[go: up one dir, main page]

WO2013051647A1 - Dispositif de radiographie et procédé de traitement d'image - Google Patents

Dispositif de radiographie et procédé de traitement d'image Download PDF

Info

Publication number
WO2013051647A1
WO2013051647A1 PCT/JP2012/075789 JP2012075789W WO2013051647A1 WO 2013051647 A1 WO2013051647 A1 WO 2013051647A1 JP 2012075789 W JP2012075789 W JP 2012075789W WO 2013051647 A1 WO2013051647 A1 WO 2013051647A1
Authority
WO
WIPO (PCT)
Prior art keywords
image
trend
subject
grating
radiation
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/JP2012/075789
Other languages
English (en)
Japanese (ja)
Inventor
拓司 多田
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.)
Fujifilm Corp
Original Assignee
Fujifilm Corp
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 Fujifilm Corp filed Critical Fujifilm Corp
Publication of WO2013051647A1 publication Critical patent/WO2013051647A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • 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
    • A61B6/484—Diagnostic techniques involving phase contrast X-ray 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
    • A61B6/5229—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data combining image data of a patient, e.g. combining a functional image with an anatomical image
    • A61B6/5235—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data combining image data of a patient, e.g. combining a functional image with an anatomical image combining images from the same or different ionising radiation imaging techniques, e.g. PET and CT
    • 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
    • A61B6/5258—Devices using data or image processing specially adapted for radiation diagnosis involving detection or reduction of artifacts or noise

