Patents by Inventor Fumito Watanabe

Fumito Watanabe 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).

  • Publication number: 20200408939
    Abstract: To provide a radiation imaging system which is adapted to downsize a photon counting radiation detector including a semiconductor layer for detecting photons of radiation and a collimator for suppressing incidence of scattered rays, and which ensures high voltage resistance. The radiation imaging system includes: a radiation source; a radiation detector; and a support portion for supporting the radiation source and the radiation detector in opposed relation. The system has a structure wherein the radiation detector includes a plurality of detecting element modules arranged in an arcuate form. The detecting element module includes a base fixed to the support portion; a semiconductor layer; a high-voltage wire for supplying high voltage to the semiconductor layer; a collimator for suppressing scattered rays, and a supporting column disposed at place within a predetermined distance from the semiconductor layer.
    Type: Application
    Filed: March 4, 2020
    Publication date: December 31, 2020
    Applicant: Hitachi, Ltd.
    Inventors: Masafumi Onouchi, Takafumi Ishitsu, Fumito Watanabe
  • 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: 20200225368
    Abstract: The present invention provides a radiation imaging apparatus capable of maintaining the quality of an image obtained even when a dose incident on a radiation detector changes suddenly. The present invention is a radiation imaging apparatus including a radiation source, a radiation detector to detect radiation emitted from the radiation source, and a cooling unit to cool the radiation detector; and is characterized in that the radiation detector has a counting circuit to output a number of photons in radiation counted per unit time as a photon counting rate, and the cooling unit controls a coolability of the radiation detector in response to the photon counting rate.
    Type: Application
    Filed: December 18, 2019
    Publication date: July 16, 2020
    Applicant: Hitachi, Ltd.
    Inventors: Masafumi ONOUCHI, Takafumi ISHITSU, Fumito WATANABE
  • Patent number: 10542947
    Abstract: The present invention is directed to make a photon-counting CT apparatus capable of more accurate data acquisition. Such apparatus is provided with a reference detection unit and a time measuring instrument to measure temporal fluctuations in a rotational direction of an X-ray irradiation unit. The apparatus corrects temporal fluctuations in the rotational direction involved in data measured by the reference detection unit, using time measurement data which is output by the time measuring instrument. Using corrected measurement data measured by the reference detection unit, the apparatus makes corrections of fluctuations pertaining to the X-ray tube of the X-ray irradiation unit and pile-up. Data corrections with high accuracy are thus enabled.
    Type: Grant
    Filed: November 17, 2016
    Date of Patent: January 28, 2020
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Kojima, Yasutaka Konno, Fumito Watanabe, Isao Takahashi
  • 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: 10302779
    Abstract: A flat pixel (20) is a single unit composing a radiation detector and is configured so as to be divided into at least four subpixels (21) such that even if a prescribed number of subpixels (21) are removed from each pixel (20) in order of largest effective area, the centroid (51) of the effective area of the entirety of the remaining subpixels (21) is positioned within a similar-shape region (30) having the same centroid (50) as the pixel (20) and having sides of lengths that are half those of the pixel (20).
    Type: Grant
    Filed: June 18, 2015
    Date of Patent: May 28, 2019
    Assignee: Hitachi, Ltd.
    Inventors: Isao Takahashi, Kazuma Yokoi, Eiji Moro, Yuichiro Ueno, Yasutaka Konno, Fumito Watanabe, Shinichi Kojima
  • Publication number: 20190021685
    Abstract: The present invention is directed to make a photon-counting CT apparatus capable of more accurate data acquisition. Such apparatus is provided with a reference detection unit and a time measuring instrument to measure temporal fluctuations in a rotational direction of an X-ray irradiation unit. The apparatus corrects temporal fluctuations in the rotational direction involved in data measured by the reference detection unit, using time measurement data which is output by the time measuring instrument. Using corrected measurement data measured by the reference detection unit, the apparatus makes corrections of fluctuations pertaining to the X-ray tube of the X-ray irradiation unit and pile-up. Data corrections with high accuracy are thus enabled.
