Generation of treatment plans and delivery of radiation by columns

Abstract

Improved column-specific radiation delivery and treatment planning therefor is provided. An exemplary method for treating a target using a particle beam includes directing a particle beam along a path that passes at least partway through the target and controlling the energy of the particle beam while the particle beam is directed along the path such that the particle beam treats at least an interior portion of the target located along the path. While the particle beam is directed along the path, the particle beam delivers a dose of radiation greater than 1 Gray per second to the target for a duration of less than 5 seconds. A treatment plan can be generated to carry out this method.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 815,721, entitled "Delivery Of Radiation By Column," filed March 8, 2019. This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 853,387, entitled "Energy Degrader Including Boron Carbide," filed May 28, 2019. This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 889,825, entitled "Generating A Treatment Plan," filed August 21, 2019. This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 889,861, entitled "Collimator For A Particle Therapy System," filed August 21, 2019. The contents of U.S. Provisional Patent Applications Nos. 62 / 815,721, 62 / 853,387, 62 / 889,825, and 62 / 889,861 are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to particle therapy systems that deliver radiation doses by columns and generating treatment plans therefor. [Background technology]

[0003] A particle therapy system uses an accelerator to generate particle beams for treating afflictions such as tumors. In operation, the particles are accelerated along trajectories within a cavity in the presence of a magnetic field and are extracted from the cavity through an extraction channel. A magnetic field regenerator creates magnetic field bumps near the outside of the cavity to distort the pitch and angle of some of the trajectories, causing them to move toward and ultimately into the extraction channel. A beam of particles exits the extraction channel.

[0004] The scanning system is down-beam of the extraction channel. In this example, "down-beam" implies closer to the irradiation target relative to the extraction channel. The scanning system moves the particle beam relative to the irradiation target to expose different parts of the irradiation target to the particle beam. For example, to treat a tumor, the particle beam may be scanned across different cross sections of the tumor, thereby exposing different parts to radiation.

[0005] Particle therapy systems typically operate according to a treatment plan, which may specify, among other things, the radiation dose to be delivered to the patient by the particle therapy system. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Pat. No. 8,791,656 [Patent Document 2] U.S. Patent No. 9,723,705 [Patent Document 3] US Patent Application Publication No. 2017 / 0128746 [Patent Document 4] U.S. Patent No. 7,728,311 [Patent Document 5] U.S. Patent No. 9,730,308 Summary of the Invention [Means for solving the problem]

[0007] An exemplary method of treating a target using a particle beam includes directing a particle beam along a path that passes at least partway through the target, and controlling the energy of the particle beam while the particle beam is directed along the path such that the particle beam treats at least an interior portion of the target located along the path. While the particle beam is directed along the path, the particle beam irradiates the target with a dose of radiation greater than 1 Gray per second for a duration of less than 5 seconds. Exemplary methods may include one or more of the following features, alone or in combination.

[0008] The directing and controlling may be performed for each of the multiple microvolumes of the target. Controlling the energy of the particle beam may include moving one or more energy absorbing plates into or out of the path of the particle beam between the target and the source of the particle beam. Moving one or more energy absorbing plates into or out of the path of the particle beam may be performed while the particle beam is directed along the path. Moving one or more energy absorbing plates into or out of the path of the particle beam may include sequentially moving multiple energy absorbing plates into the path of the particle beam. Moving one or more energy absorbing plates into or out of the path of the particle beam may include sequentially moving multiple energy absorbing plates out of the path of the particle beam. An energy absorbing plate of the one or more energy absorbing plates may include a linear motor that is controllable to move the energy absorbing plate into or out of the path of the particle beam. Each of the one or more energy absorbing plates may be movable into or out of the path of the particle beam for a duration of 100 milliseconds or less. Each of the one or more energy absorbing plates may be movable into or out of the path of the particle beam in a duration of 50 milliseconds or less. Each of the one or more energy absorbing plates may be movable into or out of the path of the particle beam in a duration of 10 milliseconds or less. Moving the one or more energy absorbing plates into or out of the path of the particle beam may include controlling a first plate of the one or more energy absorbing plates to move while the particle beam passes through the one or more energy absorbing plates to the target. The first plate may be configured and controllable to move across at least a portion of the beam field. The beam field may correspond to a plane that defines a maximum extent to which the particle beam can move relative to the target.

[0009] The particle beam may be generated by a particle accelerator configured to output a particle beam based on a current through a superconducting winding contained within the particle accelerator. Controlling the energy of the particle beam may include setting the current to one of a plurality of values. Each of the plurality of values ​​may correspond to a different energy of the particle beam output from the particle accelerator. While the particle beam is directed along the path, the particle beam may irradiate the target with a dose of radiation greater than 20 Gray per second for a duration of less than 5 seconds. While the particle beam is directed along the path, the particle beam may irradiate the target with a dose of radiation between 20 Gray per second and 100 Gray per second for a duration of less than 5 seconds. While the particle beam is directed along the path, the particle beam may irradiate the target with a dose of radiation between 40 Gray per second and 120 Gray per second. The dose of 40 to 120 Gray per second may be less than 5 seconds. While the particle beam is directed along the path, the particle beam may deliver a dose of radiation to the target that exceeds one or more of 100 Gray / sec, 200 Gray / sec, 300 Gray / sec, 400 Gray / sec, or 500 Gray / sec for a duration less than 500 ms, between 10 ms and 5 s, or less than 5 s. The particle beam may be a Gaussian pencil beam having a size of at least 2 millimeter sigma. The particle beam may be a Gaussian pencil beam having a size between 2 millimeter sigma and 20 millimeter sigma.

[0010] The path may be a first path, and the method may include directing the particle beam along a second path at least part way through a target different from the first path. The method may include controlling the energy of the particle beam such that while the particle beam is directed along the second path, the particle beam treats a portion of the target located along the second path. For example, the first and second paths may be a column that penetrates the target all the way through or part way through. While the particle beam is directed along the second path, the particle beam may deliver a dose of radiation to the target that exceeds 1 Gray per second for a duration of less than 500 milliseconds. The particle beam, in some examples, is not redirected along the first path during treatment of the target.

[0011] The method may include blocking at least a portion of the particle beam using a collimator that is configurable to block a first portion of the particle beam while allowing a second portion of the particle beam to reach the target. The collimator may include a structure made of a material that blocks the passage of the particle beam. The structure may define an edge that is moved into the path of the particle beam such that a first portion of the particle beam on a first side of the edge is blocked by the structure and a second portion of the particle beam on a second side of the edge is not blocked by the structure. The collimator may include linear motors that are controlled to configure the structure to define the edge. Each of the linear motors may include a moveable component and a fixed component. The fixed component may include a magnetic field generator for generating a first magnetic field. The moveable components may include one or more coils, where passing a current through the coils generates a second magnetic field that interacts with the first magnetic field to move the moveable component relative to the fixed component. The moveable component of each linear motor may be connected to or part of a corresponding one of the structures such that the corresponding structure moves with movement by the moveable component.

[0012] An exemplary method of treating a target using a particle beam includes directing a particle beam along a first path at least part way through the target, controlling the energy of the particle beam while the particle beam is directed along the first path such that the particle beam treats a three-dimensional cylindrical portion of the target along the first path, and repeating the directing and energy controlling of the particle beam for a number of different paths at least part way through the target without directing the particle beam multiple times along the same path through the target. While the particle beam is directed along each path through the target, the particle beam may irradiate the target with a dose of radiation greater than 1 Gray per second for a duration of less than 5 seconds. An exemplary method may include one or more of the following features, alone or in combination.

[0013] The directing and controlling may be performed for each of a plurality of microvolumes of the target. Controlling the energy of the particle beam may include moving one or more energy absorbing plates into or out of a path of the particle beam between the target and a source of the particle beam. The particle beam may be generated by a particle accelerator configured to output a particle beam based on a current through a superconducting winding contained within the particle accelerator. Controlling the energy of the particle beam may include setting the current to one of a plurality of values. Each of the plurality of values ​​may correspond to a different energy of the particle beam output from the particle accelerator.

[0014] An exemplary particle therapy system includes a particle accelerator for generating a particle beam, a scanning magnet for directing the particle beam along a path at least partially through the target, and a control system for controlling the scanning magnet to direct the particle beam along multiple paths at least partially through the target and for controlling the energy of the particle beam along each of the multiple paths such that the particle beam treats a three-dimensional cylindrical portion of the target. While the particle beam is directed along each of the multiple paths, the particle beam delivers a dose of radiation greater than 1 Gray per second to the target for a duration of less than 5 seconds. An exemplary system may include one or more of the following features, alone or in combination:

[0015] The control system may be configured to control the scanning magnet such that the particle beam is directed only once along each path through the target. The system may include energy absorbing structures, each of which may be configured to reduce the energy of the particle beam as it passes through the energy absorbing structure to the target. The control system may be configured to control the energy of the particle beam by moving one or more of the energy absorbing structures into or out of the path of the particle beam between the target and a source of the particle beam. The energy absorbing structures may include energy absorbing plates. The control system may be configured to treat a small volume of the target by controlling the scanning magnet to direct the particle beam along multiple paths at least partway through the target, and to control the energy of the particle beam such that the particle beam treats a three-dimensional cylindrical portion of the target along each of the multiple paths.

[0016] For one of the multiple paths followed by the directed particle beam, the control system may be configured to move one or more energy absorbing structures into or out of the path of the particle beam while the particle beam is in the path. For one of the multiple paths, the control system may be configured to sequentially move the multiple energy absorbing structures into the path of the particle beam. For one of the multiple paths, the control system may be configured to sequentially move the multiple energy absorbing structures out of the path of the particle beam. An energy absorbing plate of one of the energy absorbing structures may comprise a linear motor that is controllable to move the energy absorbing plate into or out of the path of the particle beam. For one of the multiple paths, the control system may be configured to move each of the one or more energy absorbing structures into or out of the path of the particle beam in a duration of 100 milliseconds or less. For one of the multiple paths, the control system may be configured to move each of the one or more energy absorbing structures into or out of the path of the particle beam in a duration of 50 milliseconds or less. For one of the multiple paths, the control system may be configured to move the one or more energy absorbing structures by performing an operation including controlling a first plate of the one or more energy absorbing structures to move as the particle beam passes through the one or more energy absorbing structures to the target.

[0017] The particle accelerator may include a superconducting winding. The particle accelerator may be configured to generate a particle beam based on a current through the superconducting winding. The control system may be configured to control the energy of the particle beam by setting the current to one of a plurality of values. Each of the plurality of values ​​may correspond to a different energy of the particle beam output from the particle accelerator. The control system may be configured to control the particle beam to irradiate the target with a dose of radiation greater than 20 Gray per second on each path for a duration less than 5 seconds. The control system may be configured to control the particle beam to irradiate the target with a dose of radiation between 20 Gray per second and 100 Gray per second on each path for a duration less than 5 seconds. The control system may be configured to control the particle beam to irradiate the target with a dose of radiation between 40 Gray per second and 120 Gray per second on each path for a specified duration.

[0018] The particle beam may be a Gaussian pencil beam having a size of at least 2 millimeters sigma.The particle beam may be a Gaussian pencil beam having a size between 2 millimeters sigma and 20 millimeters sigma.

[0019] The particle therapy system may include a collimator that is configurable to block a first portion of the particle beam while allowing a second portion of the particle beam to reach the target. The collimator may include a structure made of a material that blocks the passage of the particle beam. The structure may include an edge that moves into a path of the particle beam such that a first portion of the particle beam on a first side of the edge is blocked by the structure and a second portion of the particle beam on a second side of the edge is not blocked by the structure. The collimator may include linear motors that are controllable to configure the structure to define the edge. Each of the linear motors may include a moveable component and a fixed component. The fixed component may include a magnetic field generator for generating a first magnetic field. The moveable component may include one or more coils, where passing a current through the coil generates a second magnetic field that interacts with the first magnetic field to move the moveable component relative to the fixed component. The moveable component of each linear motor may be connected to or part of a corresponding one of the structures such that the corresponding structure moves with movement by the moveable component.

[0020] The control system can be configured to control an intensity of the particle beam along each of the multiple paths. The intensity of the particle beam can be different along at least two of the multiple paths.

[0021] The particle therapy system may include a ridge filter for expanding a Bragg peak of the particle beam. The particle therapy system may include a range modulator wheel for expanding a Bragg peak of the particle beam. The range modulator wheel may be configured to move in at least two dimensions to track the movement of the particle beam. The control system may be configured to control an intensity of the particle beam when the particle beam strikes the range modulator wheel.

[0022] In one example, one or more non-transitory machine-readable storage media store instructions executable to implement an exemplary treatment planning system for a particle therapy system. The treatment planning system includes a predictive model that characterizes the particle therapy system and a patient treated by the particle therapy system. The predictive model characterizes the particle therapy system, at least in part, by characterizing timings at which the particle therapy system can deliver radiation. The treatment planning system includes a relative biological effectiveness (RBE) model that characterizes a relative biological effectiveness of radiation on tissues based on timings of delivery of the radiation, and a dose calculation engine that determines a dose regimen for delivering radiation to voxels of the patient. The dose calculation engine is configured to determine the dose regimen based on the predictive model and the RBE model. The treatment planning system may include one or more of the following features, alone or in combination:

[0023] The dose regimen may specify the dose and dose rate of radiation to be delivered to a voxel. The treatment planning may include a sequencer that generates instructions for sequencing the delivery of the doses to optimize the effective dose determined by the dose calculation engine.

[0024] The predictive model may characterize the particle therapy system based on a pulse structure of the particle beam generated by the particle accelerator. The predictive model may characterize the particle therapy system based on a maximum dose per pulse of the particle beam generated by the particle accelerator. The predictive model may characterize the particle therapy system based on a sweep time of a scanning magnet that moves the particle beam generated by the particle accelerator. The predictive model may characterize the particle therapy system based on a time required to change the energy of the particle beam generated by the particle accelerator. The predictive model may characterize the particle therapy system based on a time required to move one or more energy absorbing structures to change the energy of the particle beam generated by the particle accelerator. The predictive model may characterize the particle therapy system based on a strategy for adjusting the radiation dose. The predictive model may characterize the particle therapy system based on a time required to move a collimator to collimate the particle beam generated by the particle accelerator. The predictive model may characterize the particle therapy system based on a time required to configure a collimator to collimate the particle beam generated by the particle accelerator. The predictive model may characterize a particle therapy system based on the time it takes to control a range modulator to change the Bragg peak of particles in a particle beam generated by a particle accelerator.

[0025] The dose calculation engine may be configured to determine a time for a voxel of the patient to be delivered with a dose specified in the dose regimen based on the RBE model. The dose calculation engine may be configured to determine whether a voxel of the voxels includes target tissue, non-target tissue, or both target and non-target tissue, and to determine a dose rate of radiation to the voxel based at least in part on whether the voxel includes target tissue, non-target tissue, or both target and non-target tissue. The target tissue may include diseased tissue, and the non-target tissue may include healthy tissue. If the voxel includes only non-target tissue, determining the dose rate of radiation to the voxel may include determining to deliver no dose to the voxel. If the voxel includes target tissue or both target and non-target tissue, determining the dose rate of radiation to the voxel may include determining to deliver an ultra-high dose rate of radiation to the voxel.

[0026] Ultra-high dose rate radiation may include a dose of radiation greater than 1 Gray per second for a duration of less than 5 seconds. Ultra-high dose rate radiation may include a dose of radiation greater than 1 Gray per second for a duration of less than 500 ms. Ultra-high dose rate radiation may include a dose of radiation between 40 Gray per second and 120 Gray per second for a duration of less than 500 ms.

[0027] A dose regimen may specify the dose and dose rate of radiation to be delivered to a voxel. These doses may include equivalent doses determined based on weighting factors from the RBE model, which allow the dose to be higher for a certain duration.

[0028] The sequencer is configured to sequence the delivery of doses based on one or more of: a structure of a pulse of the particle beam generated by the particle accelerator, a maximum dose per pulse of the particle beam, a sweep time of a scanning magnet that moves the particle beam, a time taken to change the energy of the particle beam, a time taken to move one or more energy absorbing structures to change the energy of the particle beam, a strategy for adjusting the dose, a time taken to move a collimator to collimate the particle beam, a time taken to configure a collimator, or a time taken to control a range modulator to change the Bragg peak of particles in the particle beam, or based on two or more of them, or based on three or more of them, or based on four or more of them, or based on five or more of them, or based on all of them.

[0029] For one of the voxels, the sequencer may be configured to sequence the delivery of a set of doses in a column that passes at least partway through the voxel. The voxel may be a microvolume of an irradiation target that is treated using a column of radiation, or a part of such a microvolume, or may include a number of such microvolumes. Each dose in the set may be delivered at a very high dose rate. For one of the columns, the energy of the particle beam generated by the particle accelerator may be changed while the particle beam is stationary. The order of delivery may be such that after the treatment of a column, the particle beam is not directed again to the treatment of the column.

[0030] In one example, one or more non-transitory machine-readable storage media store instructions executable to implement an exemplary treatment planning system for a particle therapy system. The treatment planning system includes a predictive model that characterizes the particle therapy system and a patient treated by the particle therapy system, and a dose calculation engine that determines a dose regimen for delivery of radiation to voxels of the patient. The dose calculation engine can be configured to determine the dose regimen based on the predictive model. The treatment planning system can include one or more of the above features, alone or in combination. The treatment planning system can include one or more of the following features, alone or in combination:

[0031] A dose regimen may specify the dose and dose rate of radiation to be delivered to a voxel. The treatment planning system may include a sequencer that generates instructions for sequencing the delivery of the doses at a rate determined by the dose calculation engine.

[0032] An exemplary method includes storing, in a computer memory, first information that characterizes a particle therapy system and a patient treated by the particle therapy system. The method includes storing, in the computer memory, second information that characterizes a relative biological effectiveness ratio of radiation to tissue. The method also includes determining, by one or more processing devices, a dose regimen for delivering radiation to voxels of the patient. The dose regimen may be determined based on the first information and the second information. The method may include one or more of the following features, alone or in combination:

[0033] The dose regimen may specify doses and dose rates of radiation to be delivered to the voxels, and the method may include generating instructions for sequencing the delivery of the doses at the rates specified in the dose regimen.

[0034] The first information may characterize the particle therapy system based on a pulse structure of the particle beam generated by the particle accelerator. The first information may characterize the particle therapy system based on a maximum dose per pulse of the particle beam generated by the particle accelerator. The first information may characterize the particle therapy system based on a sweep time of a scanning magnet that moves the particle beam generated by the particle accelerator. The first information may characterize the particle therapy system based on a time it takes to change the energy of the particle beam generated by the particle accelerator. The first information may characterize the particle therapy system based on a time it takes to move one or more energy absorbing structures to change the energy of the particle beam generated by the particle accelerator. The first information may characterize the particle therapy system based on a strategy for adjusting the dose. The first information may characterize the particle therapy system based on a time it takes to move a collimator to collimate the particle beam generated by the particle accelerator. The first information may characterize the particle therapy system based on a time it takes to configure a collimator to collimate the particle beam generated by the particle accelerator. The first information can characterize the particle therapy system based on the time it takes to control a range modulator to change a Bragg peak of particles in a particle beam generated by a particle accelerator.

