have changed in the fluoroscopic images acquired over time (step S104). Here, if the pixel value has not changed (No at step S104), the processing circuit 21 continues acquisition of fluoroscopic images and generation/display of composite images.

On the other hand, if the pixel value has changed (Yes at step S104), the processing circuit 21 further determines whether the number of changed pixels exceeds the threshold (step S105). Here, if the number of changed pixels does not exceed the threshold (No at step S105), the processing circuit 21 determines whether or not fluoroscopy is in progress (step S106).

In step S106, if fluoroscopy is not in progress (step S106 negative), the processing circuit 21 changes to fluoroscopy (step S107), and converts the pixel value of the target pixel in the reference image into the pixel value of the fluoroscopic image (step S108). ). In step S106, if fluoroscopy is in progress (Yes in step S106), the processing circuit 21 converts the pixel value of the target pixel in the reference image into the pixel value of the fluoroscopic image (step S108).

In step S105, if the number of changed pixels exceeds the threshold (Yes in step S105), the processing circuitry 21 performs alignment (step S109). After steps S108 and S109, the processing circuit 21 determines whether or not to end the imaging (step S110). Here, if it is to end (Yes at step S110), the processing circuit 21 ends the process. On the other hand, if the process is not finished (No at step S110), the processing circuit 21 returns to step S104 and continues the process.

As described above, according to the first embodiment, the control function 211 captures the subject with X-rays and sequentially acquires the first X-ray images. The generation function 212 synthesizes a second X-ray image captured with a higher X-ray dose than the first X-ray image at a time before the first X-ray image and the first X-ray image. An image is generated in parallel with the acquisition of the first X-ray image. The image processing function 213 adds pixel value information based on the first X-ray image to positions of pixels corresponding to at least the second X-ray image in the combined image based on temporal changes in the first X-ray image. To reflect. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment collects a first X-ray image (fluoroscopic image) with a normal dose, and acquires a high-definition second X-ray image (reference image). A change in pixel value can be reflected, and an increase in exposure dose can be suppressed while a high-definition image is displayed.

Further, according to the first embodiment, the image processing function 213 performs the first The information of the pixel values after the change of the X-ray image is reflected in the corresponding position of the second X-ray image. The image processing function 213 also replaces the pixel values of the pixels at the corresponding positions in the second X-ray image with the changed pixel values in the first X-ray image. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment can display changes in pixel values at accurate positions on the second X-ray image, thereby improving the precision of the procedure. .

Further, according to the first embodiment, the generation function 212 generates a composite image by superimposing the second X-ray image on the first X-ray image. By reducing the opacity of the second X-ray image, the image processing function 213 reflects the information of the pixel value after the change of the first X-ray image to the corresponding position of the second X-ray image. Let Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment generates a composite image in which the first X-ray image and the second X-ray image are superimposed. It makes it possible to easily reflect changes in values.

Also, according to the first embodiment, the control function 211 captures the first X-ray image as the second X-ray image by a detector having a higher resolution than the detector that acquired the first X-ray image. Acquire an X-ray image acquired at a higher X-ray dose. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment makes it possible to display a synthesized image using a high-definition reference image.

Further, according to the first embodiment, the generation function 212 generates the first X-ray image when the number of pixels whose pixel values have changed exceeds the threshold in the sequentially acquired first X-ray images. and the second X-ray image to generate a composite image. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment can cope with body movements of the subject during the procedure.

(Second embodiment)
In the first embodiment described above, a case has been described in which a composite image is generated while acquiring a first X-ray image (perspective image). In the second embodiment, a case of generating a composite image while acquiring a second X-ray image will be described. In addition, hereinafter, the same reference numerals may be given to the same configurations as in the first embodiment, and the description thereof may be omitted.

