Radiation imaging processing device, method, and program

Abstract

In a radiographic image processing device, method, and program, the system accurately aligns target vertebrae included in pre-acquired 3D images and fluoroscopic images. [Solution] The processor acquires at least one two-dimensional image including the subject's spine during surgery on the subject, derives a spinal image with the subject's spine highlighted based on the at least one two-dimensional image, extracts two-dimensional target vertebrae to be aligned from the two-dimensional image, and aligns the two-dimensional target vertebrae with the three-dimensional target vertebrae to be aligned, which were extracted from a three-dimensional image including the subject's spine acquired before surgery on the subject.

Description

Technical Field

[0001] The present disclosure relates to a radiation image processing apparatus, method, and program.

Background Art

[0002] In spinal surgery, the subject is imaged by a fluoroscopic device during the surgery, and the positional relationship between the surgical instrument and the vertebra to be operated on is grasped using the fluoroscopic image displayed on the display by the imaging. However, while the surgical instrument and the human body structure are in a three-dimensional positional relationship, the fluoroscopic image is a two-dimensional image. It is difficult to grasp the three-dimensional positional relationship between the surgical instrument and the human body structure even by looking at the two-dimensional fluoroscopic image.

[0003] For this reason, a method of aligning a three-dimensional image acquired in advance by a CT (Computed Tomography) device, an MRI (Magnetic Resonance Imaging) device, etc. with a two-dimensional fluoroscopic image has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, 3D images are obtained by photographing the subject in a supine position, but spinal surgery is performed with the subject in a prone position. For this reason, the curvature of the spine differs between the 3D image and the fluoroscopic image obtained during surgery. Also, since the 3D image is obtained before surgery, the state of gas inside the subject and the deformation of soft tissues such as internal organs differ between the 3D image and the fluoroscopic image obtained during surgery. For this reason, it is difficult to accurately align the 3D image and the 2D image using the method described in Patent Document 1.

[0006] This disclosure is made in view of the above circumstances and aims to accurately align the target vertebrae included in pre-acquired 3D images and fluoroscopic images. [Means for solving the problem]

[0007] The alignment device described herein is Equipped with a processor, The processor acquires at least one two-dimensional image, including the spine of the subject, during surgery on the subject. Based on the aforementioned two-dimensional image, a spinal image emphasizing the spine of the subject is derived. From the aforementioned two-dimensional image, extract the two-dimensional target vertebrae that are to be aligned, The three-dimensional target vertebrae and the two-dimensional target vertebrae, extracted from a three-dimensional image including the spine of the subject obtained before surgery on the subject, are aligned.

[0008] In the radiation image processing apparatus according to this disclosure, the processor derives multiple projected vertebral images by projecting the three-dimensional target vertebrae into two dimensions while changing the position and rotation parameters of the target vertebrae, The alignment may be performed by identifying the projection target vertebral image that matches the two-dimensional target vertebra.

[0009] In the radiation image processing apparatus according to this disclosure, the processor acquires a first two-dimensional image and a second two-dimensional image using radiation with different energy distributions. The spinal image may also be derived by weighted subtraction of the first two-dimensional image and the second two-dimensional image.

[0010] In the radiation image processing apparatus according to this disclosure, the processor removes scattered radiation components from the first two-dimensional image and the second two-dimensional image. The spinal image may also be derived by weighted subtraction of the first two-dimensional image and the second two-dimensional image from which the scattered radiation components have been removed.

[0011] In the radiation image processing apparatus according to this disclosure, the processor may extract the two-dimensional target vertebrae from the two-dimensional image based on a specification by the operator.

[0012] In the radiation image processing apparatus according to this disclosure, the processor may extract the three-dimensional target vertebrae from the three-dimensional image.

[0013] In the radiation image processing apparatus according to this disclosure, the processor may extract the three-dimensional target vertebrae from the three-dimensional image based on a specification by the operator.

[0014] In the radiation image processing apparatus according to this disclosure, the processor may display the two-dimensional image and the aligned three-dimensional image of the target vertebra on a display.

[0015] The radiographic image processing method according to this disclosure involves a computer acquiring at least one two-dimensional image, including the spine of a subject, during surgery on the subject. Based on the aforementioned two-dimensional image, a spinal image emphasizing the spine of the subject is derived. From the aforementioned two-dimensional image, extract the two-dimensional target vertebrae that are to be aligned, Align the three-dimensional target vertebra and the two-dimensional target vertebra, which are extracted from a three-dimensional image including the spine of the subject obtained before the surgery on the subject, for alignment.

