WO2021024715A1 - 画像処理装置およびその制御方法、放射線撮影装置、プログラム - Google Patents

画像処理装置およびその制御方法、放射線撮影装置、プログラム Download PDF

Info

Publication number
WO2021024715A1
WO2021024715A1 PCT/JP2020/027397 JP2020027397W WO2021024715A1 WO 2021024715 A1 WO2021024715 A1 WO 2021024715A1 JP 2020027397 W JP2020027397 W JP 2020027397W WO 2021024715 A1 WO2021024715 A1 WO 2021024715A1
Authority
WO
WIPO (PCT)
Prior art keywords
radiation
image
timing
image processing
similarity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2020/027397
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
野田　剛司
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Publication of WO2021024715A1 publication Critical patent/WO2021024715A1/ja
Priority to US17/648,477 priority Critical patent/US12036061B2/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/48—Diagnostic techniques
    • A61B6/482—Diagnostic techniques involving multiple energy imaging
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/52—Devices using data or image processing specially adapted for radiation diagnosis
    • A61B6/5211—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data
    • A61B6/5217—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data extracting a diagnostic or physiological parameter from medical diagnostic data
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/50—Image enhancement or restoration using two or more images, e.g. averaging or subtraction
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/90—Dynamic range modification of images or parts thereof
    • G06T5/92—Dynamic range modification of images or parts thereof based on global image properties
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/97—Determining parameters from multiple pictures
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/48—Diagnostic techniques
    • A61B6/481—Diagnostic techniques involving the use of contrast agents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/50—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications
    • A61B6/505—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications for diagnosis of bone
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/40—Imaging
    • G01N2223/401—Imaging image processing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/40—Imaging
    • G01N2223/423—Imaging multispectral imaging-multiple energy imaging
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10016—Video; Image sequence
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/10—Image acquisition modality
    • G06T2207/10116—X-ray image
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/20—Special algorithmic details
    • G06T2207/20092—Interactive image processing based on input by user
    • G06T2207/20104—Interactive definition of region of interest [ROI]
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/20—Special algorithmic details
    • G06T2207/20172—Image enhancement details
    • G06T2207/20182—Noise reduction or smoothing in the temporal domain; Spatio-temporal filtering
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/20—Special algorithmic details
    • G06T2207/20212—Image combination
    • G06T2207/20224—Image subtraction
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/30—Subject of image; Context of image processing
    • G06T2207/30004—Biomedical image processing

