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: 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
  • Patent number: 10299746
    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.
    Type: Grant
    Filed: December 21, 2016
    Date of Patent: May 28, 2019
    Assignee: Hitachi, Ltd.
    Inventors: Takafumi Ishitsu, Isao Takahashi, Kazuma Yokoi, Makoto Satou
  • 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
  • Patent number: 10292669
    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.
    Type: Grant
    Filed: March 18, 2016
    Date of Patent: May 21, 2019
    Assignee: Hitachi, Ltd.
    Inventors: Takafumi Ishitsu, Isao Takahashi, Kazuma Yokoi
  • Publication number: 20190105002
    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: Application
    Filed: June 2, 2017
    Publication date: April 11, 2019
    Inventor: Kazuma YOKOI
  • Publication number: 20180368790
    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.
    Type: Application
    Filed: December 21, 2016
    Publication date: December 27, 2018
    Inventors: Takafumi ISHITSU, Isao TAKAHASHI, Kazuma YOKOI, Makoto SATOU
  • Publication number: 20180061097
    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.
    Type: Application
    Filed: March 8, 2016
    Publication date: March 1, 2018
    Inventors: Kazuma YOKOI, Yushi TSUBOTA
  • Publication number: 20180049707
    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.
    Type: Application
    Filed: March 18, 2016
    Publication date: February 22, 2018
    Inventors: Takafumi ISHITSU, Isao TAKAHASHI, Kazuma YOKOI
  • 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: 20120112087
    Abstract: It is an object of the present invention to allow a gamma-ray-source's existing position direction to be detected using a small-volume gamma-ray detector. A gamma-ray's direction detecting apparatus including a plurality of detection pixels for detecting gamma rays, a memory device for memorizing a correspondence relationship in advance, the correspondence relationship being established for indicating, with respect to predetermined gamma-ray's incoming directions, what kind of actual-measurement frequency data should be acquired using the plurality of detection pixels, and a measurement/calculation unit which measures the gamma-ray's actual-measurement frequency data detected using the plurality of detection pixels, and calculates a gamma-ray's incoming direction by using the actual-measurement frequency data and the correspondence relationship memorized into the memory device.
    Type: Application
    Filed: June 11, 2010
    Publication date: May 10, 2012
    Applicant: HITACHI, LTD.
    Inventor: Kazuma Yokoi
  • Patent number: 8116427
    Abstract: A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a ?-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a ?-ray image pickup signal is output).
    Type: Grant
    Filed: June 21, 2011
    Date of Patent: February 14, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Kojima, Takashi Okazaki, Yuuichirou Ueno, Kikuo Umegaki, Kensuke Amemiya, Kazuhiro Takeuchi, Hiroshi Kitaguchi, Kazuma Yokoi, Norihito Yanagita
  • Publication number: 20110297837
    Abstract: The radiation detection module (20) is provided with a semiconductor element (1) having a plurality of pixels (Pn), radiation detection elements (30) in which a plurality of first electrodes (31n) are arranged along one side of the semiconductor element (1), and a second electrode (32m) is disposed astride a plurality of pixels (Pn) along the other side, and which output detection signals when a radioactive ray comes incident on the detection pixels (Pn), and a support PCB (21) placed to stand along the direction in which the radioactive ray comes incident. The support PCB (21) has a connection section (21a) detachably connectable to an external connecting section. Radiation detection elements (30) are connected on the support PCB (21) to fabricate a signal read-out circuit having mutually-perpendicular wiring in a pseudo way and that the incident position of the radioactive ray is identified by coincidence determination of the detection signals.
    Type: Application
    Filed: February 17, 2010
    Publication date: December 8, 2011
    Applicant: HITACHI, LTD.
    Inventors: Takafumi Ishitsu, Isao Takahashi, Katsutoshi Tsuchiya, Kazuma Yokoi, Yuichiro Ueno
  • Publication number: 20110280365
    Abstract: A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a ?-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a ?-ray image pickup signal is output).
    Type: Application
    Filed: June 21, 2011
    Publication date: November 17, 2011
    Inventors: Shinichi Kojima, Takashi Okazaki, Yuuichirou Ueno, Kikuo Umegaki, Kensuke Amemiya, Kazuhiro Takeuchi, Hiroshi Kitaguchi, Kazuma Yokoi, Norihito Yanagita
  • Patent number: 7986763
    Abstract: A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a ?-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a ?-ray image pickup signal is output).
    Type: Grant
    Filed: November 9, 2009
    Date of Patent: July 26, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Kojima, Takashi Okazaki, Yuuichirou Ueno, Kikuo Umegaki, Kensuke Amemiya, Kazuhiro Takeuchi, Hiroshi Kitaguchi, Kazuma Yokoi, Norihito Yanagita
  • Patent number: 7977647
    Abstract: A radiological imaging apparatus using a semiconductor radiation detector to make it possible to reduce a radiation measurement off time that may result from an attempt to avoid polarization, the radiological imaging apparatus comprising a capacitor that applies a voltage to a semiconductor radiation detector that detects a radiation from a subject, first current regulated means for conducting a charge current to the capacitor, and second current regulated means for conducting a discharge current from the capacitor, or comprising a capacitor that applies a voltage to the semiconductor radiation detector, a first resistor that conducts a charge current to and a discharge current from the capacitor, and a second resistor connected in parallel with the first resistor to subject the capacitor to charging and discharging.