[0016] The radiation image processing program according to the present disclosure causes a computer to execute a procedure of acquiring at least one two-dimensional image including the spine of the subject during the surgery on the subject, a procedure of deriving a spine image emphasizing the spine of the subject based on the at least one two-dimensional image, a procedure of extracting a two-dimensional target vertebra to be aligned from the two-dimensional image, and a procedure of aligning the three-dimensional target vertebra and the two-dimensional target vertebra, which are extracted from a three-dimensional image including the spine of the subject obtained before the surgery on the subject, for alignment.

[0017] Note that the technology of the present disclosure may be provided as a program product.

Advantages of the Invention

[0018] According to the present disclosure, it is possible to accurately align the positions of the target vertebrae included in the three-dimensional image and the fluoroscopic image acquired in advance.

Brief Description of the Drawings

[0019] [Figure 1] Schematic diagram showing the configuration of a fluoroscopic imaging system including a radiation image processing apparatus according to an embodiment of the present disclosure [Figure 2] Diagram showing the hardware configuration of the radiation image processing apparatus according to the present embodiment [Figure 3] Diagram showing the functional configuration of the radiation image processing apparatus according to the present embodiment [Figure 4] Diagram showing a spine image [Figure 5] Diagram showing a tomographic image of a sagittal section of a three-dimensional image [Figure 6] Diagram for explaining alignment [Figure 7]Diagram showing the display screen [Figure 8] Flowchart showing the process performed in this embodiment [Modes for carrying out the invention]

[0020] Embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of a fluoroscopy system equipped with a radiographic image processing device according to an embodiment of this disclosure. As shown in Figure 1, the fluoroscopy system 100 according to this embodiment includes a fluoroscopy device 1.

[0021] As shown in Figure 1, the fluoroscopy apparatus 1 according to this embodiment includes a C-arm 2. A detection unit 3 is attached to one end of the C-arm 2, and a radiation irradiation unit 4 is attached to the other end so as to face the detection unit 3.

[0022] The configuration of the fluoroscopy apparatus 1 will be described in detail below. Inside the detection unit 3, there is a radiation detector 5, such as a flat panel detector. Inside the detection unit 3, there is also a circuit board equipped with a charge amplifier that converts the charge signal read from the radiation detector 5 into a voltage signal, a correlated double sampling circuit that samples the voltage signal output from the charge amplifier, and an AD (Analog Digital) conversion unit that converts the voltage signal into a digital signal. In this embodiment, a radiation detector 5 is used, but it is not limited to a radiation detector 5 as long as it can detect radiation and convert it into an image. For example, it is also possible to use a detection device such as an image intensifier.

[0023] The radiation detector 5 is capable of repeatedly recording and reading out radiation images. It may use a so-called direct-type radiation detector that directly converts radiation such as X-rays into electric charge, or it may use a so-called indirect-type radiation detector that first converts radiation into visible light and then converts that visible light into an electric charge signal. Furthermore, as a method for reading out the radiation image signal, it is desirable to use a so-called TFT (Thin Film Transistor) readout method in which the radiation image signal is read out by turning a TFT switch on and off, or a so-called optical readout method in which the radiation image signal is read out by irradiating it with reading light. However, it is not limited to these, and other methods may also be used.

[0024] The radiation irradiation unit 4 houses a radiation source 6, from which radiation is emitted toward the detection unit 3. The radiation source 6 emits X-rays as radiation, and the timing of radiation emission from the radiation source 6, as well as the timing of radiation detection by the radiation detector 5, are controlled by the imaging control unit, which will be described later. Furthermore, the radiation generation conditions in the radiation source 6, namely the selection of target and filter materials, tube voltage, and irradiation time, are also controlled by the imaging control unit.

[0025] In this embodiment, the C-arm 2 is held by the C-arm holder 7 so as to be movable in the direction of arrow A shown in Figure 1, allowing the angle of the detection unit 3 and the radiation irradiation unit 4 with respect to the z-axis direction (vertical direction) shown in Figure 1 to be changed integrally. The C-arm holder 7 also has a shaft 8, which rotatably connects the C-arm 2 to the bearing 9. As a result, the C-arm 2 is rotatable in the direction of arrow B shown in Figure 1, with the shaft 8 as the axis of rotation.