Definitions

  • the present invention relates to an image processing apparatus and its control method, a radiography apparatus, and a program.
  • Patent Document 1 discloses a method of determining the tube voltage to be irradiated based on the body thickness of the subject in a configuration in which radiation of two tube voltages is irradiated to obtain an energy subtraction image. Further, Patent Document 2 discloses a method of correcting the time lag of the calibration curve for obtaining the bone mineral amount by using a reference in the bone mineral amount analysis using energy subtraction.
  • an application of energy subtraction that obtains an image (moving image) in which contrast-enhanced blood vessels are separated during treatment can be considered.
  • an auto-brightness control (ABC) function is provided on the device side to keep the amount of radiation transmitted through the subject constant. Since ABC automatically changes the tube voltage, tube current, and pulse width of the radiation generator, the energy of the radiation emitted by the radiation generator fluctuates when ABC functions. As described above, the fluctuation of the radiation energy destabilizes the energy subtraction image, so that the fluoroscopic image using the energy subtraction image becomes unstable.
  • the present invention provides a technique for performing stable energy subtraction by improving the accuracy of the energy (spectrum) of radiation used in energy subtraction.
  • the image processing apparatus has the following configurations. That is, A generation means for generating a substance property image based on a plurality of radiation images corresponding to a plurality of types of radiation energies and the plurality of types of radiation energies. Based on the substance property image generated by the generation means based on the plurality of radiographic images acquired at the first timing, and the plurality of radiographic images acquired at the second timing after the first timing. A calculation means for calculating the similarity with the substance property image generated by the generation means, and An estimation means for estimating at least one of the plurality of types of radiation energies at the second timing based on the similarity calculated by the calculation means.
  • FIG. 1 is a diagram showing a configuration example of a radiography system according to the first embodiment.
  • FIG. 2 is a flowchart showing processing by the image processing unit of the first embodiment.
  • FIG. 3 is a schematic diagram of a radiation image and a substance property image in the first embodiment. It is a figure which shows the high voltage pulse of the radiation tube in 1st Embodiment. It is a figure which shows the simulation result of 1st Embodiment. It is a flowchart which shows the processing by the image processing part of 2nd Embodiment.
  • the radiation generator 104 gives a high voltage pulse to the radiation tube 101 by a user operation to an exposure switch (not shown) to generate radiation.
  • radiation in the present specification may include, for example, ⁇ -rays, ⁇ -rays, ⁇ -ray particle beams, cosmic rays, and the like.
  • the type of radiation is not particularly limited, but X-rays are mainly used for medical diagnostic imaging.
  • the radiation generated from the radiation tube 101 irradiates the subject 103, and a part of the radiation passes through the subject 103 and reaches the FPD 102.
  • the FPD 102 accumulates electric charges based on an image signal to acquire a radiographic image, and transfers the acquired radiographic image to the information processing apparatus 120.
  • the FPD 102 has a radiation detection unit (not shown) provided with a pixel array for generating a signal corresponding to radiation, and a drive unit (not shown) that drives the radiation detection unit to read out an image signal.
  • the radiation detection unit detects the radiation that has passed through the subject 103 and reached the detection surface of the radiation detection unit as an image signal.
  • pixels that output a signal corresponding to the incident light are arranged in an array (two-dimensional region).
  • the photoelectric conversion element of each pixel converts the radiation converted into visible light by a scintillator (phosphor) into an electric signal and outputs it as an image signal.
  • the radiation detection unit is configured to detect the radiation transmitted through the subject 103 and acquire an image signal (radiation image).
  • the drive unit of the FPD 102 outputs an image signal (radiation image) read from the radiation detection unit according to an instruction from the control unit 105 to the information processing device 120 (control unit 105).
  • the information processing device 120 processes a radiation image taken by the FPD 102 of the subject.
  • the information processing device 120 includes a control unit 105, a display control unit 106, an operation unit 107, a storage unit 108, an image processing unit 109, and a monitor 116.
  • the control unit 105 includes one or a plurality of processors (not shown), and realizes various controls of the information processing device 120 by executing a program stored in the storage unit 108.
  • the storage unit 108 stores various programs executed by the control unit 105 and the like.
  • the storage unit 108 is composed of, for example, a ROM (ReadOnlyMemory), a RAM (RandomAccessMemory), a hard disk, or the like.
  • the storage unit 108 can store, for example, an image output from the control unit 105, an image processed by the image processing unit 109, and a calculation result in the image processing unit 109. ..
  • the image processing unit 109 processes the radiographic image acquired from the FPD 102.
  • the image processing unit 109 has a substance property calculation unit 110, a similarity calculation unit 111, and an energy estimation unit 112 as functional configurations. These functional configurations may be realized by the processor of the control unit 105 executing a predetermined program, or one or a plurality of processors included in the image processing unit 109 execute a program read from the storage unit 108. It may be realized by.
  • the processor of the control unit 105 and the image processing unit 109 is composed of, for example, a CPU (central processing unit). Further, a part or all of each functional unit of the control unit 105 and the image processing unit 109 may be realized by an integrated circuit or the like that performs the same function.
