Method for delivering proton radiation therapy using periodic motion

Abstract

Techniques for delivering a particle beam from a continuously rotating gantry toward a target based on a determined patient state are described herein. A set of beamlets (e.g., a pattern of radiation doses) can be delivered to a target using a determined patient state and an identified gantry angle of the gantry. The particle beam can rotate over a range of gantry angles. The set of beamlets can be delivered continuously while the gantry rotates.

Description

Background Art

[0001] Radiation therapy or "radiotherapy" can be used to treat cancer or other diseases in mammalian (e.g., human and animal) tissue. One such radiation therapy technique is called "gamma knife", by which a large number of low-intensity gamma rays are focused at a target area (e.g., a tumor) with high intensity and high precision to irradiate the patient. In another example, a linear accelerator ("linac") is used to provide radiation therapy, whereby the target area is irradiated with high-energy particles (e.g., electrons, high-energy photons, etc.). In another example, a heavy charged particle accelerator (e.g., protons, carbon ions, etc.) is used to provide radiation therapy. The arrangement and dosage of the radiation beam are precisely controlled to provide a prescribed dose of radiation to the target area. The radiation beam is also typically controlled to reduce or minimize damage to surrounding healthy tissues, which may be referred to as "organs at risk" (OARs), for example. Radiation can be referred to as "prescribed" because a physician typically prescribes a predetermined dose of radiation to be delivered to a target area such as a tumor.

[0002] Typically, ionizing radiation in the form of a collimated beam is directed toward the patient from an external radiation source. Modulation of the radiation beam may be provided by one or more attenuators or collimators (e.g., a multi-leaf collimator). The intensity and shape of the radiation beam may be adjusted by collimation to avoid damaging healthy tissue adjacent to the targeted tissue (e.g., OARs) by conforming the projection beam to the contours of the target tissue.

[0003] The treatment planning process can include using a three-dimensional image of the patient to identify a target volume (e.g., a tumor) and, for example, to identify critical organs near the tumor. The creation of a treatment plan can be a time-consuming process in which the planner attempts to comply with various treatment targets or constraints (e.g., a dose volume histogram (DVH) target or other constraints), such as taking into account the importance (e.g., weighting) of the respective constraints in order to develop a clinically acceptable treatment plan. This task can be a time-consuming trial-and-error process that is complicated by the various organs at risk (OARs) because the complexity of the process increases as the number of OARs increases (e.g., for head and neck treatment, there are approximately 13 OARs). OARs that are far from the tumor may be more easily protected from radiation, but OARs that are close to the target tumor or overlap with the target tumor may be more difficult to avoid radiation exposure during treatment.

[0004] Typically, for each patient, an initial treatment plan can be generated in an "offline" manner. For example, using one or more medical imaging techniques, the treatment plan can be fully developed before delivering radiation therapy. Imaging information can include, for example, images from X-rays, computed tomography (CT), magnetic resonance (MR), positron emission tomography (PET), single photon emission computed tomography (SPECT), or ultrasound. A healthcare provider, such as a physician, can use three-dimensional imaging information indicating the patient's anatomical structure to identify one or more target tumors and organs at risk near the tumor. The healthcare provider can use manual techniques to depict the target tumor to receive the prescribed radiation dose, and the healthcare provider can similarly depict nearby tissues, such as organs, that are at risk of damage from the radiation therapy.

[0005] Alternatively or additionally, automated tools (e.g., provided by Elekta AB of Sweden) may be used. ) to assist in identifying or delineating target tumors and organs at risk. Optimization techniques based on clinical and dosimetric targets and constraints (e.g., maximum, minimum, and mean radiation doses to tumors and critical organs) can then be used to create a radiation therapy treatment plan ("treatment plan").

[0006] The treatment planning process may include using three-dimensional images of the patient to identify a target volume (e.g., a tumor) and to identify critical organs near the tumor. Image acquisition may be performed prior to the start of delivery of a designated portion of radiation therapy. Such imaging may provide information that helps identify the location of the target volume or helps identify movement of the target volume. Such concurrent imaging may be referred to generically as "real time," but there is typically a delay or time lag between acquisition of the image and delivery of the radiation therapy.

[0007] The treatment plan may then be executed later by positioning the patient and delivering the prescribed radiation therapy. The radiation therapy treatment plan may include dose "fractionation," whereby a series of radiation therapy deliveries are provided over a predetermined period of time (e.g., 45 fractions or some other total number of fractions), such that each treatment delivery includes a specified fraction of the total prescribed dose. During treatment, the patient's position or target volume position relative to the treatment beam is important because such positioning determines, in part, whether the target volume or healthy tissue is irradiated.

[0008] In one approach, radiation therapy can be provided by using particles such as protons instead of electrons. This may generally be referred to as proton therapy. A significant known advantage of proton therapy is that it provides an excellent dose distribution with a very small exit dose compared to other forms of radiation therapy (e.g., X-ray therapy). Due to the very small exit dose, the dose to organs at risk (OARs) is significantly reduced. Additional advantages include a lower dose per treatment, which reduces the risk of side effects and can improve the quality of life during and after proton therapy.

[0009] One way to provide proton therapy is to use a wide proton beam, such as a broadened Bragg peak that provides a uniform beam with multiple energies. If the patient is to be treated using rotational therapy, this may not be possible using a wide beam. For example, a wide beam requires an ion beam compensator for each treatment area that is customized for each patient. This means that a compensator is required for each angle, so multiple compensators must be used to treat the patient. For example, a different compensator must be used at least every 4 degrees. Treatment must be stopped and started using 90 different ion compensators to provide 360 ​​degrees of rotational proton radiation therapy. Another problem with using a wide beam is that the shape of the dose at the proximal edge of the target tumor is not ideal.

[0010] definition

[0011] The beam spot is a position configured as the diameter of a beamlet to be delivered to that position.

[0012] The beamlets include a particle stream having a nominal diameter that is fed to a start point and to an end point at a predetermined rate.

[0013] The line segment is configured to feed the plurality of particles evenly between the start position and the end position.

[0014] Overview

[0015] In one approach, a method of delivering a particle beam from a continuously rotating gantry to a target, wherein the particle beam is composed of a plurality of beamlets and the target moves according to a periodic cycle. An illustrative example of this method includes determining the periodic cycle, identifying a corresponding treatment plan for radiation therapy, and selecting a set of beamlets for the periodic cycle corresponding to a rotation angle of the gantry, and optionally delivering the particle beam in a rotating pattern.

[0016] This summary is intended to provide an overview of the subject matter of this patent application. It is not intended to provide an exclusive or exhaustive description of the invention. The detailed description is included to provide further information about this patent application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 An example of a system, such as may include a particle therapy system controller, according to an embodiment is generally shown.

[0018] Figure 2 An example of a radiation therapy system, which may include, for example, a particle therapy system and an imaging acquisition device, is generally shown in accordance with an embodiment.

[0019] Figure 3 A particle therapy system according to an embodiment is generally shown and can include a radiation therapy output configured to provide a proton therapy beam.

[0020] Figure 4 Radiation dose depths in human tissue for various types of particles according to embodiments are generally shown.

[0021] Figure 5 Generally shown is a broadened Bragg peak according to an embodiment.

[0022] Figure 6 A diagram generally illustrates an active scanning proton beam delivery system in accordance with an embodiment.

[0023] FIG. 7A to FIG. 7B Generally shown is a spiral feed path on a grid, according to an embodiment.

[0024] Figure 7C A spiral beam spot delivery path with different beam spot sizes is shown according to an embodiment.

[0025] Figure 8 Example periodic phases of a patient are shown, according to an embodiment.

[0026] Fig. 9 A diagram illustrating the selection of radiation dose according to the breathing cycle and gantry angle is shown.

[0027] Fig. 10A Arc angle target position intensity and Bragg peaks are shown for various angles according to an embodiment.

[0028] Fig. 10B Composite target position intensities are shown according to an embodiment.

[0029] Figures 11 to 13 A flow chart illustrating a technique for feeding a particle beam toward a target based on a periodic cycle, according to an embodiment, is shown.