The control function 211 according to the second embodiment sequentially acquires a third X-ray image captured with an X-ray dose lower than that of the second X-ray image for the area of the second X-ray image. For example, the control function 211 controls the X-ray high voltage device 11 to emit X-rays at a dose lower than that of the second X-ray image to generate a plurality of third X-rays over time from the second photodetector 16b. Acquire X-ray images of

Then, the generation function 212 according to the second embodiment generates a composite image obtained by combining an average image obtained by averaging a plurality of third X-ray images and the first X-ray image as a third X-ray image. Generate in parallel with image acquisition. Here, the generation function 212 sequentially generates composite images in accordance with, for example, the sequential acquisition of the third X-ray images. For example, the generating function 212 weights each of the plurality of third X-ray images (eg, a predetermined number of third X-ray images) collected by the second photodetector 16b. By adding, an addition average image is generated. Here, the weighting in the averaging is set, for example, so that the weight for the latest image in chronological order is maximized and the weight decreases as the image becomes earlier in chronological order.

Then, the generating function 212 generates a composite image by combining the generated averaged image and the first X-ray image. Specifically, every time a third X-ray image is acquired, the generating function 212 performs averaging processing using the acquired third X-ray image as the latest image, and sequentially generates an averaging image. . Then, the generation function 212 generates a composite image by combining the sequentially generated addition average image and the first X-ray image. Here, the first X-ray image is an image acquired at a lower dose prior to the third X-ray image, for example a fluoroscopic image acquired by the first photodetector 16a.

The image processing function 213 according to the second embodiment converts pixel value information based on the first X-ray image sequentially acquired with the change in pixel value in the third X-ray image as a trigger to the second X-ray image. It is reflected in the corresponding position of the image or the corresponding position of the averaged image. That is, the image processing function 213, while displaying a composite image using the third X-ray image, performs When the pixel value changes, the process of the first embodiment is executed to reflect the change in pixel value in the second X-ray image. In other words, in the second embodiment, acquisition of the third X-ray image and generation and display of the composite image are continued until the pixel value changes. Then, when a pixel value change occurs in a region of the third X-ray image, the control function 211 switches to acquire the first X-ray image, and the generation function 212 switches to the acquired first X-ray image. Generate a composite image using the X-ray image. Here, in the second embodiment, the X-ray image used for the composite image with the first X-ray image may be an arithmetic mean image, or a higher dose may be detected by the second photodetector 16b. (the second X-ray image in the first embodiment) acquired in .

The image processing function 213 converts pixel value information in the first X-ray image, whose acquisition is started due to a change in pixel value in the region of the third X-ray image, into an arithmetic average image or a second photodetection image. This is reflected in the X-ray image acquired at the higher dose by the device 16b.

As described above, the X-ray diagnostic apparatus 100 according to the second embodiment generates and displays a composite image using an addition average image until a pixel value change occurs. Here, the X-ray diagnostic apparatus 100 can be controlled to automatically generate and display a composite image using an averaged image when there is no change in pixel values. For example, while the X-ray diagnostic apparatus 100 generates and displays the synthesized image described in the first embodiment, if there is no change in pixel values for a certain period of time, the synthesized image using the averaged image is generated. It can also be controlled to be generated and displayed. An example of this case will be described with reference to FIG. FIG. 7 is a diagram for explaining an example of processing of the processing circuit 21 according to the second embodiment. In the following description, the mode for generating and displaying a synthesized image described in the first embodiment is referred to as a fine image reference mode, and the mode for generating and displaying a synthesized image using an averaged image is referred to as an averaged mode. .

As shown in FIG. 7, the X-ray diagnostic apparatus 100 first generates and displays a synthesized image in the fine image reference mode. That is, the control function 211 acquires a high-definition second X-ray image I4 with the second photodetector 16b. After that, the control function 211 switches the detectors and performs temporal acquisition of the first X-ray image I3 (perspective image) by the first photodetector 16a. The generating function 212 sequentially generates composite images each time the first X-ray image I3 is acquired, and the control function 211 causes the display 23 to display the sequentially generated composite images.

Here, when the device D2 has entered the region of the second X-ray image I4, the image processing function 213, as shown in the upper diagram of FIG. Reflect the pixel value. On the other hand, if there is no change in the pixel value for a certain period of time after the display of the synthesized image in the fine image reference mode is started, or if the movement of the device D2 within the area of the second X-ray image I4 stops and remains constant. When there is no time shift, the X-ray diagnostic apparatus 100 shifts to the averaging mode as shown in the middle diagram of FIG.