Definitions

  • the present invention relates to a radiation imaging apparatus and an image processing method for detecting an image based on a phase change of radiation by a subject.
  • Radiation such as X-rays
  • X-rays has a characteristic that it is absorbed and attenuated depending on the weight (atomic number) of the elements constituting the substance and the density and thickness of the substance. Focusing on this characteristic, X-rays are used as a probe for seeing through the inside of a subject in fields such as medical diagnosis and nondestructive inspection.
  • the first diffraction grating is disposed behind the subject as viewed from the X-ray source, and the second diffraction grating is disposed at a position separated from the first diffraction grating by the Talbot distance.
  • An X-ray image detector is arranged behind.
  • the Talbot distance is the distance at which the X-rays that have passed through the first diffraction grating form a self-image (striped image) of the first diffraction grating due to the Talbot effect, and the grating pitch of the first diffraction grating and the X-ray wavelength Depends on and.
  • This self-image is modulated by refraction caused by the phase change of X-rays in the subject. By detecting this modulation amount, the phase change of the X-ray is imaged.
  • the fringe scanning method is known as a method for detecting the modulation amount.
  • the second diffraction grating is scanned with respect to the first diffraction grating in a direction parallel to the plane of the first diffraction grating and perpendicular to the grating line direction of the first diffraction grating.
  • X-rays are radiated from the X-ray source at each scanning position while being translated (scanned) at a pitch, and the X-ray image passing through the subject and the first and second diffraction gratings is imaged by the X-ray image detector. Is the method.
  • noise is superimposed on the phase differential image, resulting in image unevenness, which may hinder the observation of the subject.
  • Noise occurs due to various causes depending on the shooting conditions, such as the placement error of each grid or radiation source, the temperature environment at the time of shooting, etc., but if the shooting conditions such as the placement error and temperature environment are almost the same Regardless of the presence or absence of the subject, it appears as noise in the same manner. For this reason, it can be obtained by imaging the subject by subtracting the phase differential image obtained by imaging in the same environment and without the subject from the phase differential image obtained by imaging the subject. It is known to remove noise components from the phase differential image (see WO 2004/058070, JP 2011-045655 A).
  • the radiation imaging apparatus of the present invention includes a radiation source, a radiation detector, a phase differential image generation unit, and a noise removal unit.
  • the radiation source emits radiation toward the subject.
  • the radiation detector detects radiation emitted from a radiation source and generates image data.
  • the phase differential image generation unit generates a phase differential image based on the grating unit arranged between the radiation source and the radiation detector and the image data obtained by the radiation detector.
  • the noise removing unit remains when an unwrap processing unit that performs unwrap processing on the phase differential image and an offset image that represents offset noise when there is no subject are subtracted from the subject image that is the phase differential image after unwrap processing. To remove the trend.
  • the noise removal unit preferably includes an offset noise removal unit, a trend detection unit, and a trend removal unit.
  • the offset noise removing unit removes the offset noise by subtracting the offset image from the subject image.
  • the trend detection unit detects the trend based on the subject image from which the offset noise has been removed.
  • the trend removal unit subtracts and removes the trend detected by the trend detection unit from the subject image.
  • the trend detection unit extracts a pixel value of the subject image from which the offset noise has been removed along a predetermined direction, and detects a predetermined direction component of the trend. Then, the trend removing unit generates a trend component image in which a predetermined direction component of the trend is arranged along a direction perpendicular to the predetermined direction, and subtracts the trend component image from the subject image, thereby detecting the trend from the subject image. A predetermined direction component is removed. In this way, it is preferable that the trend detection unit and the trend removal unit detect and remove trend components in two directions, ie, a first direction that is a predetermined direction and a second direction that is perpendicular to the predetermined direction.
  • the subject image has a rectangular shape, and the first direction and the second direction are preferably a horizontal direction or a vertical direction along one side of the square.
  • the trend detection unit may detect a trend component based on at least the pixel value of the unexposed region where there is no subject among the extracted pixel values of the subject image.
  • the trend detection unit extracts the pixel value of the subject image along the first direction or the second direction, and then smoothes at least the subject region where the subject is present, whereby the first direction component of the trend or the second direction A direction component may be extracted.
  • the trend detection unit extracts the pixel value of the subject image along the first direction or the second direction, and then interpolates and extracts the data of the subject region where the subject is present based on the data of the missing region. It is preferable to extract the first direction component or the second direction component of the trend by inserting or fitting.
  • the trend detection unit detects a first direction component or a second direction component of the trend for a plurality of rows or columns along the first direction or the second direction, and the first direction component or the first direction in each row or each column. Data obtained by averaging the two direction components may be detected as the first direction component or the second direction component.
  • the trend detection unit preferably sets at least one of the first direction and the second direction to a direction not passing through the subject.
  • the absorption differential image generation unit generates a first absorption image from the image data obtained when there is no subject, generates a second absorption image from the image data obtained when there is a subject, and generates the second absorption image as the first absorption image. It is preferable to generate an absorption differential image by differentiating the third absorption image obtained by dividing by one absorption image.
  • the pixel selected by the trend detection unit is a pixel in a blank area where there is no subject.