[0030] In the accompanying drawings, which are not necessarily drawn to scale, the same reference numerals may describe similar components in different views. The same reference numerals with different letter suffixes may represent different instances of similar components. The accompanying drawings generally illustrate various embodiments discussed in this document by way of example and not limitation. DETAILED DESCRIPTION

[0031] The systems and methods described herein provide radiation therapy for patients. Radiation therapy is provided by a rotating gantry, for example, by a particle beam attached to the gantry. The gantry can rotate continuously while the particle beam applies multiple beamlets. The beamlets can be applied to a target (e.g., a tumor or a portion of a tumor or other beam spot) in a spiral pattern. In an example, rotating the gantry while delivering the particle beam may be inefficient (e.g., if dose and penetration information are planned for every degree or every half degree). In another example, the rotating gantry may introduce errors (e.g., assuming that the plan is every few degrees, such as every five degrees or every ten degrees). There are many advantages to providing rotational proton radiation therapy. First, doses can be delivered from multiple angles, rather than undesirably injected at a small number of angles.

[0032] The systems and methods described herein address both of these issues by introducing a spiral pattern for delivering the beamlets. The spiral pattern can use a planned angle at a range of angles (e.g., five degrees, ten degrees, fifteen degrees, etc.). In an example, the spiral pattern can include delivering the particle beam to the center portion of the target when at the highest error and delivering the particle beam to the outer portion of the target when at the lowest error. The amount of error can depend on the angular difference between the actual gantry angle and the planned angle, for example, a larger error corresponds to a larger difference between the angles, while a lower error corresponds to a smaller difference between the angles.

[0033] In an example, a spiral pattern for applying a particle beam to a target can reduce the time required to complete a radiation therapy treatment. For example, the beamlet size of the beamlets delivered during the treatment can be varied. Changing the size of the beamlets may cause interruptions in the treatment, for example, due to the time spent or energy used. Using a grating type pattern may require changing the beamlet size multiple times. Using a spiral pattern can allow a single change in the beamlet size to be as small as possible. For example, a smaller beamlet can be used on the outside edge of the target, while a larger beamlet can be used on the inside portion of the target.

[0034] A challenge arises in accurately tracking a target, OAR, or other object when the patient moves. Movement can be classified as periodic (e.g., breathing or heartbeat) or non-periodic. Periodic breathing presents unique problems when the target for treatment is affected by patient movement. A set of phases of a periodic cycle can be defined, such as 8 or 16 unique phases within a periodic cycle. Other sets of phases can be used, such as anywhere from 2 to 20. Phases can represent positions through the periodic cycle that are repeated with each repetition of the cycle.

[0035] Using a periodic cycle of phases, a radiation dose can be generated for the treatment of a target at each phase in the phase. Treatment of a moving target can use phases to ensure complete coverage of the target, but doing so may result in the dose reaching normal healthy tissue or any organs at risk. Non-rotating devices typically have a fixed angle to deliver particles to the target. One way to ensure that the dose is delivered to a moving target is to pause the delivery of the beam (e.g., "gate" the beam) when the target is not near its nominal (usually "stationary" at the end of exhalation or inspiration) position. Therefore, only one phase of the cycle is targeted and the dose is applied only during that phase.

[0036] However, when a non-rotating particle therapy device is used, multiple layers from fixed angles are brought together to cover the entire target. This may result in an increased dose to healthy tissue, organs at risk, or in particular the skin around the entry point. Therefore, a rotating gantry may be used to avoid an increased dose to the skin or other tissue that is in the delivery line between the beam emitter and the target. When a rotating gantry is used and a rotational delivery of particles is provided, it is usually not possible to pause the delivery of the beam without stopping the gantry rotation or without being within the angular range covered by the rotation. Solutions that rely on a non-rotating gantry to stop the beam are not compatible with a rotating gantry.

[0037] The systems and methods described herein deliver doses with continuous gantry rotation without stopping the gantry and during phase changes in a periodic cycle by using a helical delivery technique based on the patient's current phase and gantry angle (or range of gantry angles).

[0038] Instead of trying to deliver all layers of the tumor from every angle, one or two layers through or before the middle of the target can be used. The layers can include depth locations within the target to be aimed at. Multiple angles of delivering particles to the target can be used, for example, by continuously rotating the gantry. Because the target is in periodic cyclic motion, and may be in periodic motion with the patient's periodic breathing, a set of parameters corresponding to a given respiratory phase and particle delivery angle can be used to deliver a dose to a desired portion of the target.

[0039] A database or other storage of parameter groups can be used, where each group of parameters includes a specific respiratory phase, a specific gantry angle, and a specific particle dose. In an example, a specific gantry angle can include a range of angles. For example, a parameter group can correspond to angles every 5 degrees or 10 degrees (e.g., 72 or 36 angles). The specified individual angles can be matched to the individual phases of the cycle. For example, with 8 phases and 36 angles (e.g., with an amplitude of 10 degrees) in a respiratory cycle, a total of 288 radiation doses or beamlet groups can be generated or stored. The generation of doses or beamlets can occur before treatment. In another example, with 16 phases and 72 angles (5 degree amplitude), 1152 radiation doses or beamlet groups can be generated or stored. During treatment, the current phase and current gantry angle can be identified and the corresponding radiation dose or beamlet group can be selected.

[0040] Given the respiratory phase at each angle, the cumulative dose to the target using the rotating gantry can be equal to the weighted sum of all particle doses from each angle.

[0041] Figure 1 An example of a system 100, which may include, for example, a particle therapy system controller, according to an embodiment, is generally shown. The system 100 may include a database or a hospital database. The particle therapy system controller may include a processor, a communication interface, or a memory. The memory may include treatment planning software, an operating system, or a delivery controller. The delivery controller may include a beamlet module for determining or planning spot delivery (e.g., using a spot delivery module) or line segment delivery (e.g., using a line segment delivery module).

[0042] In an example, the beam spot delivery module or beamlet module can be configured to plan the size of the beamlets, the location of the target or beam spot, etc. The beamlet module can be used to determine the delivery order of the beamlets, for example, in a spiral pattern as described herein. The delivery order module can communicate with treatment planning software for planning the delivery of the beamlets. For example, the treatment planning software can be used to determine or plan the gantry angle, gantry speed, beamlet size, spiral pattern (e.g., clockwise or counterclockwise), angular amplitude of a specific spiral pattern (e.g., every ten degrees of gantry rotation), etc.

[0043] The processor may communicate with a component for implementing the plan (e.g., with a component such as the following reference) via a communication interface or other means. Figure 3 The communication interface can be used to communicate with the control device or component of those devices or components described above to implement the plan. In an example, the communication interface can be used to retrieve stored information (e.g., patient information, historical surgical information about the patient or other patients, surgical instructions, information about specific devices or components, etc.) from a database or hospital database.

[0044] Figure 2An example of a radiation therapy system 200 according to an embodiment, which may include a particle therapy system and an imaging acquisition device, is generally shown. The particle therapy system includes an ion source, an accelerator, and a scanning magnet. Figure 3 Each of the ion source, accelerator, and scanning magnet is described in more detail. The particle therapy system includes a gantry and a platform, wherein the gantry can be mounted on the platform, attached to the platform, or stabilized relative to the platform. The platform can hold a patient. The gantry can be a rotating gantry and can rotate relative to the platform (e.g., around the platform) or relative to the patient (and the platform or a portion of the platform can rotate with the gantry).

[0045] The particle therapy system can communicate with a treatment control system, which can be used to control the action of the particle therapy system. The treatment control system can communicate with an imaging acquisition device (e.g., to receive images obtained by the imaging acquisition device or an imaging database) or with an oncology information system. The oncology information system can provide the treatment control system with treatment plan details, such as those received from a treatment planning system. The treatment control system can use the treatment plan to control the particle therapy system (e.g., activate a gantry, an ion source, an accelerator, a scanning magnet, a particle beam, etc.). For example, the treatment control system can include beamlet intensity control, beamlet energy control, scanning magnet control, platform control, gantry control, etc. In an example, beamlet intensity control and beamlet energy control can be used to activate beamlets of a specific size or for targeting a specific location. Scanning magnet control can be used to deliver beamlets in a spiral pattern, for example, according to the treatment plan. Gantry control or platform control can be used to rotate the gantry.