[0026] Furthermore, as shown in Figure 1, the fluoroscopy apparatus 1 includes a main body 10. Multiple wheels 11 are attached to the bottom of the main body 10, making the fluoroscopy apparatus 1 movable. A support shaft 12 that extends and retracts in the z-axis direction of Figure 1 is provided at the upper part of the housing of the main body 10. A bearing 9 is held at the upper part of the support shaft 12 so as to be movable in the direction of arrow C. This allows the C-arm 2 to move vertically relative to the operating table 15.

[0027] Furthermore, a foot switch 13 is connected to the main unit 10 for turning the emission of radiation from the radiation source 6 of the radiation irradiation unit 4 on and off. When the surgeon steps on the foot switch 13 during surgery, it is turned on, and radiation is emitted from the radiation source 6 in pulses at predetermined time intervals. When the surgeon takes their foot off the foot switch 13, it is turned off, and the emission of radiation from the radiation source 6 stops.

[0028] The fluoroscopy device 1 performs fluoroscopic imaging of the subject H by having the configuration described above. Specifically, the fluoroscopy device 1 irradiates the subject H, who is lying face down on the operating table 15 for spinal surgery, with radiation from below, detects the pulsed radiation that has passed through the subject H with the radiation detector 5 of the detection unit 3, and continuously acquires fluoroscopic images of the subject H from the front in sync with the timing of the radiation emission.

[0029] Here, the C-arm 2 is movable in the directions of arrows A, B, and C, and the fluoroscopy device 1 is movable by wheels 11. Therefore, the fluoroscopy device 1 can adjust its own position and the position of the C-arm 2, and take images of the desired area of ​​the subject H lying face down on the operating table 15 from the desired direction.

[0030] The main unit 10 incorporates the radiation image processing device 20 according to this embodiment. Figure 2 shows the hardware configuration of the radiation image processing device according to this embodiment. As shown in Figure 2, the radiation image processing device 20 is a computer such as a workstation, server computer, or personal computer, and includes a CPU (Central Processing Unit) 21, non-volatile storage 23, and memory 26 as a temporary storage area. The radiation image processing device 20 also includes a display 24 such as a liquid crystal display, input devices 25 such as a keyboard and mouse, and a wired or wireless interface (I / F) 27 connected to the detection unit 3, radiation irradiation unit 4, and foot switch 13, and for exchanging information with external devices. The CPU 21, storage 23, display 24, input devices 25, memory 26, and I / F 27 are connected to a bus 28. Note that the CPU 21 is an example of a processor in this disclosure.

[0031] The storage 23 is implemented using an HDD (Hard Disk Drive), SSD (Solid State Drive), and flash memory, etc. The storage 23, as a storage medium, stores the radiation image processing program 22 installed in the radiation image processing device 20. The CPU 21 reads the radiation image processing program 22 from the storage 23, expands it into memory 26, and executes the expanded radiation image processing program 22.

[0032] In this embodiment, a 3D image V0 including the target area is obtained by scanning the area containing the surgical target of subject H with a CT scanner before surgery. The 3D image V0 is stored on an external image storage server, but is acquired before surgery by the radiation image processing device 20 according to this embodiment and stored in storage 23. In this embodiment, the surgical target is assumed to be the vertebrae that make up the spine of subject H.

[0033] The radiation image processing program 22 is stored in a memory device of a server computer connected to the network, or in network storage, in a state that allows external access, and is downloaded and installed on the radiation image processing device 20 upon request. Alternatively, it is recorded on a recording medium such as a DVD (Digital Versatile Disc) or CD-ROM (Compact Disc Read Only Memory) and distributed, and then installed on the radiation image processing device 20 from that recording medium.

[0034] Next, the functional configuration of the radiation image processing apparatus according to this embodiment will be described. Figure 3 is a diagram showing the functional configuration of the radiation image processing apparatus according to this embodiment. As shown in Figure 3, the radiation image processing apparatus 20 includes an imaging control unit 31, a scattered radiation removal unit 32, an output unit 33, a first extraction unit 34, a second extraction unit 35, an alignment unit 36, and a display control unit 37. The CPU 21 executes the radiation image processing program 22, and the CPU 21 functions as the imaging control unit 31, the scattered radiation removal unit 32, the output unit 33, the first extraction unit 34, the second extraction unit 35, the alignment unit 36, and the display control unit 37.

[0035] When the foot switch 13 is turned on and an ON signal is received from the foot switch 13, the imaging control unit 31 emits radiation from the radiation source 6 of the radiation irradiation unit 4 at a first tube voltage, based on preset imaging conditions. The imaging control unit 31 also detects the radiation that has passed through the subject H using the radiation detector 5 of the detection unit 3, according to the timing of the radiation emission from the radiation source 6, and generates a fluoroscopic image of the subject H. The generated fluoroscopic image is displayed on the display 24.