[0035] Determining the dose regimen may include determining a time for a voxel of the patient to be delivered with a dose specified in the dose regimen based on the second information. Determining the dose regimen may include determining whether a voxel of the voxels includes target tissue, non-target tissue, or both target and non-target tissue, and determining a dose rate of radiation to the voxel based at least in part on whether the voxel includes target tissue, non-target tissue, or both target and non-target tissue. The target tissue may include diseased tissue, and the non-target tissue may include healthy tissue. If the voxel includes only non-target tissue, determining the dose rate of radiation to the voxel may include determining to not deliver a dose to the voxel. If the voxel includes target tissue or both target and non-target tissue, determining the dose rate of radiation to the voxel may include determining to deliver an ultra-high dose rate of radiation to the voxel.

[0036] Ultra-high dose rate radiation may include a dose of radiation greater than 1 Gray per second for a duration of less than 5 seconds. Ultra-high dose rate radiation may include a dose of radiation greater than 1 Gray per second for a duration of less than 500 ms. Ultra-high dose rate radiation may include a dose of radiation between 40 Gray per second and 120 Gray per second for a duration of less than 500 ms.

[0037] The dose regimen may specify the dose and dose rate of radiation to be delivered to the voxels. These doses may include equivalent doses determined based on weighting factors from the second information, which may result in higher doses for certain durations.

[0038] The sequencing of the delivery of the doses is based on one or more of, or two or more of, or three or more of, or four or more of, or five or more of, or all of the following: the structure of the pulses of the particle beam generated by the particle accelerator, the maximum dose per pulse of the particle beam, the sweep time of a scanning magnet that moves the particle beam, the time required to change the energy of the particle beam, the time required to move one or more energy absorbing structures to change the energy of the particle beam, a strategy for adjusting the dose, the time required to move a collimator to collimate the particle beam, the time required to configure the collimator, or the time required to control a range modulator to change the Bragg peak of particles in the particle beam.

[0039] For one of the voxels, ordering the delivery of the doses may include ordering the delivery of a set of doses in a column that passes at least partway through the voxel. Each dose in the set may be delivered at a very high dose rate. For one of the columns, the energy of the particle beam generated by the particle accelerator may be changed while the particle beam is stationary. The delivery order may be such that after treatment of a column, the particle beam is not directed again to treatment of the column.

[0040] An exemplary method includes storing in a computer memory first information characterizing a particle therapy system and a patient treated by the particle therapy system, and determining, by one or more processing devices, a dose regimen for delivering radiation to voxels of the patient. The dose regimen may be determined based on the first information. The method may include one or more of the following features, alone or in combination:

[0041] The dose regimen may specify doses and dose rates of radiation to be delivered to the voxels, and the method may include generating instructions for sequencing the delivery of the doses at the rates specified in the dose regimen.

[0042] An exemplary system includes a particle accelerator for generating radiation to be irradiated to the patient, a scanning system for controlling the delivery of the radiation to the patient, a treatment planning system for generating a treatment plan that specifies how voxels of the patient are to be irradiated with the radiation, and a control system that controls the particle accelerator and the scanning system to irradiate the patient's voxels with the radiation in accordance with the treatment plan.

[0043] The treatment planning system can be programmed to generate a treatment plan by performing the following operations: storing in a computer memory first information characterizing the particle therapy system and a patient treated by the particle therapy system; storing in the computer memory second information characterizing a relative biological effectiveness of radiation on tissue; and determining, by one or more processing devices, a dose regimen for delivering radiation to voxels of the patient, where the dose regimen is determined based on the first information and the second information.

[0044] The treatment planning system can be programmed to generate a treatment plan by performing the operations of storing in a computer memory first information characterizing the particle beam therapy system and a patient to be treated by the particle beam therapy system, and determining, by one or more processing devices, a dose regimen for delivering radiation to voxels of the patient, where the dose regimen is determined based on the first information.

[0045] The treatment planning system may include a predictive model that characterizes a particle therapy system and a patient treated by the particle therapy system. The predictive model characterizes the particle therapy system, at least in part, by characterizing timings at which the particle therapy system can deliver radiation. The treatment planning system includes a relative biological effectiveness (RBE) model that characterizes a relative biological effectiveness of radiation on tissues based on the timing of delivery of the radiation, and a dose calculation engine that determines a dose regimen for delivering radiation to voxels of the patient. The dose calculation engine is configured to determine the dose regimen based on the predictive model and the RBE model.

[0046] The treatment planning may also include a sequencer that generates instructions for sequencing the delivery of doses to optimize the effective dose determined by the dose calculation engine.

[0047] The treatment planning system can include a predictive model that characterizes a particle therapy system and a patient treated by the particle therapy system, and a dose calculation engine that determines a dose regimen for delivery of radiation to voxels of the patient. The dose calculation engine can be configured to determine the dose regimen based on the predictive model.

[0048] The treatment planning may also include a sequencer that generates instructions for sequencing the delivery of doses to optimize the effective dose determined by the dose calculation engine.

[0049] The treatment planning system may include a first computing system, and the control system may include a second computing system, which may be different from the second computing system. The treatment planning system and the control system may be implemented on the same computing system. This exemplary system may include any of the features described herein, including but not limited to those described in the Summary of the Invention section above.

[0050] Two or more of the features described in this disclosure, including those described in this Summary of the Invention section, may be combined to form implementations not specifically described herein.

[0051] Control of the various systems described herein, or portions thereof, may be implemented via a computer program product containing instructions stored on one or more non-transitory machine-readable storage media and executable on one or more processing devices (e.g., programmed logic such as a microprocessor, application specific integrated circuit, field programmable gate array, or the like). The systems described herein, or portions thereof, may be implemented as an apparatus, method, or electronic system that may include one or more processing devices and a computer memory for storing executable instructions that implement control of the described functions.

[0052] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0053] [Figure 1] 1 is a perspective view of an exemplary irradiation target that is treated by sequentially scanning a particle beam across a layer. [Diagram 2] FIG. 1 is a perspective view of an exemplary irradiation target that is treated by scanning a particle beam column-by-column across the target. [Diagram 3] FIG. 2 is a cutaway view of a portion of an example particle accelerator that can be used in the particle therapy systems described herein. [Figure 4] FIG. 2 is a side view of components of an example scanning system that can be used in the particle therapy systems described herein. [Diagram 5]FIG. 2 is a perspective view of components of an exemplary scanning system that can be used in the particle therapy systems described herein. [Figure 6] FIG. 6 is a front view of an exemplary magnet for use in a scanning system of the type shown in FIGS. 4 and 5. [Figure 7] FIG. 6 is a perspective view of an exemplary magnet for use in a scanning system of the type shown in FIGS. 4 and 5. [Figure 8] FIG. 6 is a perspective view of an exemplary energy degrader (range modulator) for use in a scanning system of the type shown in FIGS. 4 and 5. [Figure 9] 1 is a perspective view of a process for moving the plates of an energy degrader into and out of the path of a particle beam. [Figure 10] FIG. 2 is a block diagram of an example linear motor and an example plate of an energy degrader controlled thereby. [Figure 11] 1 is a flow chart illustrating an exemplary process for treating an irradiation target by scanning a particle beam column-by-column across the target. [Figure 12] FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates into the path of a fixed particle beam. [Figure 13] FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates into the path of a fixed particle beam. [Figure 14] FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates into the path of a fixed particle beam. [Figure 15] FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates into the path of a fixed particle beam. [Figure 16]FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates out of the path of a fixed particle beam. [Figure 17] FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates out of the path of a fixed particle beam. [Figure 18] FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates out of the path of a fixed particle beam. [Figure 19] FIG. 1 is a perspective block diagram illustrating the treatment of a column of irradiation targets by sequentially moving energy absorbing plates out of the path of a fixed particle beam. [Figure 20] 1 is a perspective view of an example configurable collimator that may be used with the example configurable collimators described herein. FIG. [Figure 21] FIG. 13 is a top view of a configurable collimator leaf positioned relative to a treatment area of ​​an irradiation target. [Figure 22] 1 is a perspective view of an exemplary configurable collimator. [Figure 23] FIG. 2 is a front view of an exemplary configurable collimator. [Figure 24] FIG. 2 is a perspective view of an exemplary configurable collimator having components depicted as see-through to show its interior. [Diagram 25] 1 is a perspective view of an exemplary configurable collimator positioned relative to a patient during a particle therapy treatment. [Figure 26] FIG. 1 is a front view of an exemplary particle therapy system. [Figure 27] FIG. 1 is a perspective view of an exemplary particle therapy system. [Figure 28] FIG. 1 is a perspective view of an exemplary particle therapy system. [Figure 29]1 is a graph showing different materials used in an energy degrader to modify the energy of the particle beam, and the change in particle beam spot size for different particle beam energies. [Diagram 30] FIG. 1 is a block diagram illustrating components of an exemplary treatment planning system. [Diagram 31] FIG. 2 is a cross-sectional view of a voxel of a patient. [Diagram 32] FIG. 1 illustrates an exemplary spread-out Bragg peak (SOBP) and columns that are part of an exemplary irradiation target. [Diagram 33] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Diagram 34] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Diagram 35] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Diagram 36] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Figure 37] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Figure 38] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Figure 39] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Diagram 40] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Diagram 41] FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Diagram 42]FIG. 1 is a perspective block diagram illustrating an exemplary process for treating a column of irradiation targets with a microvolume. [Figure 43A] 1 is a plot showing the results of a Monte Carlo simulation to calculate the radiation dose delivered to a treatment volume and the time it takes each voxel in the dose calculation to reach the final dose. [Figure 43B] 1 is a plot showing the results of a Monte Carlo simulation to calculate the radiation dose delivered to a treatment volume and the time it takes each voxel in the dose calculation to reach the final dose. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Like reference symbols in the various drawings indicate like elements.

[0055] Described herein are exemplary implementations of a treatment planning system for a particle therapy system. The exemplary treatment plan specifies a dose regimen for treating a patient using radiation. The dose regimen may include the dose to be delivered, the rate at which the dose is delivered, referred to as the "dose rate," or both the dose to be delivered and the dose rate. The dose in the dose regimen may simply include the amount of radiation delivered during treatment. The dose in the dose regimen may include a biologically equivalent dose, also referred to as the "equivalent dose." The biologically equivalent dose may include a certain amount of radiation output necessary to treat diseased tissue in the patient's body, taking into account the biological effect of the tissue in the patient's body on the radiation deposited. In some implementations, the treatment planning system may be used to generate instructions to administer radiation at several dose rates to a three-dimensional treatment volume in the patient's body, referred to as a voxel. All or part of the treatment planning system may be implemented by executing one or more computer programs on one or more processing devices, stored in and retrieved from one or more non-transitory machine-readable storage media.

[0056] The exemplary treatment planning system and its variations described herein may be used to generate instructions for administering ultra-high dose rates of radiation - so-called "FLASH" dose rate radiation - to irradiation targets. In this regard, experimental results of radiation therapy have shown that the condition of healthy tissue receiving radiation is improved when therapeutic doses are delivered at ultra-high (FLASH) dose rates. For example, when a dose of radiation of 10-20 Gray (Gy) is delivered in pulses of less than 500 milliseconds (ms) to reach an effective dose rate of 20 to 100 Gray per second, healthy tissue is less damaged and tumors are treated with similar efficacy compared to the same dose delivered over a longer time scale. A theory that may explain this "FLASH effect" is based on the fact that radiation damage to tissue is proportional to the oxygen supply in the tissue. In healthy tissue, at ultra-high dose rates, oxygen is radicalized only once, as opposed to dose applications that radicalize oxygen multiple times over a longer time scale. This may result in less damage in healthy tissue using ultra-high dose rates.

[0057] In one example, the treatment planning system includes a predictive accelerator-dependent timing model, referred to as a "prediction model," a time-dependent relative biological effectiveness (RBE) model, a dose calculation engine that incorporates time-dependent RBE effects that may result, for example, from delivering radiation at very high dose (FLASH) rates, and a sequencer or optimizer that sequences particle beam deliveries to generate an optimized very high dose rate (or other) dose regimen. In this example, the treatment planning system is implemented at least in part using software and configured--e.g., written or programmed--to determine, for a proposed beam delivery, the time at which any dose is delivered to any given volume within the irradiation target.

[0058] The predictive model characterizes or models components of a particle therapy system that delivers radiation to a patient. For example, the predictive model may characterize components of a particle therapy system, including the system's ability to deliver a series of spots or columns of radiation in the time required to deliver an ultra-high dose of radiation. The predictive model may also characterize or model a patient and a treatment target, such as a tumor of the patient. The predictive model may be implemented using one or more computer programming objects, one or more look-up tables (LUTs), data structures such as arrays, lists, or binary trees, or any suitable software model.

[0059] The RBE model characterizes the relative biological effectiveness of radiation on tissues in a time-dependent manner. In other words, the RBE model characterizes the relative biological effectiveness of radiation on tissues based on the timing of radiation exposure to that tissue. For example, when radiation is applied at a very high (FLASH) dose rate, healthy tissue is less damaged and tumors are treated with similar effectiveness than when that same tissue is exposed to the same dose on a longer time scale. In other words, for tumors or other diseased tissues, the critical factor for treatment is the total radiation dose as opposed to the dose rate, while for healthy tissues, the dose rate is a factor that reduces damage where damage is not desired. The RBE model may include information on different types of healthy and diseased tissues and the effects of radiation at different dose rates on those different types of tissues. The RBE model may include information on how different types of healthy and diseased tissues affect the delivery and absorption of radiation. The RBE model may also include the effects of different types of radiation at different dose rates on different types of tissues. The RBE model may be implemented using one or more computer programming objects, one or more look-up tables (LUTs), data structures such as arrays, lists, or binary trees, or any suitable software model.

[0060] The dose calculation engine determines a dose regimen for the patient. For example, the dose calculation engine may determine doses of radiation to deliver to voxels of the patient and the rate at which those doses should be delivered. The dose calculation engine uses information from the predictive model and the RBE model in performing its calculations. In this regard, the dose calculation engine is configured--e.g., written or programmed--to determine doses and dose rates based at least in part on the time-dependent RBE of radiation to tissues within the patient. Thus, the dose calculation engine may identify whether the patient's tissue is healthy or diseased, use the RBE model and the predictive model to calculate the duration over which a dose or doses of radiation should be delivered to the tissue based on system constraints, and scale the dose to the target tissue based on the desired type of treatment. For example, the dose calculation engine may be configured to identify a target within the patient, such as a malignant neoplasm, and also identify healthy tissues within the patient. The dose calculation engine may then determine the RBE of radiation to the tissue based on the RBE model. The dose calculation engine may then determine the dose of radiation to deliver to the target and the rate at which the dose should be delivered given the constraints of the system delivering the dose based on the predictive model and the relevant patient information. The dose calculation engine avoids delivering radiation to healthy tissue as much as possible while maintaining an appropriate dose, such as an ultra-high dose rate, to the voxels that make up the target. To the extent that radiation affects healthy tissue, delivering that radiation at an ultra-high (FLASH) dose rate may affect the healthy tissue less than in traditional applications at lower dose rates.

[0061] Using a combination of the predictive model, the RBE model, and the dose calculation engine, all of which take timing into account in any case, the treatment planning system can generate a time-dependent treatment plan with an appropriate dose regimen, the quality of which can be assessed by the user. Also, the beam delivery sequence can be created or modified manually using a forward treatment planning approach to create an ordered treatment plan that takes advantage of the FLASH effect. For example, the user can manually arrange the delivery of radiation in columns with constant beam steering, or select beam angles or collimation that reduce the degree of overlap between different columns of different radiation.

[0062] The sequencer or optimizer may be configured--e.g., written or programmed--to generate instructions, such as computer-executable instructions, for sequencing the delivery of doses at rates determined by the dose calculation engine. The treatment planning system may use the sequencer or optimizer to automatically perform sequence optimization by sequencing treatments using an inverse planning approach. In one example, the sequencer uses the order of beam or spot delivery as an additional degree of freedom and employs optimization techniques to determine the order that best achieves input criteria specified by the user while accounting for time-dependent effects.

[0063] As previously mentioned, the sequencer may employ inverse treatment planning to determine the order in which doses of radiation are delivered. In some implementations, inverse treatment planning involves taking a target dose distribution of radiation and then performing a process, such as an optimization process, to determine how to deliver that radiation to achieve the treatment plan's objectives, such as destroying malignant tissue, under the time constraints required to achieve a very high (FLASH) dose rate. In one example, given the characteristics in the predictive model and the target dose, the sequencer may determine that radiation should be applied to the patient's voxels in columns. The sequencer may determine the radius and length of those columns at which those columns should be positioned at the target, and the order in which each column of radiation should be delivered. In an example that does not use a very high dose rate, the sequencer may determine that radiation should be applied to layers of the target in spots. The sequencer may determine the size, shape, and placement of the spots, the thickness of the layers, the number of layers, the number of protons in each spot, the order in which each spot should be applied, and the order in which the layers are treated.

[0064] In some implementations, the sequencer is configured to sequence the delivery of doses based on one or more of, or two or more of, or three or more of, or four or more of, or five or more of, or all of the following: a structure of a pulse of a particle beam generated by a particle accelerator, a maximum dose per pulse of the particle beam, a sweep time of a scanning magnet that moves the particle beam, a time required to change the energy of the particle beam, a time required to move one or more energy absorbing structures to change the energy of the particle beam, a strategy for adjusting the dose, a time required to move a collimator to collimate the particle beam, a time required to configure a collimator, or a time required to control a range modulator to change the Bragg peak of particles in the particle beam.

[0065] The treatment planning system may be used with a particle therapy system for treating an irradiation target (or simply "target"), such as a tumor, using a particle beam, such as a proton or ion beam. In this regard, some such systems treat a cross-section of the target layer by layer. For example, the energy of the particle beam may be controlled to deliver a radiation dose (or simply "dose") to one layer, and then the particle beam may be moved across all or a portion of that layer. The energy of the particle beam may then be changed to deliver a dose to another layer. The particle beam may be moved across all or a portion of another layer, and so on until the entire target is treated. For example, FIG. 1 illustrates treating an entire layer 10 of a target 11 using a particle beam 12 having sufficient energy to deliver a dose to layer 10 by moving the particle beam across the layer along the direction of arrow 15. A different layer 16 of the target 11 is then treated in the same manner using a particle beam having a different energy sufficient to deliver a dose to layer 16, and so on. Treatment of each layer is typically at a relatively average dose rate, such as 0.1 Gray per second. The particle beam often penetrates healthy tissue before reaching the target. Any one location within this healthy tissue may be visited several times during the course of treatment. The dose of such a location is received over a time scale on the order of minutes.

[0066] In contrast, particle therapy systems can treat three-dimensional columns of targets using ultra-high dose rate radiation--FLASH doses of radiation. These systems scale the delivery of ultra-high dose rates to targets using pencil beam scanning. In some examples, pencil beam scanning involves delivering a series of small beams of particle radiation, each of which may have a unique direction, energy, and charge. By combining the doses from these individual beams, a three-dimensional target treatment volume can be treated with radiation. Furthermore, instead of organizing the treatment on several layers with a constant energy, the system organizes the treatment into columns defined by a fixed beam direction. The beam direction may be toward the surface of the target.