[0046] The treatment planning software may include components such as beamlet delivery and a sequencing module with individual control of beamlet sequencing, e.g., for beam spots or line segments. Figure 1 The treatment planning software is described in more detail. The treatment planning software can access the imaging database to retrieve images or stored information. When the treatment plan is complete, the treatment planning software can send the plan to the oncology information system to communicate with the treatment control system.

[0047] Figure 3 An embodiment of a particle therapy system 300 is shown, which may include a radiation therapy output configured to provide a proton therapy beam. The particle therapy system 300 includes an ion source 301, an implanter 303, an accelerator 305, an energy selector 307, a plurality of bending magnets 309, a plurality of scanning magnets 311, and a snout 313.

[0048] Ion source 301, such as a synchrotron (not shown), can be configured to provide a particle (e.g., proton) stream. The particle stream is transmitted to an implanter 303, which uses Coulomb force to provide an initial acceleration for charged particles. The particles are further accelerated to about 10% of the speed of light by an accelerator 305. Acceleration provides energy to the particles, which determines the depth to which the particles can travel in the tissue. An energy selector 307 (e.g., range scattering) can be used to select the energy of the protons to be given to the patient. In an embodiment referred to as passive scattering, an optional range modulator 308 (e.g., also referred to as a ridge filter or range modulation wheel) can be utilized to widen the beam to accommodate the tumor. After selecting the energy, a set of bending magnets 309 can be utilized to transmit the proton stream to a treatment room for radiotherapy in a hospital. In addition, a scanning magnet 311 (e.g., an xy magnet) is used to spread the proton beam to or track an accurate image of the tumor shape. The proton beam may be further shaped using the snout 313 or a component of the snout 313 (eg, a collimator). In various embodiments, the particle stream may consist of carbon ions, muons, or positively charged ions.

[0049] Figure 4 A graphical representation of a comparison of the radiation dose depth of various types of particles in human tissue is provided. As shown, the relative depth of penetration of photons (e.g., x-rays), protons, and carbon ions into human tissue is provided (e.g., including any radiation dose provided at a distance below the surface, including secondary radiation or scatter). Each radiation dose is shown relative to the peak dose of a proton beam having a single energy that has been set to 100%.

[0050] A monoenergetic (e.g., single energy) proton beam indicates a flat region starting at about 25%, which gradually increases until about 10 cm depth in the tissue, at 15 cm it rapidly increases to a Bragg peak, and then advantageously drops to zero over a short distance. No additional dose is delivered at the end of the Bragg peak.

[0051] The photon beam (e.g., labeled X-rays) indicates an initial buildup due to electron scattering (e.g., the primary method by which X-rays deliver dose to tissue is by transferring energy to electrons in the tissue). This is followed by an exponential decay that continues beyond the distal edge of the target, which is at a depth of approximately 15 cm in the figure. The X-ray beam has an entry (skin) dose setting that matches that of the proton beam. By normalizing (e.g., scaling) at a depth of 15 cm, the dose caused by the x-rays is 40% of the dose provided by the proton beam, while the x-ray beam has a peak dose greater than 95% ("near" 100%) at a depth of approximately 3 cm. If the X-ray data were renormalized to achieve 100% dose at 15 cm, the peak dose at a depth of approximately 3 cm, at a location where dose is not desired (e.g., before the target), would be approximately 240%. Thus, with the x-rays, a substantial amount of dose is delivered before the target and a substantial amount of dose is delivered beyond the target.

[0052] The monoenergetic carbon beam shows a lower plateau region at the injection dose than the proton beam. The carbon beam has a sharp Bragg peak that drops off more steeply than the proton beam, but the carbon beam has a tail of several centimeters beyond the desired target (e.g., called a "spatulation tail" where some of the carbon nuclei fragment into helium ions), with an additional dose of about 1.0% or less. The carbon ion beam has undesirable injection and skin doses compared to the proton beam, but the carbon ion beam has a non-negligible dose delivered over the target.

[0053] Figure 5 A graphical representation of the broadened Bragg peak (SOBP) is provided. The SOBP shows the relative depth dose curve for a set of proton beam combinations of different initial energies, each of which has some energy divergence (e.g., variable absorption of energy in tissue). The expected result of having a uniform dose for a target of a particular thickness. As shown, the target is shown to have a proximal depth of approximately 10 cm, a distal depth of approximately 13 cm, and a target thickness of approximately 3 cm. Within the target, the dose is fairly uniform (with the average normalized to 100%). The figure does not start at a depth of 0 cm, and the injection (skin) dose is not explicitly shown, but the characteristic of the injection area of ​​the proton beam is a relatively flat depth dose curve. Typically, the injection (skin) dose will be approximately 70% of the target dose (e.g., shown at the rightmost edge of the x-axis). SOBP can be obtained using a variety of methods, including using a scattered proton beam (variable absorption) in which energy modulation is performed using various devices (e.g., a static ridge filter or a dynamic range modulation wheel), or by selecting a large number of monoenergetic proton beams that do not undergo scattering.

[0054] Figure 6An illustration of a diagrammatic representation of a typical actively scanned proton beam delivery system is provided. As shown, a single layer of pencil beam scan is being delivered, wherein a beam spot grid is depicted on the patient in conjunction with an outline of the cross-sectional area to which particles are to be delivered. The incoming monoenergetic proton beam has a beam spot that is shifted by a range shifter (e.g., Figure 6 A magnetic scanner is a device that can be used to deflect particles in both the vertical and horizontal directions. The strength of the magnetic field can be adjusted to control the deflection of the incoming beamlets in a direction perpendicular to the magnetic field. The rate at which the magnetic field strength can be adjusted determines the rate at which scanning can be performed. For example, the strength of the proton beam combined with the scan rate determines how much dose can be delivered to a specific area (e.g., in a specific amount of time) in a specific amount of time. Figure 6 In theory, the magnetic field strengths can be adjusted independently of each other (similar to the Spin Master developed by Toronto, Canada). TM The children's toy "Etch a " mode; where the variable pencil beam intensity is not available in children's toys). The most common scanning scheme is to scan quickly in one direction and more slowly in a vertical direction in a raster manner, similar to early television control methods (e.g., cathode ray tubes (CRTs) using electrons rather than protons), but arbitrary patterns can be scanned (similar to the toys mentioned above). Delivery of different beam spots is achieved by increasing the scanning magnetic field strength and suppressing the pencil beam intensity between increments.

[0055] FIG. 7A to FIG. 7B Generally shown is a spiral feed path on a grid, according to an embodiment. FIG. 7A to FIG. 7B The spiral pattern shown in minimizes the errors introduced by the rotating gantry. Compared to a linear raster pattern as the gantry rotates, the spiral pattern shown improves target accuracy and reduces radiation outside the target.

[0056] The systems and methods described herein use proton arc therapy to optimize the radiation dose when protons are delivered to certain beam spots. When delivered to certain beam spots, the difference between what was planned and what was actually delivered using the spiral pattern scanning described herein can be minimized. Unless a beam spot is delivered farther from the isocentric axis when the gantry is closest to the currently planned angle, the actual beam spot position obtained may be far from the expected beam spot position, and the overall trajectory of the beamlet will be significantly different from the expected trajectory. Using spiral scanning can minimize the error in the actual beam spot position and minimize the difference between the expected trajectory and the actual trajectory of the beamlet.

[0057] Figure 7CA spiral beam spot delivery path with different beam spot sizes is shown according to an embodiment.

[0058] The trade-off between small and large beam spots is that delivering only small beamlets to a small spot requires too much time to deliver the radiation therapy. Therefore, to reduce time, it is better to deliver the small beamlets to the outer edge / outside of the tumor and the larger beam spot to the inner part of the tumor. Changing the beam spot size during delivery is a time-consuming activity. By using Figure 7C In the spiral delivery pattern shown in FIG, there may be only as little as one beam spot size transition when going from a set of smaller beam spots treating the outer edge of a tumor to a set of larger beam spots treating the inner region of the tumor. Similarly, there may be only as little as one beam spot size transition when going from a set of larger beam spots treating the inner region of a tumor to a set of smaller beam spots treating the outer edge of a tumor, resulting in the entire beam changing through two beam spot sizes. In an example, the spiral pattern may be a two-dimensional spiral pattern when delivering a dose at each layer of the target.