  • the internal configuration of the information processing device 120 may include a graphic control unit such as a GPU (Graphics Processing Unit), a communication unit such as a network card, an input / output control unit such as a keyboard, a display or a touch panel, and the like.
  • a graphic control unit such as a GPU (Graphics Processing Unit)
  • a communication unit such as a network card
  • an input / output control unit such as a keyboard, a display or a touch panel, and the like.
  • the display control unit 106 displays a radiation image (digital image) received from the FPD 102 by the control unit 105, an image processed by the image processing unit 109, and the like on the monitor 116.
  • the operation unit 107 provides a user interface (not shown) for the user to input instructions to the image processing unit 109 and the FPD 102.
  • the control unit 105 receives input of user instructions to the image processing unit 109 and the FPD 102 via this user interface.
  • the radiation generator 104 applies a high voltage to the radiation tube 101 to continuously or intermittently irradiate the subject 103 with radiation from the radiation tube 101.
  • the FPD 102 generates a plurality of radiographic images by irradiation from the radiation tube 101.
  • the radiation generator 104 irradiates two types of radiation, high energy and low energy, from the radiation tube 101, and the FPD 102 generates a high energy radiation image XH n and a low energy radiation image XL n .
  • n indicates a moving image frame number.
  • the number of types of radiation images generated in one frame may be three or more by irradiating with three or more types of radiation energy.
  • the control unit 105 acquires a high-energy radiation image XH n and a low-energy radiation image XL n from the FPD 102, and displays them on the monitor 116 via the display control unit 106.
  • the radiographic image displayed on the monitor 116 can be used for diagnosis or treatment. Further, the control unit 105 stores the radiographic image in the storage unit 108 and transmits it to the image processing unit 109.
  • the energy of the radiation generated by the radiation tube 101 can be set and changed by the tube voltage / pulse width set by the radiation generator 104 in the radiation tube 101.
  • a high voltage pulse of 120 kV is applied to the radiation tube 101 when irradiated with high energy radiation
  • 80 kV is applied to the radiation tube 101 when irradiated with low energy radiation.
  • energy subtraction it is preferable that these energy differences are large, but an appropriate energy is selected in consideration of the body thickness of the subject and the exposure dose.
  • the FPD 102 one that can acquire a radiation image corresponding to a plurality of energies by one irradiation may be used.
  • this type of FPD 102 a plurality of samplings are performed for one irradiation from the radiation tube 101. That is, the FPD 102 momentarily samples at the rising and falling edges of the high-voltage pulse applied to the radiation tube 101, so that a high-energy radiation image XH n and a low-energy radiation image XL n can be obtained by one irradiation.
  • Such an imaging method is effective in preventing motion artifacts from occurring in a subject with intense movement such as the heart.
  • the FPD 102 in which the two-stage detector has a laminated structure may be used to acquire a radiation image of a plurality of energies from one irradiation from the radiation tube 101.
  • the radiation is transmitted through the first-stage detector, which causes beam hardening and increases the energy of the second-stage detector. Therefore, it is possible to obtain a low-energy radiation image XL n at the output of the first-stage detector and a high-energy radiation image XH n at the output of the second-stage detector by one irradiation.
  • Such an imaging system is effective in that a radiation image of a plurality of energies can be obtained by one irradiation without particularly controlling the radiation tube 101. In addition, the occurrence of motion artifacts is suppressed.
  • the material property calculation unit 110 solves the nonlinear simultaneous equations obtained based on the radiation attenuation corresponding to at least two kinds of energies and at least two radiation images corresponding to at least two kinds of energies to obtain the thickness of the material. Get an image of. More specifically, the substance property calculation unit 110 of the present embodiment generates a substance property image by solving a weighted difference or an inverse problem using a high-energy radiation image XH n and a low-energy radiation image XL n .
  • the substance characteristic image means, for example, an image in which the thickness of fat, bone, a contrast agent, etc. constituting the subject is used as a pixel value, or an image in which the effective atomic number of the substance constituting the subject is used as a pixel value.
  • the energy estimation unit 112 uses the radiation energy used by the material property calculation unit 110 so that the similarity indicated by the index calculated by the similarity calculation unit 111 becomes as high as possible, that is, the sum of differences squared as an index becomes small. Estimate (spectrum). The energy estimation unit 112 performs an optimization calculation in order to obtain such radiation energy. By this optimization calculation, the energy estimation unit 112 estimates the voltage applied to the radiation tube 101 by the radiation generator 104 or the energy spectrum of the radiation emitted from the radiation tube 101. The details of the optimization operation will be described later.
  • FIG. 2 is a flowchart illustrating processing by the image processing unit 109.
  • images 3a and 3b of FIG. 3 show examples of high-energy and low-energy radiographic images obtained from FPD102
  • images 3c and 3d show examples of substance property images generated by the image processing unit 109. ..
  • the image processing unit 109 executes the process shown in FIG. 2 in response to the occurrence of some trigger (for example, the imaging conditions (tube voltage, pulse width of voltage) have been changed).
  • some trigger for example, the imaging conditions (tube voltage, pulse width of voltage) have been changed.
