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公开(公告)号：US20180368790A1
公开(公告)日：2018-12-27
申请号：US16063706
申请日：2016-12-21
Applicant: HITACHI, LTD.
Inventor： Takafumi ISHITSU , Isao TAKAHASHI , Kazuma YOKOI , Makoto SATOU
Abstract: A radiation imaging apparatus provided with a detector capable of improving correction accuracy at a high counting rate. The present invention is provided with: grids that remove scattered beams that emanate from an object; and a plurality of detector sub-pixels arranged so as to divide the gap between the grids into three or more segments, wherein the area of each of the detector sub-pixels located below the wall surface of the grids is larger than that of each of the other detector sub-pixels in a planar view. The size of each of the detector sub-pixels not located below the wall surface of the grids is expressed as (Pg−Tg−Lsplit×2)/N, where Pg represents the pitch between the grids, Tg represents the thickness of each of the grids, and N represents the number of segments formed by the detector sub-pixels between the grids.
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公开(公告)号：US20210212646A1
公开(公告)日：2021-07-15
申请号：US16891831
申请日：2020-06-03
Applicant: Hitachi, Ltd.
Inventor： Kazuma YOKOI
Abstract: With the aim of providing a radiation imaging apparatus and a calibration method for photon counting detectors, being able to discriminate between soft and adipose tissues with high accuracy, there is disclosed a radiation imaging apparatus quipped with photon counting detectors which output an electric signal corresponding to photon energy which is energy of radiation photons incident thereon, the radiation imaging apparatus including a storage unit which stores relationships between linear attenuation coefficients and the photon energy with regard to multiple materials; a calculation unit which calculates normalized attenuation coefficients which are linear attenuation coefficients normalized by dividing linear attenuation coefficients per unit of photon energy by a linear attenuation coefficient at given photon energy with respect to each material; and a selection unit which selects basal materials which are used in relation to materials to be discriminated which are intended to be discriminated, based on the normalized attenuation coefficients.
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公开(公告)号：US20200323502A1
公开(公告)日：2020-10-15
申请号：US16305777
申请日：2017-09-08
Applicant: HITACHI, LTD.
Inventor： Shinichi KOJIMA , Fumito WATANABE , Yasutaka KONNO , Isao TAKAHASHI , Kazuma YOKOI
Abstract: X-ray photons are counted as to each of energy bands (bins) to which optimum energy ranges are provided, and an image with reduced noise is displayed in a short time. An energy range of at least one of multiple energy bands in an X-ray detector is adjusted, on the basis of a distribution of degrees of X-ray attenuation at respective energy levels, the distribution of degrees of X-ray attenuation being measured in advance with respect to a predetermined direction of a subject. By using the X-ray detector with the energy bands after the adjustment, photon-counting CT imaging is performed.
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公开(公告)号：US20210106292A1
公开(公告)日：2021-04-15
申请号：US16876185
申请日：2020-05-18
Applicant: Hitachi, Ltd.
Inventor： Shinichi KOJIMA , Kazuma YOKOI , Isao TAKAHASHI , Fumito WATANABE , Fuyuhiko TERAMOTO , Taiga GOTOU
Abstract: A material decomposition apparatus for performing decomposition of a material in an object. The apparatus includes a data storage section for storing correction data preliminarily generated by decomposing one of three or more materials into the other two materials, a data input section to which radiation data of the object is inputted, the radiation data being divided into a plurality of energy levels, and a decomposition processing section for repeatedly performing two-material decomposition for decomposition of the other two materials of the three or more materials using the radiation data at different energy levels and the correction data to perform decomposition of the inside of the object into the three or more materials.
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5.发明申请公开(公告)号：US20190105002A1
公开(公告)日：2019-04-11
申请号：US16099492
申请日：2017-06-02
Applicant: HITACHI, LTD.
Inventor： Kazuma YOKOI
CPC classification number: A61B6/032 , A61B6/482 , A61B6/5258 , G06T11/006 , G06T2207/10081
Abstract: Base substance thickness projection estimation values (124) and base substance thickness projection estimation error values (125) of M (M≤N) base substances are estimated based on measured count projection values (121) using N energy windows for a subject. The base substance thickness projection estimated values (124) are updated such that a likelihood in accordance with a joint probability density of all of X-ray projection paths based on the base substance thickness projection estimated error values (125) increases. The obtained second base substance thickness projection assumed value (127) is subjected to back projection, thereby obtaining a base substance concentration image estimation value (128).
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Patent Agency Ranking
公开(公告)号：US20180061097A1
公开(公告)日：2018-03-01
申请号：US15561231
申请日：2016-03-08
Applicant: HITACHI, LTD.