[0059] In an example, beamlets may be delivered at the edge of the arc range while the spiral is in the center of the target. For example, in an arc from 0 degrees to 10 degrees, the target may be planned as if the gantry was stationary at 5 degrees. In this example, the outside of the spiral appears as the gantry approaches and leaves 5 degrees, while the center of the spiral appears as the gantry leaves 0 degrees and as the gantry approaches 10 degrees. For example, starting at 0 degrees, the spiral may start in the center of the target and spiral outward until it ends around 5 degrees (at the outward point of the spiral). Then, in an example, as the gantry moves from 5 to 10 degrees, the spiral may reverse on the way back to the center of the target (e.g., moving clockwise from 0 degrees to 5 degrees, then moving counterclockwise from 5 degrees to 10 degrees, and vice versa). This process may be repeated on different layers of the target at another arc, such as from 10 to 20 degrees, etc., until the dose is completed.

[0060] Figure 8 An example periodic phase of a patient according to an embodiment is shown. The periodic breathing cycle 800 is shown with 8 phases (but other numbers (e.g., 16 phases) may be included. In an example, other patient state information may be used with the techniques described herein. For example, the patient state may be represented by a respiratory phase, an analog of a respiratory phase, an amplitude, a deformation vector field (DVF), a low-dimensional representation of a DVF, a low-dimensional representation of an image acquired using an imaging device, surface information, a target position, etc.

[0061] The periodic breathing cycle 800 is represented by position over time, where the position changes based on the movement of the lungs, throat, diaphragm, muscles, and other aspects of the respiratory system.

[0062] Gantry angle 801 is also shown with the current angle depicted and the direction of the angular motion of the gantry. Gantry angle 801 represents the movement of the gantry over time and is used with the periodic breathing cycle to deliver a predetermined radiation dose to the patient.

[0063] The periodic breathing cycle 800 is periodic and the phases or states can repeat over time. A plan for each phase or state of the cycle can be developed for delivering a therapeutic dose to a target that is nearby or affected by the cycle movement. For example, as described herein, for each phase or state, a radiation dose or beamlet group can be generated for a different gantry angle (e.g., every 10 degrees).

[0064] Imaging can be used to accomplish the detection and assignment of phases or states of the cycle 800. For example, 4D CT or MRI can be used to identify the various phases of a patient's cycle. After identification, a plan can be developed for the phases or states of a particular patient (e.g., based on the size of the target, the location of the target at each phase, the location of other tissues, etc.).

[0065] Fig. 9 A diagram showing the selection of a radiation dose according to a breathing cycle and a gantry angle is shown. The selection of a radiation dose can include determining the current phase or state of the breathing cycle and identifying the current gantry angle. The radiation dose corresponding to these two variables can be stored in a database of the system, for example with a radiation dose for each unique pair of phase and gantry angle. In an example, an approximate gantry angle (e.g., rounded to the nearest 1 degree, 5 degrees, 10 degrees) can be used. For the phase and gantry angle (or range), the radiation dose can be specific to the patient's target or layer of the target. A specific dose can be sent to a controller to deliver the dose using the gantry.

[0066] The dose may be delivered by continuously rotating the gantry. The patient phase and gantry angle may change as the gantry rotates, for example, at each angle or a range of angles, and other radiation doses may be used. In an example, the radiation dose is identified for every 10 degrees of rotation. For example, a radiation dose may be used from 0 to 10 degrees, where a plan is generated based on the position of the gantry at 5 degrees (e.g., the center angle of the range). The indicated dose may be delivered as the gantry rotates from 0 to 10 degrees - or as a function of the phase change (but the range always uses a gantry angle of 5 degrees). The radiation dose may be stored in a database, where a lookup of variables including phase and gantry angle is used to query the corresponding gantry angle and patient state.

[0067] Fig. 10A The target position intensity and Bragg peak in radians for various angles are shown according to an embodiment. The angles show how the penetration of the particle beam has different intensities and distances depending on the angle of the gantry.

[0068] Increasing the number of angles at which multiple doses can be delivered to a target tumor allows any given area of ​​the body that is not a target tumor to receive a smaller dose. By using a large number of angles, statistical errors in stopping power and any errors in patient positioning can be reduced, as these errors can be made to cancel each other out by averaging the overlapping doses. Thus, proton therapy is more robust by providing a good dose distribution even in the face of errors in positioning or stopping power.

[0069] The gantry rotation can compensate for the increased dose at the target center by using techniques such as planning the spiral to an "end" and restarting somewhere other than the target center in that plane. Fig. 10A As shown in , different angles produce different penetration depths, and by having the different penetration depths end not exactly at the center of the target, overdosing the patient can be avoided. Reducing the intensity of the beamlet along a line perpendicular to the isocenter and closer to the center along the direction of motion of the gantry can provide similar and more accurate compensation.

[0070] Fig. 10B Composite target position intensity is shown according to an embodiment. The composite image shows how some overlap occurs between the different angles, but since not all angles penetrate to the same depth in the target, the overlap can be minimized.

[0071] Proton arc therapy delivered using pencil beam scanning provides the ability to deliver different energies, where changes in energy may occur in less than a second. Pencil beam scanning enables intensity modulated proton therapy (IMPT). The choice of energy is very important because the choice of energy controls the depth of treatment of the radiation therapy. Particle therapy inherently stops at a specific depth for a specific energy. This enables the depth of treatment to enter the tissue area to be layered. For each layer, the contour of the treatment can be conformed to a specific tissue area; thereby allowing the contour to change layer by layer for the tumor, which is ideal for irregularly shaped tumors close to organs at risk. When delivered from a rotating gantry, the time for using multiple energies to deliver to different layers is limited. The choice of energy at a given angle is important because it controls the depth to which most of the dose is to be delivered into the tumor. The system is able to achieve the desired total dose to the tumor and to achieve it in a timely manner by judiciously selecting a very limited number of energies for each angle. The system is able to ensure complete radiation of the tumor by selecting the energy delivered beyond the midline of the tumor from a given angle. What is clinically significant is the total dose to the tumor from all angles.

[0072] The accumulation of actual dose delivered is important for adaptive therapy. In an example, parameters are optimized to achieve the desired dose to the target and minimize the difference between the actual dose to the target and the prescribed dose to the target. Differences may be caused by motion, and the actual dose to normal tissue may be different from (e.g., greater than) the calculated dose. When there is an interruption in the delivered dose, it is important to understand the actual dose distribution of the current treatment course. When treatment is interrupted, the dose can be recalculated based on the amount of dose delivered before the treatment course was interrupted. In an example, the treatment course can be restarted after an interruption using the techniques described herein (e.g., by identifying the current respiratory phase and the current gantry angle).

[0073] The dose distribution can be recalculated based on a set of parameters and previously delivered doses. To determine the dose, the recalculation uses each gantry angle used to deliver particles, uses the characteristics of the respiratory phase associated with each gantry angle, and uses a subset of images for a specific respiratory phase (e.g., 4D CT or MRI). The sum of all doses delivered using these weighting terms can be generated to determine the total actual dose delivered. The actual dose can be an estimate.

[0074] The delivered dose may be determined based on a set of parameters including delivered doses corresponding to pairs of respiratory phase and gantry angles, taking into account respiratory phase. In an example, a set of gantry angles and respiratory phases may be used to review dose calculations initially performed prior to treatment. Summing the individual doses given a particular angle and respiratory phase combination yields a quick approximation of the dose.

[0075] Respiratory phase dose reconstruction may be different from non-rotating delivery dose reconstruction. For non-rotating delivery, multiple layers are gathered to cover the entire target. For rotating delivery, the layer may be just one or two layers (e.g., one layer of each) just beyond or just before the middle of the target. Thus, Fig. 10B The layers shown in show a combination of layers directed just past the middle of the target. Other examples may include layers directed just before the middle of the target.