  • the image processing unit 109 uses the high-energy radiation image XH n (image 3a) and the low-energy radiation image XL n (image 3b) to produce a material property image (image 3c, image 3d).
  • the image processing unit 109 emits radiation based on the degree of similarity between the substance characteristic image generated before the trigger occurs (first timing) and the substance characteristic image generated this time (second timing).
  • the generator 104 estimates the tube voltage applied to the radiation tube 101 or the energy spectrum of the radiation emitted from the radiation tube 101. That is, the radiation energy at the second timing is estimated using the substance property image obtained at the first timing as the reference image.
  • each step will be described in detail.
  • step S201 the substance property calculation unit 110 generates a substance property image using energy subtraction.
  • the attenuation characteristics of high-energy and low-energy radiation are calculated by the following [Equation 1] and [Equation 2].
  • I H attenuation characteristics of high-energy radiation I L denotes the attenuation characteristic of the low-energy radiation.
  • n H (E) shows the energy spectrum of high-energy radiation radiated to the subject
  • n L (E) shows the energy spectrum of low-energy radiation radiated to the subject.
  • the energy spectrum may be measured in advance with a spectrometer or the like, or may be obtained by simulation.
  • E is a variable representing energy.
  • ⁇ A (E) is a linear attenuation coefficient for soft substances
  • ⁇ C (E) is a linear attenuation coefficient for contrast media.
  • d A represents the thickness of the soft substance
  • d C represents the thickness of the contrast medium.
  • Material characteristic calculating unit 110 coincides with the pixel values of the attenuation characteristic I H of the high-energy radiation as shown in Equation 1] is high energy radiation image XH n (image 3a of FIG. 3), shown in Equation 2 as the attenuation characteristic I L of the low-energy radiation matches the pixel values of the low-energy radiation image XL n (image 3b of FIG. 3), the thickness d a of ⁇ quality, determine the thickness d C of the contrast medium. Any known technique may be used for this calculation, but in this embodiment, an example using the Newton-Rapson method, which is one of the successive approximation methods, will be described. Specifically, the thickness d A of the soft substance and the thickness d C of the contrast medium are obtained by repeating the calculation according to the following [Equation 3]. In [Equation 3], k indicates the number of repetitions.
  • the thickness image d An (i) of the soft material which is a material characteristic image.
  • J) image 3c in FIG. 3
  • thickness image d Cn (i, j) of contrast agent image 3d in FIG. 3
  • i and j indicate the coordinates in the row direction and the column direction of the image, respectively.
  • the substance is separated into the thickness of the soft substance and the contrast medium, but the substance is not limited to this, and the substance is separated into any other substance, for example, the soft substance and the thickness of the bone. Is also possible. Further, when the soft substance and the contrast agent are separated by two radiation energies, the bone 301 and the contrast agent 302 are separated into the same substance characteristic image as shown in the image 3d.
  • step S202 the similarity calculation unit 111 calculates an index of similarity between material property images.
  • the shooting angle is changed in the 61st moving image frame (hereinafter referred to as the moving image frame 61), whereby the ABC function is activated and the shooting conditions are changed, and the pulse width of the high energy radiation is 4 msec.
  • the moving image frame 61 the moving image frame
  • the pulse width of the high energy radiation is 4 msec.
  • the impedance of the high-voltage cable or the like connecting the radiation tube 101 and the radiation generator 104 causes blunting in the rise and fall of the tube voltage, and a predetermined tube voltage is applied as shown in the solid line waveform in FIG. You will not be able to. As a result, the tube voltage and the effective tube voltage are different.
  • high-energy radiation of an energy spectrum n H (E) is not energy spectrum in 120kV ideal waveform shown by the broken line in FIG. 4.
  • the tube voltage changes transiently, it becomes difficult to specify the energy spectrum itself.
  • the pulse width of high-energy radiation tends to be short in order to reduce the irradiation dose.
  • the similarity calculation unit 111 includes a substance of a moving image frame 60 which is a material characteristic image generated in step S201 at the first timing and a moving image frame 61 which is a material characteristic image generated in step S201 at the second timing.
  • Calculate the similarity of characteristic images Specifically, for example, using the least squares difference (SSD), an index of similarity is calculated as shown in [Equation 4] below.
  • w and h are the number of pixels in the horizontal direction and the number of pixels in the vertical direction of the image, respectively.
  • the SSD is calculated using the thickness d C of the contrast medium as the substance property image, the thickness d A of the soft substance may be used.
  • the thickness of the contrast medium is used in the present embodiment because the thickness of the contrast medium includes the thickness of the bone, which is relatively resistant to body movement and does not change in thickness. If a bone separation image can be obtained as the material property image, the bone thickness may be used in the calculation of [Equation 4].
  • step S203 the energy estimation unit 112 estimates the radiation energy so that the similarity between the material property images is the highest. That is, in the present embodiment, for example, the following optimization calculation is performed in order to search for the radiation energy that minimizes the difference least squares sum (SSD) of [Equation 4].
  • the substance property calculation unit 110 is used to repeat the calculation according to the following [Equation 6] to sequentially obtain the thickness ⁇ A of the soft matter and the thickness ⁇ C of the contrast medium.