  • the grating unit generates a second periodic pattern image by partially shielding the first periodic pattern image and a first grating that generates a first periodic pattern image by passing radiation from a radiation source. It is preferable that the radiation image detector includes the second grating and generates the image data by detecting the second periodic pattern image.
  • the grating unit includes a scanning mechanism that moves the first grating or the second grating at a predetermined scanning pitch and sequentially sets the plurality of scanning positions.
  • the radiological image detector has a second periodic pattern at each scanning position. It is preferable that an image is detected to generate image data, and the phase differential image generation unit generates a phase differential image based on a plurality of image data generated by the radiation image detector.
  • the moving direction of the first lattice or the second lattice is a direction perpendicular to the lattice line.
  • the moving direction of the first grating or the second grating may be a direction inclined with respect to the grating line.
  • the phase differential image generation unit may generate a phase differential image based on single image data obtained by the radiation detector.
  • the first grating is an absorption grating, and it is preferable to generate the first periodic pattern image by geometrically optically projecting the incident radiation.
  • the first grating may be an absorption type grating or a phase type grating, and may generate a first periodic pattern image by causing a Talbot effect to incident radiation.
  • the second grating 22 is also an absorption-type grating, and includes a plurality of X-ray absorbing portions 22a and X-ray transmitting portions 22b that are extended in the Y direction and arranged alternately in the X direction, like the first grating 21. ing.
  • the X-ray absorbing portions 21a and 22a are formed of a material having X-ray absorption properties such as gold (Au) and platinum (Pt).
  • the X-ray transmissive portions 21b and 22b are formed of a material having X-ray permeability such as silicon (Si) or resin or a gap.
  • the X-ray image detector 13 detects the G2 image and generates image data.
  • the memory 14 temporarily stores the image data read from the X-ray image detector 13.
  • the image processing unit 15 generates a phase differential image based on the image data stored in the memory 14, and generates a phase contrast image based on the phase differential image.
  • the image recording unit 16 records a phase differential image and a phase contrast image.
  • the scanning mechanism 23 intermittently moves the second grating 22 in the X direction, and sequentially changes the relative position of the second grating 22 with respect to the first grating 21.
  • the scanning mechanism 23 includes a piezoelectric actuator or an electrostatic actuator, and is driven based on the control of the imaging control unit 17 so as to detect an X-ray image at each scanning position (position after each intermittent movement).
  • the X-ray image detector 13 detects an X-ray image while the intermittent movement of the second grating 22 is stopped, and image data of the X-ray image is stored in the memory 14. Instead of moving the second grating 22 intermittently, the second grating 22 may be moved continuously, and an X-ray image may be detected every time it moves a predetermined distance.
  • X-rays irradiated from the X-ray source 11 are cone beams having the X-ray focal point 11a as a light emitting point.
  • lattice 21 is comprised so that the Talbot effect may not arise and the X-rays which passed X-ray transmissive part 21b may be projected geometrically.
  • the width of the X-ray transmission part 21b in the X direction is set to a value sufficiently larger than the peak wavelength of X-rays irradiated from the X-ray source 11, and most of the X-rays are diffracted by the X-ray transmission part 21b. It is realized by not doing.
  • the X-ray is displaced in the X direction by an amount corresponding to the refraction angle ⁇ (x).
  • This amount of displacement ⁇ x is approximately expressed by equation (4) based on the small X-ray refraction angle ⁇ (x).
  • the unwrap processing unit 41 sets a plurality of starting points for pixels located at the end of each row or each column of the phase differential image, and follows a predetermined path (for example, a straight path along the row or column) from a certain starting point.
  • the unwrap processing is performed, and then the unwrap processing of the starting point adjacent to the starting point where the unwrapping processing is performed is performed, and the unwrap processing is performed along the route from the adjacent starting point in order while changing the starting point and the route. By repeating, the whole phase differential image is unwrapped.
  • the trend detection unit 47 When the trend detection unit 47 generates the horizontal component of the trend 72 in each row by extracting and smoothing the pixel value ⁇ of each row as described above, the trend detection unit 47 averages the horizontal component of the trend in each row (hereinafter, referred to as “trend”). Horizontal direction trend data). The trend detection unit 47 detects the horizontal trend data as a horizontal component of the trend 72 and inputs it to the trend removal unit 48 together with the phase differential image 71.
  • the subject H is partially projected in the central portion of the phase differential image 71.
  • the X-ray imaging apparatus 10 can detect and remove the trend 72 suitably. This is because, when each direction component of the trend 72 is detected and removed, data obtained by averaging each direction component of the trend 72 detected for each row (column) is detected as each direction component of the trend 72. This is because it is difficult to be affected by the presence of H.
  • the subject H is composed of bone parts 20a and 20b and soft tissue 20c, and the upper left area of the phase differential image 71 is substantially occupied by the bone part 20a, and the lower right area is substantially occupied by the bone part 20b. A portion between the bone portions 20a and 20b is the soft tissue 20c, and an example in which the phase differential image 71 does not have a blank region is shown.
  • the vertical component and the horizontal component are detected and removed separately.
  • the trend 72 can be detected and removed, It is not restricted to an aspect.
  • the first direction component of the trend 72 and the second direction are defined as an oblique direction inclined by a predetermined angle with respect to the vertical and horizontal sides of the phase differential image 71 as a first direction and a direction perpendicular to the first direction as a second direction. Components may be detected and removed. Also in this case, the phase differential image 83 from which the trend 72 is removed can be obtained as in the first embodiment described above.
  • each direction of the trend 72 is detected regardless of the presence or absence of the subject H by smoothing the extracted pixel value ⁇ when the vertical and horizontal direction components of the trend 72 are detected.
  • the trend 72 is detected based on the data on the missing areas (for example, areas E2a and E2b in FIG. 14).
  • Each direction component may be detected.