Inventor： Kazuma YOKOI , Yushi TSUBOTA
CPC classification number: G06T11/206 , A61B6/032 , A61B6/4241 , A61B6/461 , A61B6/482 , A61B6/5205 , A61B6/5217 , A61B6/5258 , G01N2223/206 , G01N2223/419 , G01N2223/6126 , G06T11/005 , G06T2211/408
Abstract: The purpose of the present invention is to reduce statistical errors in material decomposition images. In order to achieve this purpose, the present invention is characterized by having: a scatter plot generation unit (414) that generates a scatter plot in which the axes represent the concentrations of base materials used in base material decomposition and pixels of a material decomposition image output as a result of the base material decomposition are plotted against the corresponding concentrations of the base materials of the base material decomposition; an angle processing unit (415) that rotates the scatter plot to minimize the statistical errors of plot points plotted thereon; and a pixel conversion unit (416) that converts the pixels of the material decomposition image on the basis of the pixels in the scatter plot where the statistical errors are minimized by the error minimization unit.
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公开(公告)号：US20200278461A1
公开(公告)日：2020-09-03
申请号：US16797609
申请日：2020-02-21
Applicant: Hitachi, Ltd.
Inventor： Kazuma YOKOI , Isao TAKAHASHI
Abstract: A radiation imaging device capable of reducing the number of measurement times of calibration data used in pile up correction while maintaining the accuracy of the pile up correction. The radiation imaging device has a photon counting type detector to output an electric signal corresponding to energy of an incident radiation photon. The radiation imaging device includes: an extraction unit that extracts a component by the number of pile ups from a material spectrum, as a photon energy spectrum, obtained by detecting a radioactive ray transmitted through a calibration member, formed by combining plural basal substances having different radiation attenuation coefficients, with the photon counting type detector; and a synthesis unit that generates a calibrated equivalent spectrum, as a photon energy spectrum to be collated with an imaging spectrum obtained by imaging a subject by synthesizing the components by the number of pile ups based on the imaging spectrum.
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公开(公告)号：US20200245956A1
公开(公告)日：2020-08-06
申请号：US16636404
申请日：2018-06-07
Applicant: HITACHI, LTD.
Inventor： Kazuma YOKOI
Abstract: An X-ray CT device and a computing unit to use a projection-based method for image reconstruction are included. The computing unit sets a coordinate space having coordinate axes of the thicknesses of base materials and likelihood of said thicknesses, and then based on X-ray attenuation responses, executes: a first search to search in a direction perpendicular to a ridge direction of likelihood contours for a first estimated thickness having the highest likelihood, starting with an estimated thickness input value set in the coordinate space; a second search to search for a second estimated thickness having the highest likelihood, starting with a shifted starting point at a position shifted from the estimated thickness input value; and a third search to search on a line connecting the first estimated thickness with the second estimated thickness for the highest likelihood estimator having the highest likelihood, to obtain an estimated thickness output value.
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9.发明申请公开(公告)号：US20180049707A1
公开(公告)日：2018-02-22
申请号：US15560291
申请日：2016-03-18
Applicant: HITACHI, LTD.
Inventor： Takafumi ISHITSU , Isao TAKAHASHI , Kazuma YOKOI
CPC classification number: A61B6/4241 , A61B6/032 , A61B6/037 , A61B6/4233 , A61B6/4258 , A61B6/4291 , G01T1/17 , G01T1/172 , G01T1/36
Abstract: To improve performance in Photon Counting CT, pixel miniaturization, a reduction in circuit dead time, and dealing with scattered radiation and charge sharing are important. In addition, because the number of circuits increases, a reduction in power consumption of each circuit is important. Under these constraints, circuitry that deals with the scattered radiation is provided. Each pixel includes a circuit that determines whether radiation has been detected by another, adjacent pixel at the same time, and counters that count the radiation are switched on the basis of the result of the determination. On the basis of this result, counts of non-coincident events are primarily used, and coincident counts are used after being corrected, for reconstruction data.
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10.发明申请公开(公告)号：US20200301031A1
公开(公告)日：2020-09-24
申请号：US16768708
申请日：2019-01-08
Applicant: Hitachi, Ltd.
Inventor： Kazuma YOKOI
Abstract: A radiation imaging apparatus provided with a photon counting type detector for outputting an electric signal corresponding to energy of an incident radiation photon includes a measured value recording unit for measuring an attenuation value in the presence of a known calibration member while changing a threshold value of a detector output of the photon counting type detector and recording a measured value of the attenuation value for each threshold value of the detector output, a theoretical value calculation unit for calculating a theoretical value of the attenuation value in the presence of the calibration member with respect to multiple energies, a calibration information acquisition unit for acquiring a relation between the threshold value and the energy as calibration information by performing collation between the measured value and the theoretical value, and a calibration processing unit for converting the electric signal outputted from the photon counting type detector into energy.
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