  • the thickness ⁇ C of the contrast medium obtained here should be approximately close to d C when the same subject is photographed in the moving image frame 60 and the moving image frame 61. This is because even if the subject moves to cause heartbeat, respiration, and flow of contrast medium, the main bone 301 shown in image 3d of FIG. 3 does not change significantly between frames. Therefore, if the similarity calculation unit 111 calculates the following [Equation 7] and makes the SSD M the smallest, the effective tube voltage can be estimated.
  • the effective tube voltage means a tube voltage that provides the energy of the radiation emitted in the actual waveform of FIG.
  • the energy estimation unit 112 searches for radiation energy so that the similarity calculated by the similarity calculation unit increases.
  • the radiation energy that maximizes the similarity is searched for using an optimization method.
  • the gradient method is used as the optimization method, but the method is not limited to this, and for example, the Newton method, the dichotomy method, or the like may be used.
  • the tube voltage H E which is estimated is represented by the following [Equation 8].
  • ⁇ is a coefficient for adjusting the convergence of the gradient method.
  • step S204 the image processing unit 109 makes a convergence test. If this convergence determination is NO, the energy estimator 112 returns to step S201 an estimated tube voltage H E at step S203 as a new tube voltage H, and repeats the processing of steps S201 ⁇ S203. That is, the energy estimation unit 112 calculates the SSD for the new tube voltage H (S201), fluctuates the new tube voltage H by ⁇ H to calculate the SSD M (S202), and is estimated by [Equation 8]. ) is calculated tube voltage H E.
  • the convergence conditions of the optimization method used for the convergence test in step S204 are set in advance, for example, that the similarity represented by the index exceeds the threshold value and that the change in similarity falls within a predetermined range.
  • the fact that the loop count was executed can be mentioned.
  • the similarity exceeds the threshold value for example, the least squares SSD M indicated by [Equation 7] is sufficiently small (the SSD M is less than the threshold value).
  • the change in similarity falls within a predetermined range, for example, when
  • executing the preset number of loops means that, for example, the loops of steps S201 to S203 are repeated a predetermined number of times. When any of these convergence conditions is satisfied, it is determined that the convergence has occurred.
  • the energy estimation unit 112 ends the process as an estimated tube voltage tube voltage H E obtained by the calculation of Equation 8].
  • a effective tube voltage the estimated tube voltage H E corresponds to the actual voltage waveform shown in FIG. 4, with the actual voltage waveform energy spectrum n HE for the estimated tube voltage H E is shown in Figure 4 Corresponds to the effective energy spectrum of radiation.
  • FIG. 5 is a simulation result showing the effect of estimating the tube voltage according to the present embodiment.
  • a high-energy radiation image is obtained by irradiating a numerical phantom consisting of a soft substance, a contrast agent, and bone that simulates the human body with X-rays with a high-energy radiation tube voltage of 120 kV and a low-energy radiation tube voltage of 70 kV.
  • XH n low energy radiographic image XL n is obtained.
  • Material characteristic calculating unit 110, the high-energy radiation image XH n, low-energy radiation image XL n thick image d An of ⁇ quality by calculation in step S201, and sequentially generates a thickness image d Cn of the contrast agent.
  • the tube voltage of high-energy radiation is intentionally changed to 90 kV in the moving image frame 61. In such a state, the tube voltage is estimated by performing the processes of steps S202 and S203.
  • the convergence test (S204) is not performed, and S201 to S203 are not looped. That is, the estimated value of the tube voltage obtained by performing the processes of S201 to S203 once is shown. As shown in FIG. 5, the estimated value of the tube voltage according to the first embodiment gradually starts to approach the set value by the simulation from the moving image frame 61, and almost matches the set value of 90 KV by the simulation at about the moving image frame 80. You can see that there is. If the convergence test (S204) is performed as shown in FIG. 2 and the processing loops of S201 to S203 are sufficiently performed, the estimated value of the tube voltage can be 90 kV in the moving image frame 61. However, since a sufficient number of loops is required to obtain an accurate estimated value, it is necessary to set the number of loops in consideration of the required moving speed.
  • the processing of steps S201 to S204 is the estimation of the effective tube voltage, that is, the energy spectrum according to the present embodiment.
  • this process is started with the occurrence of some event as a trigger, but it may be always executed during fluoroscopy.
  • the control unit 105 receives at least the imaging conditions (for example, tube voltage (kV), tube current (mA), pulse width (msec)) from the radiation generator 104. You can be notified of one) change.
  • the event for starting the process of estimating the radiation energy there is the detection of deterioration (change in image quality) of the substance characteristic image generated by the substance property calculation unit 110.
  • the SSD is calculated by [Equation 4] in order to detect the occurrence of deterioration of the substance characteristic image, it is not limited to the comparison with the immediately preceding frame, but the substance characteristic image of the current frame and the predetermined number of frames. Similarities with previous material property images may be compared.
  • the substance property image obtained at the first timing is used as a reference, and the substance property image obtained at the second timing after the first timing is similar to the reference.
  • To estimate the radiation energy This is the same whether the process of estimating the radiation energy is always performed during fluoroscopy or in response to a trigger.
  • the material property image immediately before the occurrence of the event in the above embodiment, the moving image frame 60
