Patents by Inventor Keiji Koyanagi

Keiji Koyanagi 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: 8208600
    Abstract: There are provided an X-ray generating apparatus capable of switching X-ray beams of high energy and low energy to each other at high speed, and an X-ray CT apparatus capable of performing high-speed and high-quality multi-energy imaging by using the same. The X-ray generating apparatus is constructed by an X-ray tube 9 having two anodes 200a, 200b, a rotational anode 204 for radiating X-ray from an X-ray focal point by electron beams emitted from filaments of these cathodes, and two grid electrodes 202a and 202b for controlling emission of the electron beams, a tube voltage generator 9a and a tube voltage controller 9d1 for controlling an X-ray condition, a filament heater 9b and a tube current controller 9d2, a grid voltage generator 9c and a grid opening/closing controller 9d3, and a grid switching unit 9e. High energy X-ray and low energy X-ray are switched and emitted to an examinee every adjacent projection angles, thereby collecting projection data.
    Type: Grant
    Filed: July 18, 2008
    Date of Patent: June 26, 2012
    Assignee: Hitachi Medical Corporation
    Inventors: Yoshiaki Tsumuraya, Hironori Ueki, Keiji Koyanagi
  • Publication number: 20100183117
    Abstract: There are provided an X-ray generating apparatus capable of switching X-ray beams of high energy and low energy to each other at high speed, and an X-ray CT apparatus capable of performing high-speed and high-quality multi-energy imaging by using the same. The X-ray generating apparatus is constructed by an X-ray tube 9 having two anodes 200a, 200b, a rotational anode 204 for radiating X-ray from an X-ray focal point by electron beams emitted from filaments of these cathodes, and two grid electrodes 202a and 202b for controlling emission of the electron beams, a tube voltage generator 9a and a tube voltage controller 9d1 for controlling an X-ray condition, a filament heater 9b and a tube current controller 9d2, a grid voltage generator 9c and a grid opening/closing controller 9d3, and a grid switching unit 9e. High energy X-ray and low energy X-ray are switched and emitted to an examinee every adjacent projection angles, thereby collecting projection data.
    Type: Application
    Filed: July 18, 2008
    Publication date: July 22, 2010
    Applicant: HITACHI MEDICAL CORPORATION
    Inventors: Yoshiaki Tsumuraya, Hironori Ueki, Keiji Koyanagi
  • Patent number: 5561697
    Abstract: Disclosed is a microtron electron accelerator having an accelerating cavity accepting microwave electric power for generating a high-frequency accelerating electric field E disposed within a uniform magnetic field B and adapted such that electrons are accelerated and caused to move in a circular trajectory under action of the magnetic field B and the electric field E, comprising an electron source formed of a cathode and an anode, which has a minute slit allowing an electron beam extracted from the cathode to pass therethrough, disposed on the outer side of the wall of the accelerating cavity, a first electron beam through-hole and a second electron beam through-hole formed in the wall of the accelerating cavity in two positions, with the electron source therebetween, along the decreasing or increasing direction of the strength of the electric field E in the accelerating cavity, and a third electron beam through-hole formed in the wall of the accelerating cavity in a position in confrontation with the first e
    Type: Grant
    Filed: January 13, 1995
    Date of Patent: October 1, 1996
    Assignee: Hitachi Medical
    Inventors: Atsuko Takafuji, Katsuya Sugiyama, Katsuhiro Kuroda, Keiji Koyanagi, Ichiro Miura, Masatoshi Nishimura
  • Patent number: 5399873
    Abstract: Disclosed is a microtron electron accelerator having an accelerating cavity accepting microwave electric power for generating a high-frequency accelerating electric field E disposed within a uniform magnetic field B and adapted such that electrons are accelerated and caused to move in a circular trajectory under action of the magnetic field B and the electric field E, comprising an electron source formed of a cathode and an anode, which has a minute slit allowing an electron beam extracted from the cathode to pass therethrough, disposed on the outer side of the wall of the accelerating cavity, a first electron beam through-hole and a second electron beam through-hole formed in the wall of the accelerating cavity in two positions, with the electron source therebetween, along the decreasing or increasing direction of the strength of the electric field E in the accelerating cavity, and a third electron beam through-hole formed in the wall of the accelerating cavity in a position in confrontation with the first e
    Type: Grant
    Filed: December 14, 1993
    Date of Patent: March 21, 1995
    Assignee: Hitachi Medical
    Inventors: Atsuko Takafuji, Katsuya Sugiyama, Katsuhiro Kuroda, Keiji Koyanagi, Ichiro Miura, Masatoshi Nishimura