# US 2026/0097237 A1 · Dose adjustment mechanism and radiation therapy device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0097237 A1 - Document ID: US20260097237A1 - Status: Published application - Kind: A1 - Application number: 19/112,311 - Filed: 2023-07-19 - Published: 2026-04-09 - Earliest claimed: 2022-12-01 - Assignees: Hitachi High-Tech Corporation - Applicants: Hitachi High-Tech Corporation - Inventors: Koki YOSHIDA; Keiji TANIMOTO; Takashi ISHIZUKA; Yu SAITOH - Web page: https://patentgrep.com/patent/US20260097237A1 ## CPC - A61N 5/1048: {Monitoring, verifying, controlling systems and methods} - A61N 5/1081: {Rotating beam systems with a specific mechanical construction, e.g. gantries} - A61N 5/1042: {with spatial modulation of the radiation beam within the treatment head} - A61N 2005/1095: {Elements inserted into the radiation path within the system, e.g. filters or wedges} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract A dose adjustment mechanism is to reduce an influence of radiation in the dose adjustment mechanism of a radiation therapy apparatus and to prevent occurrence of a failure. A dose adjustment mechanism 40 includes an actuator 42 disposed apart from a radiation axis irradiated with radiation by a radiation therapy apparatus 10, and a flattening filter 33 which is an interference element that moves in a direction perpendicular to the radiation axis by an operation of the actuator 42 and that is capable of switching between a state in which the interference element is disposed on an axis of the radiation axis and a state in which the interference element is not disposed on the axis of the radiation axis. An operation shaft of the actuator 42 does not intersect the radiation axis. ## Claims ### Claim 1 A dose adjustment mechanism comprising: an actuator disposed apart from a radiation axis irradiated with radiation by a radiation therapy apparatus; and an interference element configured to move in a direction perpendicular to the radiation axis by an operation of the actuator and switch between a state in which the interference element is disposed on an axis of the radiation axis and a state in which the interference element is not disposed on the axis of the radiation axis, wherein an operation shaft of the actuator does not intersect the radiation axis. ### Claim 2 (depends on 1) The dose adjustment mechanism according to claim 1, further comprising: a frame member fixed with respect to the radiation axis, wherein the actuator is attached to a place where the actuator is stationary with respect to the frame member, and the operation shaft passes outside an irradiation range of the radiation. ### Claim 3 (depends on 1) The dose adjustment mechanism according to claim 1, wherein the operation shaft of the actuator is parallel to a moving direction of the interference element, and the interference element is held via a support member extending from the operation shaft. ### Claim 4 (depends on 1) The dose adjustment mechanism according to claim 1, wherein a direction between an operation direction of the actuator and a moving direction of the interference element is changed via a link member that connects the operation shaft of the actuator and a moving shaft of the interference element. ### Claim 5 (depends on 1) The dose adjustment mechanism according to claim 1, wherein the interference element is a filter that smooths an intensity distribution of the radiation. ### Claim 6 (depends on 1) The dose adjustment mechanism according to claim 1, wherein the interference element is an optical element. ### Claim 7 (depends on 1) The dose adjustment mechanism according to claim 1, further comprising: a moving member on which the interference element is mounted and which is moved by the operation of the actuator; and a frame member fixed with respect to the radiation axis, wherein the interference element is disposed on the axis of the radiation axis in a state in which the moving member is in contact with a predetermined surface of the frame member. ### Claim 8 (depends on 7) The dose adjustment mechanism according to claim 7, wherein the interference element is not disposed on the axis of the radiation axis in a state in which the moving member is in contact with a surface facing the predetermined surface. ### Claim 9 (depends on 7) The dose adjustment mechanism according to claim 7, further comprising: a sensor provided in a vicinity of the predetermined surface, wherein a consistency between an output of the sensor and a control state of the actuator is determined. ### Claim 10 (depends on 7) The dose adjustment mechanism according to claim 7, wherein the interference element is disposed on the axis of the radiation axis when a control state of the actuator is a reference position. ### Claim 11 (depends on 7) The dose adjustment mechanism according to claim 7, further comprising: a nozzle configured to inject air to the predetermined surface. ### Claim 12 A radiation therapy apparatus comprising: a radiation irradiation apparatus; a gantry configured to rotate the radiation irradiation apparatus around an isocenter; a patient support device configured to support a patient such that a therapy target site is positioned at the isocenter; and a dose adjustment mechanism configured to adjust a dose of radiation emitted by the radiation irradiation apparatus, wherein the dose adjustment mechanism includes an actuator disposed apart from a radiation axis irradiated with radiation by a radiation therapy apparatus, and an interference element configured to move in a direction perpendicular to the radiation axis by an operation of the actuator and switch between a state in which the interference element is disposed on an axis of the radiation axis and a state in which the interference element is not disposed on the axis of the radiation axis, and an operation shaft of the actuator does not intersect the radiation axis.