# US 10,870,018 B2 · Apparatus and methods for magnetic control of radiation electron beam > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,018 B2 - Document ID: US10870018B2 - Status: Granted - Kind: B2 - Application number: 16/331,459 - Filed: 2017-09-05 - Published: 2019-07-18 - Granted: 2020-12-22 - Earliest claimed: 2016-09-09 - Assignees: Board of Regents, The University of Texas System; Tel-Hashomer Medical Research Infrastructure and Services Ltd. At the Chaim Sheba Medical Center - Applicants: Board of Regents, The University of Texas System; Tel-Hashomer Medical Research Infrastructure and Services Ltd. At the Chaim Sheba Medical Center - Inventors: Dirk Bartkoski; Dror Alezra; Mohammad Salehpour; Thomas Buchholz - Web page: https://patentgrep.com/patent/US10870018B2 ## CPC - A61N 5/1043: {Scanning the radiation beam, e.g. spot scanning or raster scanning} - A61N 1/36157: {Current (A61N1/3616 takes precedence)} - A61N 1/3718: {Monitoring of or protection against external electromagnetic fields or currents} - A61N 1/37223: {Circuits for electromagnetic coupling} - A61N 2/02: using magnetic fields produced by coils, including single turn loops or electromagnets (A61N2/12 takes precedence) - A61N 5/1038: {taking into account previously administered plans applied to the same patient, i.e. adaptive radiotherapy} - G21K 1/093: by magnetic means - A61N 2005/1089: {Electrons} - 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) - G21K: HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES ## Abstract Apparatus and methods for controlling a radiotherapy electron beam. Exemplary embodiments provide for focusing the electron beam at different depths by altering parameters of a plurality of magnets. Exemplary embodiments can also provide for focusing the electron beam at different depths while maintaining the energy level of the electron beam at a consistent level. ## Claims ### Claim 1 An apparatus for controlling a radiotherapy electron beam, the apparatus comprising: an electron beam generator configured to generate an electron beam; a plurality of magnets producing a plurality of magnetic fields configured to focus the electron beam to a focal spot; and a control system configured to alter one or more parameters of the plurality of magnets to move the focal spot from a first location to a second location, wherein the first location is located at a first depth within a target region and the second location is located at a second depth within the target region. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein: the target region is below an epidermal surface of a subject; and the first location or the second location is at a depth between 0 and 50 centimeters from the epidermal surface. ### Claim 3 (depends on 1) The apparatus of claim 1 wherein the electron beam has a energy of between 50 and 250 megaelectron volts (MeV). ### Claim 4 (depends on 3) The apparatus of claim 3 wherein the energy of the beam is not modulated when the focal spot is moved from the first location to the second location. ### Claim 5 (depends on 1) The apparatus of claim 1 wherein the plurality of magnets comprise a plurality of collinear multipole magnets. ### Claim 6 (depends on 5) The apparatus of claim 5 wherein the plurality of collinear multipole magnets comprises at least two collinear quadrupole magnets. ### Claim 7 (depends on 5) The apparatus of claim 5 wherein: the one or more parameters of the plurality of magnets comprises a separation distance between the plurality of collinear multipole magnets; and the control system is configured to alter the separation distance between the plurality of collinear multipole magnets. ### Claim 8 (depends on 1) The apparatus of claim 1 wherein the plurality of magnets comprise an anterior lens magnet, a posterior reflective magnet, and a plurality of radial focal magnets. ### Claim 9 (depends on 1) The apparatus of claim 1 wherein: the plurality of magnets comprise electromagnets; the one or more parameters of the plurality of magnets comprises an electrical current through the electromagnets; and the control system is configured to alter the electrical current through the electromagnets. ### Claim 10 (depends on 9) The apparatus of claim 9 wherein the electromagnets are iron-dominated or coil dominated superconducting electromagnets. ### Claim 11 (depends on 1) The apparatus of claim 1 wherein the plurality of magnetic fields are configured to focus the electron beam at a convergence angle of between 50 and 500 mrad. ### Claim 12 (depends on 1) The apparatus of claim 1 wherein the plurality of magnetic fields are configured to focus the electron beam at a convergence angle of between 200 and 400 mrad. ### Claim 13 (depends on 1) The apparatus of claim 1 wherein the control system comprises an algorithm to calculate the one or more parameters of the plurality of magnets. ### Claim 14 (depends on 13) The apparatus of claim 13 wherein the control system receives input from a treatment planning software program configured to calculate a dose distribution. ### Claim 15 (depends on 1) The apparatus of claim 1 wherein the focal spot comprises a maximum electron dose concentration. ### Claim 16 A method of controlling a radiotherapy electron beam, the method comprising: generating an electron beam; directing the electron beam through a plurality of magnetic fields produced by a plurality of magnets; focusing the electron beam to a focal spot with the plurality of magnetic fields; and altering one or more parameters of the plurality of magnets to move the focal spot from a first location to a second location wherein the first location is located at a first depth within a target region and the second location is located at a second depth within the target region. ### Claim 17 An apparatus for controlling a radiotherapy electron beam, the apparatus comprising: an electron beam generator configured to generate an electron beam with a power between 50 megaelectron volts and 250 megaelectron volts; a plurality of magnets configured to focus the electron beam at a focal spot; and a control system configured move the focal spot from a first location at a first depth to a second location at a second depth, wherein the power of the electron beam is maintained at a consistent level when the focal spot is moved from the first location to the second location. ### Claim 18 (depends on 17) The apparatus of claim 17 wherein the control system is configured to alter one or more parameters of the plurality of magnets to move the focal spot from the first location to the second location. ### Claim 19 (depends on 18) The apparatus of claim 18 wherein the control system comprises an algorithm to calculate the one or more parameters of the plurality of magnets. ### Claim 20 A method of controlling a radiotherapy electron beam, the method comprising: generating an electron beam having a power between 50 megaelectron volts and 250 megaelectron volts; focusing the electron beam to a focal spot with a plurality of magnets; and moving the focal spot from a first location at a first depth to a second location at a second depth while maintaining the power of the electron beam at a consistent level.