[0067] In some implementations, all or a portion of the column is treated before the particle beam is directed along another path through the irradiation target. In some implementations, the path through the target is to the end or partway through the target. In one example, the particle beam may be directed along a path through the target and not deviate from that path. While being directed along that path, the energy of the particle beam is changed. The particle beam is stationary as its energy is changed, so that the particle beam treats all or a portion of the interior portion of the target that extends along the length of the particle beam and along the width of the beam spot. Thus, a depth treatment is performed along the length of the beam. For example, the portion of the target being treated may extend from the spot of the beam on the surface of the target down through all or a portion of the interior of the target. As a result, the particle beam treats a three-dimensional columnar portion of the target using an ultra-high dose rate of radiation. In some examples, ultra-high dose rate radiation includes, for example, a dose of radiation greater than 1 Gray per second for a duration less than 500 milliseconds (ms), greater than 1 Gray per second for a duration between 10 ms and 5 seconds (s), or greater than 1 Gray per second for a duration less than 5 s. Other examples are provided herein.

[0068] In some implementations, after a column of the target is treated as described in the previous paragraph, the particle beam is directed along a new, different path through the target. For example, as shown in FIG. 2, column 20 of target 21 is treated by varying the energy of particle beam 22 traveling along the direction of arrow 28. The particle beam is then directed along a new path 24 through target 21, where it travels along the direction of arrow 29. Column 25 is then treated along that new path by varying the energy of the particle beam while the particle beam is stationary. As noted, the columns are positioned along the longitudinal extent of the beam. In some implementations, the particle beam is directed only once along each path through the target when treating a column of the target.

[0069] As a result of the above protocol, healthy tissue above or below the target 21 is exposed only once to an ultra-high dose rate of radiation, and not to multiple low doses of radiation as occurs when the target is treated layer by layer as in FIG. 1. Thus, in some implementations, the particle beam is directed along a new path and does not again access tissue upstream along that path. In this way, each location within the target can be treated at a rate comparable to an individual pencil beam modulated with the layer switching time. The average dose rate over the entire treatment may be comparable to a layer by layer radiation delivery, but the local dose rate to any one spot is an ultra-high dose rate.

[0070] In some cases, reduced damage to healthy tissue can occur when radiation is delivered at very high dose rates. For example, a dose of 10-20 Gray radiation delivered in a pulse of less than 500 ms -- resulting in an effective dose rate of 20 to 100 Gray per second -- can cause less damage to healthy tissue than the same dose delivered over a longer time scale, and the delivered radiation can treat tumors with the same level of effectiveness.

[0071] In some implementations, to achieve ultra-high dose rates, the energy of the particle beam may be changed at a rate that exceeds the change in energy used for layer-by-layer scanning. For example, ultra-high dose rates applied to a column of targets may be achieved by switching beam energies within a duration of 50 ms. For example, ultra-high dose rates applied to a column of targets may be achieved by switching beam energies within a duration of 10 ms or less. This may be achieved, for example, by controlling the movement of the particle beam and the movement of energy absorbing plates or other structures into and out of the path of the particle beam. For example, a column that is 5 centimeters (cm) deep may require a 5-layer switch, but may require 250 ms of downtime during which the particle beam is not delivered, allowing for a 250 ms beam delivery during which a dose of 10 to 20 Gray may be delivered. Faster movement of the energy absorbing plates and / or additional adjustments to the beam movement may further reduce the layer switching time, allowing for even more time to deliver the required therapeutic dose while still meeting the localized ultra-high dose rate requirements.

[0072] Described below is an exemplary implementation of a particle therapy beam system configured to deliver ultra-high dose rate radiation through a three-dimensional column of a target according to a treatment plan determined by a treatment planning system. In one exemplary implementation, the particle therapy system is a proton therapy system. As described herein, the exemplary proton therapy system scans a proton beam in three dimensions across an irradiation target to destroy malignant tissue. FIG. 3 shows a cross-sectional view of an exemplary superconducting synchrocyclotron component 310 that may be used to deliver a particle (e.g., proton) beam in a proton therapy system. In this example, the component 310 comprises a superconducting magnet 311. The superconducting magnet comprises superconducting coils 312 and 313. The superconducting coils are formed from a plurality of integrated conductors, each of which comprises superconducting strands--e.g., four strands or six strands--wound around a central strand that may itself be superconducting or non-superconducting. Each of the superconducting coils 312, 313 is for conducting an electric current that generates a magnetic field (B). The shape of the magnetic yokes 314, 315 or smaller pole pieces shapes that magnetic field within a cavity 316 in which the particles to be accelerated are placed. In one example, a cryostat (not shown) uses liquid helium (He) to conductively cool each coil to a superconducting temperature, e.g., about 4 degrees Kelvin (K).

[0073] In some implementations, the particle accelerator includes a particle source 317, such as a Penning Ion Gauge--PIG source, to provide an ionized plasma column to the cavity 316. Hydrogen gas, or a combination of hydrogen gas and a noble gas, generates the plasma column when ionized. A voltage source applies a variable radio frequency (RF) voltage to the cavity 316 to accelerate particles from the plasma column within the cavity. As noted, in one example, the particle accelerator is a synchrocyclotron. Thus, when accelerating particles within the acceleration cavity, the RF voltage is swept over a range of frequencies to account for relativistic effects on the particles, such as increasing particle mass. The RF voltage drives a D-shaped plate housed within the cavity, with the frequency swept downward in the acceleration cycle to account for the increasing relativistic mass of protons and the decreasing magnetic field. A dummy D-shaped plate serves as a prescribed reference for this D-shaped plate. A magnetic field generated by passing a current through a superconducting coil, combined with a sweep of an RF voltage, causes particles from the plasma column to accelerate onto orbits within the cavity, gaining more energy as their rotation rate increases.

[0074] The magnetic field within the cavity is shaped to move the particles in an orbit within the cavity. An exemplary synchrocyclotron employs a magnetic field with a uniform rotation angle that decreases in strength with increasing radius. In some implementations, the maximum magnetic field generated in the superconducting (main) coils may be in the range of 4 Tesla (T) to 20 T at the center of the cavity, decreasing with increasing radius. For example, superconducting coils are 4.0T, 4.1T, 4.2T, 4.3T, 4.4T, 4.5T, 4.6T, 4.7T, 4.8T, 4.9T, 5.0T, 5.1T, 5.2T, 5.3T, 5.4T, 5.5T, 5.6T, 5.7T , 5.8T, 5.9T, 6.0T, 6.1T, 6.2T, 6.3T, 6.4T, 6.5T, 6.6T, 6.7T, 6.8T, 6.9T, 7.0T, 7.1T, 7.2T, 7.3T, 7.4T, 7.5T, 7.6T, 7.7T, 7. 8T, 7.9T, 8.0T, 8.1T, 8.2T, 8.3T, 8.4T, 8.5T, 8.6T, 8.7T, 8.8T, 8.9T, 9.0T, 9.1T, 9.2T, 9.3T, 9.4T, 9.5T, 9.6T, 9.7T, 9.8T , 9.9T, 10.0T, 10.1T, 10.2T, 10.3T, 10.4T, 10.5T, 10.6T, 10.7T, 10.8T, 10.9T, 11.0T, 11.1T, 11.2T, 11.3T, 11.4T, 11.5T, 1 1.6T, 11.7T, 11.8T, 11.9T, 12.0T, 12.1T, 12.2T, 12.3T, 12.4T, 12.5T, 12.6T, 12.7T, 12.8T, 12.9T, 13.0T, 13.1T, 13.2T, 1 3.3T, 13.4T, 13.5T, 13.6T, 13.7T, 13.8T, 13.9T, 14.0T, 14.1T, 14.2T, 14.3T, 14.4T, 14.5T, 14.6T, 14.7T, 14.8T, 14.9T, 15 .0T, 15.1T, 15.2T, 15.3T, 15.4T, 15.5T, 15.6T, 15.7T, 15.8T, 15.9T, 16.0T, 16.1T, 16.2T, 16.3T, 16.4T, 16.5T, 16.6T, 16 .7T, 16.8T, 16.9T, 17.0T, 17.1T, 17.2T, 17.3T, 17.4T, 17.5T, 17.6T, 17.7T, 17.8T, 17.9T, 18.0T, 18.1T, 18.2T, 18.3T, 18.Superconducting coils may be used in generating magnetic fields of one or more of the following magnitudes: 4T, 18.5T, 18.6T, 18.7T, 18.8T, 18.9T, 19.0T, 19.1T, 19.2T, 19.3T, 19.4T, 19.5T, 19.6T, 19.7T, 19.8T, 19.9T, 20.0T, 20.1T, 20.2T, 20.3T, 20.4T, 20.5T, 20.6T, 20.7T, 20.8T, 20.9T, or more. Additionally, superconducting coils may be used in generating magnetic fields outside the range of 4T to 20T or within the range of 4T to 20T but not specifically listed above.

[0075] In some implementations, such as that shown in Figure 3, relatively large ferromagnetic magnetic yokes 314, 315 act as a return for stray magnetic fields generated by the superconducting coils. In some systems, a magnetic shield (not shown) surrounds the yoke. Together, the return yoke and shield act to reduce the stray magnetic fields, thereby reducing the likelihood that the stray magnetic fields will adversely affect the operation of the particle accelerator.

[0076] In some implementations, the feedback yoke and shields may be replaced or augmented by an active feedback system. One exemplary active feedback system includes one or more active feedback coils that pass current in a direction opposite to the current through the main superconducting coils. In some exemplary implementations, there is an active feedback coil for each superconducting main coil, e.g., there are two active feedback coils--one for each main superconducting coil. Each active feedback coil may be a superconducting coil that concentrically surrounds the outside of the corresponding main superconducting coil.

[0077] By using an active return system, the relatively large ferromagnetic magnetic yokes 314, 315 can be replaced with smaller, lighter pole pieces. Thus, the size and weight of the synchrocyclotron can be reduced without further sacrificing performance. One example of an active return system that can be used is described in U.S. Patent No. 6,333,633 entitled "Active Return System," the contents of which are incorporated herein by reference.

[0078] At or near the output of the extraction channel of the particle accelerator, there may be one or more beam shaping elements, including a scanning system. The components of the scanning system may be mounted on or otherwise attached to the nozzle for positioning relatively close to the patient being treated.

[0079] Referring to FIG. 4, in an exemplary embodiment, at the output of the extraction channel 420 of the synchrocyclotron 421 (which may have the configuration of FIG. 3), there is an exemplary scanning component 422 that may be used to move the particle beam in three-dimensional space over and through the irradiation target. FIG. 5 also shows examples of the components of FIG. 4. These include, but are not limited to, one or more scanning magnets 424, an ionization chamber 425, an energy degrader 426, and a configurable collimator 428. Some implementations may not include a configurable collimator. In exemplary implementations such as these, the particle beam passes through the energy degrader to the patient without subsequent adjustments such as collimation. Other components that may be downstream of the beam from the extraction channel are not shown in FIG. 4 or FIG. 5 and may include, for example, one or more scattering devices to change the beam spot size. Exemplary scattering devices include a plate or range modulator that disperses the particle beam as it passes through the scattering device.

[0080] In an exemplary operation, the scanning magnet 424 is controllable in two dimensions (e.g., XY dimensions in a Cartesian coordinate system) to position the particle beam in these two dimensions and move the particle beam across at least a portion of the irradiation target. The ionization chamber 425 detects the dose of the beam and feeds that information back to the control system to adjust the beam movement. The energy degrader 426 is controllable to move structures into and out of the path of the particle beam to vary the energy of the particle beam and therefore the depth to which the dose of the particle beam is deposited on the irradiation target. Examples of such structures include, but are not limited to, energy absorbing plates, wedges, polyhedrons such as tetrahedrons or toroidal polyhedrons, curved three-dimensional shapes such as cylinders, spheres, or cones. In this manner, the energy degrader can cause the particle beam to deposit a radiation dose inside the irradiation target to treat a column of the target. In this regard, as the protons travel through the tissue, they ionize the atoms of the tissue and deposit a dose along their path. The Bragg peak is a prominent peak on the Bragg curve, which plots the energy loss of ionizing radiation as it travels through tissue. The Bragg peak represents the depth at which most protons are deposited in tissue. For protons, the Bragg peak appears just before the particle comes to rest. Thus, the energy of the particle beam is changed to change the location of its Bragg peak, and thus deposit most of the proton dose deep within the tissue.

[0081] 6 and 7 show an exemplary scanning magnet 424. In this example, the scanning magnet 424 comprises two coils 441 that control particle beam movement in the X dimension and two coils 442 that control particle beam movement in the Y dimension. Control is achieved in some implementations by varying the current through one or both sets of coils, thereby varying the generated magnetic field. By appropriately varying the magnetic field, the particle beam can be moved in the X and / or Y dimensions on the irradiation target. The energy degrader previously described can move the beam in the Z direction through the target, thereby enabling scanning in three dimensions.

[0082] Referring again to FIG. 4, the current sensor 427 may be connected to the scanning magnet 424 or associated in some other way. For example, the current sensor may be in communication with the scanning magnet but not connected. In some implementations, the current sensor samples the current applied to the magnet 424, which may include the current to the coils for controlling the beam scanning in the X dimension and / or the current to the coils for controlling the beam scanning in the Y dimension. The current sensor may sample the current passing through the magnet at times corresponding to the occurrence of pulses in the particle beam or at a rate exceeding the rate at which pulses occur in the particle beam. The samples that identify the magnet current correlate to the detection of pulses by an ionization chamber, described below. For example, the number of times a pulse is detected using an ionization chamber may correlate in time to the samples from the current sensor, thereby identifying the current in the magnet coil with the number of pulses from the current sensor. Thus, using the magnet current, it may be possible to determine the location within the irradiation target where each pulse, and therefore the dose of radiation--i.e., the dose of particles--was delivered. The placement of the delivered dose within the target may also be determined based on the configuration of the energy degrader, for example based on the number of plates in the beam path.

[0083] In operation, the magnet current magnitude value may be stored at each location where the dose is delivered along with the amount of dose (e.g., intensity). A control system, which may be on the accelerator or off-site and may include memory and one or more processing devices, may correlate the magnet current with coordinates within the irradiation target, which may be stored along with the amount of dose. For example, the locations may be identified by the number of layers per depth and Cartesian XY coordinates, or by Cartesian XYZ coordinates, with the layers per depth corresponding to the Z coordinate. In some implementations, both the magnet current magnitude and the coordinate location may be stored along with the dose at each location. This information may be stored in memory, either on the accelerator or off-site. This information may be used to track and maintain a record of the treatment of the target.

[0084] The ionization chamber 425 detects the dose, such as one or more discrete doses, applied by the particle beam to a location in the irradiation target by detecting the number of ion pairs formed in the gas caused by the incident radiation. The number of ion pairs corresponds to the dose delivered by the particle beam. That information is fed back to the control system and stored in memory along with the time at which the dose is delivered. This information may be correlated to and stored in relation to the location at which the dose was delivered and / or the magnitude of the magnet current at which it was delivered, as described above.

[0085] As mentioned above, some implementations do not include a configurable collimator. In an exemplary implementation that includes a configurable collimator, the configurable collimator 428 may be positioned in the beam downstream of the scanning magnet and the beam downstream of the energy degrader, as shown in FIG. 4 and FIG. 5. The configurable collimator may trim the particle beam spot by spot as it moves from path to path through the target. The configurable collimator may also trim the particle beam while it is stationary on the target and as the energy of the stationary particle beam changes to impinge on different parts of the target's interior. For example, the particle beam may expand along the diameter of the target as it enters the interior. The expansion may change for different depths within the interior. The collimator may be configured to trim the particle beam to account for the expansion. For example, the collimator may be configured and reconfigured such that the diameter or size of the spot remains the same throughout the treated column.

[0086] In some implementations, the configurable collimator may include a set of leaves that face each other and are movable in and out of the carriage to form an aperture shape. Portions of the particle beam that exceed the aperture shape are blocked and do not reach the patient. Portions of the beam that reach the patient are at least partially collimated, thereby causing the beam to have a relatively precise edge. In some implementations, each leaf in a set of leaves in the configurable collimator, for example disposed on a carriage, is controllable using a single linear motor to define an edge that is movable into the path of the particle beam such that a first portion of the particle beam on a first side of the edge is blocked by the multiple leaves and a second portion of the particle beam on a second side of the edge is not blocked by the multiple leaves. The leaves in each set are individually controllable during scanning to trim areas as small as a single spot and can also be used to trim larger multi-spot areas. Being able to trim a single spot can be important when treating a column of targets, since different amounts of trimming may need to be performed for different particle beam energies.

[0087] FIG. 8 illustrates an exemplary range modulator 460, which is an exemplary implementation of the energy degrader 426. In some implementations, the range modulator 460 may be positioned downstream of the beam of the scanning magnet between the configurable collimator and the patient. In some implementations, as illustrated in FIG. 8, the range modulator comprises a series of plates 461. The plates may be made from one or more exemplary materials: polycarbonate, such as LEXAN™, carbon, beryllium, boron carbide, a composite of boron carbide and graphite, or a low atomic number material. However, other materials may be used instead of or in addition to these exemplary materials. In other implementations of the energy degrader, including polyhedrons such as wedges, tetrahedrons, or toroidal polyhedrons, or curved three-dimensional structures such as cylinders, spheres, or cones, these structures may be made from one or more exemplary materials such as polycarbonates such as LEXAN™, carbon, beryllium, boron carbide, composites of boron carbide and graphite, or low atomic number materials.

[0088] In some implementations, the range modulator structures that include boron carbide may include only boron carbide, i.e., the structures may be pure boron carbide. In some implementations, the structures that include boron carbide may include boron carbide in combination with another material, such as graphite, polycarbonate, carbon, or beryllium. In some implementations, all structures within the energy degrader, such as plates, polyhedrons, or curved three-dimensional structures, may include all or part of boron carbide. In some implementations, different structures within the energy degrader, such as plates, polyhedrons, or curved three-dimensional structures, may include different materials. For example, one or more plates within an energy degrader may be made from pure boron carbide, and one or more other plates of the same energy degrader may be made from or include one or more of polycarbonate, carbon, and / or beryllium. Other materials may also be used. For example, one or more plates or portions thereof in the energy degrader may be made from a composite material made of boron carbide and graphite.

[0089] One or more of these plates can be moved in and out of the beam path, thereby changing the energy of the particle beam and therefore the depth to which most of the dose of the particle beam is deposited in the irradiation target. The plates are moved to physically move in and out of the path of the particle beam. For example, as shown in FIG. 9, plate 470 moves along the direction of arrow 472 between a position in the path of particle beam 473 and a position outside the path of the particle beam. The plates are computer controlled. In general, the number of plates that are in the path of the particle beam corresponds to the depth to which the scanning of the irradiation target is to be performed. Thus, the dose from the particle beam can be directed inside the target by appropriate control of one or more plates.