    Type: Application
    Filed: November 17, 2016
    Publication date: January 24, 2019
    Inventors: Shinichi KOJIMA, Yasutaka KONNO, Fumito WATANABE, Isao TAKAHASHI
  • Patent number: 10022099
    Abstract: A change of X-ray radiation quality due to a material existing between an X-ray source and a detection element is estimated and corrected. Accordingly, deterioration of material discrimination ability in a dual energy imaging method can be prevented. An X-ray imaging apparatus is provided with an inherent filtration calculator configured to use measured data obtained by imaging air at two or more types of different tube voltages to calculate a deviation from a reference radiation quality, as a transmission length (inherent filtration) of a predetermined reference material. A reference-material transmission-length conversion is applied to the measured data according to the dual energy imaging method, thereby calculating the reference material transmission length (inherent filtration). When a subject is imaged, the dual energy imaging is performed by adding the inherent filtration calculated as to each detection element, and this produces an image with the change of radiation quality having been corrected.
    Type: Grant
    Filed: October 22, 2014
    Date of Patent: July 17, 2018
    Assignee: Hitachi, Ltd.
    Inventors: Yushi Tsubota, Fumito Watanabe, Yasutaka Konno, Shinichi Kojima, Keisuke Yamakawa, Shinji Kurokawa
  • Patent number: 9977137
    Abstract: Provided is a technique in an X-ray imaging apparatus for implementing data interpolation approximating an ideal point response trajectory interpolation, along with reducing calculation load. A method is provided to perform interpolation at high speed, in a direction along the point response trajectory. Sinograms are interpolated in advance from measured data, as to representative angles (e.g., 0°, ±30°, ±60°, and 90°) only. When a pixel targeted for back projection is determined at the time of reconstruction, a slope of the point response trajectory is determined as to each view. According to the slope of the trajectory, each representative sinogram is added with weight, whereby interpolation data in association with any angle can be obtained.
    Type: Grant
    Filed: July 23, 2015
    Date of Patent: May 22, 2018
    Assignee: Hitachi, Ltd.
    Inventors: Yushi Tsubota, Shinji Kurokawa, Keisuke Yamakawa, Yasutaka Konno, Shinichi Kojima, Fumito Watanabe
  • Patent number: 9924917
    Abstract: The present invention is capable of distinguishing four types or more of substances such as air, water (soft tissues), contrast medium, and bones (calcification) to diagnose progress of atherosclerotic sites using dual energy imaging. A subject is imaged with two types of different tube voltages and an image obtained by image reconstruction is binarized to carry out a reprojection process; thereby, the distance of penetration of air is estimated, the contribution of air in measurement projection data is determined, and the amount of reduction by the air is deducted from the projection data so as to enable distinction between four or more substances such as air, water (soft tissues), contrast medium, and bones (calcification).
    Type: Grant
    Filed: May 2, 2014
    Date of Patent: March 27, 2018
    Assignee: Hitachi, Ltd.
    Inventors: Yushi Tsubota, Fumito Watanabe, Yasutaka Konno, Shinichi Kojima, Keisuke Yamakawa
  • Patent number: 9888902
    Abstract: In X-ray CT devices, degradation of quantitative determination ability for CT values resulting from the beam hardening (BH) effect of X-ray is prevented. X-ray absorption characteristic S obtained by simulation and a target value T thereof are saved beforehand, the simulation value S is revised by using projection data measured by maintenance measurement for obtaining basic data required for BH correction, and a BH correction coefficient is calculated by using the revised X-ray absorption characteristic S and the target value T. With a few actually measured values, BH correction accuracy can be improved, and reduction of incorrect diagnosis resulting from inhomogeneity of the CT values and improvement in the diagnostic ability based on improvement in quantitative determination ability for the CT values can be realized.
    Type: Grant
    Filed: July 5, 2012
    Date of Patent: February 13, 2018
    Assignee: Hitachi, Ltd.