  • the material property image used as a reference is not limited to this.
  • a material property image obtained at any time before the occurrence of the event can be used as a reference.
  • the material property image of the immediately preceding frame is used as a reference, and the material property image calculated with accurate radiation energy obtained at any time during shooting is used as a reference. It can be used as an energy source.
  • the similarity shown in [Equation 7] may be calculated for the set area (ROI (area of interest)).
  • ROI area of interest
  • the mediastinum part moves greatly due to the beating heart and the diaphragm moved by breathing.
  • the tube voltage can be estimated more accurately by excluding the portion having a large movement during moving image shooting from the region (ROI) for calculating the similarity, such as the portion of the mediastinum.
  • the energy estimation unit 112 sets the similarity between frames of the radiation image (which may be a high-energy radiation image or a low-energy radiation image) in a portion where the fluctuation of the pixel value is larger than a predetermined threshold value. Exclude from the area to be calculated.
  • the predetermined threshold value may be set by the user via the user interface.
  • a user interface may be provided so that an operator such as a doctor or a radiologist can specify an area (ROI) for calculating the similarity on the monitor 116.
  • the similarity calculation unit 111 uses the tube voltage included in the imaging conditions notified from the radiation generator as an initial value, and searches for the tube voltage that maximizes the similarity by the gradient method. did.
  • the present invention is not limited to this, and an effective tube voltage may be estimated from the notified imaging conditions and used as an initial value.
  • the similarity calculation unit 111 roughly estimates an effective tube voltage from the tube voltage and pulse width included in the imaging conditions, and uses this as an initial value to set the tube voltage that maximizes the similarity by the gradient method. You may try to estimate. By setting the initial value more appropriately, it is possible to reduce the processing time and the processing amount until the convergence condition of the gradient method is satisfied.
  • the substance property calculation unit 110 has a table in which the effective tube voltage is registered according to the imaging conditions including the tube voltage and the pulse width, and the effective tube voltage acquired from this table based on the notified imaging conditions.
  • a material characteristic image is generated using a flexible tube voltage.
  • the similarity calculation unit 111 can estimate the tube voltage that maximizes the similarity by the method described above by using the effective tube voltage obtained from the table as an initial value, so that the radiation energy can be estimated more quickly. You can get the result.
  • the substance characteristic image is generated by changing the tube voltage from H to ⁇ H in step S203, a radiation energy spectrum corresponding to the changed tube voltage is required.
  • the radiation energy may be measured and held in advance by changing the tube voltage in ⁇ H increments.
  • the energy estimation unit 112 may calculate and use the radiation spectrum corresponding to the changed tube voltage by an approximate formula.
  • the tube voltage can be estimated in real time by using the similarity between the substance property images.
  • stable energy subtraction can be performed even if the tube voltage fluctuates due to ABC (auto brightness control) during imaging. Can be done.
  • the control unit 105 stores the radiation image captured by the FPD 102 in the storage unit 108, and transfers the radiation image to the image processing unit 109.
  • n H (E) ⁇ (E H )
  • n L (E) ⁇ .
  • ⁇ is a Dirac delta function.
  • E H, E L are representative of the energy spectrum can be used, for example a peak position value of the average energy and spectrum.
  • [Equation 1] and [Equation 2] become the following [Equation 9] and [Equation 10], respectively.
  • the thickness d A of the soft substance and the thickness d C of the contrast medium represented by [Equation 11] and [Equation 12] can be obtained by the following [Equation 13].
  • the numerical integration of [Equation 1] and [Equation 2] and the iterative calculation of [Equation 3] of the first embodiment become unnecessary, so that the speed is higher than that of the first embodiment.
  • the material property image can be calculated.
  • the processes of steps S602, S603, and S604 are the same as the processes of steps S202, S203, and S204 of the first embodiment (FIG. 2), respectively.
  • E H, the E L in real time.
  • energy subtraction technology when the energy subtraction technology is used in the angiography apparatus, energy subtraction can be stably performed when the tube voltage fluctuates due to, for example, ABC (auto brightness control) during imaging.
  • the case where only the energy of the high-energy radiation changes has been described for the sake of clarity, but the case where the energy of the low-energy radiation, the high-energy radiation and the low-energy radiation changes can be similarly estimated. ..
  • the tube voltages of high-energy radiation and low-energy radiation may be changed by ⁇ H to search for the radiation energy that provides the maximum similarity.
  • the present invention can also be applied to radiation still image imaging.
  • the present invention when taking a plurality of still images while changing the radiation energy, if a substance characteristic image as a reference is obtained in advance, the radiation energy in each still image shooting can be estimated, and accurate material characteristics can be obtained. An image is obtained.
  • the present invention is not limited to the above embodiment, and can be appropriately modified and implemented without changing the gist.
  • the present invention may also take embodiments as, for example, a system, device, method, program or storage medium. Specifically, it may be applied to a system composed of a plurality of devices, or may be applied to a device composed of one device.
  • the present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