That is, the control function 211 starts sequential acquisition of the third X-ray image on the condition that the change in pixel value in the region of the first X-ray image corresponding to the second X-ray image is less than the threshold. do. For example, the control function 211 switches the detectors to acquire a third x-ray image over time by the second photodetector 16b. When a plurality of time-series third X-ray images are acquired, the generating function 212 generates an averaged image I41 by performing averaging processing using n frames (Frame 1 to Frame n). The generation function 212 then generates a composite image by combining the first X-ray image I3 acquired in the fine image reference mode and the averaged image I41. The generation function 212 generates a new averaged image each time a third X-ray image is acquired, and uses the generated new averaged image to generate a composite image. The control function 211 causes the display 23 to display the synthesized images that are sequentially generated.

In addition, in the averaging mode, by controlling to use the electrical signals from the first photodetector 16a and the second photodetector 16b (collecting X-ray images simultaneously with each detector), the Regions of one X-ray image can also be updated in real time. That is, by expanding the irradiation range of X-rays to the region of the first X-ray image and irradiating X-rays, the first X-ray image and the third X-ray image are acquired simultaneously, and each image is obtained. can also be used to generate composite images.

The averaging mode described above continues until a change in pixel value is detected. Then, when a change in pixel value is detected, the X-ray diagnostic apparatus 100 shifts to the fine image reference mode again, as shown in the lower diagram of FIG. For example, generation function 212 determines whether a change in pixel value has occurred in the third sequentially acquired x-ray image. Here, when a change in pixel value occurs (for example, when the device D2 moves), the control function 211 switches the detectors to obtain the first X-ray image over time by the first photodetector 16a. collection. The generation function 212 then generates a composite image each time the first X-ray image is acquired.

Here, the generation function 212 can use the acquired second X-ray image I4 or the averaged image I41 to generate the composite image. For example, the generation function 212 generates a composite image obtained by synthesizing the newly generated first X-ray image I31 and the second X-ray image I4, or generates the first X-ray image I31 and the addition average image I41. A synthesized composite image can be generated.

The image processing function 213 reflects the information of the pixel values changed in the first X-ray image in the second X-ray image I4 or the addition average image I41 in the composite image generated by the generation function 212 . For example, the image processing function 213 reflects information on pixel values that have changed in the first X-ray image I31 to corresponding positions in the second X-ray image I4. Alternatively, the image processing function 213 reflects the information of the pixel value changed in the first X-ray image I31 to the corresponding position of the addition average image I41.

Next, processing of the X-ray diagnostic apparatus 100 according to the second embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 and 9 are flowcharts showing processing procedures of the X-ray diagnostic apparatus 100 according to the second embodiment. Note that FIG. 8 shows processing for generating and displaying a composite image using an addition average image when there is no change in pixel values for a certain period of time. Further, FIG. 9 shows processing for performing averaging processing from the start of processing. Further, in FIG. 8, the same reference numerals are given to the same processes as the processes in the first embodiment (the processes shown in FIG. 6). In addition, in FIG. 9, the same reference numerals are assigned to the same processes as in FIGS.

Steps S201 and S202 shown in FIG. 8 are steps in which the processing circuit 21 reads a program corresponding to the control function 211 from the storage circuit 25 and executes it. Step S203 is a step in which the processing circuit 21 reads out a program corresponding to the generation function 212 from the storage circuit 25 and executes it.

For example, as shown in FIG. 8, processing circuitry 21 acquires a reference image (step S101) and then acquires fluoroscopic images over time (step S102). Next, the processing circuit 21 sequentially generates and displays synthesized images while acquiring fluoroscopic images (step S103). Here, the processing circuit 21 appropriately aligns the reference image and the fluoroscopic image.

Then, the processing circuit 21 determines whether or not the pixel values of the region corresponding to the reference image have changed in the fluoroscopic images acquired over time (step S104). Here, if the pixel value has not changed (No at step S104), the processing circuit 21 further determines whether or not fluoroscopy is in progress (step S201). Here, if fluoroscopy is in progress (Yes at step S201), the processing circuit 21 changes the reference image to the collection target (step S202). For example, the processing circuitry 21 switches the detector to the second photodetector 16b and begins acquiring time-lapse X-ray images at lower doses than the reference image acquired in step S101.