    Inventors: Hironori Ueki, Fumito Watanabe
  • Publication number: 20170276808
    Abstract: A flat pixel (20) is a single unit composing a radiation detector and is configured so as to be divided into at least four subpixels (21) such that even if a prescribed number of subpixels (21) are removed from each pixel (20) in order of largest effective area, the centroid (51) of the effective area of the entirety of the remaining subpixels (21) is positioned within a similar-shape region (30) having the same centroid (50) as the pixel (20) and having sides of lengths that are half those of the pixel (20).
    Type: Application
    Filed: June 18, 2015
    Publication date: September 28, 2017
    Inventors: Isao TAKAHASHI, Kazuma YOKOI, Eiji MORO, Yuichiro UENO, Yasutaka KONNO, Fumito WATANABE, Shinichi KOJIMA
  • Publication number: 20170176609
    Abstract: Provided is a technique in an X-ray imaging apparatus for implementing data interpolation approximating an ideal point response trajectory interpolation, along with reducing calculation load. A method is provided to perform interpolation at high speed, in a direction along the point response trajectory. Sinograms are interpolated in advance from measured data, as to representative angles (e.g., 0°, ±30°, ±60°, and 90°) only. When a pixel targeted for back projection is determined at the time of reconstruction, a slope of the point response trajectory is determined as to each view. According to the slope of the trajectory, each representative sinogram is added with weight, whereby interpolation data in association with any angle can be obtained.
    Type: Application
    Filed: July 23, 2015
    Publication date: June 22, 2017
    Inventors: Yushi TSUBOTA, Shinji KUROKAWA, Keisuke YAMAKAWA, Yasutaka KONNO, Shinichi KOJIMA, Fumito WATANABE
  • Patent number: 9552659
    Abstract: Difference of resolution depending on imaging position in one reconstructed image generated in the FFS method is reduced to improve measurement accuracy. The X-ray CT device interpolates missing data of the projection data obtained by the FFS method with view direction interpolation processing using real data of the projection data lining up along the angular direction of the rotational movement, and channel direction interpolation processing using real data of the projection data lining up along the channel direction, and generates a reconstructed image, in which contribution ratios of the projection data having been subjected to the view direction interpolation processing and the projection data having been subjected to the channel direction interpolation processing differ according to position of pixel in the reconstructed image.
    Type: Grant
    Filed: January 15, 2014
    Date of Patent: January 24, 2017
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Kojima, Keisuke Yamakawa, Fumito Watanabe, Yushi Tsubota, Yasutaka Konno
  • Patent number: 9482629
    Abstract: An X-ray CT apparatus includes: an X-ray generating unit configured to generate an X ray; an X-ray detecting unit including a plurality of X-ray detectors, each configured to detect the X ray generated from the X-ray generating unit and transmitted through an object; and an image generating unit configured to correct and reconstruct signals acquired by the X-ray detecting unit. While crosstalk correction of a plurality of the X-ray detectors is performed at the image generating unit, correction of a locally attenuating component is previously performed and correction of a whole component of the crosstalk is performed when the image is reconstructed.
    Type: Grant
    Filed: June 3, 2011
    Date of Patent: November 1, 2016
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Kojima, Fumito Watanabe, Hironori Ueki, Yasutaka Konno, Yushi Tsubota, Yukiko Ueki
  • Publication number: 20160199018
    Abstract: A change of X-ray radiation quality due to a material existing between an X-ray source and a detection element is estimated and corrected. Accordingly, deterioration of material discrimination ability in a dual energy imaging method can be prevented. An X-ray imaging apparatus is provided with an inherent filtration calculator configured to use measured data obtained by imaging air at two or more types of different tube voltages to calculate a deviation from a reference radiation quality, as a transmission length (inherent filtration) of a predetermined reference material. A reference-material transmission-length conversion is applied to the measured data according to the dual energy imaging method, thereby calculating the reference material transmission length (inherent filtration). When a subject is imaged, the dual energy imaging is performed by adding the inherent filtration calculated as to each detection element, and this produces an image with the change of radiation quality having been corrected.