  • the method of calculating the data of the removed subject region portion is arbitrary. Data that simply connects the boundary point between the subject region and the missing region (for example, the boundary point between the region E1 and the regions E2a and E2b in FIG.
  • the trend 72 has a tendency to increase (decrease) linearly in the phase differential image 71.
  • the trend 86 shown in FIG. May have periodic features.
  • the X-ray imaging apparatus 10 can suitably detect and remove the trend.
  • a curve using a trigonometric function or the like is used. It is necessary to perform interpolation, extrapolation, fitting, etc.
  • the index 92 is provided at the center of the detection surface 13a.
  • the index 92 may be provided so as to be biased in any direction, up, down, left, or right with respect to the detection surface 13a.
  • the trend detection unit 47 extracts the pixel value ⁇ of the phase differential image 71 for each row, and then smoothes the extracted pixel value ⁇ to detect the lateral component of the trend 72. Further, the horizontal component of the trend in each row is averaged to detect one horizontal trend data, but the smoothing of the extracted pixel value ⁇ may be omitted. That is, the trend detection unit 47 may average the extracted pixel values ⁇ themselves to obtain horizontal trend data without smoothing the pixel values ⁇ extracted for each row. This is effective when the signal of the subject H becomes dull and the data becomes almost trend only by averaging the pixel values between the rows.
  • smoothing or averaging may be omitted as described above, or both smoothing and averaging may be omitted. The same applies to each embodiment described later.
  • the trend detection unit 47 when the trend detection unit 47 detects horizontal trend data or vertical trend data, the trend detection unit 47 does not consider the size of the pixel value ⁇ . It is preferable to compare the pixel value ⁇ of the row (or column) with a predetermined threshold value, and based on the magnitude relationship, only the portion where the pixel value ⁇ is in the predetermined range is used for detecting trend data in each direction.
  • the pseudo-absorber 96 since the pseudo-absorber 96 is not arranged, the pixel region where the pixel value ⁇ is saturated and the metal portion of the fixing jig of the subject H are reflected and the pixel value is extremely small (for example, approximately 0).
  • the pixel value ⁇ (phase differential value) is not a normal value. For this reason, if trend data is detected in consideration of even pixel values ⁇ in a region where these pixel values ⁇ are extremely large or regions where pixel values ⁇ are extremely small, they are detected by being affected by these inappropriate values. Trend data may be incorrect.
  • a first threshold value that determines the lower limit of the pixel value ⁇ to be used and a second threshold value that determines the upper limit of the pixel value ⁇ to be used are determined in advance, and the trend detection unit 47 extracts the pixel value ⁇ of each row or each column. It is preferable that the trend data in each direction is detected using only data in a range that falls within the range from the first threshold value to the second threshold value.
  • the X-ray imaging apparatus of the second embodiment includes an absorption differential image generation unit 101 in the image processing unit 100.
  • the absorption differential image generation unit 101 acquires M main captured image data 52 obtained by fringe scanning, and averages them to generate an absorption image.
  • the absorption image is an image in which the X-ray absorption rate (transmittance) of the subject H is expressed as contrast.
  • each of the actual captured image data 52 stripes by the first grating 21 and the second grating 22 are projected, and the stripes move according to the scanning position “k” of the second grating 22. If M pieces of actual captured image data 52 are compared in the order of photographing, they are moved by one cycle. For this reason, when the M actual captured image data 52 are averaged, the fringes by the first grating 21 and the second grating 22 are averaged to form a substantially uniform background, and thus there is no fringe in the absorption image. Only the image of the subject H is projected.
  • the absorption differential image generation unit 101 generates an absorption differential image by differentiating the absorption image. Differentiation of the absorption image can be performed, for example, by taking a difference from an image shifted by one pixel in a predetermined direction (direction of differentiation).
  • the absorption differential image generated by the absorption differential image generation unit 101 in this manner is input to the trend detection unit 102 and used when the trend 72 is detected.
  • the direction which differentiates an absorption image is arbitrary, for example, it is preferable to carry out to the X direction (refer FIG. 1) perpendicular
  • the trend detection unit 102 detects each direction component of the trend 72 from the phase differential image from which the offset noise has been removed, as with the trend detection unit 47 of the first embodiment, but the trend detection unit 102 refers to the absorption differential image. Meanwhile, each direction component of the trend 72 is detected.
  • the captured screen is 103 and the subject H is in the center of the captured screen 103.
  • the subject H is spherical.
  • a solid line 105a is displayed when there is no offset noise.
  • the pixel value is flat in the portion of the unexposed region 104, and a curve or the like corresponding to the X-ray absorption rate is formed in the portion of the subject H.
  • the pixel value changes in the background region 104 reflecting the offset noise. Further, the curve shape also changes in the portion of the subject H due to the offset noise. However, the boundary position between the subject H and the blank area 104 is not changed by the offset noise.
  • the trend detection unit 102 detects the horizontal direction component of the trend 72 using the data of the area E2a and the area E2b corresponding to the blank area 104 as described above. Specifically, first, at least two pixels are selected from the region E2a or the region E2b where the pixel value is flat in the absorption differential image. Here, the pixel A1 with the region E2a and the pixel A2 with the region E2b are selected, but two points may be selected from either the region E2a or the region E2b. Further, three or more pixels may be selected, and if there are three or more regions where the change in the pixel value is flat corresponding to the blank region 104, one point may be selected from each region.
  • the horizontal direction component of the trend 72 is detected by the trend detection unit 102, the same applies to the case where the vertical direction component of the trend 72 is detected.
  • the aspect which removes the trend 72 from a phase differential image using the detected trend component 107 in the trend removal part 48 is the same as that of 1st Embodiment mentioned above.