[0076] In an example, the dose may be recalculated based on the actual parameters selected at each angle and respiratory phase. Using a continuously rotating gantry and based on the respiratory phase, treatment may result in a dose to normal tissue (and organs at risk) that is different from the dose for any of the parameter sets (for a given respiratory phase) and is not a weighted sum of the doses for all respiratory phases. The accumulation of the actual dose delivered may be important for adaptive therapy, and the current treatment course dose distribution may be important in the event of a delivery interruption (e.g., continuing delivery from the point of interruption or restarting at a later time or date, which may be more difficult without knowing the angle and phase and the actual delivered delivery dose).

[0077] In an example, a dose can be calculated based on actual parameters combined with identification of the respiratory phase and using a subset of the 4DCT images for that respiratory phase. For example, a set of gantry angles and respiratory phases can be used to generate a quick approximation of the dose using the actual parameters to review the dose calculations initially performed prior to treatment and sum the individual doses given a particular angle and respiratory phase combination. As the patient changes weight or the tumor shrinks (or grows), the total dose information can be used to modify the treatment plan or further plan the treatment.

[0078] Figures 11 to 13 A flow chart illustrating a technique for feeding a particle beam toward a target based on a periodic cycle, according to an embodiment, is shown.

[0079] Fig.11 A technique 1100 for delivering a particle beam toward a target based on a periodic cycle is shown, including an operation 1102 of determining a breathing phase based on the periodic cycle. The periodic cycle may include, for example, a breathing cycle with 8 or 16 breathing phases. The technique 1100 includes an operation 1104 to identify a current gantry angle of the particle beam.

[0080] The technique 1100 includes an operation 1108 of dynamically selecting a pattern of beam spots based on the respiratory phase and the current gantry angle. The technique 1100 includes an operation 1110 of determining a set of energies (eg, beamlets) for the respiratory phase based on the pattern of beam spots.

[0081] Technique 1100 includes an operation 1112 of continuously delivering the set of energies using a particle beam. The set of beamlets may be delivered toward a target from a rotating gantry (e.g., a continuously rotating gantry). Technique 1100 may include determining a radiation dose based on a set of selected parameters for a particular gantry position, wherein at least one parameter is an angle and a respiratory phase.

[0082] In an example, the energy may be determined based on an amount similar to the radiation path length to the layer of the intended target, and the intensity of the individual beamlets may be determined based on how much dose is to be delivered to the individual beam spots. The energy selection may be different based on the respiratory phase, for example when (the equivalent of) the radiation path length changes, while the beam spot pattern may remain substantially similar and have substantially similar intensity. Or the energy may remain the same, while the beam spot pattern changes with intensity changes caused, for example, by lateral motion of the tumor relative to the central beam axis. The above set of beamlets may include energy changes or beam spot pattern changes over time when delivered to the target.

[0083] Fig.12A technique 1200 is shown for delivering a particle beam toward a moving target at a specific gantry angle, wherein the particle beam is delivered based on a set of control points. The technique 1200 includes an operation 1202 of identifying a layer of a target having a specific position within the target. In an example, a set of parameters includes a beam energy, and the beam energy travels to a predetermined depth in the target for the layer. In an example, a set of parameters includes a beam spot size.

[0084] In an example, a set of parameters may include a plurality of beamlets, each beamlet having a different intensity. The intensity may include the number of particles delivered. Each beamlet in this example may have a specific coordinate position. Technique 1200 may also include a first beamlet of the plurality of beamlets having a first intensity for a layer in a first phase of a periodic cycle, a second beamlet of the plurality of beamlets having a second intensity for a layer in a second phase of a periodic cycle, and a third beamlet of the plurality of beamlets having a third intensity for a second layer in the first phase of the periodic cycle.

[0085] Technique 1200 includes an operation 1204 of tracking movement of the target in the x-, y-, and z-directions. Technique 1200 includes an operation 1206 of identifying the physical position of the layer during a particular phase of the periodic cycle. In an example, the particular phase is a respiratory phase of the respiratory breathing cycle.

[0086] The technique 1200 includes an operation 1208 of selecting a set of parameters to deliver a predetermined radiation dose to a layer during a particular phase. In an example, the selected set of parameters may include a particular gantry angle or a range of gantry angles. The technique 1200 includes an operation 1210 of delivering a predetermined radiation dose to a layer during a particular phase using the set of parameters. The predetermined radiation dose may be delivered at a particular gantry angle.

[0087] Technique 1200 may include iterating through multiple target layers at various respiratory phases and gantry angles until each target layer has received its respective predetermined dose. Technique 1200 may include verifying the delivery of radiation dose to each layer in the specified target layer or to the target as a whole. Verifying the delivery of radiation dose may include determining that the correct meter set has been delivered. In another example, verifying the delivery may include determining an estimate of the actual expected dose received by the target compared to the prescribed dose. An estimate of the actual expected dose may be determined using external measurements (e.g., 4D CT scans). Technique 1200 may include delivering different radiation doses at the physical location of the layer during different phases of a periodic cycle.

[0088] Fig.13A technique 1300 for delivering a particle beam toward a target based on a periodic cycle is shown, including an operation 1302 of determining a current patient state of a patient. The current patient state may be a phase of a periodic cycle. In an example, the phase is a respiratory phase and the periodic cycle is a respiratory cycle having 8 or 16 respiratory phases. In an example, the patient state includes at least one of a respiratory phase, an analog of a respiratory phase, an amplitude, a deformation vector field (DVF), a low-dimensional representation of the DVF, a low-dimensional representation of an image acquired using an imaging device, surface information, a target position, and the like.

[0089] Technique 1300 includes an operation 1304 of identifying a current gantry angle.

[0090] Technique 1300 includes an operation 1306 of determining a radiation dose corresponding to a current patient state and a current gantry angle.

[0091] Technique 1300 includes an operation 1308 of delivering a radiation dose to a target, starting at a current patient state and throughout a range of gantry angles, the range of gantry angles including the current gantry angle. For example, the range of gantry angles may include a 10 degree range, with the center angle being the current gantry angle.

[0092] Technique 1300 may include iterating through a range of multiple gantry angles with respective patient states until the target has received its predetermined dose. In an example, the operation may include determining an estimate of the actual expected dose received by the target by reconstructing a given dose for each gantry angle in the range of multiple gantry angles. The operation may also include determining the estimate using a weighted sum of the given doses for each gantry angle in the range of multiple gantry angles.

[0093] The technique 1300 may also include an operation for determining a plurality of predefined beam spots in the target for the current gantry angle, wherein the plurality of predefined beam spots are configured in a spiral pattern. The operation may include ordering the plurality of predefined beam spots in the spiral pattern in an order from a beam spot closest to a concentric axis for the corresponding gantry angle to a beam spot farthest from the concentric axis. Delivering a predetermined radiation dose may include delivering a plurality of beamlets according to the spiral pattern of the plurality of predefined beam spots.

[0094] Technique 1300 may also include resuming delivery of a predetermined radiation dose at a specific gantry angle when delivery at the specific gantry angle is interrupted. Delivery may be resumed using the radiation dose corresponding to the specific gantry angle and the new current patient state.

[0095] The radiation dose described herein may include a plurality of beamlets. The plurality of beamlets may include a first beamlet having a first intensity for a target in a first patient state that cycles periodically, and a second beamlet having a second intensity for a target in a second patient state that cycles periodically. In an example, the patient state may be a respiratory phase calculated from a respiratory cycle.

[0096] Each of the non-limiting examples described in this document may stand alone, or may be combined in various permutations or combinations with one or more of the other examples.

[0097] Example 1 is a method for delivering a particle beam toward a target based on a periodic cycle, the method comprising: determining a breathing phase based on the periodic cycle; identifying a current gantry angle of the particle beam; dynamically selecting a pattern of a beam spot based on the breathing phase and the current gantry angle; and determining a group of sub-beams based on the pattern of the beam spot; and continuously delivering the group of sub-beams using the particle beam.

[0098] In Example 2, the subject matter of Example 1 includes, wherein feeding a set of beamlets further comprises feeding the set of beamlets from a rotating gantry toward a target.

[0099] In Example 3, the subject matter of Example 2 includes determining a radiation dose for a current gantry angle based on a set of selected parameters, wherein at least one parameter is angle and respiratory phase.

