# US 10,770,196 B2 · Binary multileaf collimator delivery with per-leaf field width > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,196 B2 - Document ID: US10770196B2 - Status: Granted - Kind: B2 - Application number: 16/056,114 - Filed: 2018-08-06 - Published: 2020-02-06 - Granted: 2020-09-08 - Earliest claimed: 2018-08-06 - Assignees: Accuray Incorporated - Applicants: Accuray Incorporated - Inventors: Eric Schnarr; Hari Gopalakrishnan; Jari Toivanen; Matthew Orton - Web page: https://patentgrep.com/patent/US10770196B2 ## CPC - A61N 5/1045: {using a multi-leaf collimator, e.g. for intensity modulated radiation therapy or IMRT} - G21K 1/046: {varying the contour of the field, e.g. multileaf collimators} - A61N 5/1047: {with movement of the radiation head during application of radiation, e.g. for intensity modulated arc therapy or IMAT} - G21K 1/093: by magnetic means - 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 A radiation treatment delivery system, includes a linear accelerator (LINAC) and a multileaf collimator (MLC), coupled with the distal end of the LINAC, wherein the MLC has two banks of leaves, organized into a plurality of opposing leaf pairs. The system further includes a processing device, operatively coupled to the LINAC and the MLC, to control the plurality of leaf pairs of the MLC such that for each of a plurality of radiation beam delivery positional sections corresponds to a range of radiation beam positions over a discrete time interval, wherein each leaf pair of the plurality of opposing leaf pairs is open to a fixed opening for a fraction of time in the discrete time interval and closed for the remaining fraction of time in the discrete time interval, while a radiation beam of the radiation treatment system is active. ## Claims ### Claim 1 A method of controlling a two-bank multileaf collimator (MLC) of a radiation treatment delivery system, comprising: determining a plurality of radiation beam delivery positional sections to contain MLC leaf control instructions while a radiation beam is active, wherein each of the plurality of radiation beam delivery positional sections corresponds to a range of radiation beam positions over a discrete time interval, wherein the discrete time interval is based on an average open-time and a modulation factor; generating a plurality of openings for each of the plurality of radiation beam delivery positional sections, each of the plurality of openings corresponding to one of a plurality of leaf pairs of the MLC, wherein two or more of the plurality of openings correspond to different widths; generating a plurality of leaf open-time fractions for each of the plurality of radiation beam delivery positional sections, each of the plurality of leaf open-time fractions corresponding to one of the plurality of leaf pairs of the MLC; and controlling, by a processing device, the plurality of leaf pairs of the MLC such that each leaf pair of the plurality of leaf pairs is opened to a corresponding opening of the plurality of openings for a corresponding leaf open-time fraction of the plurality of leaf open-time fractions during the discrete time interval corresponding to the range of radiation beam positions, while the radiation beam of the radiation treatment system is active. ### Claim 2 (depends on 1) The method of claim 1, wherein the plurality of radiation beam delivery positional sections corresponds to the radiation beam delivered from at least one of: a different position or a different direction. ### Claim 3 (depends on 1) The method of claim 1, wherein two or more of the plurality of leaf open-time fractions during the discrete time interval are different. ### Claim 4 (depends on 2) The method of claim 2, wherein the different direction remains constant while the different position follows a linear trajectory that sweeps the radiation beam over a length of a treatment target. ### Claim 5 (depends on 2) The method of claim 2, wherein the different directions are non-coplanar. ### Claim 6 (depends on 2) The method of claim 2, wherein the plurality of openings and the plurality of leaf open-time fractions form overlapping radiation fields of different intensities that combine to result in an intensity modulated fluence field delivered to a treatment target. ### Claim 7 (depends on 1) The method of claim 1, wherein the plurality of openings conform to an outline of a treatment target, projected back along the radiation beam to the MLC, and within a maximum range of travel of the plurality of leaf pairs within the MLC. ### Claim 8 (depends on 1) The method of claim 1, wherein the range of radiation beam positions is along an arc of a gantry of the radiation treatment system. ### Claim 9 (depends on 8) The method of claim 8, wherein the arc corresponds to approximately seven degrees of gantry rotation. ### Claim 10 A radiation treatment delivery system, comprising: a linear accelerator (LINAC) to output a radiation beam at a distal end; a multileaf collimator (MLC), coupled with the distal end of the LINAC, wherein the MLC has two banks of leaves, organized into a plurality of opposing leaf pairs; and a processing device, operatively coupled to the LINAC and the MLC, to: control the plurality of leaf pairs of the MLC such that for each of a plurality of radiation beam delivery positional sections corresponding to a range of radiation beam positions over a discrete time interval, wherein each leaf pair of the plurality of opposing leaf pairs is open to a fixed opening for a fraction of time in the discrete time interval and