  • the absorption differential image generation unit 101 generates an absorption differential image from the actual captured image data 52, but the absorption differential image is preferably generated as follows. First, the absorption differential image generation unit 101 generates a first absorption image from the pre-photographed image data 51 at the time of pre-photographing, and stores it in the offset image storage unit 42, for example. Next, at the time of actual imaging, the absorption differential image 101 generates a second absorption image from the actual captured image data 52. Then, a third absorption image is generated by dividing the second absorption image by the first absorption image, and an absorption differential image to be input to the trend detecting unit 102 is generated by differentiating the third absorption image.
  • the trend can be removed even in the subject H as in the second embodiment. Further, as is clear from the fact that the pixels in the subject H can be used, even when the subject H is present in the entire imaging range 10, the trend is detected by the same method as in the second embodiment described above. Can do.
  • the noise removing unit 43 is configured by a trend removing unit 121 (first noise removing unit) and an offset removing unit 122 (second noise removing unit).
  • the trend removing unit 121 When the phase differential image that has been subjected to the unwrap processing is input from the unwrap processing unit 41, the trend removing unit 121 performs Fourier transform on the phase differential image to remove low-frequency components that are equal to or lower than a predetermined frequency. Thereafter, inverse Fourier transform is performed to generate a phase differential image from which low frequency components are removed. In the case of pre-shooting, the trend removing unit 121 stores the phase differential image from which the low frequency component has been removed in the offset image storage unit 42 as an offset image. In the case of actual photographing, the trend removing unit 121 inputs a phase differential image from which low frequency components are removed to the offset removing unit 122.
  • the offset removing unit 122 acquires an offset image from the offset image storage unit 42 when a phase differential image from which low frequency components are removed is input during the main photographing. Then, the offset noise is removed from the phase differential image by subtracting the offset image from the phase differential image obtained by the actual photographing.
  • the X-ray imaging apparatus configured as described above performs pre-imaging as shown in FIG.
  • a shooting instruction input standby state is set (step S51).
  • the X-ray source 11 performs X at each scanning position “k” while the second grating 22 is intermittently moved by a predetermined scanning pitch by the scanning mechanism 23.
  • the G2 image is detected by the beam irradiation and the X-ray image detector 13 (step S52).
  • M pieces of pre-captured image data 51 are generated and stored in the memory 14.
  • step S 53 a phase differential image is generated from the pre-captured image data 51 by the phase differential image generation unit 40 (step S 53) and unwrapped by the unwrap processing unit 41. Processing is performed (step S54).
  • the unwrapped phase differential image is input to the trend removing unit 121, subjected to Fourier transform (step S55), low frequency components equal to or lower than a predetermined frequency are removed (step S56), and inverse Fourier transform is performed. Is given. Thereby, the inputted phase differential image becomes a phase differential image from which a predetermined low frequency component is removed.
  • the phase differential image from which the low frequency component has been removed is stored in the offset image storage unit 42 as an offset image, and pre-imaging is completed.
  • the main shooting mode is selected as the shooting mode using the operation unit 18a (step S70).
  • a shooting instruction standby state is set (step S71).
  • stripe scanning is performed (step S72), and M main captured image data 52 are stored in the memory 14.
  • the captured image data 52 is read out by the image processing unit 15, a phase differential image is generated by the phase differential image generation unit 40 (step S73), and unwrap processing is performed by the unwrap processing unit 41 (step S74).
  • the unwrapped phase differential image is input to the trend removing unit 121, subjected to Fourier transform (step S75), low frequency components equal to or lower than a predetermined frequency are removed (step S76), and inverse Fourier transform is performed. Is given.
  • the inputted phase differential image becomes a phase differential image from which a predetermined low frequency component is removed.
  • the phase differential image from which the low-frequency component has been removed is input to the offset removing unit 122, and the offset noise is further removed by subtracting the offset image (step S77).
  • the phase differential image from which the offset noise has been removed is recorded in the image recording unit 16.
  • phase contrast image generation unit 44 generates a phase contrast image from the phase differential image from which the offset noise has been removed, and records it in the image recording unit 16 (step S78).
  • the phase differential image and phase contrast image generated in this way are displayed on the monitor 18b (step S79).
  • the phase differential image generated from the pre-captured image data 51 and the main captured image data 52 is Fourier transformed to remove a predetermined low frequency component
  • the low frequency component of offset noise is removed from the phase differential image.
  • the offset noise at the time of pre-photographing and that at the time of main photographing do not completely match, the trend remains when the offset image is subtracted. For this reason, as described above, no trend occurs when the difference between the phase differential image and the offset image from which the low-frequency component, which is mainly offset noise, is previously removed is taken.
  • offset noise also has high frequency components.
  • a pixel defect in the X-ray detector 13 generates high-frequency offset noise.
  • an offset image is acquired and the phase differential image low-frequency component generated at the time of actual imaging. Is subtracted from the offset image.
  • high-frequency offset noise is also removed.
  • the offset noise may be removed by removing low frequency components from the phase differential image obtained by the actual photographing. Thereby, a phase differential image in which neither offset noise nor trend remains can be obtained.
  • the subject H is disposed between the X-ray source 11 and the first lattice 21.
  • the subject H is disposed between the first lattice 21 and the second lattice. It may be arranged between the two.
  • the second grating 22 is moved at the time of fringe scanning.
  • the first grating 21 is oriented in a direction perpendicular to the grating lines or inclined. It may be moved in the direction of
  • the X-ray source 11 that emits cone-beam X-rays emitted from the X-ray source 11 is used.
  • X-rays that emit parallel-beam X-rays are used. It is also possible to use a source.
  • the X-rays emitted from the X-ray source 11 are incident on the first grating 21, and the X-ray source 11 has a single focal point.