[0090] In some implementations, each individual plate of the range modulator 460 is coupled to and driven by a corresponding motor 464. In general, a motor includes a device that converts some form of energy into motion. The motors may be rotary or linear, and may be electric, hydraulic, or pneumatic. For example, each motor may be an electric motor that drives a lead screw to extend or retract the plate into or from the beam field, including causing the movement of the plate to track or follow the movement of the particle beam in the beam field. For example, each motor may be a rotary motor that drives a corresponding linear actuator to control the movement of the corresponding structure. In some implementations, each individual plate of the range modulator 460 is coupled to and driven by a corresponding actuator. In some examples, the actuators include mechanical or electromechanical devices that provide controlled motion and may be electrically, hydraulically, pneumatically, mechanically, or thermally operated by the motor. In some examples, an actuator includes any type of motor that is powered by a source of energy, such as electrical current, hydraulic pressure, or pneumatic pressure, and converts that energy into motion.

[0091] In some implementations, an energy degrader including a boron carbide structure (or a structure constructed from other materials) may be placed in the treatment room where the particle beam is applied to the patient. For example, the energy degrader may be placed between the scanning magnet and the patient. In one example, the energy degrader may be placed in a nozzle on the internal gantry of the system, an example of which is described with respect to FIG. 26, FIG. 27, and FIG. 28.

[0092] The energy degrader may be positioned near the patient to limit the amount that the particle beam is scattered or dispersed after passing through the one or more plates or other structures. In some implementations, the energy degrader may be positioned 4 meters or less from the patient along the particle beam line. In some implementations, the energy degrader may be positioned 3 meters or less from the patient along the particle beam line. In some implementations, the energy degrader may be positioned 2 meters or less from the patient along the particle beam line. In some implementations, the energy degrader may be positioned 1 meter or less from the patient along the particle beam line. In some implementations, the energy degrader may be positioned ½ meter or less from the patient along the particle beam line. In some implementations, the energy degrader may be positioned in a nozzle 4 meters or less from the patient along the particle beam line. In some implementations, the energy degrader may be positioned in a nozzle 3 meters or less from the patient along the particle beam line. In some implementations, the energy degrader can be positioned in the nozzle at a distance of 2 meters or less from the patient along the beamline of the particle beam. In some implementations, the energy degrader can be positioned in the nozzle at a distance of 1 meter or less from the patient along the beamline of the particle beam. In some implementations, the energy degrader can be positioned in the nozzle at a distance of ½ meter or less from the patient along the beamline of the particle beam.

[0093] In general, boron carbide is cheap and safe to use compared to some other materials that may be used to attenuate the energy of a particle beam, such as beryllium. In general, boron carbide has a relatively low atomic weight and high density, and its scattering properties may be advantageous compared to some other materials that may be used to attenuate the energy of a particle beam, such as carbon (e.g., graphite) and polycarbonate. Reducing the scattering of the beam results in a smaller spot size of the beam, i.e., the cross-sectional size of the beam. A smaller spot size improves the conformability of the pencil beam scanning system and increases the localized dose rate. In other words, reducing the spot size reduces the area over which the dose is deposited. As a result, the concentration of protons deposited in a single spot increases, thereby increasing the dose rate in the area of ​​the single spot. Increasing the dose rate in the area of ​​the single spot is desirable because it facilitates the deposition of an ultra-high dose of protons within a prescribed period when scanning using an ultra-high (or FLASH) dose rate. Examples of periods during which an ultra-high dose is applied are described herein.

[0094] FIG. 29 is a graph showing the change in particle beam spot size for different materials used in the energy degrader to change the energy of the particle beam, and different particle beam energies. In this example, LEXAN™, carbon (e.g., graphite), boron carbide, and beryllium are shown. According to the graph in FIG. 29, for example, the boron carbide degrader structure produces a particle beam with a spot size of less than 1.2 centimeters (cm) sigma at an energy of 70 MeV (one million electron volts). In this example, the spot size is measured at the output of the degrader structure. The spot scatters the farther the beam travels in air, and the spot size increases. However, by placing the degrader close enough to the patient, scattering is limited. In addition, in some cases, but not all cases, a configurable collimator may be placed between the energy degrader and the patient to collimate the particle beam.

[0095] In addition to the aforementioned advantages, the boron carbide-based energy degrader may be reduced in size compared to, for example, an energy degrader using polycarbonate. That is, the boron carbide-based energy degrader may achieve substantially the same effect as a polycarbonate-based energy degrader, but the boron carbide-based energy degrader may have a smaller form factor than the polycarbonate-based energy degrader. This is because the density of boron carbide is greater than that of polycarbonate. In some examples, an energy degrader made of pure boron carbide plates may be 30 centimeters (cm) to 40 cm thick along the beamline. The plates may have the same or variable thickness. The thickness of the plates and the energy degrader itself depends on various factors such as the overall amount of energy change required and the number of layers to be treated, which may determine the number and thickness of each of the plates.

[0096] The reduction in size of the energy degrader made of boron carbide makes the energy degrader less noticeable in the treatment room. For example, the energy degrader made of all or some of the boron carbide structure can be housed in a nozzle on the inner gantry. The nozzle including the energy degrader may be fully retracted into the inner gantry, so that the energy degrader does not get in the way of the technician performing the treatment. In some implementations, the inner gantry may be flush with the wall of the treatment room, in which case fully retracting the nozzle and energy degrader into the inner gantry will fully retract the nozzle and energy degrader into the wall.

[0097] Figure 10 shows an example implementation of a range modulator, such as a boron carbide based range modulator that uses linear motors to control the movement of energy absorbing plates 101, 102, and 103. The range modulator of Figure 10 may otherwise have the configuration of the range modulator of Figure 8. Although only three plates are shown in the example of Figure 10, any suitable number of plates may be included, as illustrated by oval 106.

[0098] Taking plate 102 as an example, an exemplary linear motor that controls the movement of plate 102 includes a movable component consisting of two parts, in this example magnets 110a and 110b, and a fixed component. The two magnets are arranged side by side with their poles aligned, i.e., the positive pole (+) of magnet 110a is aligned with the positive pole (+) of magnet 110b, and the negative pole (-) of magnet 110a is aligned with the negative pole (-) of magnet 110b, as shown. The movable component includes a coil carrier plate 109 between magnets 110a and 110b. The coil carrier plate 109 is physically connected to the energy absorbing plate 102 and controls the movement of the energy absorbing plate 102 in and out of the path of, for example, a particle beam along the direction of arrow 111.

[0099] As described, the coil carrier plate 109 comprises one or more conductive traces or other conductive structures that pass a current to generate a magnetic field. The magnetic field is controlled by controlling the current through the coil carrier plate to control the movement of the coil carrier plate, and thus the energy absorbing plate 102. That is, the current through the coil generates a magnetic field that interacts with the magnetic field generated by the magnets 110a and 110b. This interaction causes the coil carrier plate 109 and the energy absorbing plate 102 to move either into or out of the particle beam path along the direction of arrow 111. For example, a larger magnetic field generated by the coil carrier plate 109 may cause the energy absorbing plate to move into the particle beam path, and a smaller or opposite magnetic field generated by the coil carrier plate may cause the energy absorbing plate to retract away from the particle beam path.

[0100] In some implementations, the conductive traces or other conductive structures on the coil carrier plate may comprise three windings embedded in aluminum. In some implementations, the energy absorbing plate may be physically attached to the coil carrier plate and move with the coil carrier plate. In some implementations, the number and materials of windings used may differ from those described herein. In some implementations, the coil carrier plate may be integral with the energy absorbing plate. For example, the energy absorbing plate itself may comprise the conductive structures or traces.

[0101] As shown in FIG. 10, in some implementations, the current through the coil carrier plate may be controlled by a signal received by a control system such as the computing system 114. The computing system may be susceptible to neutron radiation and therefore may be located in the remote room 116. In some implementations, the remote room 116 may be shielded from neutron radiation generated by the particle accelerator. In some implementations, the remote room may be located far enough away from the treatment room 117 that it is not susceptible to neutron radiation from the particle accelerator. In some implementations, the computing system may be located in the treatment room but shielded from neutrons emitted by the particle accelerator. In some implementations, all computing functions are shielded from neutron radiation, and unshielded electronics may still operate in the presence of neutron radiation. An encoder is an example of such electronics.

[0102] In this regard, the encoder (not shown) may comprise one or more of a laser sensor, an optical sensor, or a diode sensor. The encoder detects the movement of the coil carrier plate, for example, by detecting where a marking or other indicia on the coil carrier plate or on a structure connected to the coil carrier plate and moving with the coil carrier plate is disposed relative to the encoder. This information about where the coil carrier plate is is fed back to the computing system and used by the computing system to ascertain the position of the coil carrier plate during operation. The encoder may be located in any suitable arrangement. In some implementations, the encoder is located on a housing that houses the coil carrier plate. As the coil carrier plate moves, the marking or other indicia that moves with the coil carrier plate moves past the encoder. The encoder then relays the information to the computing system 114. The computing system 114 may use the information to control the operation of the range modulator, including the positioning of the energy absorbing plate.

[0103] The computing system 114, which may be comprised of one or more processing device devices, may be programmed to control a proton therapy system that delivers proton therapy based on a treatment plan, including components of a scanning system for delivering ultra-high dose rate radiation therapy per column to an irradiation target, such as a patient volume including diseased tissue. For example, the computing system may be controllable based on the treatment plan to output one or more control signals to control one or more of the linear motors to extend or retract one or more of the energy absorbing plates during scanning. For example, the computing system may be controllable based on the treatment plan to output one or more control signals to control one or more electric motors to extend or retract one or more of the energy absorbing plates during scanning. The computing system may include one or more processing devices, such as, for example, a microprocessor, a microcontroller, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc.

[0104] 30 illustrates components of an exemplary treatment planning system 1200, which may be implemented on a control system such as computing system 114 or on a computing system separate from the control system. The treatment planning system comprises modules, which may include data and / or routines, e.g., source code, compiled code, or interpretive executable code, that implement different functions of the treatment planning system. These modules may be time-dependent in the sense that delivery of a very high dose rate of radiation depends on the ability to deliver that radiation at a particular dose at a particular time. Examples of dose and time are provided herein.

[0105] Exemplary modules include a predictive model 1201. The predictive model characterizes or models a particle therapy system, including, but not limited to, a particle accelerator that generates radiation for delivery to the patient, and a scanning system used to direct the radiation. The predictive model also characterizes or models a patient to be treated, including volumes to which radiation should be delivered and volumes to which radiation should not be delivered. In some implementations, the predictive model may be implemented, at least in part, using one or more data structures stored in computer memory. Exemplary data structures include a collection of data values, relationships between those values, and functions or operations that can be applied to the data. Examples of data structures that may be used to implement the predictive model may include one or more of a look-up table (LUT), an array, a stack, a queue, a linked list, a tree, a graph, a trie or prefix tree, or a hash table. The predictive model may also include executable code for interacting with other modules and retrieving data from the data structure. The predictive model may also be implemented using one or more computer programming objects written in an object-oriented language.

[0106] The predictive model 1201 may be populated with values ​​manually, automatically, or a combination of manually and automatically. For example, to manually input values ​​into the predictive model, code implementing a portion of the predictive model may be executed and generate prompts to be displayed on an electronic display device to a treatment planning technician. The treatment planning technician may input information into the predictive model in response to the prompts. The information may include values ​​based on or assigned to physical characteristics of the particle therapy system, the patient, targets within the patient, and other relevant parameters. The information may relate to the ability of the particle therapy system to deliver radiation to the patient in a time sequence, for example, in a series of spots or columns over the FLASH dose or the time it takes to deliver the radiation. For example, the information may relate to, but is not limited to, the structure of the pulses of the particle beam generated by the particle accelerator--e.g., the duration of each pulse, the maximum dose per pulse of the particle beam--e.g., the number of particles per pulse, the sweep time of a scanning magnet to move the particle beam a specified distance, the time it takes to change the energy of the particle beam--e.g., by changing the energy of a variable energy accelerator, the time it takes to move one or more energy absorbing structures to change the energy of the particle beam, a strategy for adjusting the dose--e.g., for applying very high dose rate radiation in a column of the target or applying lower rates of dose layer by layer in the target, the time it takes to move a collimator to collimate the particle beam, the time it takes to configure the collimator, and / or the time it takes to control a range modulator to change the Bragg peak of the particles in the particle beam. Thus, in general, the predictive model may characterize the timing at which radiation--e.g., particle beam therapy--is or may be administered to a patient.The information may include the type of disease--e.g., a tumor--to be treated, the location of the tumor within the patient's body, e.g., specified in XYZ coordinates, the size and shape of the diseased tissue, including its volume, the type of healthy tissue surrounding the diseased tissue, the location of the healthy tissue, e.g., specified in XYZ coordinates, the size and shape of the healthy tissue, including its volume, and any other information about the patient and disease that may be relevant to the treatment, such as medical history, prior treatments, surgeries, and the like.

[0107] In some implementations, all or a portion of the aforementioned information in the predictive model may be stored in a control system, such as the computing system 114. The treatment planning system may query the control system to obtain all or a portion of this information in the absence of input from a user.

[0108] Exemplary modules include an RBE model 1202. As previously described, an RBE model characterizes the relative biological effectiveness of radiation on tissues in a time-dependent manner. For example, when radiation is applied at an ultra-high (FLASH) dose rate, healthy tissue is less damaged and tumors are treated with similar effectiveness than when the same tissue is irradiated with the same dose on a longer time scale. The RBE model may include information about different types of healthy and non-healthy tissues and the effects that radiation at different dose rates has on those different types of tissues. For example, an RBE model may specify the dose of radiation required to effectively treat an adenoma, carcinoma, sarcoma, or lymphoma. The dose required to treat such tumors is not necessarily time-dependent, and therefore the dose rate may not be specified. However, in some implementations, the dose rate for treating tumors may be specified in the RBE model. For reasons previously described, the rate at which dose is applied to healthy tissues during radiation therapy may affect the damage that radiation causes to healthy tissues. Thus, the RBE model may specify the time-dependent effect of dose rate on healthy tissue. In this regard, examples of non-healthy tissue include benign and malignant neoplasms, and body tissues affected by other types of disease. Examples of healthy tissue include bone, skin, muscle, or organs that are not affected by disease. The RBE model may also include the effect of different types of radiation on different types of tissue at different dose rates. Although the exemplary system described herein uses proton irradiation, the RBE model may include information about other types of radiation, such as other types of ionizing radiation, photon radiation, or x-rays.

[0109] The RBE model may also include information about how different types of healthy and non-healthy tissues affect the radiation applied to them. As previously explained, the equivalent dose may include a certain amount of radiation deposited that is necessary to treat diseased tissue in a patient's body, taking into account the biological effect of the tissue in the patient's body on the deposited radiation. In this regard, some tissues may not absorb the entire dose of radiation deposited. Thus, the dose may be weighted using information from the RBE model, thereby taking into account the biological effect of the tissue on the radiation. The resulting equivalent dose takes into account the biological effect of the radiation. For example, a given tissue may attenuate the destructive effect of a certain type of radiation by 10%. Thus, the equivalent dose may be increased by 10% to take into account this biological factor.

[0110] In some implementations, the RBE model may be implemented, at least in part, using one or more data structures stored in computer memory. Exemplary data structures include a collection of data values, relationships between those values, and functions or operations that can be applied to the data. Examples of data structures that may be used to implement the RBE model may include one or more of a look-up table (LUT), an array, a stack, a queue, a linked list, a tree, a graph, a trie or prefix tree, or a hash table. The RBE model may also include executable code for interacting with other modules and retrieving data from the data structures. The RBE model may also be implemented using one or more computer programming objects written in an object-oriented language.

[0111] The RBE model 1202 may be entered with values ​​manually, automatically, or a combination of manually and automatically. For example, to manually enter values ​​into the RBE model, code implementing a portion of the RBE model may be executed and generate prompts that are displayed on an electronic display device to a treatment planning technician. The treatment planning technician may enter information into the RBE model in response to the prompts. The information may include values ​​based on or assigned to different types of tumors, different types of radiation, different doses, and different dose rates. For example, the RBE model may include one or more lists of diseases, such as tumors. The RBE model may identify different types of radiation, such as protons, photons, or x-rays, that can treat each disease. The RBE model may identify, for each type of radiation, one or more ranges of doses that can treat a given volume of disease. The RBE model may identify, for each type of radiation, one or more ranges of dose rates that can treat a given volume of disease. In this regard, as noted, dose rate is not always a factor in treating diseased tissue, and dose itself may be critical in some cases independent of dose rate. The RBE model may distinguish between different types of healthy tissue, such as muscle, bone, skin, and organs. The RBE may specify the effect of different dose rates of different types of radiation--e.g., doses applied over a period of time--on those types of tissue. For example, the RBE may specify the effect of different levels of FLASH and non-FLASH dose rates of different types of radiation on different types of tissue. For example, the RBE may specify the effect of different levels of FLASH and non-FLASH dose rates of proton radiation on healthy muscle, bone, skin, and organs. These effects may be quantified. For example, damage to tissue may be specified on a numeric scale from 0 to 10, with 0 being no damage and 10 being destruction of the tissue. For example, these effects may be specified using descriptive information that may be electronically read and understood, for example, by a dose calculation engine. The RBE model specifies the effects of different types of radiation on the effectiveness of that radiation and may include weighting factors to counter these effects.

[0112] In some implementations, all or a portion of the aforementioned information in the RBE model may be stored in a control system, such as the computing system 114. The treatment planning system may query the control system to obtain all or a portion of this information in the absence of input from a user, such as a treatment planning technician.

[0113] Exemplary modules include a dose calculation engine 1203. The dose calculation engine 1203 is configured--e.g., written or programmed--to determine doses of radiation to deliver to a patient's voxels and, in some examples, the rates at which those doses should be delivered to the patient. In this regard, the dose calculation engine 1203 may receive, for example, from a treatment planning technician, a total target radiation dose to deliver to the patient's diseased tissue, a dose distribution across the tissue, or both the total target dose and dose distribution. The dose calculation engine obtains information about the system and the patient delivering the radiation from the predictive model. The dose calculation engine obtains information about the RBE of the radiation to be delivered by the system to the diseased and healthy tissues from the RBE model. Information from the predictive model and the RBE model is then used to determine the dose and dose rate of radiation to be administered to the patient.

[0114] For example, the dose calculation engine obtains the composition of the tumor to be treated in the patient. As mentioned, this information may be obtained, for example, from a predictive model or from input by a treatment planning technician. The composition may include the type of tumor, the size or volume of the tumor, and the shape of the tumor. The dose calculation engine obtains information about the patient's healthy tissue adjacent to the tumor. This information may be obtained, for example, from a predictive model or from input by a treatment planning technician. This information may include the type of healthy tissue, the relative placement of the healthy tissue with respect to the diseased tissue, and whether the healthy tissue has been previously exposed to radiation. The dose calculation engine also obtains information about the maximum dose rate that can be achieved using the particle accelerator, scanning system, and other hardware in the particle therapy system. This information may be obtained from a predictive model or may be determined based on information in the model. The dose calculation engine also obtains information about how the dose of radiation applied by the system will treat, benefit, or both treat and benefit the diseased and healthy tissues. This information may be obtained from an RBE model. The dose calculation engine also obtains information about how tissues in the patient affect the radiation applied by the system (e.g., radiation absorption) and the weighting factors required to counter such effects. This information may be obtained from the RBE model.