    Type: Grant
    Filed: March 5, 2009
    Date of Patent: July 12, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Tomoyuki Seino, Yuuichirou Ueno, Katsutoshi Tsuchiya, Kazuma Yokoi, Shinya Kominami
  • Patent number: 7952076
    Abstract: A radiation imaging system is configured by a collimator 30A including a detector 21 with a discrete detection pixel corresponding with a pixel and a plurality of radiation passages 31 and looks into a plurality of detectors 21 through one radiation passage 31 to set a step width of rotation around a rotation center axis X1 only for an angle ?p made by lines provided by connecting a center detector 21 of the radiation passage 31 and the adjacent two detectors 21. In the case of generating a flat plane projection image for one direction, radio-graphing is carried out on a projection image in a plurality of predetermined angle positions (??p, 0, +?p) in the circumferential direction of the rotation center axis X1 and thereby one plane projection image is obtained.
    Type: Grant
    Filed: April 15, 2009
    Date of Patent: May 31, 2011
    Assignees: Hitachi, Ltd., National University Corporation Hokkaido University
    Inventors: Katsutoshi Tsuchiya, Tsuneaki Kawaguchi, Yuichi Morimoto, Masatoshi Tanaka, Hiroshi Kitaguchi, Kazuma Yokoi, Takafumi Ishitsu, Naoki Kubo, Nagara Tamaki
  • Patent number: 7759646
    Abstract: A radiological imaging apparatus of the present invention includes an X-ray source for emitting an X-ray, a ?-ray detecting section for outputting a detection signal of a ?-ray, and an X-ray detecting section for outputting a detecting signal of an X-ray. The X-ray source moves around a bed for placing an examinee. The ?-ray detecting section has a plurality of radiation detectors aligned in the longitudinal direction of the bed and placed around the bed. The X-ray detecting section is positioned in a region formed between one end and the other end of the ?-ray detecting section in the longitudinal direction of the bed. The X-ray source is also positioned in the region. Since the X-ray detecting section is placed in the region, it is possible to accurately combine a PET image and an X-ray computed tomographic image.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: July 20, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Kensuke Amemiya, Yuuichirou Ueno, Hiroshi Kitaguchi, Kikuo Umegaki, Shinichi Kojima, Norihito Yanagida, Kazuma Yokoi, Takashi Okazaki
  • Patent number: 7745795
    Abstract: In a gamma camera, a plurality of radiation detector elements having a rod-shaped first electrode, a semiconductor device surrounds the first electrode to contact with it for entering a radiation, and a second electrode provided for the side surface of the semiconductor device are detachably attached to a holding member. The holding member has a first electrode contact portion contacted with the first electrode and a second electrode contact portion contacted with the second electrode. A collimator in which a plurality of radiation paths provided corresponding to the plurality of radiation detector elements are formed is arranged on the radiation entering side of the plurality of radiation detector elements. A ?-ray detection signal outputted from the first electrode contact portion is sent to a signal processing integrated circuit. A high voltage is applied to the second electrode via the second electrode contact portion.
    Type: Grant
    Filed: March 11, 2008
    Date of Patent: June 29, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Katsutoshi Tsuchiya, Hiroshi Kitaguchi, Kazuma Yokoi, Kikuo Umegaki, Kensuke Amemiya, Yuuichirou Ueno, Norihito Yanagita, Shinichi Kojima
  • Patent number: 7683338
    Abstract: The radiological imaging system which can improve an energy resolution and perform a diagnosis with high accuracy includes a bed for carrying an examinee H, first and second imaging apparatuses and disposed along the longitudinal direction of the bed. The first imaging apparatus has a plurality of semiconductor radiation detectors for detecting ?-rays emitted from the examinee H, arranged around the bed, the second imaging apparatus has an X-ray source for emitting X-rays to the examinee H and a radiation detector for detecting X-rays which have been emitted from the X-ray source and passed through the examinee H, and the bed is shared by the first imaging apparatus and the second imaging apparatus.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: March 23, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Yuuichirou Ueno, Hiroshi Kitaguchi, Katsutoshi Tsuchiya, Kensuke Amemiya, Kazuma Yokoi, Shinichi Kojima, Norihito Yanagita, Takafumi Ishitsu
  • Publication number: 20100054571
    Abstract: A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a ?-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a ?-ray image pickup signal is output).
    Type: Application
    Filed: November 9, 2009
    Publication date: March 4, 2010
    Inventors: Shinichi Kojima, Takashi Okazaki, Yuuichirou Ueno, Kikuo Umegaki, Kensuke Amemiya, Kazuhiro Takeuchi, Hiroshi Kitaguchi, Kazuma Yokoi, Norihito Yanagita