  • the X focus may be dispersed by providing a multi-slit (source grid) described in WO 2006/131235 or the like immediately after the exit side of the X-ray source 11.
  • the grid line direction of the multi slit is the Y direction.
  • the lattice lines (lattice grooves) of the multi-slit 150 extend in the Y direction and are parallel to at least one of the first and second lattices 21 and 22.
  • the lattice pitch p 0 in the X direction of the multi slit 150 needs to satisfy Expression (10).
  • the distance L 0 is a distance in the Z direction from the multi slit 150 to the first grating 21.
  • the position of the multi-slit 150 becomes the position of the X-ray focal point, and thus the distance L 1 in the above embodiment is replaced with the distance L 0 .
  • the first and second gratings are used in addition to performing the fringe scanning by moving the first grating 21 or the second grating 22 while the multi-slit 150 is fixed. It is possible to perform fringe scanning by moving the multi slit 150 while 21 and 22 are fixed.
  • the multi slit 150 may be intermittently moved in the X direction using a value (p 0 / M) obtained by dividing the pitch p 0 of the multi slit 150 by M described above as a scanning pitch.
  • the first grating 21 projects the incident X-ray geometrically, but the first grating 21 is known as disclosed in WO 2004/058070 and the like. May be configured to generate the Talbot effect.
  • a small-focus X-ray light source or a multi-slit 150 may be used so as to enhance the spatial coherence of X-rays.
  • the first grating 21 may be a phase grating instead of the absorption grating.
  • the phase type grating is configured by replacing the X-ray absorption part of the absorption type grating with an X-ray phase forming part.
  • the X-ray phase forming part is formed of a material (air, resin, etc.) having a predetermined refractive index difference with respect to the adjacent X-ray transmitting part.
  • the phase-type grating there are known a phase grating that transmits incident X-rays with a phase modulation of ⁇ / 2 and a grating that transmits incident X-rays with a phase modulation of ⁇ / 2.
  • the self-image (G1 image) of the first grating 21 is generated at a position away from the first grating 21 by the Talbot distance Z m downstream in the Z direction.
  • the distance L 2 from the first grid 21 to the second grid 22 is required to be Talbot distance Z m.
  • Talbot distance Z m is dependent on the beam shape of the structure and the X-ray of the first grating 21.
  • the first grating 21 is absorption grating, if X-rays emitted from the X-ray source 11 is a cone beam shape, Talbot distance Z m is represented by the formula (11).
  • “m” is a positive integer.
  • the grating pitches p 1 and p 2 are set so as to substantially satisfy the expression (1) (however, when the multi slit 150 is used, the distance L 1 is replaced with the distance L 0 ).
  • the Talbot distance Z m is And represented by equation (12).
  • “m” is “0” or a positive integer.
  • the grating pitches p 1 and p 2 are set so as to substantially satisfy the expression (1) (however, when the multi slit 150 is used, the distance L 1 is replaced with the distance L 0 ).
  • the Talbot distance Z m is expressed by the equation It is represented by (13).
  • “m” is “0” or a positive integer.
  • “m” is “0” or a positive integer.
  • the grating pitches p 1 and p 2 are set so as to substantially satisfy Expression (14) ( However, in the case of using the multi-slit 150, the distance L 1 is replaced by a distance L 0).
  • the first grating 21 is absorption grating, if X-rays emitted from the X-ray source 11 is a parallel beam shape, Talbot distance Z m is represented by the formula (15).
  • “m” is a positive integer.
  • the Talbot distance Z m is And represented by equation (16).
  • “m” is “0” or a positive integer.
  • the Talbot distance Z m It is represented by (17).
  • “m” is “0” or a positive integer.
  • the grating portion 12 is provided with the two gratings of the first and second gratings 21 and 22.
  • the second grating 22 is omitted and the first grating 21 is omitted. It is also possible to use only.
  • the second grating 22 can be omitted and only the first grating 21 can be provided.
  • This X-ray image detector is a direct conversion type X-ray image detector including a conversion layer that converts X-rays into electric charges and a charge collection electrode that collects electric charges converted in the conversion layer.
  • the charge collection electrode includes a plurality of linear electrode groups.
  • One linear electrode group is obtained by electrically connecting linear electrodes arranged at a constant period, and is arranged so that the phases thereof are different from those of other linear electrode groups.
  • This linear electrode group functions as the second grating 22, and the presence of a plurality of linear electrode groups allows detection of a plurality of G2 images having different phases in one imaging. Therefore, in this configuration, the scanning mechanism 23 can be omitted.
  • the single image data obtained by the X-ray image detector 13 is divided into groups of pixel rows (pixels arranged in the X direction) having different phases from each other with respect to the moire fringes, and a plurality of divided image data is obtained.
  • a phase differential image is generated in the same procedure as the above-described fringe scanning method, assuming that the images are based on a plurality of different G2 images by fringe scanning.
  • the intensity modulation signal described above is expressed as a change in intensity of pixel values for one cycle of moire fringes generated in single image data.
  • the scanning mechanism 23 is omitted, and the phase differential image is obtained based on the single image data obtained by the X-ray image detector 13 via the first and second gratings 21 and 22.
  • a Fourier transform method described in WO2010 / 050484 is known. This Fourier transform method obtains a Fourier spectrum by performing a Fourier transform on the single image data, separates a spectrum corresponding to a carrier frequency (a spectrum carrying phase information) from the Fourier spectrum, and then reverses the spectrum.
  • This is a method of generating a phase differential image by performing Fourier transform.
  • the intensity modulation signal described above is expressed as a change in intensity of pixel values for one cycle of moire fringes generated in a single image data, as in the case of the pixel division method.
  • the present invention can be applied to an industrial radiography apparatus and the like in addition to a radiography apparatus for medical diagnosis.
  • a radiography apparatus for medical diagnosis In addition to X-rays, gamma rays or the like can be used as radiation.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Medical Informatics (AREA)
  • Pathology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Physics & Mathematics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Optics & Photonics (AREA)
  • Veterinary Medicine (AREA)
  • Radiology & Medical Imaging (AREA)
  • Biomedical Technology (AREA)
  • Biophysics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Apparatus For Radiation Diagnosis (AREA)