Landscapes

  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Medical Informatics (AREA)
  • Pathology (AREA)
  • General Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biophysics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Biomedical Technology (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • Optics & Photonics (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Theoretical Computer Science (AREA)
  • Physiology (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Immunology (AREA)
  • Apparatus For Radiation Diagnosis (AREA)
PCT/JP2020/027397 2019-08-02 2020-07-14 画像処理装置およびその制御方法、放射線撮影装置、プログラム Ceased WO2021024715A1 (ja)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US17/648,477 US12036061B2 (en) 2019-08-02 2022-01-20 Image processing apparatus and control method thereof, radiography apparatus, and computer-readable storage medium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019143310A JP7246281B2 (ja) 2019-08-02 2019-08-02 画像処理装置およびその制御方法、放射線撮影装置、プログラム
JP2019-143310 2019-08-02

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US17/648,477 Continuation US12036061B2 (en) 2019-08-02 2022-01-20 Image processing apparatus and control method thereof, radiography apparatus, and computer-readable storage medium

Publications (1)

Publication Number Publication Date
WO2021024715A1 true WO2021024715A1 (ja) 2021-02-11

Family

ID=74504043

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/027397 Ceased WO2021024715A1 (ja) 2019-08-02 2020-07-14 画像処理装置およびその制御方法、放射線撮影装置、プログラム

Country Status (3)

Country Link
US (1) US12036061B2 (https=)
JP (1) JP7246281B2 (https=)
WO (1) WO2021024715A1 (https=)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022065318A1 (ja) * 2020-09-28 2022-03-31 富士フイルム株式会社 画像処理装置、画像処理方法、及び画像処理プログラム
JP7619821B2 (ja) 2021-02-09 2025-01-22 キヤノン株式会社 情報処理装置、放射線撮影システム、情報処理方法およびプログラム
JP2022134547A (ja) * 2021-03-03 2022-09-15 キヤノン株式会社 画像処理装置、放射線撮像システム、画像処理方法及びプログラム
JP2024025211A (ja) 2022-08-10 2024-02-26 キヤノン株式会社 放射線撮像装置、放射線撮像システム、制御装置、放射線撮像装置の制御方法、および、放射線撮像装置を制御するためのプログラム
JP7540107B1 (ja) * 2024-02-27 2024-08-26 ジーイー・プレシジョン・ヘルスケア・エルエルシー 医用システムおよび記録媒体
JP7540108B1 (ja) * 2024-02-27 2024-08-26 ジーイー・プレシジョン・ヘルスケア・エルエルシー 医用システムおよび記録媒体

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010512826A (ja) * 2006-12-15 2010-04-30 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ スペクトル分解ｘ線撮像装置
JP2017086901A (ja) * 2015-11-02 2017-05-25 東芝メディカルシステムズ株式会社 データ収集装置、ｘ線ｃｔ装置及び核医学診断装置
JP2018057669A (ja) * 2016-10-06 2018-04-12 キヤノン株式会社 放射線撮影装置、放射線撮影システム、放射線撮影方法、及びプログラム