[0115] The dose calculation engine is configured to determine a dose regimen to be applied to the patient. The dose regimen may include equivalent doses to be delivered to the patient and rates at which those equivalent doses should be delivered based on the aforementioned information obtained from the predictive model and the aforementioned information obtained from the RBE model. For example, as previously described, when radiation is applied at a very high (FLASH) dose rate, healthy tissue is damaged less and tumors are treated with similar effectiveness than when that same tissue is irradiated with the same dose on a longer time scale. In other words, for tumors or other diseased tissues, the critical factor for treatment is the total radiation dose as opposed to the dose rate, while for healthy tissues, the dose rate is a factor that reduces damage where none is desired. In this example, knowing the characteristics of the diseased tissue to be treated in the patient, the characteristics of the healthy tissue adjacent to the diseased tissue, the capabilities of the system to deliver radiation, the RBE of the radiation for the diseased and healthy tissues, the target dose and / or dose distribution to be applied, the dose calculation engine divides the diseased tissue to be treated--e.g., the target volume--into voxels, determines the dose of radiation to be applied to each voxel, and sets the rate at which the dose is to be delivered. For example, the dose calculation engine may determine to apply to each voxel a dose of radiation greater than 1 Gray per second for a duration less than 5 seconds. For example, the dose calculation engine may determine to apply to each voxel a dose of radiation greater than 1 Gray per second for a duration less than 500 ms. For example, the dose calculation engine may determine to apply to each voxel a dose of radiation between 40 Gray per second and 120 Gray per second for a duration less than 500 ms. Radiation may be applied column by column as described, for example, with respect to Figures 12 to 19 or Figures 33 to 42, thereby reducing damage to healthy tissue through which the radiation passes on its way to the target.In some implementations, very high dose rate radiation can be applied to the entire target at once, for example, by scattering the radiation across the target, varying the energy while the radiation is stationary as described with respect to Figures 12-19 or 33-42, and using a bolus to limit exposure of healthy tissue to radiation.

[0116] In some implementations, the dose calculation engine may apply one or more weights to individual doses in looking at the time scale over which the dose should be delivered and attempting to adjust the RBE of the radiation. For example, the dose calculation engine may be configured to apply weighting factors to the dose to a voxel to adjust the RBE based on the duration over which the dose should be applied. As mentioned, biology may affect how the dose of radiation is deposited and how tissue responds to the dose. Weighting factors may be applied to counteract these biological effects. The weighting factors generate an equivalent dose that is adjusted to account for biological effects to deliver a certain amount of destructive radiation that can actually be absorbed by the patient, as previously described. In one example, the weighting factors cause the dose to increase for a certain duration, thereby creating an ultra-high dose rate or enhancing an already existing ultra-high dose rate. In one example, the weighting factors cause the dose to decrease for a duration while still at an ultra-high dose rate, or to decrease to a normal dose rate.

[0117] Exemplary modules include a sequencer 1204 (or "optimizer"). The sequencer 1204 generates instructions for sequencing the delivery of doses based on the model. In some implementations, the sequencer is configured to generate instructions for sequencing the delivery of doses to optimize the effective dose determined by the dose calculation engine. For example, the instructions may be executable by a control system to control the particle therapy system to provide a specified dose to each voxel at a specified dose rate. The delivery of the doses may be automatic or require input from a user. As previously described, the sequencer is configured--e.g., written or programmed--to sequence the delivery of doses based on information from a predictive model or other information provided, for example, by a technician. The order of doses is intended to optimize--e.g., minimize--the time it takes to deliver the doses, thus facilitating the delivery of radiation at ultra-high dose rates. For example, the sequencer may be configured to sequence the delivery of the dose based on one or more of the following: the structure of the pulse of the particle beam generated by the particle accelerator, the maximum dose per pulse of the particle beam, the sweep time of the scanning magnet that moves the particle beam, the time required to change the energy of the particle beam, the time required to move one or more energy absorbing structures to change the energy of the particle beam, the strategy for adjusting the dose, the time required to move a collimator to collimate the particle beam, the time required to configure the collimator, or the time required to control a range modulator to change the Bragg peak of the particles in the particle beam, or two or more of them, or three or more of them, or four or more of them, or five or more of them, or all of them. In this regard, operations such as these affect the time at which the dose can be delivered. To achieve ultra-high dose rates, timing is a consideration as described herein. Thus, factors such as these are considered when determining where the dose should be delivered to the irradiation target to meet the time constraints necessary to achieve ultra-high dose rates and their advantages.

[0118] In some implementations, values ​​may be determined or assigned for all or some of: the structure of a pulse of a particle beam generated by a particle accelerator, the maximum dose per pulse of the particle beam, the sweep time of a scanning magnet that moves the particle beam, the time required to change the energy of the particle beam, the time required to move one or more energy absorbing structures to change the energy of the particle beam, a strategy for adjusting the dose, the time required to move a collimator to collimate the particle beam, the time required to configure the collimator, and the time required to control a range modulator to change the Bragg peak of particles in the particle beam.

[0119] The sequencer knows how the doses should be delivered - for example, in columns or spots, at very high dose rates - and determines the order in which to deliver the doses based on calculations performed that take into account the aforementioned values. For example, referring to FIG. 31, overlapping voxels of a target are shown, including adjacent voxels 1205, 1206, 1207, and 1208. The sequencer may determine, based on its calculations, that it is possible to move the particle beam from voxel 1205 to voxel 1206, which then moves to adjacent voxel 1207, adjacent voxel 1208, etc., and still achieve very high dose rates for all voxels in the target. The sequencer may determine, based on its calculations, that it is not possible to achieve very high dose rates for all voxels in the target by moving the particle beam from voxel 1205 to voxel 1207. This may be because it takes too long to move or reconfigure hardware in the system, such as collimators or energy absorbing plates, when the beam moves between non-adjacent voxels 1206 and 1208 without interrupting the particle beam. In other words, the sequencer determines a treatment sequence that treats adjacent voxels in turn with very high dose rates, thereby reducing the amount of mechanical movement to reconfigure the system between treatment configurations while maintaining the particle beam.

[0120] In some implementations, the sequencer may assign several different values ​​to each of the following: the structure of the pulses of the particle beam generated by the particle accelerator, the maximum dose per pulse of the particle beam, the sweep time of the scanning magnet that moves the particle beam, the time it takes to change the energy of the particle beam, the time it takes to move one or more energy absorbing structures to change the energy of the particle beam, the strategy for adjusting the dose, the time it takes to move the collimator to collimate the particle beam, the time it takes to configure the collimator, and the time it takes to control the range modulator to change the Bragg peak of the particles in the particle beam. The sequencer may perform calculations that iterate through these different values ​​to obtain an optimized sequence in which doses of radiation should be applied to meet a desired dose rate. Optimization may include obtaining the best sequence in terms of time and treatment, or obtaining an improved sequence in terms of time and treatment.

[0121] As an example, a cubic treatment volume, such as a tumor, approximately 4 cm x 4 cm x 4 cm should be treated with 2 Gy. The treatment plan includes 5 layers with 25 spots each, i.e., 5 rows x 5 columns, for a total of 125 spots in the volume. The system delivers one pulse of protons every 1.3 ms. In this example, each spot must receive at least 4 pulses, and the dose to that spot can be delivered precisely through active dose control of the charge in each pulse. The deepest layer requires 6 pulses since more charge is needed there. No additional time is needed for beam scanning, since the scanning magnet moves fast enough to move from one spot to the next in under 1.3 ms. Energy layer switching takes 50 ms in this example.

[0122] The following treatment plan excerpt is performed using layer-by-layer treatment as described with respect to FIG. 1. If the treatment is arranged in layers from deepest layer (1) to shallowest layer (5): - Beam irradiation begins at time t=0. - Each spot in layer 1 takes 1.3ms x 6 pulses = 7.8ms to illuminate. - You don't have time to move from spot to spot. - The whole layer takes 7.8ms x 25 spots = 195ms. - Switching to the next layer takes 50ms, and beam irradiation on the next layer starts at t=245ms. - Each spot in layers 2 to 5 takes 4 pulses x 1.3ms = 5.2ms to illuminate. Each layer takes 5.2ms x 25 spots = 130ms. - Beam irradiation of layer 2 ends at t=325ms. - Beam irradiation of layer 3 ends at t=505ms. - Beam irradiation of layer 4 ends at t=685ms. - Beam delivery of layer 5 ends at t=865ms, completing the entire treatment. In the above example, 2 Gy is delivered to the entire volume over 865 ms at an average dose rate of 2.3 Gy / s, which is well below an exemplary "FLASH" dose such as 40 Gy / s under some definitions. However, each spot in the deepest layer reaches 2 Gy within about 7.8 ms, ignoring the dose spillover from each pulse onto neighboring spots. That's a dose rate of 256 Gy / s for those spots. Once the dose is delivered to the deepest layers, it is also delivered to the shallower layers. Thus, each spot in the shallowest layers receives the dose over almost the entire 865 m / s, and as a result receives a dose rate lower than 256 Gy / s.

[0123] The following treatment plan excerpt is performed using a column-by-column treatment as described with respect to Figure 2. If the same amount of treatment described in the previous paragraph were to be rearranged into 25 columns instead of 5 layers, with each column being 5 spots deep, then: - Beam firing begins at t=0. - The spot on layer 1 takes 7.8ms to illuminate. - 50ms to switch to the next shallower depth. - Spot beam illumination for layer 2 begins at 57.8ms. - Tier 3 spot beam illumination begins at 113ms. - Spot beam illumination for layer 4 begins at 168.2ms. - This column is completed in 223.4ms. - Treatment is completed in 223.4ms x 25 columns = 5.6s. This treatment results in a longer overall treatment time, but each column receives a dose rate of 2Gy / 223.4ms = 9Gy / s. This is a higher dose rate, but may not be the FLASH dose rate under some definitions for all parts of all columns. However, assume that the maximum proton charge per pulse is increased and can reach 10Gy instead of 2Gy for the same number of pulses. In this case, the dose rate for the treatment case per layer increases to 11.5Gy / s. In this case, all voxels in the treatment case per column are irradiated with a rate of 45Gy / s. Also, the layer switching time is reduced from 50ms to 25ms. In this example, each column in the column irradiation takes 123.4ms instead of 223.4ms. In this example, the column dose rate for the lower maximum pulse charge is 16.3Gy / s, and the column dose rate for the higher maximum pulse charge is 81.5Gy / s for all voxels in the treatment volume. A dose rate of 81.5 Gy / s for 123.4 ms qualifies as a FLASH dose rate under most definitions of FLASH.

[0124] With reference to FIG. 11, the control system may be configured--e.g., programmed--to implement a treatment plan for a target, such as a tumor in a patient. As previously described, the treatment plan may specify parameters including the dose of the particle beam to be delivered (e.g., equivalent dose) and the rate at which the dose should be delivered to the patient's voxels (e.g., ultra-high dose rate or standard dose rate). The treatment plan may also specify the arrangement at which the dose should be delivered to the target and the order in which portions of the target should be treated. For example, with reference to FIGS. 1 and 2, the portions of the target may be columns or layers as described herein. Initially, the control system may control a particle accelerator--in this example, the synchrocyclotron 310--to generate (1101) a particle beam having specified parameters, including beam current and intensity. In some implementations, the beam current of the particle beam is a current of 100 nanoamperes (nA) or less. In some implementations, the beam current of the particle beam is a current of 50 nA or less. Beam current levels on the order of nanoamperes may reduce the risk of injury to the patient, reduce the risk of damage to the accelerator or other electronics in the treatment room, or reduce the risk of both such injury and damage.

[0125] The intensity of the particle beam can also be controlled (1102) or modulated to control or change the dose applied to the target at different particle beam energies. Thus, intensity modulated proton therapy (IMPT) can be administered using the techniques described herein. In some implementations, the same irradiation target can be treated using beams having different intensities or the same intensity from multiple different angles, either at a FLASH dose rate or at a dose rate lower than the FLASH dose rate. For example, the irradiation target can be treated at a FLASH dose rate or a non-FLASH dose rate by irradiating columns at different angles. In such an example, the radiation is irradiated at different angles, so that healthy tissue that is not being treated can be exposed to radiation only once.

[0126] The beam intensity is based, at least in part, on the number of particles in the particle beam. For example, the beam intensity may be determined by the number of particles in the particle beam. The intensity of the particle beam may vary from spot to spot of the particle beam. Furthermore, the intensity of one spot of the particle beam may be independent of the intensity of one or more other spots of the particle beam, including immediately neighboring spots. Thus, in some examples, any spot in a three-dimensional volume may be treated with any dose independent of the dose of one or more adjacent spots. The control system may control the particle beam intensity using one or more techniques.

[0127] In one exemplary technique, the intensity of the particle beam can be controlled by varying the pulse duration of the particle pulses retrieved from the plasma column. More specifically, the RF voltage is swept from a start (e.g., highest) frequency (e.g., 135 megahertz (MHz)) to an end (e.g., lowest) frequency (e.g., 90 MHz). The particle source is operated for a period of time in the RF sweep to generate the plasma column. For example, in some implementations, the particle source operates at 132 MHz for a period of time. During that period, the particles are extracted from the plasma column by the electric field generated by the RF voltage. The particles accelerate outward in an expanding orbit as the RF voltage frequency is decreased, keeping pace with the decreasing magnetic field and increasing relativistic mass until the particles are swept out after a period of time (e.g., about 600 microseconds). Varying the duration for which the particle source is operated changes the width of the pulse of particles extracted from the plasma column in the frequency sweep. Increasing the pulse width increases the amount of particles extracted and therefore increases the intensity of the particle beam. Conversely, decreasing the pulse width reduces the amount of particles extracted and therefore reduces the intensity of the particle beam.

[0128] In another exemplary technique, the intensity of the particle beam can be controlled by varying the voltage applied to the cathodes in the particle source. In this regard, a plasma column is generated by applying a voltage to two cathodes of the particle source and outputting a gas, such as hydrogen (H2), near the cathodes. Applying a voltage to the cathodes ionizes the hydrogen, and the background magnetic field collimates the ionized hydrogen, thereby generating the plasma column. Increasing the cathode voltage increases the amount of ions in the plasma column, and decreasing the cathode voltage decreases the amount of ions in the plasma column. More ions present in the plasma column will result in more ions being extracted with an RF voltage sweep, which can increase the intensity of the particle beam. Fewer ions present in the plasma column will result in fewer ions being extracted with an RF voltage sweep, which can decrease the intensity of the particle beam.

[0129] In another exemplary technique, the intensity of the particle beam may be controlled by varying the amount of hydrogen supplied to the particle source. For example, increasing the amount of hydrogen supplied to the particle source increases the opportunity for ionization to occur in the plasma column in response to the cathode voltage. Conversely, decreasing the amount of hydrogen supplied to the particle source decreases the opportunity for ionization to occur in the plasma column in response to the cathode voltage. As noted above, more particles present in the plasma column may result in more particles being drawn off with an RF voltage sweep, which may increase the intensity of the particle beam. Fewer particles present in the plasma column may result in fewer particles being drawn off with an RF voltage sweep, which may decrease the intensity of the particle beam.

[0130] In another exemplary technique, the intensity of the particle beam can be controlled by varying the magnitude of the RF voltage used to extract particles from the plasma column. For example, increasing the magnitude of the RF voltage extracts more particles from the plasma column. Conversely, decreasing the magnitude of the RF voltage extracts fewer particles from the plasma column. When more particles are extracted, the particle beam has a greater intensity than when fewer particles are extracted.

[0131] In another exemplary technique, the intensity of the particle beam can be controlled by varying the start time in the frequency sweep at which the particle source is operated, and therefore the duration during which the particles are extracted. More specifically, there is a finite window in the duration of the frequency sweep during which the particles can be extracted from the plasma column. In one exemplary implementation, the frequency sweeps from about 135 MHz to about 90 MHz at a substantially constant rate. In this example, the particles are extracted at approximately the beginning of the downward slope from the start frequency to the end frequency, e.g., from 132 MHz to 131 MHz, respectively, and the particle source can be operated for a period of time, e.g., from about 0.1 microseconds (μs) to 100 μs (e.g., from 1 μs to 10 μs or from about 1 μs to 40 μs). Changing the frequency at which the particle source is operated affects the amount of particles extracted from the particle beam, and therefore the intensity of the particle beam.

[0132] In another exemplary technique, pulse blanking may be used to control the intensity of the particle beam. In this regard, an RF frequency sweep is repeated many times per second (e.g., 500 times / second). A particle source may be activated for each frequency sweep (e.g., every 2 ms). Pulse blanking reduces the number of particles drawn from the particle beam by not activating the particle source for each frequency sweep. To achieve maximum beam intensity, the particle source may be activated for each frequency sweep. To reduce beam intensity, the particle source may be activated less frequently, for example, once every 2, 3, or 100 sweeps.

[0133] In another exemplary technique, the intensity of the particle beam may be controlled by applying a DC bias voltage to one or more D-shaped sections used to apply RF voltage to the particle accelerator cavity. In this regard, the particle accelerator comprises an active D-shaped plate, which is a hollow metal structure with two hemispherical surfaces that encloses a space in which protons are accelerated as it rotates around a cavity surrounded by a magnet yoke. The active D-shaped section is driven by an RF signal applied to the end of the RF transmission line, generating an electric field in the space. The RF field is varied with respect to time as the accelerated particle beam increases in distance from the geometric center. The dummy D-shaped section may comprise a rectangular metal wall with slots spaced near the exposed edges of the active D-shaped section. In some implementations, the dummy D-shaped section is connected to a reference voltage at the vacuum chamber and the magnet yoke.

[0134] Application of RF voltage in the presence of a strong magnetic field can cause multipactoring, reducing the magnitude of the RF field and possibly causing electrical shorts. To reduce the amount of multipactoring and thereby maintain the RF field, a DC (direct current) bias voltage is applied to the active D-shaped section and, in some implementations, may also be applied to the dummy D-shaped section. In some implementations, a differential DC bias voltage between the active D-shaped section and the dummy D-shaped section may be controllable to reduce multipactoring and thereby increase the beam intensity. For example, in some implementations, there may be a 50% difference between the DC bias voltage on the active D-shaped section and the DC bias voltage on the dummy D-shaped section. In one exemplary implementation, a DC bias voltage of -1.9 KV is applied to the dummy D-shaped section and a DC bias voltage of -1.5 KV is applied to the active D-shaped section.

[0135] In another exemplary technique, the intensity of the particle beam may be controlled by controlling the rate at which the RF voltage is swept--e.g., the slope of the decrease. By decreasing the slope, it is possible to increase the amount of time that particles can be extracted from the plasma column, which may result in more particles being extracted, thereby increasing the intensity of the particle beam. The converse is also true, e.g., by increasing the slope, the length of time that particles can be extracted from the plasma column may be decreased, which may result in a decrease in particle beam intensity.