Then, the processing circuit 21 performs averaging processing on a plurality of acquired X-ray images (step S203), generates a composite image using the reference image generated by the averaging processing, and generates a composite image. is displayed on the display 23. Thereafter, the processing circuit 21 performs determination processing in step S110. Note that if fluoroscopy is not being performed at step S201 (No at step S201), the processing circuit 21 proceeds to step S203 and executes the averaging process.

On the other hand, if the pixel value has changed in the determination of step S104 (Yes in step S104), the processing circuit 21 further determines whether or not the number of changed pixels exceeds the threshold (step S105). Here, if the number of changed pixels does not exceed the threshold (No at step S105), the processing circuit 21 determines whether or not fluoroscopy is in progress (step S106).

In step S106, if fluoroscopy is not in progress (step S106 negative), the processing circuit 21 changes to fluoroscopy (step S107), and converts the pixel value of the target pixel in the reference image into the pixel value of the fluoroscopic image (step S108). ). In step S106, if fluoroscopy is in progress (Yes in step S106), the processing circuit 21 converts the pixel value of the target pixel in the reference image into the pixel value of the fluoroscopic image (step S108).

In step S105, if the number of changed pixels exceeds the threshold (Yes in step S105), the processing circuitry 21 performs alignment (step S109). After steps S108, S109, and S203, the processing circuit 21 determines whether or not to end the imaging (step S110). Here, if it is to end (Yes at step S110), the processing circuit 21 ends the process. On the other hand, if the process is not finished (No at step S110), the processing circuit 21 returns to step S104 and continues the process.

Steps S301 to S303 shown in FIG. 9 are steps in which the processing circuit 21 reads out a program corresponding to the control function 211 from the storage circuit 25 and executes it. Further, step S303 is a step in which the processing circuit 21 reads out a program corresponding to the generation function 212 from the storage circuit 25 and executes it.

For example, as shown in FIG. 9, processing circuitry 21 acquires fluoroscopic images (step S301) and then acquires reference images over time (step S302). Next, the processing circuit 21 sequentially generates and displays synthesized images while sequentially generating reference images obtained by averaging the X-ray images acquired over time (step S303). Here, the processing circuit 21 appropriately aligns the reference image and the fluoroscopic image.

Then, the processing circuit 21 determines whether or not the pixel values of the region corresponding to the reference image have changed in the fluoroscopic images acquired over time (step S104). Here, if the pixel value has not changed (No at step S104), the processing circuit 21 further determines whether or not fluoroscopy is in progress (step S201). Here, if fluoroscopy is in progress (Yes at step S201), the processing circuit 21 changes the reference image to the collection target (step S202).

Then, the processing circuit 21 performs averaging processing on a plurality of acquired X-ray images (step S203), generates a composite image using the reference image generated by the averaging processing, and generates a composite image. is displayed on the display 23. Thereafter, the processing circuit 21 performs determination processing in step S110. Note that if fluoroscopy is not being performed at step S201 (No at step S201), the processing circuit 21 proceeds to step S203 and executes the averaging process.

On the other hand, if the pixel value has changed in the determination of step S104 (Yes in step S104), the processing circuit 21 further determines whether or not the number of changed pixels exceeds the threshold (step S105). Here, if the number of changed pixels does not exceed the threshold (No at step S105), the processing circuit 21 determines whether or not fluoroscopy is in progress (step S106).

In step S106, if fluoroscopy is not in progress (step S106 negative), the processing circuit 21 changes to fluoroscopy (step S107), and converts the pixel value of the target pixel in the reference image into the pixel value of the fluoroscopic image (step S108). ). In step S106, if fluoroscopy is in progress (Yes in step S106), the processing circuit 21 converts the pixel value of the target pixel in the reference image into the pixel value of the fluoroscopic image (step S108).

In step S105, if the number of changed pixels exceeds the threshold (Yes in step S105), the processing circuitry 21 performs alignment (step S109). After steps S108, S109, and S203, the processing circuit 21 determines whether or not to end the imaging (step S110). Here, if it is to end (Yes at step S110), the processing circuit 21 ends the process. On the other hand, if the process is not finished (No at step S110), the processing circuit 21 returns to step S104 and continues the process.