closed for the remaining fraction of time in the discrete time interval, while the radiation beam of the radiation treatment system is active, wherein the discrete time interval is based on an average open-time and a modulation factor. ### Claim 11 (depends on 10) The system of claim 10, wherein the MLC is an electromagnetically actuated multileaf collimator (eMLC). ### Claim 12 (depends on 10) The system of claim 10, wherein the LINAC is mounted on a rotating gantry, and wherein radiation beams delivered from the range of radiation beam positions rotate around a treatment target. ### Claim 13 (depends on 12) The system of claim 12, wherein the treatment target is moved axially through a bore of the rotating gantry, and wherein the radiation beams delivered from the range of radiation beam positions follow a helical path about the treatment target. ### Claim 14 (depends on 10) The system of claim 10, wherein the LINAC and the MLC are mounted on a robotic arm, and wherein the radiation beam delivered from the range of radiation beam positions is non-coplanar. ### Claim 15 (depends on 10) The system of claim 10, wherein the fixed opening and the fraction of time form overlapping radiation fields of different intensities that combine to result in an intensity modulated fluence field delivered to a treatment target. ### Claim 16 (depends on 10) The system of claim 10, wherein the fixed opening conforms to an outline of a treatment target, projected back along the radiation beam to the MLC, and within a maximum range of travel of plurality of leaf pairs within the MLC. ### Claim 17 (depends on 10) The system of claim 10, wherein the plurality of radiation beam delivery positional sections corresponds to the radiation beam delivered from at least one of: a different position or a different direction, and wherein the at least one of: the different position or the different direction follows a helical trajectory about a treatment target. ### Claim 18 (depends on 10) The system of claim 10, wherein the system is a helical radiation treatment delivery system. ### Claim 19 (depends on 10) The system of claim 10, wherein the system is a robotic-based LINAC radiation treatment system. ### Claim 20 (depends on 10) The system of claim 10, wherein the system is gantry-based radiation treatment delivery system. ### Claim 21 A non-transitory computer readable medium comprising instructions that, when executed by a processing device of a radiation treatment delivery system, cause the processing device to: generate a plurality of radiation beam delivery positional sections to contain MLC leaf control instructions while a radiation beam is active, wherein each of the plurality of radiation beam delivery positional sections corresponds to a range of radiation beam positions over a discrete time interval, wherein the discrete time interval is based on an average open-time and a modulation factor; generate a plurality of openings for each of the plurality of radiation beam delivery positional sections, each of the plurality of openings corresponding to one of a plurality of leaf pairs of the MLC; generate a plurality of leaf open-time fractions for each of the plurality of radiation beam delivery positional sections, each of the plurality of leaf open-time fractions corresponding to one of the plurality of leaf pairs of the MLC; and control, by the processing device, the plurality of leaf pairs of the MLC such that each leaf pair of the plurality of leaf pairs is opened to a corresponding opening of the plurality of openings for a corresponding leaf open-time fraction of the plurality of leaf open-time fractions during the discrete time interval corresponding to the range of radiation beam positions, while the radiation beam of the radiation treatment system is active. ### Claim 22 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the plurality of radiation beam delivery positional sections corresponds to the radiation beam delivered from at least one of: a different position or a different direction. ### Claim 23 (depends on 22) The non-transitory computer readable medium of claim 22, wherein the at least one of: the different position or the different direction follows a helical trajectory about a treatment target. ### Claim 24 (depends on 22) The non-transitory computer readable medium of claim 22, wherein the different direction remains constant while the different position follows a linear trajectory that sweeps the radiation beam over a length of a treatment target. ### Claim 25 (depends on 22) The non-transitory computer readable medium of claim 22, wherein the different directions are non-coplanar. ### Claim 26 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the plurality of openings and the plurality of leaf open-time fractions form overlapping radiation fields of different intensities that combine to result in an intensity modulated fluence field delivered to a treatment target. ### Claim 27 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the plurality of openings conform to an outline of a treatment target, projected back along the radiation beam to the MLC, and within a maximum range of travel of the plurality of leaf pairs within the MLC. ### Claim 28 (depends on 21) The non-transitory computer readable medium of claim 21, wherein the range of radiation beam positions is along an arc of a gantry of the radiation treatment system. ### Claim 29 (depends on 28) The non-transitory computer readable medium of claim 28, wherein the arc corresponds to approximately seven degrees of gantry rotation.