[0136] An implementation of the aforementioned techniques for controlling particle beam intensity is described in US Pat. No. 6,399,633, entitled "Controlling Intensity Of A Particle Beam," the contents of which are incorporated herein by reference.

[0137] The control system may also control (1103) the spot size of the particle beam. As shown above, one or more scattering devices may move into the path of the particle beam to change its spot size. Motors may be used to control the movement of the scattering devices. The motors may respond to commands from the control system based on instructions in the treatment plan. In some implementations, the inherent spot size of the synchrocyclotron is the smallest spot size generated by the system. This spot size also produces the largest beam intensity, since the beam intensity is also a function of the spot size. In some implementations, the spot size that can be generated by the system is less than 2 millimeters (mm) sigma. In some implementations, the spot size that can be generated by the system is at least 2 millimeters (mm) sigma. In some implementations, the spot size that can be generated by the system is between 2 mm sigma and 20 mm sigma. In some implementations, the spot size that can be generated by the system is greater than 20 mm sigma. In some implementations, operation 1103 may be omitted.

[0138] The control system controls (1104) the scanning magnet to move the particle beam through the target 21 in a path 24 according to the treatment plan, for example as shown in FIG. 2. Controlling the scanning magnet may include controlling currents through coils of the scanning magnet (FIGS. 6 and 7) that control the movement of the particle beam in a Cartesian X dimension, controlling currents through coils of the scanning magnet that control the movement of the particle beam in a Cartesian Y dimension, or both. In that arrangement, the system delivers a very high dose rate of radiation to a column that extends along a beam path through the target. In this example, the column includes an interior portion of the target that is disposed along a particle beam direction 29 (FIG. 2). The column 25 is three-dimensional in that it extends radially from the center of the beam spot toward the periphery of the spot, and the column extends downward through the target. In some implementations, the column extends through the entirety of the target, as shown in FIG. 2. In some implementations, the column only passes partway through the target. In some implementations, the column is completely inside the target. In some implementations, the columns begin on one surface of the target and extend into the target but do not reach the other surface of the target, hi some implementations, adjacent columns overlap in part.

[0139] The columns are treated (1105) using ultra-high dose rate radiation. Examples of ultra-high dose rates of radiation are described herein, including, but not limited to, 1 Gray per second or higher for durations less than 5 s. A control system controls the energy of the particle beam while the particle beam is stationary so that the particle beam treats columns in the target. Treating columns in the target includes varying the energy of the particle beam such that with each change in energy, a majority of the dose of protons in the particle beam (its Bragg peak) is deposited at a different depth in the target. As described herein, the energy of the particle beam can be changed by moving a structure, which may be made of boron carbide, into or out of the path of the particle beam, as shown in the examples of Figures 12 to 19 and Figures 33 to 42. All or some of the operations of Figure 11 can be repeated to treat different columns on the irradiation target. For example, operations 1102, 1103, 1104, and 1105 can be repeated for each column to be treated on the irradiation target.

[0140] In implementations described below that use a variable energy synchrocyclotron (or other types of variable energy particle accelerators), the energy of the particle beam can be varied by varying the current through the synchrocyclotron's main coil. In some implementations, the energy of the particle beam is varied by moving structures, such as the energy absorbing plates of the range modulator 460, in and out of the path of the particle beam. In this regard, as the treatment plan specifies the placement of columns on the target, the energy absorbing plates of the range modulator can be pre-positioned near those placements to reduce the time it takes for those plates to move in and out of position. With reference to FIG. 12, for example, plate 500--which can be made, for example, from pure boron carbide or a boron carbide composite--can be positioned near column 501 in target 503 before treatment of column 501 with radiation begins. The plate can be moved from that placement into the particle beam, thereby reducing the distance the plate needs to move. That is, plate 500 can be configured to retract completely into the range modulator. The plates may be partially or fully extended prior to treatment so that they do not have to move from a fully retracted position to reach the path of the particle beam.

[0141] One or more of the plates can be controlled to move in and out of the path of the particle beam to change the energy of the particle beam, as described. In one example, each of the one or more plates can be moved in and out of the path of the particle beam in a duration of 100 ms or less. In one example, each of the one or more plates can be moved in and out of the path of the particle beam in a duration of 50 ms or less. In one example, each of the one or more plates can be moved in and out of the path of the particle beam in a duration of 20 ms or less. As previously described, the use of linear motors can facilitate rapid movement of the plates, although electric motors can also be used. In this example, rapid movement includes movements on the order of tens of milliseconds.

[0142] One or more of the plates may be moved in and out of the path of the particle beam based on a sequence defined in the treatment plan. For example, referring to Fig. 12, Fig. 13, Fig. 14 and Fig. 15, the particle beam 504 is positioned by a scanning system to treat a column 501 of a target 503 at a very high dose rate. In this example, to treat increasingly shallow parts of the column 501, the treatment is first performed without a plate in the path of the particle beam. This is shown in Fig. 12. Thus, the deepest part 502 of the column 501 is treated. In Fig. 13, the plate 500a enters the path of the particle beam 504 along the direction of the arrow 505 and reduces the energy of the particle beam. With this plate configuration, the second deepest part 506 of the column 501 is treated. In Fig. 14, the plate 500b also enters the path of the particle beam 504 along the direction of the arrow 505 and further reduces the energy of the particle beam. In this plate configuration, the third deepest portion 508 of the column 501 is treated. In Fig. 15, plate 500c is also in the path of particle beam 504 along the direction of arrow 505, further reducing the energy of the particle beam. In this plate configuration, the shallowest portion 510 of the column 501 is treated. By varying the energy of particle beam 504 while particle beam 504 is stationary, the entire column 501 can be irradiated with very high dose rate radiation. Examples of very high dose rates are presented herein.

[0143] The particle beam can be directed by a scanning magnet into a new path through the target to treat a different column of the target 503. The different column may or may not be immediately adjacent to the column 501. In some implementations, the beam spots may overlap. For example, referring to Figs. 16, 17, 18, and 19, the particle beam 604 is positioned by a scanning system to treat the column 601 of the target 503 at a very high dose rate. In this example, to treat the increasingly deeper parts of the column 601, the treatment is first performed with all plates 500a, 500b, and 500c in the path of the particle beam. This is shown in Fig. 16. Thus, the shallowest part 602 of the column 601 is treated first. In Fig. 17, the plate 500c exits the path of the particle beam 604 along the direction of the arrow 605, increasing the energy of the particle beam. In this plate configuration, the second shallowest portion 602 of the column 601 is treated. In Fig. 18, plate 500b also exits the path of particle beam 604 along the direction of arrow 605, further increasing the energy of the particle beam. In this plate configuration, the third shallowest portion 608 of the column 601 is treated. In Fig. 19, plate 500c also exits the path of particle beam 604 along the direction of arrow 605, further increasing the energy of the particle beam. In this plate configuration, the deepest portion 610 of the column 601 is treated. By varying the energy of particle beam 604 while particle beam 604 is stationary, the entire column 601 can be irradiated with very high dose rate radiation.

[0144] In some implementations, the plates do not have to be sequenced to treat a column: for example, plate 500a can be moved into the path of the particle beam first, followed by plate 500c, then plate 500b, and so on.

[0145] During delivery of the ultra-high dose rate radiation to the column 501 or 601, the intensity of the particle beam 504 or 604 may be changed as necessary to deliver the ultra-high dose rate radiation specified in the treatment plan. It is noteworthy that the particle beam is stationary during delivery of the ultra-high dose rate radiation to each column. For example, the path of the particle beam does not change with respect to the target and the particle beam does not move while the ultra-high dose rate radiation is delivered to different depths within the column. After the column is delivered with the ultra-high dose rate radiation, the particle beam is directed to a new path through the target according to the treatment plan. The ultra-high dose rate radiation is then applied in the new path according to the treatment plan in the same manner as described with respect to FIG. 11. This process is repeated until all of the target is treated using ultra-high dose rate radiation or until a specified portion of the target is treated using ultra-high dose rate radiation. In some implementations, the columns may be parallel as shown in the figure, and in some implementations may overlap. In some implementations, at least some of the columns may not be parallel and may result in overlap. In some implementations, sets of columns may be applied to the same target or microvolume from different angles, thereby allowing the target to be treated with radiation multiple times while preventing healthy tissue from being hit multiple times by radiation.

[0146] In some implementations, the particle beam is never redirected along a path that has already been treated using ultra-high dose rate radiation. For example, the particle beam steps from path to path through the target 503. In this example, each column that extends into the target along a path is treated only once using ultra-high dose rate radiation. The columns are not revisited and retreated. By treating the columns only once using ultra-high dose rate radiation, healthy tissue above and possibly below the target is less susceptible to damage from radiation. However, it should be noted that the exemplary systems described herein are not limited to treating each column only once using ultra-high dose rate radiation. For example, in some examples, each column may be revisited any suitable number of times and receive one or more additional doses of ultra-high dose rate radiation. Furthermore, the exemplary systems described herein are not limited to treating each column only using ultra-high dose rate radiation. For example, a column of a target may be treated as described herein using a dose rate of radiation that is less than what would be considered an ultra-high dose rate. For example, a column of targets may be treated as described herein using radiation at a dose rate such as 0.1 Gray per second for a duration of one minute or more. In some implementations, column-by-column treatment as shown in FIG. 2 may be combined with layer-by-layer treatment as shown in FIG. 1. For example, a target may be treated column-by-column and then layer-by-layer, or layer-by-layer and then column-by-column. In some implementations, some of the targets may be treated column-by-column and some of the targets may be treated layer-by-layer, in each case using radiation at or below the ultra-high dose rate.

[0147] In some implementations, the energy absorbing plates of the range modulator can be sequenced differently for different columns on the target to reduce treatment time. For example, for column 501, the plates can be moved sequentially into the particle beam as described with respect to FIGS. 12-15. The particle beam can then be directed to treat an adjacent--or other--column 601 of the target. If the plates are already covering the path of the particle beam, they can be moved sequentially out of the path of the particle beam as described with respect to FIGS. 16-19. If the plates are not already covering the path of the particle beam, the plates can be moved together to cover the path of the particle beam and then moved sequentially out of the path of the particle beam. Thus, for a first column, the plates can be moved sequentially to treat successively shallower portions of the first column, e.g., layers. For a second column adjacent to the first column, the plates can be moved sequentially to treat successively deeper portions of the second column, e.g., layers. This process can be repeated across the target for adjacent paths of the particle beam. In some implementations, the movement of the plate can be incremental within the beam field, e.g., based on the spot size (e.g., on the order of millimeters), rather than from a fully retracted position. For example, the plate can be moved from a particle beam path to an adjacent particle beam path, rather than being fully retracted and extended for each column.

[0148] In some implementations, the energy absorbing plates are movable across all or a portion of the beam field. In some examples, the beam field is the maximum extent that the beam can be moved across a plane parallel to the treatment area on the patient body. One or more of the plates can track the particle beam as it moves from particle beam to adjacent particle beam. For example, one or more of the plates can move with the movement of the particle beam such that the particle beam passes through one or more of the plates while the plates are moving.

[0149] In some implementations, a dose of radiation less than the ultra-high (or FLASH) dose rate radiation can be applied layer by layer to the target using an energy degrader having a structure such as a plate, polyhedron, or curved three-dimensional shape made of boron carbide. For example, referring to FIG. 1, an entire layer 10 of the target 11 can be treated using a particle beam 12 having sufficient energy to dose the layer 10 by moving the particle beam across the layer along the direction of the arrow 15. The energy degrader can then be reconfigured--for example, the plate made of boron carbide can be moved out of the beam path to increase the energy level of the particle beam. A different layer 16 of the target 11 can then be treated in the same manner using a particle beam having a different energy sufficient to dose the layer 16, and so on.

[0150] In some implementations, the FLASH dose of radiation can be delivered along a single column with the beam direction fixed to a single spot at the isocenter of the particle accelerator. In some implementations, the FLASH dose of radiation can be delivered using a slightly larger localized volume, referred to as a microvolume, rather than a column directed to a single spot. The microvolume can be a voxel, a portion of a voxel, or can include multiple voxels as specified in the treatment plan. Figures 33 to 42 show examples of column-specific radiation delivery using a FLASH dose rate to a microvolume of an irradiation target. Examples of FLASH dose rates are described herein. In some implementations, the column-specific radiation delivery to the microvolumes of Figures 33 to 42 can be a non-FLASH dose rate or a combination of a FLASH dose rate and a non-FLASH dose rate.

[0151] FIG. 33 shows an example of a portion 1400 of an irradiation target, such as a tumor in a patient. The portion 1400 is divided into four microvolumes 1401, 1402, 1403, and 1404. Although a cubic microvolume is shown, the microvolumes may have any suitable shape, such as a three-dimensional supercuboid, a regular curved shape, or an amorphous shape. In this example, each microvolume is treated through delivery of radiation by column, for example, in the manner described herein with respect to FIGS. 12 through 19. For example, the depth of a column of microvolumes may be treated with radiation by varying the beam energy using an energy degrader plate or by controlling a variable energy synchrocyclotron to vary the beam energy. After an individual microvolume is treated, the next microvolume is treated, and so on until the entire irradiation target is treated. The treatment of the microvolumes may follow any suitable sequence or order.

[0152] In the examples of Figures 33 to 42, only eight columns 1405 are shown. However, any suitable number of columns may be treated per microvolume. In some examples, a microvolume may be treated with 10 to 20 spots, and therefore columns. In addition, each spot corresponds to a column of radiation, but only the previous column is shown in the figures for clarity. Furthermore, while the examples described herein treat the microvolumes from the deepest to the shallowest of the columns, this need not be the case. For example, the energy degrader plate may be controlled to treat one microvolume from the deepest to the shallowest of the columns, as described with respect to Figures 12 to 19, then treat a neighboring microvolume from the shallowest to the deepest of the columns, and so on. In other examples, different column depths may be treated non-sequentially.

[0153] In Fig. 33, the deepest portion 1407 of column 1405 is treated. The treated portions of the column are shaded, as is customary herein, and the untreated portions are not. In Fig. 34, the next deepest portion 1408 of column 1405 is treated. In Fig. 35, the next deepest portion 1409 of column 1405 is treated. In Fig. 36, the next deepest portion 1410 of column 1405 is treated. In Fig. 37, the shallowest portion 1411 of column 1405 is treated, thereby completing treatment of microvolume 1401. At this point, although the columns are separated for clarity, the columns may actually overlap at least in part, as is the case with respect to Figs. 12-19, to ensure that the entire microvolume is treated with radiation.

[0154] After micro-volume 1401 is treated, the next micro-volume 1402 is treated in a similar manner. In Fig. 38, the deepest portion 1417 of column 1415 is treated. In Fig. 39, the next deepest portion 1418 of column 1415 is treated. In Fig. 40, the next deepest portion 1419 of column 1415 is treated. In Fig. 41, the next deepest portion 1420 of column 1415 is treated. In Fig. 42, the shallowest portion 1421 of column 1415 is treated, thereby completing the treatment of micro-volume 1402. As above, although the columns are separated for clarity, the columns may actually overlap at least in part as in the case with Figs. 12-19 to ensure that the entire micro-volume is treated with radiation.

[0155] After micro-volume 1402 is treated, the remaining micro-volumes are treated in a similar manner. The micro-volumes may be treated using any suitable number and arrangement of columns in any order or sequence. In addition, as described herein, individual columns may be treated using different beam intensities. These intensities may vary from column to column, from micro-volume to micro-volume, or both from column to column and from micro-volume to micro-volume. Furthermore, each micro-volume may be treated from multiple different angles as part of intensity modulated proton therapy (IMPT).

[0156] In one example, the plots in Figures 43A and 43B show the results of a Monte Carlo simulation to calculate the radiation dose delivered to the treatment volume, as well as the time it takes for each voxel in the dose calculation to reach the final dose. As an example, by applying performance modifications to some parameters of the synchrocyclotron, such as layer switching time of 10 ms or less instead of 50 ms, increasing the beam current, and improving pulse-to-pulse stability, a spot delivered to a cube measuring 3 cm on each side can be irradiated with all parts of the treatment volume receiving that dose in less than 500 ms. These small cubes are not irradiated strictly in columns with each energy layer having a single spot, but rather in microvolumes with each layer having several (e.g., 10-20) spots. In addition, collimation may be used to separate one microvolume from another, allowing these volumes to be irradiated within a reasonable total treatment time. For example, the configurable collimators described herein or other suitable collimating devices may be used, including standard multi-leaf collimators (MLC).

[0157] In some implementations, each microvolume may be treated in the manner described with respect to Figures 12-19. For example, an entire column in a microvolume may be treated before moving to the next column in the same microvolume. After all columns in the microvolume are treated, treatment proceeds to the next microvolume. There, treatment is repeated until all columns in the microvolume are treated. Treatment then proceeds to the next microvolume, and the next, and so on, until the entire irradiation target is treated. These implementations differ from the implementations of Figures 33-42 in that the entire depth--or microlayer--of each column in the microvolume is treated at once for all columns in that microvolume. Treatment then proceeds to the next depth, and the next, and so on, until all columns in the microvolume are treated.

[0158] As described herein, applying a very high dose (FLASH) rate of radiation to all or a portion of the columns may be performed to deposit a dose of radiation in any random manner. For example, referring to FIG. 32, an exemplary column 1299 in a radiation target may consist of multiple depth portions. Each depth portion may include a microlayer of the target having a diameter on the order of the particle beam spot. Using column-by-column application or irradiation as described herein, radiation may be applied at a very high dose (FLASH) rate to each of depths 1301, 1302, and 1303. The dose may be applied in any manner established by the treatment plan. For example, a higher dose of radiation may be applied to depth 1303 than to depths 1301 or 1302. In another example, the highest dose may be applied to depth 1303, the next highest dose to depth 1302, and the lowest dose to depth 1302. In another example, the highest dose may be applied to depth 1301, the next highest dose to depth 1303, and the lowest dose to depth 1302. Thus, the doses may be applied without regard to--e.g., independently of--the shape of the Bragg peak produced by adding together the doses. In other words, in some cases the doses may not be configured to obtain a spread-out Bragg peak along a column of radiation irradiated to an irradiation target at a very high dose (FLASH) rate or lower dose rate.

[0159] In some implementations, one or more ridge filters or range modulator wheels may be added to the path of the particle beam to widen--e.g., elongate--the Bragg peak of the particle beam. The elongated or widened Bragg peak is generated by using a uniform depth-dose curve. That is, the dose is calibrated based on the depth of the tissue to which the dose is to be delivered to achieve a flat or substantially flat elongated Bragg peak. With reference to FIG. 32, for example, to achieve a widened Bragg peak such as 1300 using column-by-column delivery of radiation, a full (100%) dose may be applied to depth 1301 of column 1299 of the irradiation target for a period of time. Then, 80% dose may be applied to depth 1302 for a period of time. Depth 1302 is up-beam (i.e., shallower) than depth 1301. Then, 66% dose may be applied to depth 1303 for a period of time. Depth 1303 is upbeam (i.e., shallower) than depth 1302. This can be repeated until the spread-out Bragg peak 1300 is achieved.