As described above, according to the second embodiment, the control function 211 controls the area of the second X-ray image to obtain a third X-ray image captured with an X-ray dose lower than that of the second X-ray image. are obtained sequentially. The generation function 212 sequentially generates a composite image obtained by synthesizing an arithmetic average image obtained by averaging a plurality of third X-ray images and the first X-ray image in accordance with the sequential acquisition of the third X-ray images. do. The image processing function 213 converts pixel value information based on the first X-ray image sequentially acquired with a change in pixel value in the third X-ray image to the corresponding position of the second X-ray image or the above-mentioned It is reflected in the corresponding position of the averaged image. Therefore, the X-ray diagnostic apparatus 100 according to the second embodiment enables real-time observation of reference images while suppressing an increase in exposure dose.

Further, according to the second embodiment, the control function 211 performs the third sequential acquisition of X-ray images is started. Therefore, the X-ray diagnostic apparatus 100 according to the second embodiment makes it possible to improve the image quality of X-ray images when there is no change in pixel values.

Also, according to the second embodiment, the control function 211 provides that the second X-ray image is acquired at a higher X-ray dose than the first X-ray image by the detector that acquired the first X-ray image. An averaged X-ray image obtained by averaging a plurality of X-ray images is acquired. Therefore, the X-ray diagnostic apparatus 100 according to the second embodiment makes it possible to generate composite images using various images.

(Third embodiment)
Now, although the first and second embodiments have been described so far, various different modes other than the above-described first and second embodiments may be implemented.

In the first and second embodiments described above, the case of using the X-ray image collected by the second photodetector 16b as the second X-ray image has been described. However, the embodiment is not limited to this, and may be, for example, the case of using an X-ray image collected by the first photodetector 16a.

FIG. 10 is a diagram showing an example of a synthesized image according to the third embodiment. For example, as shown in FIG. 10, the generating function 212 according to the third embodiment generates a perspective image collected by the first photodetector 16a, a photographed image collected by the first photodetector 16a, or A composite image is generated by synthesizing a plurality of captured images with an averaged image obtained by subjecting the averaged image to an averaged image. In such a case, for example, the control function 211 first controls the aperture control circuit 20 to set the irradiation range of X-rays, and irradiates the X-rays under the acquisition conditions of the photographed image to obtain the first light. A radiographic image of the region of the second X-ray image is acquired from the detector 16a.

After that, the control function 211 controls the diaphragm control circuit 20 to widen the irradiation range of X-rays and irradiate the X-rays under the acquisition condition of the fluoroscopic image, thereby obtaining the first X-ray from the first photodetector 16a. Acquire a fluoroscopic image of the area of the line image. The generation function 212 sequentially generates composite images from the captured image that is acquired first and the fluoroscopic images that are acquired sequentially. Note that when collecting an averaged image, the control function 211 collects a plurality of captured images, and the generation function 212 uses the plurality of captured images to generate an averaged image. Note that when using an averaged image, an X-ray image acquired with a dose lower than that of a photographed image may be used. In addition, the above-described mode for generating a composite image using captured images (normal image reference mode) can be appropriately applied instead of the fine image reference mode in the first and second embodiments.

Further, in the above-described embodiment, the case where the X-ray detector 16 shared by the first photodetector 16a and the second photodetector 16b is used as the scintillator 16c has been described as an example. However, the embodiment is not limited to this, and the X-ray detector 16 may be composed of a plurality of detectors each having a scintillator and a photodetector. FIG. 11 is a diagram showing an example of the configuration of the X-ray detector 16 according to the third embodiment.

As shown in FIG. 11, the X-ray detector 16 according to the third embodiment includes a first detector having a first photodetector 16d and a first scintillator 16e, and a second photodetector 16f. and a second detector having a second scintillator 16g. The first photodetector 16d has the same resolution as the first photodetector a. Also, the second photodetector 16f has the same resolution as the second photodetector 16b. Here, the second detector is supported by a support with a rotating mechanism 40, as shown in FIG. 11, and its position is changed according to the detector used for collection.

