Patents by Inventor Kazuma Yokoi

Kazuma Yokoi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 12053321
    Abstract: There are provided a phantom capable of reducing the time required to acquire calibration data even if a radiation field is large, a radiographic imaging device, and a method for calibrating a photon counting detector. A phantom, which is used in acquisition of calibration data for a photon counting detector that outputs an electric signal based on photon energy of incident radiation, includes a first basis material and a second basis material that are known materials. The first basis material has a smaller attenuation coefficient for the radiation than that of the second basis material. The first basis material varies in thickness in a stepwise fashion in a direction perpendicular to a radiation field of the radiation and, in each step, the step decreases in thickness with distance from a center of the radiation field in a direction of arrangement of detection elements of the photon counting detector.
    Type: Grant
    Filed: June 2, 2022
    Date of Patent: August 6, 2024
    Assignee: FUIIFILM Healthcare Corporation
    Inventor: Kazuma Yokoi
  • Patent number: 12048672
    Abstract: Provided is packaged medicine capable of inhibiting deterioration of electrodes over a long period of time and reliably transmitting a signal after ingestion even when a long period of time has elapsed since production to ingestion. The packaged medicine includes a solid medicine including drug powder and a micro-device, a container provided with a solid medicine accommodating space accommodating the solid medicine therein, and inert gas encapsulated in the solid medicine accommodating space. The micro-device includes two electrodes with mutually different ionization tendencies and a transmitter operable to transmit a signal using electromotive force generated when the electrodes come in contact with electrolyte.
    Type: Grant
    Filed: May 1, 2018
    Date of Patent: July 30, 2024
    Assignee: Otsuka Pharmaceutical Co., Ltd.
    Inventors: Kazuma Yokoi, Kenzo Kashihara, Kenta Yamamoto, Takahiro Sonoki, Shohei Yamada
  • Patent number: 11944468
    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.
    Type: Grant
    Filed: May 18, 2020
    Date of Patent: April 2, 2024
    Assignee: FUJIFILM HEALTHCARE CORPORATION
    Inventors: Shinichi Kojima, Kazuma Yokoi, Isao Takahashi, Fumito Watanabe, Fuyuhiko Teramoto, Taiga Gotou
  • Publication number: 20230233164
    Abstract: There is provided a PCCT apparatus capable of correcting a band artifact of one material decomposition image and a band artifact of another material decomposition image. The PCCT apparatus obtains projection data divided into plural energy bins by irradiating a subject with X-rays, and includes: a first correction unit that corrects a band artifact of a first material decomposition image among plural material decomposition images created on the basis of the projection data, and calculates a first correction amount that is a correction amount for the band artifact; an energy calculation unit that calculates an average energy of X-rays that transmit the subject; and a second correction unit that corrects the band artifact of a second material decomposition image using a second correction amount that is a correction amount calculated on the basis of the first correction amount and the average energy.
    Type: Application
    Filed: October 12, 2022
    Publication date: July 27, 2023
    Inventors: Shinichi Kojima, Fumito Watanabe, Isao Takahashi, Kazuma Yokoi, Taiga Goto, Fuyuhiko Teramoto, Ryosuke Tsuchida
  • Publication number: 20230200757
    Abstract: An X-ray CT apparatus and a correction method of projection data that are capable of suppressing artifacts generated in the vicinity of an edge portion of a test subject are provided. The X-ray CT apparatus for photographing a test subject is characterized by comprising: a correction data creation unit that creates correction data using difference data between measurement projection data for each X-ray energy obtained by photographing a known phantom having a known composition, a known shape, and a size smaller than a photographing field of view of the X-ray CT apparatus and calculation projection data for each X-ray energy calculated on the basis of X-ray transmission lengths obtained from the shape of the known phantom; and a correction unit that corrects projection data for each X-ray energy of the test subject using the correction data.
    Type: Application
    Filed: October 4, 2022
    Publication date: June 29, 2023
    Inventor: Kazuma Yokoi
  • Publication number: 20220395248
    Abstract: There are provided a phantom capable of reducing the time required to acquire calibration data even if a radiation field is large, a radiographic imaging device, and a method for calibrating a photon counting detector. A phantom, which is used in acquisition of calibration data for a photon counting detector that outputs an electric signal based on photon energy of incident radiation, includes a first basis material and a second basis material that are known materials. The first basis material has a smaller attenuation coefficient for the radiation than that of the second basis material. The first basis material varies in thickness in a stepwise fashion in a direction perpendicular to a radiation field of the radiation and, in each step, the step decreases in thickness with distance from a center of the radiation field in a direction of arrangement of detection elements of the photon counting detector.
    Type: Application
    Filed: June 2, 2022
    Publication date: December 15, 2022
    Inventor: Kazuma Yokoi
  • Patent number: 11300696
    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.