[0100] Example 4 is a method for delivering a particle beam at a specific gantry angle toward a moving target, wherein the particle beam is delivered based on a set of control points, the method comprising: identifying a layer of a target having a specific position within the target; tracking the movement of the target in the x-direction, the y-direction, and the z-direction; identifying the physical position of the layer during a specific phase of a periodic cycle; selecting a set of parameters to deliver a predetermined radiation dose to the layer during the specific phase and at the specific gantry angle; and using the set of parameters to deliver the predetermined radiation dose to the layer during the specific phase and at the specific gantry angle.

[0101] In Example 5, the subject matter of Example 4 includes iteratively traversing the plurality of target layers at various respiratory phases and gantry angles until each target layer has received its respective predetermined dose.

[0102] In Example 6, the subject matter of Examples 4-5 includes wherein the radiation dose to be delivered at the physical location of the layer is different during different phases of the periodic cycle.

[0103] In Example 7, the subject matter of Examples 4 to 6 includes, wherein the set of parameters includes a beam energy, the beam energy traveling to a predefined depth for the layer in the target.

[0104] In Example 8, the subject matter of Examples 4 to 7 includes, wherein the set of parameters includes beam spot size.

[0105] In Example 9, the subject matter of Examples 4 to 8 includes, wherein the set of parameters includes a plurality of beamlets, each beamlet having a different intensity, wherein the intensity is the number of particles delivered and each beamlet has a specific coordinate position.

[0106] In Example 10, the subject matter of Example 9 includes, wherein a first beamlet of the plurality of beamlets has a first intensity with respect to a layer at a first phase of a periodic cycle, a second beamlet of the plurality of beamlets has a second intensity with respect to the layer at a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets of the second layer has a third intensity with respect to the second layer at the first phase of the periodic cycle.

[0107] In Example 11, the subject matter of Examples 4 to 10 includes, wherein the periodic cycle is a respiratory breathing cycle.

[0108] Example 12 is a method of delivering a particle beam toward a target, the method comprising: determining a current patient state of a patient; identifying a current gantry angle; determining a radiation dose corresponding to the current patient state and the current gantry angle; and delivering the radiation dose to the target, starting at the current patient state and traversing a range of gantry angles, the range of gantry angles including the current gantry angle.

[0109] In Example 13, the subject matter of Example 12 includes iterating through a range of multiple gantry angles at each patient state until the target receives its predetermined dose.

[0110] In Example 14, the subject matter of Example 13 includes determining an estimate of an actual expected dose received by the target by reconstructing a dose given for each gantry angle in a range of multiple gantry angles.

[0111] In Example 15, the subject matter of Example 14 includes determining the estimate using a weighted sum of doses given for each gantry angle in a range of multiple gantry angles.

[0112] In Example 16, the subject matter of Examples 12 to 15 includes, wherein the current stage angle is a center angle of the range of stage angles.

[0113] In Example 17, the subject matter of Examples 12 to 16 includes: determining a plurality of predefined beam spots in a target for a current gantry angle, wherein the plurality of predefined beam spots are configured in a spiral pattern; ordering the plurality of predefined beam spots in the spiral pattern in an order from a beam spot closest to a concentric axis for a corresponding gantry angle to a beam spot farthest from the concentric axis; and wherein delivering a predetermined radiation dose includes delivering a plurality of sub-beams according to the spiral pattern of the plurality of predefined beam spots.

[0114] In Example 18, the subject matter of Examples 12 to 17 includes, wherein the radiation dose includes a plurality of beamlets, and wherein a first beamlet of the plurality of beamlets has a first intensity with respect to a target in a first patient state that cycles periodically, and a second beamlet of the plurality of beamlets has a second intensity with respect to the target in a second patient state that cycles periodically.

[0115] In Example 19, the subject matter of Examples 12 to 18 includes, wherein the patient state includes at least one of a respiratory phase, an analog of a respiratory phase, an amplitude, a deformation vector field (DVF), a low dimensional representation of the DVF, a low dimensional representation of an image acquired using an imaging device, surface information, or a target position.

[0116] In Example 20, the subject matter of Examples 12 to 19 includes, wherein the patient state is a respiratory phase calculated based on a respiratory cycle.

[0117] Example 21 is a system for delivering a particle beam toward a target based on a periodic cycle, the system comprising: one or more processors coupled to a storage device, the storage device containing instructions that, when executed by the one or more processors, cause the system to perform the following operations: determine a respiratory phase based on a periodic cycle; identify a current gantry angle of the particle beam; dynamically select a pattern of a beam spot based on the respiratory phase and the current gantry angle; and determine a group of sub-beams based on the pattern of the beam spot; and continuously deliver the particle beam to the group of sub-beams.

[0118] In Example 22, the subject matter of Example 21 includes, wherein feeding the set of beamlets further comprises feeding the set of beamlets from a rotating gantry toward a target.

[0119] In Example 23, the subject matter of Example 22 includes, wherein the instructions further cause the one or more processors to determine the radiation dose based on a set of selected parameters for the current gantry angle, wherein at least one parameter is angle and respiratory phase.

[0120] Example 24 is a system for delivering a particle beam toward a moving target at a specific gantry angle, wherein the particle beam is delivered based on a set of control points, the system comprising: one or more processors coupled to a storage device, the storage device containing instructions that, when executed by the one or more processors, cause the system to perform the following operations: identifying a layer of a target having a specific position within the target; tracking the movement of the target in the x-direction, the y-direction, and the z-direction; identifying the physical position of the layer during a specific phase of a periodic cycle; selecting a set of parameters to deliver a predetermined radiation dose to the layer during the specific phase and at a specific gantry angle; and using the set of parameters to deliver a predetermined radiation dose to the layer during the specific phase and at the specific gantry angle.

[0121] In Example 25, the subject matter of Example 24 includes, wherein the instructions further cause the one or more processors to iterate through the plurality of target layers at corresponding respiratory phases and gantry angles until each target layer receives its corresponding predetermined dose.

[0122] In Example 26, the subject matter of Examples 24-25 includes, wherein the radiation dose to be delivered at the physical location of the layer is different during different phases of the periodic cycle.

[0123] In Example 27, the subject matter of Examples 24 to 26 includes, wherein the set of parameters includes a beam energy that travels to a predetermined depth for the layer in the target.

[0124] In Example 28, the subject matter of Examples 24 to 27 includes, wherein the set of parameters includes a beam spot size.

[0125] In Example 29, the subject matter of Examples 24 to 28 includes, wherein the set of parameters includes a plurality of beamlets, each beamlet having a different intensity, wherein the intensity is the number of particles delivered and each beamlet has a specific coordinate position.

[0126] In Example 30, the subject matter of Example 29 includes, wherein a first beamlet of the plurality of beamlets has a first intensity with respect to a layer at a first phase of a periodic cycle, a second beamlet of the plurality of beamlets has a second intensity with respect to the layer at a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets has a third intensity with respect to the second layer at the first phase of the periodic cycle.

[0127] In Example 31, the subject matter of Examples 24 to 30 includes, wherein the periodic cycle is a respiratory breathing cycle.

[0128] Example 32 is a system for delivering a particle beam toward a target, the system comprising: one or more processors coupled to a storage device, the storage device containing instructions that, when executed by the one or more processors, cause the system to: determine a current patient state of the patient; identify a current gantry angle; determine a radiation dose corresponding to the current patient state and the current gantry angle; and deliver the radiation dose to the target, starting at the current patient state and traversing a range of gantry angles, the range of gantry angles including the current gantry angle.

[0129] In Example 33, the subject matter of Example 32 includes, wherein the instructions further cause the one or more processors to iterate through the range of multiple gantry angles in the corresponding patient state until the target receives its predetermined dose.

[0130] In Example 34, the subject matter of Example 33 includes, wherein the instructions further cause the one or more processors to determine an estimate of an actual expected dose received by the target by reconstructing a dose given for each gantry angle in a range of a plurality of gantry angles.

[0131] In Example 35, the subject matter of Example 34 includes, wherein the instructions further cause the one or more processors to determine the estimate using a weighted sum of the doses given for each gantry angle in a range of a plurality of gantry angles.

[0132] In Example 36, the subject matter of Examples 32 to 35 includes, wherein the current stage angle is a center angle of the range of stage angles.