For example, when acquiring an X-ray image with the first detector, the second detector is rotated about the rotation mechanism 40 to move it out of the field of view of the first detector. On the other hand, when the X-ray image is acquired by the second detector, the second detector is moved to a position facing the X-ray tube 12 by rotating around the rotating mechanism 40 as a fulcrum. The X-ray detector 16 according to the third embodiment can be applied as the X-ray detector in the first and second embodiments described above. In such a case, the rotation mechanism 40 is used as a fulcrum to rotate the second detector at the switching timing of the detector.

Further, in the above-described embodiment, a case has been described in which the synthesized image is generated using the entire acquired second X-ray image. However, the embodiments are not limited to this, and for example, a case where a part of the second X-ray image is used to generate a composite image may be used. In such a case, the generation function 212 identifies regions in the second X-ray image to be used for the composite image. Further, the generation function 212 identifies regions in the first X-ray image that correspond to the identified regions. Then, the generation function 212 generates a composite image by combining the region identified in the second X-ray image with the region identified in the first X-ray image. For example, the generation function 212 generates a composite image in which only a specific vascular region or a region of a device (eg, stent, etc.) placed in the blood vessel is composited.

Also, in the above-described embodiment, a case has been described in which pixel values corresponding to movement of a device being inserted into a blood vessel are reflected. However, the embodiment is not limited to this, and any change in pixel value that occurs within an X-ray image being acquired may be reflected. For example, if the shape of an indwelling stent changes during catheter manipulation, the changed shape may be reflected in the stent depicted in the second X-ray image.

Further, the change in pixel value may be caused not only by movement of the device but also by inflow/outflow of a contrast medium, for example. In such a case, the generation function 212 reflects the pixel values changed by the inflow of the contrast agent in the second X-ray image, and reflects the pixel values changed by the outflow of the contrast agent in the second X-ray image. . As a result, the flow of the contrast medium can be observed on a high-definition image. In addition, for example, a blood vessel image can be obtained by performing control so that the pixel values that have changed due to the outflow of the contrast agent are not reflected in the second X-ray image.

In the above-described embodiment, the case where the X-ray diagnostic apparatus 100 executes each process has been described. However, the embodiments are not limited to this, and for example, the image processing apparatus may acquire an X-ray image from the X-ray diagnostic apparatus 100 and execute the above-described processing. FIG. 12 is a diagram showing an example configuration of an image processing apparatus 300 according to the third embodiment. As shown in FIG. 12, the image processing apparatus 300 has a communication interface 31, a memory circuit 32, an input interface 33, a display 34, and a processing circuit 35.

The communication interface 31 is connected to the processing circuit 35 and controls transmission and communication of various data with the X-ray diagnostic apparatus 100 connected via the network. For example, the communication interface 31 is implemented by a network card, network adapter, NIC (Network Interface Controller), or the like. In this embodiment, the communication interface 31 receives an X-ray image from the X-ray diagnostic apparatus 100 and outputs the received X-ray image to the processing circuit 35 . Here, the communication interface 31 can receive real-time X-ray images acquired by the X-ray diagnostic apparatus 100 and output them to the processing circuitry 35 .

The storage circuit 32 is connected to the processing circuit 35 and stores various data. For example, the storage circuit 32 is implemented by a semiconductor memory device such as a RAM (Random Access Memory) or flash memory, a hard disk, an optical disk, or the like. In this embodiment, the storage circuit 32 stores X-ray images received from the X-ray diagnostic apparatus 100 . For example, the storage circuit 32 stores fluoroscopic and radiographic images collected by the first photodetectors 16a, 16d collected by the X-ray diagnostic apparatus, high-resolution images collected by the second photodetectors 16b, 16f. Stores X-ray images and the like.

The storage circuit 32 also stores various information used in the processing of the processing circuit 35, processing results of the processing circuit 35, and the like. For example, the storage circuit 32 stores an average image generated by the processing circuit 35, a synthesized image, and the like.