    Type: Grant
    Filed: February 21, 2020
    Date of Patent: April 12, 2022
    Assignee: FUJIFILM Healthcare Corporation
    Inventors: Kazuma Yokoi, Isao Takahashi
  • Patent number: 11291416
    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 the 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.
    Type: Grant
    Filed: June 7, 2018
    Date of Patent: April 5, 2022
    Assignee: FUJIFILM HEALTHCARE CORPORATION
    Inventor: Kazuma Yokoi
  • Patent number: 11163074
    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.
    Type: Grant
    Filed: January 8, 2019
    Date of Patent: November 2, 2021
    Assignee: HITACHI, LTD.
    Inventor: Kazuma Yokoi
  • Patent number: 11096641
    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 equipped 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
    Type: Grant
    Filed: June 3, 2020
    Date of Patent: August 24, 2021
    Assignee: HITACHI, LTD.
    Inventor: Kazuma Yokoi
  • Publication number: 20210212646
    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
    Type: Application
    Filed: June 3, 2020
    Publication date: July 15, 2021
    Inventor: Kazuma YOKOI
  • Publication number: 20210106292
    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.
    Type: Application
    Filed: May 18, 2020
    Publication date: April 15, 2021
    Inventors: Shinichi KOJIMA, Kazuma YOKOI, Isao TAKAHASHI, Fumito WATANABE, Fuyuhiko TERAMOTO, Taiga GOTOU
  • Patent number: 10905388
    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.
    Type: Grant
    Filed: September 8, 2017
    Date of Patent: February 2, 2021
    Assignee: HITACHI, LTD.
    Inventors: Shinichi Kojima, Fumito Watanabe, Yasutaka Konno, Isao Takahashi, Kazuma Yokoi
  • Publication number: 20200323502
    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.
    Type: Application
    Filed: September 8, 2017
    Publication date: October 15, 2020
    Applicant: HITACHI, LTD.
    Inventors: Shinichi KOJIMA, Fumito WATANABE, Yasutaka KONNO, Isao TAKAHASHI, Kazuma YOKOI
  • Publication number: 20200301031
    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.
    Type: Application
    Filed: January 8, 2019
    Publication date: September 24, 2020
    Inventor: Kazuma YOKOI
  • Publication number: 20200278461
    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.
    Type: Application
    Filed: February 21, 2020
    Publication date: September 3, 2020
    Inventors: Kazuma YOKOI, Isao TAKAHASHI
  • Publication number: 20200245956
    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.
    Type: Application
    Filed: June 7, 2018
    Publication date: August 6, 2020
    Inventor: Kazuma YOKOI
  • Publication number: 20200093700
    Abstract: Provided is packaged medicine capable of inhibiting deterioration of electrodes over a long period of time and reliably transmitting a signal after ingestion even when a long period of time has elapsed since production to ingestion. The packaged medicine includes a solid medicine including drug powder and a micro-device, a container provided with a solid medicine accommodating space accommodating the solid medicine therein, and inert gas encapsulated in the solid medicine accommodating space. The micro-device includes two electrodes with mutually different ionization tendencies and a transmitter operable to transmit a signal using electromotive force generated when the electrodes come in contact with electrolyte.
    Type: Application
    Filed: May 1, 2018
    Publication date: March 26, 2020
    Applicant: Otsuka Pharmaceutical Co., Ltd.
    Inventors: Kazuma YOKOI, Kenzo KASHIHARA, Kenta YAMAMOTO, Takahiro SONOKI, Shohei YAMADA
  • Publication number: 20200015769
    Abstract: To provide an X-ray CT apparatus capable of correcting a difference of scattered radiation quantities contained in the projection data even in a case where a plurality of detection elements are disposed between collimator plates. The X-ray CT apparatus includes: an X-ray irradiation section for X-ray radiation; an X-ray detector including a plurality of detection elements for detecting the X-ray; a plurality of collimator plates disposed between the X-ray irradiation section and the X-ray detector so as to reduce scattered radiation; a reconstruction portion for reconstructing a tomographic image by using projection data generated based on an output from the X-ray detector; and a correction portion for correcting the projection data by using different correction functions according to the positions of the plural detection elements disposed between the collimator plates.
    Type: Application
    Filed: June 13, 2019
    Publication date: January 16, 2020
    Inventors: Shinichi KOJIMA, Fumito WATANABE, Kazuma YOKOI, Fuyuhiko TERAMOTO
  • Patent number: 10363002
    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).
    Type: Grant
    Filed: June 2, 2017
    Date of Patent: July 30, 2019
    Assignee: Hitachi, Ltd.
    Inventor: Kazuma Yokoi