    Type: Application
    Filed: October 22, 2014
    Publication date: July 14, 2016
    Inventors: Yushi TSUBOTA, Fumito WATANABE, Yasutaka KONNO, Shinichi KOJIMA, Keisuke YAMAKAWA, Shinji KUROKAWA
  • Patent number: 9380987
    Abstract: In order to suppress reduction in sensitivity when acquiring high-resolution data, an X-ray CT device is provided with an X-ray source that irradiates a patient with X-rays, and an X-ray detector that detects the X-rays. The X-ray detector includes a plurality of detection elements (scintillators and photodiodes) arrayed in a first direction, and a plurality of separators that separate the detection elements arrayed in the first direction respectively from each other. The separators each have a first-direction width which is a width in the first direction, first-direction widths of some separators each arrayed every predetermined number of separators being different from first-direction widths of the other separators.
    Type: Grant
    Filed: December 12, 2012
    Date of Patent: July 5, 2016
    Assignee: Hitachi Medical Corporation
    Inventors: Shinichi Kojima, Fumito Watanabe, Hironori Ueki, Yasutaka Konno, Yushi Tsubota
  • Patent number: 9307949
    Abstract: It is an object to prevent a poor X-ray CT image due to scattered X-rays. An X-ray CT scanner (100) uses an X-ray detector (4), etc., to scan (F1) an object (3) to obtain X-ray transmission image data, and estimate (F3) an X-ray absorption coefficient distribution inside the object (3) based on the scanned X-ray transmission image data. Next, the X-ray CT scanner (100) performs a Monte Carlo simulation on a simulated object (3) having the X-ray absorption coefficient distribution estimated, and estimates (F4 and F7) a point spread function or scattered X-ray distribution derived from the object. Then, the X-ray CT scanner (100) corrects (F5 and F8), based on the point spread function or scattered X-ray distribution estimated, the X-ray transmission image data, and finally creates (F6 and F9) an image of the X-ray absorption coefficient distribution of the object (3).
    Type: Grant
    Filed: December 12, 2012
    Date of Patent: April 12, 2016
    Assignee: HITACHI MEDICAL CORPORATION
    Inventors: Yushi Tsubota, Fumito Watanabe, Hironori Ueki, Yasutaka Konno, Shinichi Kojima
  • Publication number: 20160081643
    Abstract: The present invention is capable of distinguishing four types or more of substances such as air, water (soft tissues), contrast medium, and bones (calcification) to diagnose progress of atherosclerotic sites using dual energy imaging. A subject is imaged with two types of different tube voltages and an image obtained by image reconstruction is binarized to carry out a reprojection process; thereby, the distance of penetration of air is estimated, the contribution of air in measurement projection data is determined, and the amount of reduction by the air is deducted from the projection data so as to enable distinction between four or more substances such as air, water (soft tissues), contrast medium, and bones (calcification).
    Type: Application
    Filed: May 2, 2014
    Publication date: March 24, 2016
    Inventors: Yushi TSUBOTA, Fumito WATANABE, Yasutaka KONNO, Shinichi KOJIMA, Keisuke YAMAKAWA
  • Publication number: 20150325012
    Abstract: Difference of resolution depending on imaging position in one reconstructed image generated in the FFS method is reduced to improve measurement accuracy. The X-ray CT device interpolates missing data of the projection data obtained by the FFS method with view direction interpolation processing using real data of the projection data lining up along the angular direction of the rotational movement, and channel direction interpolation processing using real data of the projection data lining up along the channel direction, and generates a reconstructed image, in which contribution ratios of the projection data having been subjected to the view direction interpolation processing and the projection data having been subjected to the channel direction interpolation processing differ according to position of pixel in the reconstructed image.
    Type: Application
    Filed: January 15, 2014
    Publication date: November 12, 2015
    Inventors: Shinichi KOJIMA, Keisuke YAMAKAWA, Fumito WATANABE, Yushi TSUBOTA, Yasutaka KONNO