The input interface 33 includes a trackball, a switch button, a mouse, a keyboard, a touch pad for performing input operations by touching the operation surface, a touch screen in which the display screen and the touch pad are integrated, It is realized by a non-contact input circuit using an optical sensor, an audio input circuit, and the like.

The input interface 33 is connected to the processing circuit 35 , converts an input operation received from an operator into an electric signal, and outputs the electric signal to the processing circuit 35 . It should be noted that the input interface 33 in this specification is not limited to having physical operation parts such as a mouse and a keyboard. For example, an example of an input interface includes a processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs this electrical signal to a control circuit.

The display 34 is connected to the processing circuit 35 and displays various information and various images output from the processing circuit 35 . For example, the display 34 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, or the like. For example, the display 34 displays a GUI (Graphical User Interface) for receiving instructions from the operator, various images, and various processing results by the processing circuit 35 .

The processing circuit 35 controls each component of the image processing apparatus 300 according to an input operation received from an operator via the input interface 33 . For example, processing circuitry 35 is implemented by a processor. In this embodiment, the processing circuit 35 causes the storage circuit 32 to store the X-ray image output from the communication interface 31 . The processing circuit 35 also reads out the X-ray image from the storage circuit 32 and causes the display 34 to display a composite image generated from the read X-ray image.

The processing circuitry 35 executes, for example, a control function 351, a generation function 352, and an image processing function 353, as shown in FIG. Here, for example, each processing function executed by the control function 351, the generation function 352, and the image processing function 353, which are components of the processing circuit 35 shown in FIG. recorded in The processing circuit 35 is, for example, a processor, and reads each program from the storage circuit 32 and executes the read program to implement the function corresponding to the read program. In other words, the processing circuit 35 with each program read has each function shown in the processing circuit 35 of FIG.

The control function 351 controls the entire image processing apparatus 300 . Also, the control function 351 acquires an X-ray image from the X-ray diagnostic apparatus 100 and executes the same processing as the control function 211 described above. The generation function 352 performs processing similar to that of the generation function 212 described above. The image processing function 353 executes processing similar to that of the image processing function 213 described above.

In the above-described embodiment, an example in which each processing function is realized by a single processing circuit (processing circuit 21 and processing circuit 35) has been described, but the embodiment is not limited to this. For example, the processing circuit 21 (and the processing circuit 35) may be configured by combining a plurality of independent processors, and each processor may implement each processing function by executing each program. Further, each processing function of the processing circuit 21 (and the processing circuit 35) may be appropriately distributed or integrated in a single or a plurality of processing circuits and implemented.

In addition, the term "processor" used in the above description includes, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an application specific integrated circuit (ASIC), a programmable logic device ( For example, it means circuits such as Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA). The processor implements its functions by reading and executing a program stored in the memory circuit 25 (or memory circuit 32). Note that instead of storing the program in the memory circuit 25 (or the memory circuit 32), the program may be configured to be directly embedded in the circuit of the processor. In this case, the processor implements its functions by reading and executing the program embedded in the circuit. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, and may be configured as one processor by combining a plurality of independent circuits to realize its function. good.

Here, the image processing program executed by the processor is preinstalled in a ROM (Read Only Memory), storage unit, or the like and provided. This image processing program is a file in a format that can be installed in these devices or in a format that can be executed on CD (Compact Disk)-ROM, FD (Flexible Disk), CD-R (Recordable), DVD (Digital Versatile Disk). ) or other computer-readable storage medium. Also, this image processing program may be stored on a computer connected to a network such as the Internet, and may be provided or distributed by being downloaded via the network. For example, this image processing program is composed of modules including each functional unit described later. As actual hardware, the CPU reads out a program from a storage medium such as a ROM and executes it, so that each module is loaded onto the main storage device and generated on the main storage device.

Also, each component of each device illustrated in the above-described embodiment is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution and integration of each device is not limited to the one shown in the figure, and all or part of them can be functionally or physically distributed and integrated in arbitrary units according to various loads and usage conditions. Can be integrated and configured. Furthermore, all or any part of each processing function performed by each device can be implemented by a CPU and a program analyzed and executed by the CPU, or implemented as hardware based on wired logic.

