B Dot Medical Inc.

Ryohei Tansho

Takuji Furukawa

Yousuke Hara

Kota Mizushima

Eri Takeshita

Naoya Saotome

Yuichi Saraya

Yoshiaki Taki

The invention provides a charged particle irradiation apparatus including: a collimator apparatus provided in an irradiation nozzle that emits a charged particle beam to an irradiation target; and a collimator control unit that controls the collimator apparatus. The collimator apparatus includes a collimator mechanism having one or more arm-shape collimators extending from a base part and a drive mechanism that moves the collimator mechanism on a plane perpendicular to a traveling direction of a charged particle beam. The arm-shape collimator includes one or more movable leaves that rotate independently of each other on the perpendicular plane. By moving the collimator mechanism and/or rotating the movable leaves so that the arm-shape collimators are arranged along a shape of an edge of an irradiation target on the perpendicular plane, the collimator control unit causes the arm-shape collimators to block a charged particle beam that would otherwise irradiate outside of the edge of the irradiation target.

Charged particle irradiation apparatus

Provided is a charged particle irradiation apparatus that performs scanning with a charged particle beam and irradiates an irradiation target spot by spot. An embodiment of the present invention provides a charged particle irradiation apparatus () including: a first dose monitor () mounted in an irradiation nozzle (); an irradiation pattern converting device () that generates irradiation control data used for controlling the charged particle irradiation apparatus () from treatment plan data including information on a dose rate and a dose of a charged particle beam for each spot; and a dose correction factor storage unit () that stores data of a dose correction factor with respect to a dose rate of a charged particle beam. The irradiation pattern converting device () is configured to select one spot in the treatment plan data, for instance.

An embodiment of the invention is a focusing magnet including a coil pair arranged on both sides of a path of a charged particle beam. The coil pair generates an effective magnetic field region in which a magnetic field is oriented in a direction (z-axis) perpendicular to a traveling direction (x-axis) of a charged particle beam. In an xy-plane, an incident charged particle beam deflected at a deflection angle &#x3d5; with respect to the x-axis at a deflection point Q is deflected by the effective magnetic field region, and irradiates an isocenter at an irradiation angle &#x3b8; with respect to the x-axis; an arbitrary point Pon a boundary on an exit side of the effective magnetic field region is at an equal distance rfrom the isocenter; a point Pon a boundary on an incident side of the effective magnetic field region and the point Pare on a radius rand an arc of a central angle (&#x3b8;+&#x3d5;); and when a distance between the deflection point Q and the isocenter is L, a distance R between the deflection point Q and the point Psatisfies a relational equation (4).

Focusing magnet and charged particle irradiation apparatus

An embodiment of the invention is a focusing magnet including a coil pair arranged on both sides of a path of a charged particle beam. The coil pair generates an effective magnetic field region in which a magnetic field is oriented in a direction (z-axis) perpendicular to a traveling direction (x-axis) of a charged particle beam. In an xy-plane, an incident charged particle beam deflected at a deflection angle &#x3d5; with respect to the x-axis at a deflection point Q is deflected by the effective magnetic field region, and irradiates an isocenter at an irradiation angle &#x3b8; with respect to the x-axis; an arbitrary point P2 on a boundary on an exit side of the effective magnetic field region is at an equal distance rfrom the isocenter; a point P1 on a boundary on an incident side of the effective magnetic field region and the point P2 are on a radius rand an arc of a central angle (&#x3b8;+&#x3d5;); and when a distance between the deflection point Q and the isocenter is L, a distance R between the deflection point Q and the point P1 satisfies a relational equation (4).

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Tokyo, Japan

Ryohei Tansho