[0160] The motors may control the movement of one or more ridge filters or range modulator wheels into or out of the path of the particle beam. The motors may respond to commands from a control system. The broadening of the Bragg peak of the particle beam may be used for both column treatment as shown in Figures 12 to 19 or layer-by-layer treatment as shown in Figure 1. In some implementations, the intensity of the particle beam may be increased using techniques as described herein when the Bragg peak is broadened.

[0161] In some implementations, the range modulator wheel can be robotically controlled to move in two or three dimensions in the beam field to track the movement of the particle beam. For example, referring to FIG. 23, the range modulator wheel can be robotically controlled to move in the X dimension 918 and Z dimension 917 of a Cartesian coordinate system in the path of the particle beam. The range modulator wheel can have a variety of thicknesses and can be spun to vary the Bragg peak of the particle beam and therefore the depth into the target where the majority of the particles are deposited. In some implementations, the range modulator wheel can include a step to define its variety of thicknesses. In some implementations, the intensity of the particle beam can be controlled to control the dose delivered at each location on the range modulator wheel. This can be performed to control the depth-dose distribution.

[0162] As described above, in some implementations, the scanning system does not include a configurable collimator. For example, in a system including boron carbide in the energy degrader, the spot size may be small and accurate enough to eliminate the need for a configurable collimator. However, in some implementations, the scanning system includes a configurable collimator. The configurable collimator may be controlled by the control system to trim the particle beam before it reaches the irradiation target. Also, as described, the configurable collimator may be controlled to trim the stationary particle beam differently as the energy of the particle beam changes to treat different portions of the column, e.g., depth portions, within the target. More specifically, the cross-sectional area of ​​the particle beam, or in other words, the spot size of the particle beam, may change as the particle beam passes through different amounts of tissue. To ensure that the size of the particle beam, and therefore the radius of the treated column, is consistent throughout the length of the column, the configuration of the collimator may be changed to provide different amounts of trimming. In other words, the configuration of the configurable collimator may be changed in response to changes in the energy of the particle beam. That is, because beams of different energies penetrate different amounts of tissue, they undergo different amounts of dispersion and therefore may require different amounts of collimation to produce regularly shaped columns, such as columns having a cylindrical shape with a constant radius.

[0163] In some implementations, the configurable collimator includes generally flat structures, referred to as "plates" or "leaves," that are controllable to move into the beam or treatment region to block the passage of some radiation and allow the passage of others. There may be two sets of leaves that face each other, as described above. The sets of leaves are controllable to form an opening of a size and shape appropriate for treatment. For example, each set of leaves is configurable to define an edge that is moveable into the path of the particle beam such that a first portion of the particle beam on a first side of the edge is blocked by the leaf, and a second portion of the particle beam on a second side of the edge is not blocked by the leaf and is allowed to move into the treatment region. In some implementations, the leaves are connected to, part of, or include linear motors--one for each leaf--that are controllable to control the movement of the leaves toward or away from the treatment region to define the edges.

[0164] In some implementations, the linear motor is controllable to configure a set of leaves to define a first edge and another set of leaves to define a second edge facing the first edge. The linear motors used in the configurable collimator may have a similar or identical configuration to the linear motors used in the range modulator plate described with respect to FIG. 10. For example, each of the linear motors may include a movable component and a fixed component. The fixed component includes a magnetic field generator for generating a first magnetic field. One example of a magnetic field generator includes two fixed magnets spaced adjacent to each other and with aligned poles. The movable component includes one or more coils, which when energized generate a second magnetic field that interacts with the first magnetic field to move the movable component relative to the fixed component. For example, the movable component may be a coil-carrying plate between the two magnets that make up the fixed component. When a current passes through the coil, it interacts with the magnetic field generated by the two magnets to generate a magnetic field that causes a moveable component (e.g., a current carrying plate) to move relative to the two magnets. Because the leaves are attached to the moveable component, the leaves move with the moveable component. The linear motors of the different leaves can be controlled to control the movement of the leaves and thus define the edges of the configurable collimator described above.

[0165] As noted, in some implementations, the linear motor comprises two magnets spaced apart and adjacent with aligned poles, and a coil carrier plate sandwiched between the two magnets and moving relative to the two magnets. This configuration allows multiple linear motors to be arranged in a row, each in close proximity to its neighbor, which may be necessary to control the leaves of a configurable collimator. For example, in some implementations, the leaf thickness is on the order of millimeters (e.g., 5 millimeters or less). Although leaves of this thickness allow for relatively high-precision edges, they may make implementations using conventional motors impractical in some cases. However, the linear motors described herein allow for the use of leaves having thicknesses of this magnitude. For example, two fixed magnets shield the coil carrier plate that moves between them, thereby controlling the movement of the leaf. By shielding the coil carrier plate from stray magnetic fields, it is possible to control the movement of the plate even when multiple coil carrier plates and corresponding fixed magnets are in close proximity to each other.

[0166] In some implementations, a control system, which may consist of one or more processing devices, is programmed to control the linear motors and thereby control the positioning of the leaves to define the edges. For example, the control system may be controllable to output one or more control signals to control one or more of the linear motors to extend or retract one or more of the leaves to define the edges. In some implementations, the motion of the linear motors may be tracked using an encoder. In some examples, the encoder includes an electronic device connected to the same assembly as the leaves and the linear motors. The encoder may comprise one or more of a laser sensor, an optical sensor, or a diode sensor. The encoder detects the movement of the leaves, for example, by detecting where markings or other indicia on the leaves or on a structure connected to and moving with the leaves are disposed relative to the encoder. Information regarding the placement of the leaves is fed back to the control system and used by the control system to ascertain and, in some implementations, change the position of the leaves during operation. The encoder may be or comprise a simple electronic sensor that is not as sensitive to neutron radiation as the processing device as described above and therefore may be placed in the treatment room.

[0167] As already mentioned, some implementations may not include a configurable collimator. In exemplary implementations such as these, the particle beam passes through the energy degrader to the patient without subsequent adjustments such as collimation. For example, in implementations in which the structure--such as a plate, a polyhedron, or a curved three-dimensional shape--includes boron carbide, the spot size of the beam may be reduced relative to the spot size of a beam produced using other materials in the energy degrader. In such cases, additional collimation may not be necessary to achieve the spot resolution required to treat the irradiation target. As mentioned, in some implementations, the configurable collimator may be between the energy degrader and the patient. Exemplary implementations of configurable collimators that may be used are described with respect to FIG. 20 to FIG. 25.

[0168] FIG. 20 shows an example of leaves 740 that may be used in a configurable collimator, but the configurable collimator is not limited to use with this type of leaf. The leaf height 750 is along the beamline (e.g., the direction of the particle beam). The leaf length 752 is along the actuation direction into and out of the treatment region and is based on the size of the field, or a portion thereof, that the system can treat. The field size corresponds to the treatment region that the beam can impinge on. The leaf width 753 is the direction in which multiple leaves are stacked when actuated. In general, the more leaves used, the higher the resolution of the aperture that can be formed, including in the case of curved boundaries.

[0169] 20, the leaf 740 includes tongue and groove features 755 along its sides that are configured to reduce leakage between the leaves when multiple such leaves are stacked. In this example, the curved ends 756 of the leaf 740 are configured to maintain a surface that contacts the beam at all locations within the treatment area. However, the ends of each leaf may be flat and not curved.

[0170] In some implementations, the configurable collimator leaves have a height sufficient to block at least the maximum beam energy (e.g., the maximum energy of the particle beam output by the accelerator). In some implementations, the configurable collimator leaves have a height that blocks energy less than the maximum beam energy. In some implementations, the configurable collimator leaves have a length that is not dictated by the area of ​​the entire treatment area, but rather the area of ​​a single beam spot (cross-sectional area of ​​the particle beam) or multiple beam spots.

[0171] FIG. 21 illustrates some example implementations of a configurable collimator 800. The configurable collimator 800 includes leaves 801 that have a height sufficient to block or prevent the passage of radiation at a given energy and are made of a metal, such as nickel, brass, tungsten, or other metal, sufficient to block or prevent the passage of radiation at a given energy. For example, in some systems, the particle accelerator is configured to generate a particle beam having a maximum energy of 100 MeV (one million electron volts) to 300 MeV. Thus, in such systems, the leaves may be fabricated to prevent the passage of beams having energies of 100 MeV, 150 MeV, 200 MeV, 250 MeV, 300 MeV, etc. For example, in some systems, the particle accelerator is configured to generate a particle beam having a maximum energy of over 70 MeV. Thus, in such systems, the leaves may be fabricated to prevent the passage of beams having energies of 70 MeV or more.

[0172] The leaves 801 are mounted on a carriage for controlled movement relative to a treatment area of ​​an irradiation target, such as a cross-sectional layer of a patient's tumor. The movement is controlled to cover some portions of the treatment area 804 with the leaves 801, thereby preventing radiation from hitting those portions during treatment, while leaving other portions of the treatment area exposed to radiation. In the exemplary implementation of FIG. 21, there are 7 leaves on the left and 7 leaves on the right, for a total of 14 leaves. In some implementations, there may be a different number of leaves, such as 5 leaves on the left and 5 leaves on the right for a total of 10 leaves, 6 leaves on the left and 6 leaves on the right for a total of 12 leaves, etc.

[0173] In FIG. 21 , location 802 represents the center of the beam spot and therefore the location of the row in the target where radiation should be delivered. Circle 808 represents a portion of the treatment boundary that the delivered radiation is not intended to exceed. Beam spots close to this boundary (e.g., within one standard deviation of the particle beam profile) are adjacent to healthy tissue. These spots may be trimmed (i.e., blocked) by appropriately configuring and positioning leaves on the configurable collimator. An example of a beam spot to be trimmed is beam spot 811, whose center is located at location 806. As shown, leaves 801 are configured to block the portion of beam spot 811 that goes beyond circle 808 and into healthy tissue (or at least tissue not designated for treatment).

[0174] In one exemplary implementation, there are five leaves on each of the two separate carriages that are about 5 mm wide and two leaves that are about 80 mm wide. In some implementations, there are seven leaves on each of the two separate carriages, two of which each have a width that is three or more times the width of each of the other five leaves. Other implementations may include different numbers, sizes, and configurations of leaves, and different numbers and configurations of carriages. For example, some implementations may include any number of leaves between 5 and 50 per carriage, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 (or more) leaves per carriage.

[0175] The carriages can move both horizontally and vertically as described herein. The leaves can also move horizontally relative to each carriage into and out of the treatment area. In this manner, the leaves can be configured to approximate the shape of the treatment boundary (e.g., a circle 811 or a portion thereof in this example) in an area near the area to be treated.

[0176] The leaves can be moved vertically and / or horizontally between different columns to be treated so that the leaves are in the proper position when the beam is applied to a particular column. As mentioned, the leaves can be reconfigured based on the beam energy to assume different configurations for different beam energies while the beam is stationary. As explained, the beam can diverge somewhat in tissue. The configurable collimator can be reconfigured as the beam energy is changed to maintain a regular (e.g., cylindrical) shaped column.

[0177] 22, 23, and 24 show an example implementation of a configurable collimator including carriages 913, 914, 915 configured to hold and move the leaves described above both vertically and horizontally relative to a treatment target. As shown, vertical movement involves movement in a Cartesian Z dimension 917, and horizontal movement involves movement in a Cartesian X dimension 918 (the Cartesian Y dimension is into or out of the page of FIG. 23). FIGS. 23 and 24 show a portion of the carriage housing as if it were transparent to show the components inside the housing, however, the housing is not actually transparent.

[0178] The carriage 913 is referred to herein as a primary carriage, and the carriages 914 and 915 are referred to herein as secondary carriages. The secondary carriages 914, 915 are coupled to the primary carriage 913 as shown in FIGS. 22-24. In this example, the secondary carriages 914, 915 each comprise a housing that is fixed to the primary carriage 915 via a corresponding member 918, 919. In this example, the primary carriage 913 is movable vertically (in the Z dimension) relative to the irradiation target and relative to the particle accelerator along a track 920. The vertical movement of the primary carriage 913 also causes the secondary carriages to move vertically. In some implementations, the secondary carriages move vertically in unison. In some implementations, the vertical movement of each secondary carriage is independent of the vertical movement of the other secondary carriages.

[0179] As shown in Figures 22-24, each secondary carriage 914, 915 is connected to a corresponding rod or rail 922, 923 along which the secondary carriage moves. More specifically, in this example, a motor 925 drives the secondary carriage 914 to move along the rod 922 towards or away from the secondary carriage 915. Similarly, in this example, a motor 926 drives the secondary carriage 915 to move along the rod 923 towards or away from the secondary carriage 914. Control over the movement of the primary and secondary carriages is implemented to position the leaves relative to the irradiation target, as described herein. In addition, the leaves themselves are configured to move into and out of the carriage, as also described herein.

[0180] As shown in Fig. 24, the motor 930 drives the vertical movement of the primary carriage 913. For example, as shown in Fig. 24, the lead screw 931 is coupled to a housing 932, which holds the motors 925, 926 that drive the corresponding secondary carriages 914, 915 and is mounted on the track 920. The lead screw 931 is coupled to the motor 930 and is driven vertically by the motor 430. That is, the motor 930 drives the lead screw 931 in the vertical (Cartesian coordinate system Z dimension) direction. Because the lead screw 931 is fixed to the housing 932, this movement also causes the housing 932 and thus the secondary carriages 914, 915 to move along the track 920 either toward or away from the irradiation target.

[0181] In this illustrative example, as noted, seven leaves 935, 936 are mounted on each secondary carriage 914, 915. Each secondary carriage can be configured to move its leaves horizontally into or out of the treatment area. Individual leaves on each secondary carriage can be independently linearly movable using linear motors in the X dimension relative to other leaves on the same secondary carriage. In some implementations, the leaves can also be configured to move in the Y dimension. Additionally, the leaves on the secondary carriage 914 can be independently movable from the leaves on the other secondary carriages 915. These independent movements of the leaves on the secondary carriages, along with the vertical movements allowed by the primary carriage, allow the leaves to be moved into various configurations. As a result, the leaves can conform both horizontally and vertically to a treatment area that is randomly shaped both horizontally and vertically. The size and shape of the leaves can be varied to provide different conformations. For example, the size and shape can be varied to treat a single beam spot, and thus a single column. In some implementations, individual leaves on each secondary carriage may be independently linearly movable in the X dimension relative to other leaves on the same secondary carriage using electric motors driving lead screws.

[0182] The leaves may be made of any suitable material that prevents or blocks the passage of radiation. The type of radiation used may dictate what materials are used in the leaves. For example, if the radiation is x-rays, the leaves may be made of lead. In the examples described herein, the radiation is a proton or ion beam. Thus, different types of metals or other materials may be used for these leaves. For example, the leaves may be made of nickel, tungsten, lead, brass, steel, iron, or suitable combinations thereof. The height of each leaf may determine the extent to which the leaf blocks the passage of radiation.

[0183] In some implementations, the leaves may have the same height, while in other implementations, some of the leaves may have a different height than the other of the leaves. For example, a set of leaves may each be 5 mm in height. However, any suitable height may be used. For example, the leaves 935, 936 may have any of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 3 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, etc. (or other heights). The leaves may have any combination of the aforementioned heights. In addition, each of the leaves may have a different height than one or more of the other leaves.

[0184] In some implementations, the leaves are tall enough to not only completely stop particle beams of the maximum expected proton energy (e.g., 3.3 cm of tungsten for 230 MeV or, for example, 5.2 cm of nickel), but also have enough extra material to impede proton transmission between the leaves. This material may have a tongue and groove structure as shown in FIG. 20, or a similar configuration. The leaf ends may be configured with curved or tapered surfaces to enhance the penumbra delivered for proton beams of various divergences.

[0185] In some implementations, there may be multiple primary carriages and corresponding motors and rails. For example, a first primary carriage may control the vertical movement of a first secondary carriage, and a second primary carriage may control the vertical movement of a second secondary carriage. Thus, in such implementations, the two secondary carriages may be moved vertically independently, if desired. In any case, the primary carriages may be computer controlled. For example, executable instructions are stored in a computer memory (e.g., one or more non-transitory machine-readable storage media) and executed by one or more processing devices to control the movement. The control may be performed with or without user input during treatment.

[0186] As described, each secondary carriage 914, 915 includes a corresponding motor for controlling horizontal carriage movement, as described above. In some implementations, all leaves on a single carriage are independently movable using linear motors - one linear motor for each leaf. Each leaf may be controlled by a linear motor of the type described in FIG. 10 to form an edge and block at least some radiation from reaching the patient, for example, to trim one or more spots generated by the particle beam. As noted, the linear motors used in the configurable collimator may have the same structure and function as the linear motors used with the range modulator. However, in this case, the leaves of the collimator are attached to linear motors instead of energy absorbing plates. Each linear motor drives the corresponding leaf linearly to reach a position within the edge that is being configured.

[0187] In the exemplary implementations described above, each leaf is independently actuated using separate and independently controllable linear motors such that any suitable shape can be traced by the leaf configuration. However, such flexibility may not be necessary to achieve acceptable edge conformance. The leaves may be mechanically constrained by the ability to achieve only a finite number of configurations. For example, the leaves may be limited to configurations that result in vertical lines, forward diagonals, backward diagonals, concave shapes, convex shapes, or any other achievable shape. In this way, flexibility may be traded for mechanical simplicity.

[0188] In some cases, better beam performance (penumbra or edge definition) results when the particle beam is tangent to the surface of the leaf edge. However, since the beam effectively originates from a single point source, the angle at which it passes through the plane of the configurable collimator changes as the beam moves away from the field center. For this reason, the leaves may have curved edges, as shown in FIG. 20, so that the edges are always placed in a configuration that makes them tangent to the particle beam. In an exemplary implementation of the configurable collimator, the tracks along which both the primary and secondary carriages travel are curved so that flat leaf edges can be used in place of curved leaf edges, and remain flat but tangent to the particle beam.

[0189] In summary, in some implementations, the configurable collimator may have a relatively small size due at least in part to the linear motors described herein. Thus, in contrast to standard multi-leaf collimators, the exemplary configurable collimator may thus be used to trim a fraction of the treatment area at a time, e.g., less than the entire treatment area, and an area approximately equal to 1 spot size, 2 spot sizes, 3 spot sizes, 4 spot sizes, 5 spot sizes, etc. Thus, in some implementations, the configurable collimator may be small enough to trim a single spot at a time, and large enough to trim several spots at one location, but not the entire field, without moving. As noted, the ability to trim a single spot may be used to maintain the regular shape of the treatment column as the energy of the particle beam used to create that column is changed.

[0190] The scanning system may include a configurable collimator as described herein that can be positioned relative to the irradiation target to limit the range of the particle beam. For example, the configurable collimator can be positioned in the beam path downstream of the energy degrader and before the particle beam hits the treatment area of ​​the irradiation target. The configurable collimator can be controlled by the control system to allow the particle beam to pass therethrough and then hit some parts of the treatment area while preventing the particle beam from hitting other parts of the patient according to the treatment plan. Figure 25 shows the placement of an implementation of the configurable collimator 970 relative to the patient 971. The direction of the beam 971a is also shown.

[0191] One example of a configurable collimator that may be used is described in US Pat. No. 6,399,323 entitled "Adaptive Aperture," the contents of which are incorporated herein by reference.