As described above, according to at least one embodiment, it is possible to suppress an increase in exposure dose while displaying a high-definition image.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

21, 35 processing circuit 100 X-ray diagnostic apparatus 211, 351 control function 212, 352 generation function 213, 353 image processing function 300 image processing apparatus

Claims (11)

an acquisition unit that sequentially acquires first X-ray images obtained by imaging a subject using X-rays;
A portion of the first X-ray image was shown in a second X-ray image taken at an earlier time than the first X-ray image with a higher X-ray dose than the first X-ray image. a generation unit that generates a composite image in parallel with acquisition of the first X-ray image;
detecting a change in pixel value in a region corresponding to the second X-ray image in the first X-ray image, and transmitting information of the changed pixel value to a corresponding position in the second X-ray image; a processing unit for reflecting on pixels ;
An image processing device comprising: The image processing apparatus according to claim 1 , wherein the processing unit replaces pixel values of pixels at corresponding positions in the second X-ray image with pixel values after the change in the first X-ray image. The generation unit generates the composite image by superimposing the second X-ray image on the first X-ray image,
The processing unit reduces the opacity of the second X-ray image so that the pixel value information after the change of the first X-ray image is transferred to the corresponding position of the second X-ray image. 2. The image processing apparatus according to claim 1 , wherein the image is reflected in the image. The acquisition unit sequentially acquires a third X-ray image captured with an X-ray dose lower than that of the second X-ray image for the region of the second X-ray image,
The generation unit generates a composite image obtained by synthesizing an average image obtained by averaging the plurality of third X-ray images and the first X-ray image in parallel with acquisition of the third X-ray image. and generate
The processing unit stores pixel value information based on the first X-ray image sequentially acquired with a change in the pixel value in the third X-ray image as a trigger for transferring the pixel value information to the corresponding position of the second X-ray image. 4. The image processing device according to any one of claims 1 to 3 , wherein the image is reflected in the corresponding position of the addition average image. The acquisition unit sequentially acquires the third X-ray image on condition that a change in pixel value in a region of the first X-ray image corresponding to the second X-ray image is less than a threshold. 5. The image processing apparatus of claim 4 , starting. The acquisition unit acquires the second X-ray image at a higher X-ray dose than the first X-ray image by a detector having a higher resolution than the detector that acquired the first X-ray image. 6. The image processing apparatus according to any one of claims 1 to 5 , which acquires an X-ray image obtained by The acquisition unit uses, as the second X-ray image, an X-ray image acquired with a higher X-ray dose than the first X-ray image by the detector that acquired the first X-ray image, or The image processing apparatus according to any one of claims 1 to 5 , wherein a plurality of X-ray images are used and averaged to obtain an averaged image. The generator generates the first X-ray image and the second X-ray image when the number of pixels whose pixel values have changed exceeds a threshold in the first X-ray images that are sequentially acquired. 8. The image processing apparatus according to any one of claims 1 to 7 , wherein the synthesized image is generated after executing the registration process of . The image processing apparatus according to any one of claims 1 to 8 , wherein said generation unit sequentially generates said composite image in accordance with sequential acquisition of X-ray images by said acquisition unit. an imaging unit for imaging a subject with X-rays and sequentially acquiring first X-ray images;
A composite showing a portion of the first X-ray image with a second X-ray image taken at an earlier time than the first X-ray image with a higher X-ray dose than the first X-ray image. a generating unit that generates a combined image obtained by the above in parallel with acquisition of the first X-ray image;
detecting a change in pixel value in a region corresponding to the second X-ray image in the first X-ray image, and transmitting information of the changed pixel value to a corresponding position in the second X-ray image; a processing unit for reflecting on pixels ;
An X-ray diagnostic apparatus comprising: Sequentially acquiring first X-ray images in which the subject is imaged by X-rays,
A portion of the first X-ray image was shown in a second X-ray image taken at an earlier time than the first X-ray image with a higher X-ray dose than the first X-ray image. generating a composite image in parallel with acquiring the first X-ray image;
detecting a change in pixel value in a region corresponding to the second X-ray image in the first X-ray image, and transmitting information of the changed pixel value to a corresponding position in the second X-ray image; reflected in pixels ,
An image processing program that causes a computer to execute each process.

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