[0036] In this embodiment, while the foot switch 13 is turned on, the imaging control unit 31 controls the radiation source 6 to emit radiation in pulses at predetermined intervals. As a result, pulsed radiation is emitted from the radiation source 6, and a fluoroscopic image is generated by the radiation detector 5 at timings corresponding to the emission of radiation. Therefore, the fluoroscopic images are displayed on the display 24 in a continuous, video-like manner at a frame rate corresponding to the emission interval of the pulsed radiation.

[0037] When the foot switch 13 is turned off, the imaging control unit 31 saves the fluoroscopic image (referred to as the LIH (Last Image Hold) image) acquired at the last moment the foot switch 13 was turned off to the storage 23. Also, when the foot switch 13 is turned off, the imaging control unit 31 emits radiation from the radiation source 6 with a second tube voltage different from the first tube voltage to acquire a second LIH image of the subject H. The LIH image acquired with the first tube voltage is referred to as the first LIH image G1, and the LIH image acquired with the second tube voltage is referred to as the second LIH image G2. Since the first LIH image G1 and the second LIH image G2 are acquired with different tube voltages, they are acquired with radiation of different energy distributions. The second tube voltage is assumed to be higher than the first tube voltage, but this is not limited to the second tube voltage.

[0038] Here, each of the first LIH image G1 and the second LIH image G2 includes a scattered radiation component based on radiation scattered within the subject H, in addition to the primary radiation component of the radiation transmitted through the subject H. Therefore, the scattered radiation removal unit 32 removes the scattered radiation component from the first LIH image G1 and the second LIH image G2. For example, the scattered radiation removal unit 32 may remove the scattered radiation component from the first LIH image G1 and the second LIH image G2 by applying the method described in Japanese Patent Application Publication No. 2015-043959. When using the method described in Japanese Patent Application Publication No. 2015-043959, the derivation of the body thickness distribution of the subject H and the derivation of the scattered radiation component for removal are performed simultaneously.

[0039] The following describes the removal of scattered radiation components from the first LIH image G1, but the removal of scattered radiation components from the second LIH image G2 can be performed in the same manner. First, the scattered radiation removal unit 32 acquires a virtual model K of the subject H having an initial body thickness distribution T0(x,y). The virtual model K is data that virtually represents the subject H, in which the body thickness according to the initial body thickness distribution T0(x,y) is associated with the coordinate position of each pixel in the first LIH image G1. Note that the virtual model K of the subject H having an initial body thickness distribution T0(x,y) may be stored in the storage 23 in advance. Alternatively, the body thickness distribution T(x,y) of the subject H may be calculated based on SID (Source Image receptor Distance), which is the distance between the radiation source 6 and the surface of the radiation detector 5 in the fluoroscopy apparatus 1, and SOD (Source Object Distance), which is the distance between the radiation source 6 and the surface of the subject H. In this case, the body thickness distribution can be obtained by subtracting SOD from SID.

[0040] Next, the scattered radiation removal unit 32 generates an estimated image by combining an estimated primary radiation image, which is an estimated primary radiation image obtained by imaging the virtual model K, and an estimated scattered radiation image, which is an estimated scattered radiation image obtained by imaging the virtual model K, as an estimated first LIH image G1 obtained by imaging the subject H.

[0041] Next, the scattered radiation removal unit 32 modifies the initial body thickness distribution T0(x,y) of the virtual model K so that the difference between the estimated image and the first LIH image G1 is minimized. The scattered radiation removal unit 32 repeatedly generates the estimated image and modifies the body thickness distribution until the difference between the estimated image and the first LIH image G1 satisfies predetermined termination conditions. The scattered radiation removal unit 32 derives the body thickness distribution when the termination conditions are met as the body thickness distribution T(x,y) of the subject H. Furthermore, the scattered radiation removal unit 32 removes the scattered radiation component contained in the first LIH image G1 by subtracting the scattered radiation component when the termination conditions are met from the first LIH image G1. In the following explanation, it is assumed that the scattered radiation component has been removed from both the first LIH image G1 and the second LIH image G2.

[0042] In this fluoroscopy apparatus 1, air is present because the distance between the subject H and the radiation detector 5 is relatively large. Air has its own unique radiation properties. Therefore, the quality of the primary and scattered radiation components that pass through the subject H changes according to the radiation properties of the air as they pass through the air. Accordingly, in this embodiment, it is preferable to consider the radiation properties of the air interposed between the subject H and the radiation detector 5 when removing the scattered radiation component.