[0192] 26 and 27 show a portion of an example of a proton therapy system 1082 including a particle accelerator mounted on a gantry. Since the accelerator is mounted on the gantry, it is in or adjacent to the treatment room. The particle accelerator may be a synchrocyclotron as in FIG. 3, but the system is not limited to use with a synchrocyclotron. The gantry and particle accelerator, along with a scanning system, may be controlled according to a treatment plan to treat a column of irradiation targets using ultra-high dose rate radiation in the manner described herein. In some implementations, the gantry is made of steel and has two legs (not shown) that are rotatably mounted on two respective bearings disposed on either side of the patient. The gantry may include a steel truss (not shown) connected to each of its legs that is long enough to span the treatment area where the patient lies and is attached at both ends to the rotating legs of the gantry. The particle accelerator may be supported by the steel truss so that it can move around the patient's body.

[0193] In the example of Figures 26 and 27, the patient is positioned on a treatment table 1084. In this example, the treatment table 1084 comprises a platform that supports the patient. The platform may also comprise one or more restraints (not shown) to hold the patient in place and to immobilize the patient substantially immobile during table movement and treatment. The platform may or may not be padded and / or have a shape (e.g., a recess) that corresponds to the shape of a portion of the patient's body. The table may be moved via an arm 1085.

[0194] FIG. 28 shows an example of a gantry configuration described in U.S. Patent Application Publication No. 2009 / 0239994, incorporated herein by reference, including components of an alternative implementation of a proton therapy system that can be used to treat a column of irradiation targets with very high dose rate radiation in the manner described herein. The exemplary proton therapy system of FIG. 28 includes an inner gantry 1190 having a nozzle 1191, a treatment couch 1192, and a particle accelerator 1193 (e.g., a synchrocyclotron of the type described herein) mounted on an outer gantry 1194 for rotating at least partway around the patient body to irradiate targets within the patient body. The treatment couch 1192 is controllable according to a treatment plan and is configured to rotate and translate the patient in the manner described herein.

[0195] In the example of Figure 28, the particle accelerator 1193 is mounted to an external gantry 1194 to also allow linear motion (e.g., translational motion) of the particle accelerator in the direction of arrow 1195 along an arm 1196. As also shown in Figure 28, the particle accelerator 1193 may be connected to a gimbal 1199 for pivotal motion relative to the gantry. This pivotal motion may be used to position the accelerator, and therefore the beam, for treatment.

[0196] The scanning system components, including the scanning magnet, ionization chamber, range modulator, and configurable collimator, may be mounted to, in, or coupled to the nozzles 1081, 1191 of the internal gantry of the proton therapy system. These components may be controlled by a control system according to a treatment plan for treating a column of irradiation targets using very high dose rate radiation. In both examples, the nozzles are movable along a track of the internal gantry (1080 or 1190) relative to the patient and particle accelerator, and are extendable towards the patient and retractable away from the patient, thereby extending and retracting the components mounted thereon.

[0197] In some implementations, the synchrocyclotron used in the proton therapy system described herein may be a variable energy synchrocyclotron. In some implementations, the variable energy synchrocyclotron is configured to vary the energy of the output particle beam by varying the magnetic field through which the particle beam is accelerated. For example, the current may be set to any one of a plurality of values ​​to generate a corresponding magnetic field. In one exemplary implementation, one or more sets of superconducting coils receive a varying current to generate a varying magnetic field within the cavity. In some examples, one coil set receives a fixed current, while one or more other coil sets receive a varying current such that the total current received by the coil sets changes. In some implementations, all coil sets are superconducting. In some implementations, some coil sets, such as the set for the fixed current, are superconducting, while other coil sets, such as the set or sets for the varying current, are non-superconducting (e.g., copper) coils.

[0198] Generally, in a variable energy synchrocyclotron, the magnitude of the magnetic field may scale with the magnitude of the current. The total current of the coils may be adjusted within a predetermined range to generate a magnetic field that varies within a corresponding predetermined range. In some examples, continuous adjustment of the current may cause a continuous variation of the magnetic field and a continuous variation of the output beam energy. Alternatively, if the current applied to the coils is adjusted in a non-continuous stepwise manner, the magnetic field and the output beam energy may vary accordingly in a non-continuous (stepwise) manner. By scaling the magnetic field with the current, the beam energy may be varied relatively precisely, thus reducing the need for an energy degrader. One example of a variable energy synchrocyclotron that may be used in the particle therapy system described herein is described in U.S. Patent No. 5,399,343 entitled "Particle Accelerator That Produces Charged Particles Having Variable Energies," the contents of which are incorporated herein by reference.

[0199] In implementations of particle therapy systems using a variable energy synchrocyclotron, controlling the energy of a particle beam for treating a column of targets may be performed according to a treatment plan by varying the energy of the particle beam output by the synchrocyclotron. In such implementations, a range modulator may or may not be used. For example, controlling the energy of the particle beam may include setting a current in a main coil of the synchrocyclotron to one of a number of values, each value corresponding to a different energy at which the particle beam is output from the synchrocyclotron. A range modulator may be used with a variable energy synchrocyclotron, for example, to provide additive changes in energy between the discrete energy levels provided by the synchrocyclotron.

[0200] In some implementations, particle accelerators other than synchrocyclotrons may be used in the particle therapy systems described herein. For example, cyclotrons, synchrotrons, linear accelerators, or the like may be substituted for the synchrocyclotrons described herein. Although a rotating gantry is described (e.g., an external gantry), the exemplary particle therapy systems described herein are not limited to use with a rotating gantry. Rather, the particle accelerator may be mounted on any type of robot or other controllable mechanism--characterized herein as a type of gantry--to implement movement of the particle accelerator, as appropriate. For example, the particle accelerator may be mounted on one or more robotic arms to implement rotational, pivotal, and / or translational movement of the accelerator relative to the patient. In some implementations, the particle accelerator may be mounted on a track, and movement along the track may be computer controlled. In this configuration, rotational and / or translational and / or pivotal movement of the accelerator relative to the patient may also be achieved through appropriate computer control. In some implementations, the particle accelerator may be stationary and located outside the treatment chamber, and the beam may be directed to a nozzle inside the treatment chamber.

[0201] In some examples, as noted above, ultra-high dose rate radiation may include a dose of radiation greater than 1 Gray per second for a duration less than 500 ms. In some examples, ultra-high dose rate radiation may include a dose of radiation greater than 1 Gray per second for a duration between 10 ms and 5 s. In some examples, ultra-high dose rate radiation may include a dose of radiation greater than 1 Gray per second for a duration less than 5 s.

[0202] In some examples, ultra-high dose rate radiation includes a dose of radiation greater than one of 2 Gray / sec, 3 Gray / sec, 4 Gray / sec, 5 Gray / sec, 6 Gray / sec, 7 Gray / sec, 8 Gray / sec, 9 Gray / sec, 10 Gray / sec, 11 Gray / sec, 12 Gray / sec, 13 Gray / sec, 14 Gray / sec, 15 Gray / sec, 16 Gray / sec, 17 Gray / sec, 18 Gray / sec, 19 Gray / sec, 20 Gray / sec, 30 Gray / sec, 40 Gray / sec, 50 Gray / sec, 60 Gray / sec, 70 Gray / sec, 80 Gray / sec, 90 Gray / sec, or 100 Gray / sec in a duration of less than 500 ms. In some examples, ultra-high dose rate radiation includes a dose of radiation greater than one of 2 Gray / sec, 3 Gray / sec, 4 Gray / sec, 5 Gray / sec, 6 Gray / sec, 7 Gray / sec, 8 Gray / sec, 9 Gray / sec, 10 Gray / sec, 11 Gray / sec, 12 Gray / sec, 13 Gray / sec, 14 Gray / sec, 15 Gray / sec, 16 Gray / sec, 17 Gray / sec, 18 Gray / sec, 19 Gray / sec, 20 Gray / sec, 30 Gray / sec, 40 Gray / sec, 50 Gray / sec, 60 Gray / sec, 70 Gray / sec, 80 Gray / sec, 90 Gray / sec, or 100 Gray / sec, for a duration between 10 ms and 5 s. In some examples, ultra-high dose rate radiation includes a dose of radiation greater than one of 2 Gray / sec, 3 Gray / sec, 4 Gray / sec, 5 Gray / sec, 6 Gray / sec, 7 Gray / sec, 8 Gray / sec, 9 Gray / sec, 10 Gray / sec, 11 Gray / sec, 12 Gray / sec, 13 Gray / sec, 14 Gray / sec, 15 Gray / sec, 16 Gray / sec, 17 Gray / sec, 18 Gray / sec, 19 Gray / sec, 20 Gray / sec, 30 Gray / sec, 40 Gray / sec, 50 Gray / sec, 60 Gray / sec, 70 Gray / sec, 80 Gray / sec, 90 Gray / sec, or 100 Gray / sec in duration less than 5 s.

[0203] In some examples, an ultra-high dose rate of radiation includes a dose of radiation exceeding one or more of 100 Gray per second, 200 Gray per second, 300 Gray per second, 400 Gray per second, or 500 Gray per second for a duration less than 500 ms, a duration between 10 ms and 5 s, or a duration less than 5 s.

[0204] In some examples, the very high dose rate of radiation includes a dose of radiation between 20 Gray per second and 100 Gray per second for a duration of less than 500 ms. In some examples, the very high dose rate of radiation includes a dose of radiation between 20 Gray per second and 100 Gray per second for a duration of between 10 ms and 5 s. In some examples, the very high dose rate of radiation includes a dose of radiation between 20 Gray per second and 100 Gray per second for a duration of less than 5 s. In some examples, the very high dose rate of radiation includes a dose of radiation between 40 Gray per second and 120 Gray per second for a time period, such as less than 5 s. Other examples of time periods are provided above.

[0205] The operation of the example proton therapy systems described herein, as well as all or some of their components, may be controlled at least in part (as appropriate) through the use of one or more computer program products, e.g., one or more computer programs tangibly embodied in one or more non-transitory machine-readable media, for execution by or to control the operation of one or more data processing devices, e.g., programmable processors, computers, multiple computers, and / or programmable logic components.

[0206] A computer program may be written in any form of programming language, including compiled or interpreted languages, and may be deployed in any form, including a stand-alone program, or a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a network.

[0207] Actions associated with controlling all or a portion of the operation of the example proton therapy systems described herein may be performed by one or more programmable processors that execute one or more computer programs to perform the functions described herein. All or a portion of these operations may be controlled using special purpose logic circuitry, e.g., a field programmable gate array (FPGA), and / or an application specific integrated circuit (ASIC).

[0208] Processors suitable for executing computer programs include, for example, general purpose microprocessors, special purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a processor receives instructions and data from a read-only or random access memory area or both. Elements of a computer (including a server) include one or more processors for executing instructions and one or more storage devices for storing instructions and data. Typically, a computer also includes one or more machine-readable storage media for storing data, for example, magnetic disks, magneto-optical disks, or optical disks, and is operatively coupled to receive data from them and / or transfer data to them. Non-transitory machine-readable storage media suitable for storing computer program instructions and data include all forms of non-volatile storage, including, for example, semiconductor storage devices, for example, EPROM, EEPROM, and flash storage devices, magnetic disks, for example, internal hard disks or removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks.

[0209] Any two further of the above-mentioned embodiments may be used in a suitable combination in a suitable particle accelerator (e.g., a synchrocyclotron). Similarly, any two further individual features of the above-mentioned implementations may be used in a suitable combination. Elements may be removed from the processes, systems, apparatus, etc. described herein without adversely affecting their operation. Various separate elements may be combined into one or more individual elements to perform the functions described herein. [Explanation of symbols]

[0210] 1 to 5 layers 10 layers 11. Target 12 Particle Beam 15 Arrow 16 layers 20 Columns 21 Target 22 Particle Beam 24 Routes 25 Columns 28 Arrow 29 Arrow 310 Components 311 Superconducting Magnet 312, 313 Superconducting coil 314, 315 Magnetic yoke 316 Cavity 317 Particle Source 420 Withdrawal Channel 421 Synchrocyclotron 422 Scanning Component 424 Scanning Magnet 425 Ionization chamber 426 Energy Degrader 427 Current Sensor 428 Configurable Collimator 430 Motor 441 Coil 442 Coil 460 Range Modulator 461 Plate 464 Motor 101, 102, 103 Energy absorbing plates 106 Oval 109 Coil transport plate 110a, 110b magnet 111 Arrow 114 Computing Systems 116 Separate Room 310 Synchrocyclotron 500 plates 500b plate 500c plate 501 Column 502 Deepest 503 Target 504 Particle Beam 505 Arrow 506 The Second Deepest Depths 508 The Third Deepest Depths 510 Shallowest part 601 Column 602 Shallowest part 604 Particle Beam 605 Arrow 608 Third Shallowest Point 610 Deepest 740 Leaf 750 Height 752 Length 753 Width 755 Groove Features 756 End 800 Configurable Collimator 801 Leaf 802 placement 804 Treatment area 806 Placement 808 yen 811 Beam Spot 913, 914, 915 Carriage 917 Z dimension 918 X dimension 918, 919 Parts 920 Trucks 922, 923 Rod or Rail 925 Motor 926 Motor 930 Motor 931 Lead Screw 932 Housing 935, 936 Leaf 970 Configurable Collimator 971 patients 971a Beam 1082 Proton Therapy System 1084 Treatment table 1085 Arm 1103 Operation 1102, 1103, 1104, 1105 operation 1190 Internal Gantry 1191 Nozzle 1192 Treatment table 1193 Particle Accelerator 1194 External Gantry 1195 Arrow 1196 Arm 1199 Gimbal 1200 Treatment Planning System 1201 Predictive Model 1202 RBE model 1203 Dose Calculation Engine 1205, 1206, 1207, 1208 Voxels 1299 Column 1301, 1302, 1303 Depth 1400 pieces 1401, 1402, 1403, 1404 Microvolume 1405 Column 1407 Deepest 1408 Next Deepest Depths 1409 Next Deepest Part 1410 Next Deepest Part 1411 Shallowest part 1415 Column 1417 Deepest 1418 Next Deepest Part 1419 Next Deepest Depths 1420 Next Deepest Depths 1421 Shallowest part

Claims

1. 1. A particle beam therapy system, comprising: a particle accelerator for generating a particle beam; a scanning magnet for directing a particle beam along a plurality of paths, each of the plurality of paths penetrating at least partway through a target of the particle beam, the target including at least a first target volume and a second target volume, each of the first target volume and the second target volume having the plurality of paths; a control system for controlling at least the scanning magnet to perform an operation, the operation being treating the first target volume with the particle beam; treating the second target volume using the particle beam after treatment of the first target volume is completed; Including, Treating the first target volume or the second target volume may include: directing the particle beam along a path at least partway through the first target volume or the second target volume; controlling a particle beam energy level such that the particle beam treats an interior portion of the first target volume or the second target volume along the path at a depth corresponding to the particle beam energy level; performing the steps of directing the particle beam and controlling the particle beam energy level for a plurality of different paths that penetrate at least partway through the first target volume or the second target volume until an interior portion of the first target volume or the second target volume along each of the plurality of different paths at a depth corresponding to the particle beam energy level is treated; repeating the steps of directing the particle beam, controlling the particle beam energy level, and performing until different depths of an interior portion of the first target volume or the second target volume corresponding to different particle beam energy levels along each of the multiple paths are treated; Including, A particle therapy system, wherein the particle beam delivers a dose of radiation to the target between 1 Gray per second and 500 Gray per second for a duration between 10 milliseconds and 5 seconds.

2. and further comprising an energy absorbing structure, each of the energy absorbing structures configured to reduce the energy of the particle beam as the particle beam passes through the energy absorbing structure to the target.

2. The particle therapy system of claim 1, wherein the control system is configured to control the energy of the particle beam by moving one or more of the energy absorbing structures into or out of the path of the particle beam between the target and a source of the particle beam.

3. 3. The particle therapy system of claim 2, wherein the control system is configured to move the one or more energy absorbing structures into or out of the path of the particle beam while the particle beam is in the path.

4. 3. The particle therapy system of claim 2, wherein the control system is configured to move the one or more energy absorbing structures into or out of the path of the particle beam in a duration of 100 milliseconds or less.

5. 3. The particle therapy system of claim 2, wherein the control system is configured to move the one or more energy absorbing structures into or out of the path of the particle beam in a duration of 50 milliseconds or less.

6. the particle accelerator comprises a superconducting winding, the particle accelerator configured to generate the particle beam based on a current passing through the superconducting winding; 2. The particle therapy system of claim 1, wherein the control system is configured to control the energy of the particle beam by setting the current to one of a plurality of values, each of the plurality of values ​​corresponding to a different energy of the particle beam output from the particle accelerator.

7. 2. The particle therapy system of claim 1, wherein the control system is configured to control the particle beam to deliver a dose of radiation to the target on each path between 20 Gray per second and 500 Gray per second for a duration between 10 milliseconds and 5 seconds.

8. 2. The particle therapy system of claim 1, wherein the control system is configured to control the particle beam to deliver a dose of radiation to the target on each path between 20 Gray per second and 100 Gray per second for a duration between 10 milliseconds and 5 seconds.

9. a collimator configurable to block a first portion of the particle beam while allowing a second portion of the particle beam to reach the target; The collimator comprises: a structure made of a material for blocking passage of the particle beam, the structure defining an edge, the edge being moved into the path of the particle beam such that the first portion of the particle beam on a first side of the edge is blocked by the structure and the second portion of the particle beam on a second side of the edge is not blocked by the structure; linear motors controllable to configure the structure to define the edge, each of the linear motors comprising a moveable component and a fixed component, the fixed component comprising a magnetic field generator for generating a first magnetic field, the moveable component comprising one or more coils, the application of a current to the coils generating a second magnetic field that interacts with the first magnetic field to move the moveable component relative to the fixed component; 2. The particle therapy system of claim 1, wherein the movable component of each linear motor is connected to or is part of a corresponding one of the structures such that the corresponding structure moves with movement by the movable component.

10. 2. The particle therapy system of claim 1, wherein the control system is configured to control an intensity of the particle beam along each of the different paths, and wherein the intensity of the particle beam is different along at least two of the different paths.

11. The step of controlling the particle beam energy level is performed by an energy degrader comprising plates between the particle beam and the target volume, each of the plates being for varying the particle beam energy level of the particle beam passing therethrough; a control system for controlling the energy degrader, wherein the different particle beam energy levels are applied independently of a shape of a Bragg peak produced by summing multiple doses of the particle beam; The particle therapy system of claim 1 , further comprising:

12. 12. The particle therapy system of claim 11, wherein the multiple doses of the particle beam do not produce a spread-out Bragg peak along the path through the target volume.

13. 12. The particle therapy system of claim 11, wherein the control system is configured to control one or more elements of the particle therapy system such that the particle beam sequentially treats at least two passes of the target volume without interruption of the particle beam.

14. 12. The particle therapy system of claim 11, wherein the control system is configured to control the energy degrader to switch a plate in and out between the particle accelerator and the target volume for a duration of 10 milliseconds or less to change the particle beam energy level.

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