[0133] In Example 37, the subject matter of Examples 32 to 36 includes, wherein the instructions further cause the one or more processors to perform the following operations: determining a plurality of predefined beam spots in the target for a current gantry angle, wherein the plurality of predefined beam spots are configured as a spiral pattern; and ordering the plurality of predefined beam spots in the spiral pattern in an order from a beam spot closest to a concentric axis for a corresponding gantry angle to a beam spot farthest from the concentric axis; and wherein delivering the radiation dose includes delivering a plurality of sub-beams according to the spiral pattern of the plurality of predefined beam spots.

[0134] In Example 38, the subject matter of Examples 32 to 37 includes, wherein the radiation dose includes a plurality of beamlets, and wherein a first beamlet of the plurality of beamlets has a first intensity with respect to a target in a periodically cycled first patient state, and a second beamlet of the plurality of beamlets has a second intensity with respect to the target in a periodically cycled second patient state.

[0135] In Example 39, the subject matter of Examples 32 to 38 includes, wherein the patient state includes at least one of a respiratory phase, an analog of a respiratory phase, an amplitude, a deformation vector field (DVF), a low dimensional representation of the DVF, a low dimensional representation of an image acquired using an imaging device, surface information, or a target position.

[0136] In Example 40, the subject matter of Examples 32 to 39 includes, wherein the patient state is a respiratory phase calculated based on a respiratory cycle.

[0137] Example 41 is a machine-readable medium comprising instructions for delivering a particle beam toward a target based on a periodic cycle, which instructions, when executed by one or more processors, cause the one or more processors to perform the following operations: determine a respiratory phase based on the periodic cycle; identify a current gantry angle of the particle beam; dynamically select a pattern of a beam spot based on the respiratory phase and the current gantry angle; determine a group of sub-beams based on the pattern of the beam spot; and cause the particle beam to continuously deliver the group of sub-beams.

[0138] In Example 42, the subject matter of Example 41 includes, wherein feeding the set of beamlets further comprises feeding the set of beamlets from a rotating gantry toward a target.

[0139] In Example 43, the subject matter of Example 42 includes, wherein the instructions further cause the one or more processors to determine the radiation dose based on a set of selected parameters for the current gantry angle, wherein at least one parameter is the angle and the respiratory phase.

[0140] Example 44 is a machine-readable medium comprising instructions for delivering a particle beam at a specific gantry angle toward a moving target, wherein the particle beam is delivered based on a set of control points, and the instructions, when executed by one or more processors, cause the one or more processors to perform the following operations: identify a layer of a target having a specific position within the target; track the movement of the target in the x-direction, the y-direction, and the z-direction; identify the physical position of the layer during a specific phase of a periodic cycle; select a set of parameters to deliver a predetermined radiation dose to the layer during the specific phase and at the specific gantry angle; and use the set of parameters to deliver the predetermined radiation dose to the layer during the specific phase and at the specific gantry angle.

[0141] In Example 45, the subject matter of Example 44 includes, wherein the instructions further cause the one or more processors to iterate through the plurality of target layers at corresponding respiratory phases and gantry angles until each target layer receives its corresponding predetermined dose.

[0142] In Example 46, the subject matter of Examples 44-45 includes, wherein the radiation dose to be delivered at the physical location of the layer is different during different phases of the periodic cycle.

[0143] In Example 47, the subject matter of Examples 44 to 46 includes, wherein the set of parameters includes a beam energy that travels to a predetermined depth for the layer in the target.

[0144] In Example 48, the subject matter of Examples 44 to 47 includes, wherein the set of parameters includes beam spot size.

[0145] In Example 49, the subject matter of Examples 44 to 48 includes, wherein the set of parameters includes a plurality of beamlets, each beamlet having a different intensity, wherein the intensity is the number of particles delivered and each beamlet has a specific coordinate position.

[0146] In Example 50, the subject matter of Example 49 includes, wherein a first beamlet of the plurality of beamlets has a first intensity with respect to a layer at a first phase of a periodic cycle, a second beamlet of the plurality of beamlets has a second intensity with respect to the layer at a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets has a third intensity with respect to the second layer at the first phase of the periodic cycle.

[0147] In Example 51, the subject matter of Examples 44 to 50 includes, wherein the periodic cycle is a respiratory breathing cycle.

[0148] Example 52 is a machine-readable medium comprising instructions for delivering a particle beam toward a target, which instructions, when executed by one or more processors, cause the one or more processors to perform the following operations: determine a current patient state of a patient; identify a current gantry angle; determine a radiation dose corresponding to the current patient state and the current gantry angle; and deliver the radiation dose to the target, starting at the current patient state and traversing a range of gantry angles, the range of gantry angles including the current gantry angle.

[0149] In Example 53, the subject matter of Example 52 includes, wherein the instructions further cause the one or more processors to iterate through the range of multiple gantry angles in the corresponding patient state until the target receives its predetermined dose.

[0150] In Example 54, the subject matter of Example 53 includes, wherein the instructions further cause the one or more processors to determine an estimate of an actual expected dose received by the target by reconstructing a dose given for each gantry angle in a range of a plurality of gantry angles.

[0151] In Example 55, the subject matter of Example 54 includes, wherein the instructions further cause the one or more processors to determine the estimate using a weighted sum of the doses given for each gantry angle in a range of a plurality of gantry angles.

[0152] In Example 56, the subject matter of Examples 52 to 55 includes, wherein the current gantry angle is a center angle of the range of gantry angles.

[0153] In Example 57, the subject matter of Examples 52 to 56 includes, wherein the instructions further cause the one or more processors to perform the following operations: determining a plurality of predefined beam spots in the target for a current gantry angle, wherein the plurality of predefined beam spots are configured as a spiral pattern; and ordering the plurality of predefined beam spots in the spiral pattern in an order from a beam spot closest to a concentric axis for a corresponding gantry angle to a beam spot farthest from the concentric axis; and wherein delivering the radiation dose includes delivering a plurality of sub-beams according to the spiral pattern of the plurality of predefined beam spots.

[0154] In Example 58, the subject matter of Examples 52 to 57 includes, wherein the radiation dose includes a plurality of beamlets, and wherein a first beamlet of the plurality of beamlets has a first intensity with respect to a target in a periodically cycled first patient state, and wherein a second beamlet of the plurality of beamlets has a second intensity with respect to the target in a periodically cycled second patient state.

[0155] In Example 59, the subject matter of Examples 52 to 58 includes, wherein the patient state includes at least one of a respiratory phase, an analog of a respiratory phase, an amplitude, a deformation vector field (DVF), a low dimensional representation of the DVF, a low dimensional representation of an image acquired using an imaging device, surface information, or a target position.

[0156] In Example 60, the subject matter of Examples 52 to 59 includes, wherein the patient state is a respiratory phase calculated based on a respiratory cycle.

[0157] Example 61 is at least one machine-readable medium comprising instructions that, when executed by a processing circuit system, cause the processing circuit system to perform operations to implement any one of Examples 1-60.

[0158] Example 62 is an apparatus comprising means for implementing any one of Examples 1 to 60.

[0159] Example 63 is a system for implementing any one of Examples 1 to 60.

[0160] Example 64 is a method for implementing any one of Examples 1 to 60.

[0161] The above detailed description includes reference to the accompanying drawings, which form a part of the detailed description. The accompanying drawings illustrate specific embodiments in which the present invention can be implemented by way of illustration. These embodiments are also referred to as "examples" in this article. Such examples may include elements other than those shown or described. However, the inventors also contemplate that only examples of those elements shown or described are provided. In addition, the inventors also contemplate examples (or one or more aspects thereof) using any combination or permutation of those elements shown or described with respect to a specific example (or one or more aspects thereof) or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0162] In the event of inconsistent usages between this document and any document incorporated by reference, the usage in this document controls.

[0163] As is common in patent literature, in this document, the term "a" or "an" is used to include one or more than one, independent of any other instance or usage of "at least one" or "one or more". In this document, unless otherwise specified, the term "or" is used to indicate non-exclusivity, so that "A or B" includes "A but not B", "B but not A", and "A and B". In this document, the terms "including" and "in which" are used as the plain English equivalents of the corresponding terms "comprising" and "wherein". In addition, in the appended claims, the terms "including" and "comprising" are open-ended, that is, systems, devices, articles, compositions, formulations, or processes that include elements other than the elements listed after such terms in the claims are still considered to be within the scope of the claims. In addition, in the appended claims, the terms "first", "second", and "third", etc. are used only as labels and are not intended to impose numerical requirements on their objects.