Abstract

La présente invention a pour but d'obtenir une image différentielle de phase détaillée qui n'a pas de bruit. Un dispositif de radiographie à rayons X (10) comprend une source de rayons X (11), un détecteur de rayons X (13), une grille (12), une unité de génération d'image différentielle de phase (40), une unité de traitement de déroulement (41) et une unité d'élimination de bruit (43). La source de rayon X (11) émet un rayonnement vers un sujet. Le détecteur de rayons X (13) détecte les rayons X qui sont émis à partir de la source de rayons X et génère des données d'image. La grille (12) est positionnée entre la source de rayons X et le détecteur de rayons X. L'unité de génération d'image différentielle de phase (40) génère une image différentielle de phase sur la base de données d'images (51, 52) qui sont obtenues par le détecteur de rayons X. L'unité de traitement de déroulement (41) réalise un traitement de déroulement sur l'image différentielle de phase. Lors de la soustraction d'une image de décalage qui représente un bruit de décalage lorsqu'un sujet (H) n'est pas présent à partir d'une image de sujet qui est obtenue par photographie du sujet (H), l'unité d'élimination de bruit (43) élimine une tendance qui est un bruit qui reste dans l'image de sujet à partir de l'image de sujet.
PCT/JP2012/075789 2011-10-06 2012-10-04 Dispositif de radiographie et procédé de traitement d'image Ceased WO2013051647A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2011-222237 2011-10-06
JP2011222237 2011-10-06
JP2012221899A JP2013090920A (ja) 2011-10-06 2012-10-04 放射線撮影装置及び画像処理方法
JP2012-221899 2012-10-04