[0043] As a method for removing scattered radiation while considering the radiation characteristics of air, for example, the method described in International Publication 2021 / 100413 can be used. Specifically, for the air interposed between the subject H and the radiation detector 5, the primary radiation transmittance and scattered radiation transmittance are generated in advance as a table or the like according to various imaging conditions and the thickness distribution of the subject H, and stored in storage 23.

[0044] Then, when the scattered radiation removal unit 32 estimates the body thickness distribution of the subject H and removes scattered radiation, it refers to a table to obtain the radiation characteristics of the air corresponding to the body thickness distribution, namely the primary radiation transmittance and the scattered radiation transmittance. The scattered radiation removal unit 32 also uses the acquired radiation characteristics, imaging conditions, and body thickness distribution to obtain an estimated primary radiation image and an estimated scattered radiation image, and adds the estimated primary radiation image and the estimated scattered radiation image to generate an estimated image. Furthermore, the scattered radiation removal unit 32 repeatedly generates estimated images and corrects the body thickness distribution until the difference between the estimated image and the first LIH image G1 satisfies a predetermined termination condition.

[0045] The scattered radiation removal unit 32 then removes the scattered radiation component from the first LIH image G1 by subtracting the estimated scattered radiation image obtained when the body thickness distribution satisfying the termination conditions was acquired from the first LIH image G1. This makes it possible to remove the scattered radiation component from the first LIH image G1 while also considering the radiation characteristics of the object interposed between the subject H and the radiation detector 5. Similarly, the scattered radiation component can also be removed from the second LIH image G2.

[0046] The derivation unit 33 derives a spine image Gb from the first LIH image G1 and the second LIH image G2 by performing energy subtraction processing. In deriving the spine image Gb, the derivation unit 33 performs weighted subtraction between corresponding pixels on the first LIH image G1 and the second LIH image G2, as shown in equation (1) below, thereby deriving a spine image Gb from which the spine of subject H contained in each LIH image G1 and G2 is extracted, as shown in Figure 4. In equation (1), β1 is the weighting coefficient. Gb(x, y)=G1(x, y)-β1×G2(x, y) (1)

[0047] The first extraction unit 34 extracts the target vertebra to be operated on from the 3D image V0. In this embodiment, the first extraction unit 34 displays a tomographic image of the sagittal section passing through the spine in the 3D image V0 on the display 24 using the display control unit 37. Figure 5 shows a tomographic image of the sagittal section displayed on the display 24. The operator uses the input device 25 to specify the target vertebra in the sagittal image D0 displayed on the display 24. In Figure 5, the selection of the 5th lumbar vertebra is indicated by the addition of hatching to the 5th lumbar vertebra. The first extraction unit 34 extracts the specified target vertebra from the 3D image V0. Hereinafter, the target vertebra extracted by the first extraction unit 34 from the 3D image V0 will be referred to as the 3D target vertebra T3.

[0048] Furthermore, the extraction of target vertebrae by the first extraction unit 34 is not limited to specification by the operator. For example, the operator may input the name of a target vertebra via the input device 25, and an extraction model trained on machine learning to extract a specific vertebra from a 3D image V0 may be used to extract the specified vertebra as the target vertebra.

[0049] The second extraction unit 35 extracts the target vertebra to be operated on from the spinal image Gb. In this embodiment, the second extraction unit 35 displays the spinal image Gb on the display 24 using the display control unit 37. The operator uses the input device 25 to specify the target vertebra in the spinal image Gb displayed on the display 24. The second extraction unit 35 extracts the specified target vertebra from the spinal image Gb. Hereinafter, the target vertebra extracted from the spinal image Gb by the second extraction unit 35 will be referred to as the two-dimensional target vertebra T2.

[0050] Furthermore, the extraction of target vertebrae by the second extraction unit 35 is not limited to designation by the operator. For example, the operator may input the name of a target vertebra via the input device 25, and an extraction model trained on machine learning to extract a specific vertebra from the spinal image Gb may be used to extract the designated vertebra as the target vertebra.