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08266529A (ja) 1995-03-31 1996-10-15 Fuji Photo Film Co Ltd 骨塩定量分析方法
JP5315157B2 (ja) 2009-07-27 2013-10-16 キヤノン株式会社 情報処理装置、ライン状ノイズ低減処理方法、及びプログラム
JP2011104103A (ja) 2009-11-17 2011-06-02 Canon Inc エネルギサブトラクション画像撮影装置
JP5543194B2 (ja) 2009-12-24 2014-07-09 キヤノン株式会社 情報処理装置、処理方法及びプログラム
JP6214128B2 (ja) 2010-11-22 2017-10-18 キヤノン株式会社 画像処理装置、画像処理方法、及び記憶媒体
JP6122269B2 (ja) 2011-12-16 2017-04-26 キヤノン株式会社 画像処理装置、画像処理方法、及びプログラム
JP6312401B2 (ja) 2012-11-30 2018-04-18 キヤノン株式会社 画像処理装置、画像処理方法、及びプログラム
JP6497912B2 (ja) 2014-12-01 2019-04-10 キヤノン株式会社 画像処理装置、放射線撮影システム、制御方法、及びプログラム
JP2018110794A (ja) 2017-01-13 2018-07-19 キヤノン株式会社 情報処理装置、放射線撮像装置、情報処理方法およびプログラム
JP6974948B2 (ja) 2017-02-10 2021-12-01 キヤノン株式会社 放射線撮像装置および放射線撮像方法
JP7080025B2 (ja) 2017-09-01 2022-06-03 キヤノン株式会社 情報処理装置、情報処理方法およびプログラム
JP7093233B2 (ja) 2018-06-07 2022-06-29 キヤノン株式会社 放射線撮影装置、放射線撮影方法およびプログラム
WO2020003744A1 (ja) 2018-06-27 2020-01-02 キヤノン株式会社 放射線撮影装置、放射線撮影方法およびプログラム
JP7169853B2 (ja) 2018-11-09 2022-11-11 キヤノン株式会社 画像処理装置、放射線撮影装置、および画像処理方法
JP7185596B2 (ja) 2019-06-11 2022-12-07 キヤノン株式会社 画像処理装置および画像処理方法、プログラム

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010512826A (ja) * 2006-12-15 2010-04-30 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ スペクトル分解ｘ線撮像装置
JP2017086901A (ja) * 2015-11-02 2017-05-25 東芝メディカルシステムズ株式会社 データ収集装置、ｘ線ｃｔ装置及び核医学診断装置
JP2018057669A (ja) * 2016-10-06 2018-04-12 キヤノン株式会社 放射線撮影装置、放射線撮影システム、放射線撮影方法、及びプログラム

Also Published As

Publication number Publication date
JP7246281B2 (ja) 2023-03-27
JP2021023515A (ja) 2021-02-22
US20220142597A1 (en) 2022-05-12
US12036061B2 (en) 2024-07-16

Similar Documents

Publication Publication Date Title
JP7246281B2 (ja) 画像処理装置およびその制御方法、放射線撮影装置、プログラム
JP5124363B2 (ja) エネルギーサブトラクション処理装置、方法、およびプログラム
US11234641B2 (en) Body fat percentage measurement device, method and program
US10172583B2 (en) Radiography apparatus, radiography method, and radiography program
JP6704374B2 (ja) 体脂肪率測定装置、方法およびプログラム
US11357455B2 (en) Information processing apparatus, radiation imaging apparatus, information processing method, and storage medium
US10258305B2 (en) Radiographic image processing device, method, and program
JP6667462B2 (ja) エネルギーサブトラクション処理装置、方法およびプログラム
US7940892B2 (en) Energy substraction method and apparatus
JP7093233B2 (ja) 放射線撮影装置、放射線撮影方法およびプログラム
WO2015015745A1 (ja) 放射線画像解析装置および方法並びにプログラム
US10143432B2 (en) X-ray apparatus and control method for the same
US12148156B2 (en) Estimation device, estimation method, and estimation program
CN111163698A (zh) 图像处理设备、图像处理方法以及程序
US12097062B2 (en) Estimation device, estimation method, and estimation program
WO2020095578A1 (ja) 情報処理装置および方法、放射線撮影システム
JP6301439B2 (ja) 放射線画像解析装置および方法並びにプログラム
CN111315297A (zh) 图像处理装置、图像处理方法、放射线摄像装置、放射线摄像装置的控制方法和程序
JP2018117900A (ja) 放射線撮影装置、放射線撮影システム、放射線撮影方法、及びプログラム
US20220240882A1 (en) Image processing apparatus, radiation imaging apparatus, image processing method, and non-transitory computer readable storage medium
US12533098B2 (en) Radiation image processing device, radiation image processing method, and radiation image processing program
JP2016059509A (ja) 画像処理装置、ｘ線ｃｔ装置および画像処理方法
WO2018105493A1 (ja) 放射線撮影装置、放射線撮影システム、放射線撮影方法、及びプログラム
JP6313402B2 (ja) 放射線画像撮影装置、放射線画像撮影方法、及び放射線画像撮影プログラム
CN117717360A (zh) 放射线图像处理装置、其工作方法及计算机可读介质

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20849823

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20849823

Country of ref document: EP

Kind code of ref document: A1