Publications (1)

Publication Number Publication Date
WO2013051647A1 true WO2013051647A1 (fr) 2013-04-11

Family

ID=48043800

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2012/075789 Ceased WO2013051647A1 (fr) 2011-10-06 2012-10-04 Dispositif de radiographie et procédé de traitement d'image

Country Status (2)

Country Link
JP (1) JP2013090920A (fr)
WO (1) WO2013051647A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018199739A (ja) * 2018-10-02 2018-12-20 ロート製薬株式会社 ミノキシジル含有外用組成物

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004058070A1 (fr) * 2002-12-26 2004-07-15 Atsushi Momose Systeme d'imagerie a rayons x et procede d'imagerie associe
JP2008082869A (ja) * 2006-09-27 2008-04-10 Mitsutoyo Corp 干渉縞解析における位相接続方法
JP2011045655A (ja) * 2009-08-28 2011-03-10 Konica Minolta Medical & Graphic Inc Ｘ線撮影装置
WO2012147671A1 (fr) * 2011-04-25 2012-11-01 富士フイルム株式会社 Dispositif de radiographie et procédé de traitement de l'image

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004058070A1 (fr) * 2002-12-26 2004-07-15 Atsushi Momose Systeme d'imagerie a rayons x et procede d'imagerie associe
JP2008082869A (ja) * 2006-09-27 2008-04-10 Mitsutoyo Corp 干渉縞解析における位相接続方法
JP2011045655A (ja) * 2009-08-28 2011-03-10 Konica Minolta Medical & Graphic Inc Ｘ線撮影装置
WO2012147671A1 (fr) * 2011-04-25 2012-11-01 富士フイルム株式会社 Dispositif de radiographie et procédé de traitement de l'image

Also Published As

Publication number Publication date
JP2013090920A (ja) 2013-05-16

Similar Documents

Publication Publication Date Title
JP5475737B2 (ja) 放射線撮影装置及び画像処理方法
JP5378335B2 (ja) 放射線撮影システム
JP5731214B2 (ja) 放射線撮影システム及びその画像処理方法
JP5548085B2 (ja) 回折格子の調整方法
JP2012090944A (ja) 放射線撮影システム及び放射線撮影方法
JP2012090945A (ja) 放射線検出装置、放射線撮影装置、放射線撮影システム
JP5783987B2 (ja) 放射線撮影装置
JP2011224329A (ja) 放射線撮影システム及び方法
JP2012200567A (ja) 放射線撮影システム及び放射線撮影方法
JP2011224330A (ja) 放射線撮影システム及びそのオフセット補正方法
JP2011206490A (ja) 放射線撮影システム及び放射線撮影方法
JP2013116313A (ja) 放射線撮影装置及び放射線撮影方法
JP2013146537A (ja) 放射線撮影装置及び画像処理方法
JP2013042788A (ja) 放射線撮影装置及びアンラップ処理方法
WO2013038881A1 (fr) Dispositif de radiographie et procédé de traitement d'image
JP5635169B2 (ja) 放射線撮影システム
WO2013051647A1 (fr) Dispositif de radiographie et procédé de traitement d'image
JP5610480B2 (ja) 放射線画像処理装置及び方法
JP6365746B2 (ja) 画像処理装置、ｘ線撮影システム及び画像処理方法
JP2013150780A (ja) 放射線撮影装置及び放射線撮影方法
JP2013063098A (ja) 放射線撮影装置及び画像処理方法
JP2013063166A (ja) 放射線撮影装置及び画像処理方法
WO2013027519A1 (fr) Dispositif de radiographie et procédé de déroulement
WO2013088878A1 (fr) Procédé et appareil radiographiques
WO2013027536A1 (fr) Dispositif de radiographie et procédé de radiographie

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: 12838217

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: 12838217

Country of ref document: EP

Kind code of ref document: A1