[0051] The alignment unit 36 ​​aligns the 3D target vertebra T3 with the 2D target vertebra T2. To do this, the alignment unit 36 ​​projects the 3D target vertebra T3 onto the 2D plane while changing the position and rotation parameters, deriving multiple projected target vertebra images Si (i=1~n: n is the number of parameters) with different parameters. Figure 6 is a diagram illustrating the derivation of the projected target vertebra images. For the 3D target vertebra T3, the alignment unit 36 ​​sets the x-axis in the left-right direction of the human body, the y-axis in the front-back direction of the human body, and the z-axis in the up-down direction of the human body. Then, while changing the position parameter tx in the x-direction, the position parameter ty in the y-direction, the position parameter tz in the z-direction, the rotation parameter θx around the x-axis, the rotation parameter θy around the y-axis, and the rotation parameter θz around the z-axis, the alignment unit 36 ​​projects the 3D target vertebra T3 toward the projection plane 40 on the xz plane, as shown by the arrows in Figure 6. This derives the projected target vertebra image Si.

[0052] The alignment unit 36 ​​identifies the projection target vertebral image St that best matches the two-dimensional target vertebra T2 from among multiple projection target vertebral images Si. For example, the projection target vertebral image St is identified by determining the correlation between each of the multiple projection target vertebral images Si and the two-dimensional target vertebra T2. This completes the alignment process.

[0053] The display control unit 37 displays the projected vertebral image St alongside the fluoroscopic image. Figure 7 shows the display screen according to this embodiment. As shown in Figure 7, the display screen 50 displays the fluoroscopic image 51 and the projected vertebral image St. The fluoroscopic image 51 is the first LIH image G1. By comparing the first LIH image G1 with the projected vertebral image St, the operating physician can easily grasp the three-dimensional position and inclination of the target vertebra within the subject H, as displayed in the fluoroscopic image 51, during the surgery.

[0054] Next, the process performed in this embodiment will be described. Figure 8 is a flowchart showing the process performed in this embodiment. It is assumed that the 3D image V0 is stored in the storage 23 acquired before the surgery. First, the first extraction unit 34 displays the 3D image V0 on the display 24 and extracts the 3D target vertebra T3 according to the operator's instructions (step ST1).

[0055] Next, when the foot switch 13 is turned on, the imaging control unit 31 performs fluoroscopic imaging of the subject H (step ST2), and monitoring is performed to determine whether or not the foot switch 13 has been turned off (step ST3). If step ST3 is confirmed, the imaging control unit 31 acquires the first LIH image G1 (step ST4), and then acquires the second LIH image G2 (step ST5).

[0056] The scattered radiation removal unit 32 removes scattered radiation components from the first LIH image G1 and the second LIH image G2 (step ST6), and the derivation unit 33 derives a spinal image Gb based on the first LIH image G1 and the second LIH image G2 from which the scattered radiation components have been removed (step ST7). Subsequently, the second extraction unit 35 displays the spinal image Gb on the display 24 and extracts the two-dimensional target vertebra T2 according to the operator's instructions (step ST8).

[0057] Then, the alignment unit 36 ​​aligns the 3D target vertebra T3 and the 2D target vertebra T2 and derives the projected target vertebral image St (step ST9). Furthermore, the display control unit 37 displays the fluoroscopic image (first LIH image G1) and the projected target vertebral image St on the display 24 (step ST10), and the process ends.

[0058] Thus, in this embodiment, the three-dimensional target vertebra T3 extracted from the three-dimensional image V0 is aligned with the two-dimensional target vertebra T2. Therefore, even if the curvature of the spine differs between the time the three-dimensional image V0 is acquired and the time of surgery, or if the state of gas and soft tissue within the subject H differs, the alignment of the target vertebra included in the three-dimensional image V0 with the target vertebra included in the fluoroscopic image can be performed with high accuracy. Consequently, by displaying the aligned projected target vertebral image St and the fluoroscopic image, the operator can easily confirm the three-dimensional position and state of the target vertebra in the fluoroscopic image.

[0059] Furthermore, in this embodiment, the position and rotation parameters of the 3D target vertebra T3 extracted from the 3D image V0 are changed while deriving the projection target vertebra image Si and performing alignment. Therefore, alignment processing can be performed faster than when alignment is performed while changing the overall parameters of the 3D image V0.

[0060] In the above embodiment, the radiation image processing device 20 of this embodiment extracts the 3D target vertebra T3 from the 3D image V0, but it is not limited to this. The 3D target vertebra T3 extracted from the 3D image V0 may be stored in the storage 23 in advance, and the stored 3D target vertebra T3 may be used to perform alignment.

[0061] Furthermore, in the above embodiment, the radiation is not particularly limited, and in addition to X-rays, alpha rays or gamma rays, etc., can be applied.

[0062] In this embodiment, each process is executed on any computer. Furthermore, any computer may execute these processes using a processor as hardware, a program as software, or a combination thereof. In that case, the processor is configured to work in cooperation with the program to execute the various processes in this embodiment, and can function as a unit or means in this embodiment. Also, the execution order of the processes by the processor is not limited to the order described and may be changed as appropriate. Any computer may be a general-purpose computer, a computer designed for a specific purpose, a workstation, or any other system capable of executing each process.

[0063] A processor may consist of one or more hardware components, and the type of hardware is not limited. For example, a processor may consist of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a programmable logic device such as an FPGA (Field Programmable Gate Array), a dedicated circuit for executing a specific process such as an ASIC (Application Specific Integrated Circuit), a GPU (Graphic Processing Unit), or an NPU (Neural Processing Unit). Furthermore, the type of hardware may be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of a processor, these components may reside in physically separate devices or in the same device. Also, in any embodiment, the order of each process performed by the processor is not limited to the order described above and may be changed as appropriate. Hardware is composed of electrical circuits (circuitry) that combine circuit elements such as semiconductor elements.

[0064] Furthermore, the program may be firmware or software such as microcode. Alternatively, the program may be, for example, a set of program modules, each function of which may be implemented by a processor configured to perform its respective function. The program may be program code or multiple code segments stored on one or more non-temporary computer-readable media (e.g., storage media or other storage). The program may be divided and stored on multiple non-temporary computer-readable media located on physically separate devices. Program code or code segments may represent any combination of procedures, functions, subprograms, routines, subroutines, modules, software packages, classes, or instructions, data structures, or program statements. Program code or code segments may be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents.

[0065] Furthermore, although the above embodiment describes a configuration in which the radiation image processing program 22 is pre-stored (installed) in the storage 23, the invention is not limited to this configuration. The information processing program 30 may be provided in a form recorded on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory), or USB (Universal Serial Bus) memory. Alternatively, the radiation image processing program 22 may be provided in a form that is downloaded from an external device via a network.

[0066] The technology disclosed herein extends to all program products. A program product includes all forms of products for providing programs. For example, a program product includes programs provided via a network such as the Internet, and non-temporary computer-readable recording media such as CD-ROMs, DVDs, and USB memory sticks on which programs are stored.

[0067] The following are additional notes to this disclosure. (Additional note 1) Equipped with a processor, The aforementioned processor, During surgery on the subject, at least one two-dimensional image including the subject's spine is acquired. Based on the aforementioned two-dimensional image, a spinal image emphasizing the spine of the subject is derived. From the aforementioned two-dimensional image, extract the two-dimensional target vertebrae that are to be aligned, A radiographic image processing device for aligning a three-dimensional target vertebra and a two-dimensional target vertebra, extracted from a three-dimensional image including the spine of the subject obtained before surgery on the subject. (Additional note 2) The processor derives multiple projected vertebral images by projecting the three-dimensional target vertebrae into two dimensions while changing the position and rotation parameters of the vertebrae, The radiographic image processing apparatus according to Appendix 1, which performs the alignment by identifying the projection target vertebral image that matches the two-dimensional target vertebral. (Additional note 3) The processor acquires a first two-dimensional image and a second two-dimensional image using radiation with different energy distributions. A radiation image processing apparatus according to appendix 1 or 2, which derives the spinal image by weighted subtraction of the first two-dimensional image and the second two-dimensional image. (Additional note 4) The processor removes scattered radiation components from the first two-dimensional image and the second two-dimensional image. The radiation image processing apparatus according to Appendix 3, which derives the spinal image by weighted subtraction of the first two-dimensional image and the second two-dimensional image from which the scattered radiation components have been removed. (Additional note 5) The radiographic image processing apparatus according to any one of the appendices 1 to 4, wherein the processor extracts the two-dimensional target vertebrae from the two-dimensional image based on a specification by the operator. (Additional note 6) The processor is a radiographic image processing apparatus according to any one of the appendices 1 to 5, which extracts the three-dimensional target vertebrae from the three-dimensional image. (Additional note 7) The processor is a radiographic image processing apparatus according to Appendix 6, which extracts the three-dimensional target vertebrae from the three-dimensional image based on a specification by the operator. (Additional note 8) The radiographic image processing apparatus according to any one of the appendices 1 to 7, wherein the processor displays the two-dimensional image and the aligned three-dimensional image of the target vertebra on a display. (Additional note 9) The computer acquires at least one two-dimensional image, including the spine of the subject, during surgery on the subject. Based on the aforementioned two-dimensional image, a spinal image emphasizing the spine of the subject is derived. From the aforementioned two-dimensional image, extract the two-dimensional target vertebrae that are to be aligned, A radiographic image processing method for aligning a three-dimensional target vertebra and a two-dimensional target vertebra, extracted from a three-dimensional image including the spine of the subject obtained before surgery on the subject. (Additional note 10) A procedure for acquiring at least one two-dimensional image including the spine of a subject during surgery on the subject, A procedure for deriving a spinal image of the subject with the spine emphasized based on the at least one two-dimensional image, A procedure for extracting the two-dimensional target vertebrae to be aligned from the aforementioned two-dimensional image, A radiographic image processing program that causes a computer to perform a procedure for aligning a 3D target vertebra and a 2D target vertebra, which are extracted from a 3D image including the spine of the subject obtained before surgery on the subject. [Explanation of Symbols]

[0068] 1. Fluoroscopy equipment 2 C-arm 3. Photography Department 4. Radiation irradiation area 5. Radiation detector 6 Radiation source 7 C-arm holding part 8. Shaft section 9 bearings 10 Main body 11 wheels 12 Spindle 13 Footswitch 15 Operating table 20 Radiation Image Processing Equipment 21 CPU 22. Radiation Image Processing Program 23 Storage 24 displays 25 Input Devices 26 memory 27 I / F 28 buses 31. Image capture control unit 32 Scattered radiation removal section 33 Derivation part 34 1st extraction part 35 Second extraction part 36 Alignment section 37 Display Control Unit 40 Projection plane 50 display screen 51 Projection Image D0 Sagittal Image V0 3D image

Claims

1. Equipped with a processor, The aforementioned processor, During surgery on the subject, at least one two-dimensional image including the subject's spine is acquired. Based on the aforementioned two-dimensional image, a spinal image emphasizing the spine of the subject is derived. From the aforementioned two-dimensional image, extract the two-dimensional target vertebrae that are to be aligned, A radiographic image processing device for aligning a three-dimensional target vertebra and a two-dimensional target vertebra, extracted from a three-dimensional image including the spine of the subject obtained before surgery on the subject.

2. The processor derives multiple projected vertebral images by projecting the three-dimensional target vertebrae into two dimensions while changing the position and rotation parameters of the vertebrae, The radiation image processing apparatus according to claim 1, which performs the alignment by identifying the projection target vertebral image that matches the two-dimensional target vertebral.

3. The processor acquires a first two-dimensional image and a second two-dimensional image using radiation with different energy distributions. The radiation image processing apparatus according to claim 1 or 2, wherein the spinal image is derived by weighted subtraction of the first two-dimensional image and the second two-dimensional image.

4. The processor removes scattered radiation components from the first two-dimensional image and the second two-dimensional image. The radiation image processing apparatus according to claim 3, wherein the spinal image is derived by weighted subtraction of the first two-dimensional image and the second two-dimensional image from which the scattered radiation component has been removed.

5. The radiographic image processing apparatus according to claim 1, wherein the processor extracts the two-dimensional target vertebrae from the two-dimensional image based on a specification by the operator.

6. The radiographic image processing apparatus according to claim 1, wherein the processor extracts the three-dimensional target vertebrae from the three-dimensional image.

7. The radiographic image processing apparatus according to claim 6, wherein the processor extracts the three-dimensional target vertebrae from the three-dimensional image based on a specification by the operator.

8. The radiographic image processing apparatus according to claim 1, wherein the processor displays the two-dimensional image and the aligned three-dimensional image of the target vertebrae on a display.

9. The computer acquires at least one two-dimensional image, including the spine of the subject, during surgery on the subject. Based on the aforementioned two-dimensional image, a spinal image emphasizing the spine of the subject is derived. From the aforementioned two-dimensional image, extract the two-dimensional target vertebrae that are to be aligned, A radiographic image processing method for aligning a three-dimensional target vertebra and a two-dimensional target vertebra, extracted from a three-dimensional image including the spine of the subject obtained before surgery on the subject.

10. A procedure for acquiring at least one two-dimensional image including the spine of a subject during surgery on the subject, A procedure for deriving a spinal image of the subject with the spine emphasized based on the at least one two-dimensional image, A procedure for extracting a two-dimensional target vertebra to be aligned from the aforementioned two-dimensional image, A radiographic image processing program that causes a computer to perform a procedure for aligning a three-dimensional target vertebra and a two-dimensional target vertebra, which are extracted from a three-dimensional image including the spine of the subject obtained before surgery on the subject.

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