[0164] The method examples described herein may be at least partially machine or computer-implemented. Some examples may include a computer-readable medium or machine-readable medium encoded with instructions, which can be operated to configure an electronic device to perform the method described in the above example. The implementation of this method may include code, such as microcode, assembly language code, higher-level language code, etc. Such code may include computer-readable instructions for performing various methods. The code may form a part of a computer program product. In addition, in an example, the code may be tangibly stored in one or more volatile non-transient or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media may include, but are not limited to, hard disks, removable disks, removable optical disks (e.g., compact disks and digital video disks), tapes, memory cards or sticks, random access memory (RAM), read-only memory (ROM), etc.

[0165] The above description is intended to be illustrative and not restrictive. For example, the examples described above (or one or more aspects thereof) can be used in combination with each other. Other embodiments can be used, such as by a person of ordinary skill in the art after browsing the above description. An abstract is provided to comply with 37C.FR§1.72(b) so that the reader can quickly determine the nature of the technical disclosure. The abstract is submitted with the following understanding: the abstract is not used to interpret or limit the scope or meaning of the claims. Moreover, in the above detailed description, various features can be combined together to streamline the disclosure. This should not be interpreted as meaning that the disclosed features that are not requested for protection are essential to any claim. On the contrary, the subject matter of the invention may be less than all the features of a specific disclosed embodiment. Therefore, the attached claims are incorporated into the detailed description as examples or embodiments, wherein each claim itself is a separate embodiment, and it can be expected that these embodiments can be combined with each other in various combinations or permutations. The scope of the present invention should be determined with reference to the attached claims and the full range of equivalents to which such claims are entitled.

Claims

1. A system for feeding a particle beam toward a target based on a periodic cycle, the system comprising: One or more processors coupled to a memory device, the memory device containing instructions that, when executed by the one or more processors, cause the system to: determining a current respiratory phase based on the periodic cycle, the current respiratory phase being determined according to a set of respiratory phases of the periodic cycle, and the respiratory phase indicating a position of the target; identifying a current gantry angle of the particle beam; dynamically selecting a pattern of a beam spot having a specific size including a first size and a second size from a set of beam spot patterns corresponding to each of the set of respiratory phases at the current gantry angle based on the current respiratory phase and the current gantry angle; as well as determining a group of beamlets based on the pattern of beam spots, wherein respective beamlets in the group of beamlets have diameters corresponding to sizes of respective beam spots for delivery, the group of beamlets including at least one beamlet having a first diameter corresponding to the first size and selected to be delivered at a first beam spot in the pattern of beam spots, and at least one beamlet having a second diameter corresponding to the second size and selected to be delivered at a second beam spot in the pattern of beam spots, the second diameter being different from the first diameter; and The particle beam is continuously delivered to the target using the particle beam over a range of gantry angles including the current gantry angle without gating, wherein the particle beam is continuously delivered along a plurality of gantry angle ranges including the current gantry angle during the entire radiation therapy session.

2. The system according to claim 1, wherein: Feeding the set of beamlets further includes feeding the set of beamlets from a rotating gantry toward the target.

3. The system according to claim 2, wherein: The instructions further cause the one or more processors to determine a radiation dose based on a set of selected parameters for the current gantry angle, wherein at least one parameter is angle and respiratory phase.

4. A system for delivering a particle beam at a specific gantry angle toward a moving target, wherein: The particle beam is delivered based on a set of control points, the system comprising: One or more processors coupled to a memory device, the memory device containing instructions that, when executed by the one or more processors, cause the system to: identifying a layer of the target having a specific location within the target; tracking the movement of the target in the x-, y-, and z-directions; identifying a physical location of the layer during a particular phase of a periodic cycle, the particular phase being determined based on a set of phases of the periodic cycle; selecting a set of parameters to deliver a predetermined radiation dose to the layer during the particular phase and at a particular gantry angle, the set of parameters being selected from a group of parameter groups corresponding to each of the set of phases at the particular gantry angle, wherein the predetermined radiation dose comprises a set of beamlets, the set of beamlets comprising at least one beamlet having a first diameter corresponding to a first size specified in the set of parameters and selected to be delivered at a first portion of the physical location, and at least one beamlet having a second diameter corresponding to a second size specified in the set of parameters and selected to be delivered at a second portion of the physical location, the second diameter being different from the first diameter; and At least a portion of the predetermined radiation dose is delivered to the layer using the set of parameters during the particular phase and within a gantry angle range that includes the particular gantry angle without gating, wherein the particle beam is delivered continuously along a plurality of gantry angle ranges that includes the gantry angle range throughout the radiation therapy session.

5. The system according to claim 4, wherein: The instructions further cause the one or more processors to iterate through a plurality of target slices at corresponding respiratory phases and gantry angles until each target slice receives its corresponding predetermined dose.

6. The system according to claim 4, wherein: During different phases of the periodic cycle, the radiation dose to be delivered at the physical location of the slice is different.

7. The system according to claim 4, wherein: The set of parameters includes a beam energy that travels to a predefined depth in the target for the layer.

8. The system according to claim 4, wherein: The set of parameters includes beam spot size.

9. The system according to claim 4, wherein: The set of parameters includes a plurality of beamlets, each beamlet having a different intensity, wherein the intensity is the number of particles fed and each beamlet having a specific coordinate position.

10. The system according to claim 9, wherein: A first beamlet of the multiple beamlets has a first intensity with respect to the layer in a first phase of the periodic cycle, a second beamlet of the multiple beamlets has a second intensity with respect to the layer in a second phase of the periodic cycle, and a third beamlet of the multiple beamlets has a third intensity with respect to the second layer in the first phase of the periodic cycle.

11. The system according to claim 4, wherein: The periodic cycle is a respiratory breathing cycle.

12. A system for delivering a particle beam toward a target, the system comprising: One or more processors coupled to a memory device, the memory device containing instructions that, when executed by the one or more processors, cause the system to: determining a current patient state of the patient, the current patient state being determined based on a set of patient states that cycle periodically, and the current patient state being indicative of a location of the target; Identify the current gantry angle; determining a radiation dose corresponding to the current patient state and the current gantry angle, the radiation dose selected from a set of radiation doses corresponding to each of the set of patient states at the current gantry angle, wherein the radiation dose comprises a set of beamlets, the set of beamlets comprising at least one beamlet having a first diameter selected to be delivered at a first portion of the target and at least one beamlet having a second diameter selected to be delivered at a second portion of the target, the second diameter being different from the first diameter; and and causing at least a portion of the radiation dose to be delivered to the target without gating, starting at the current patient state and traversing a range of gantry angles, the range of gantry angles including the current gantry angle, wherein the particle beam is continuously delivered along a plurality of gantry angle ranges including the range of gantry angles throughout the radiation therapy session.

13. The system according to claim 12, wherein: The instructions further cause the one or more processors to iterate through a range of multiple gantry angles under corresponding patient conditions until the target receives its predetermined dose.

14. The system according to claim 13, wherein: The instructions also cause the one or more processors to determine an estimate of an actual expected dose received by the target by reconstructing a dose given for each gantry angle in the range of the plurality of gantry angles.

15. The system of claim 14, wherein: The instructions further cause the one or more processors to determine the estimate using a weighted sum of doses given for each gantry angle in the range of the plurality of gantry angles.

16. The system of claim 12, wherein: The current stage angle is a center angle of the range of stage angles.

17. The system of claim 12, wherein: The instructions further cause the one or more processors to: determining a plurality of predefined beam spots in the target for the current gantry angle, wherein the plurality of predefined beam spots are configured in a spiral pattern; ordering the plurality of predefined beam spots in the spiral pattern in order from a beam spot closest to a concentric axis for a corresponding gantry angle to a beam spot farthest from the concentric axis; and Wherein delivering the radiation dose comprises delivering a plurality of sub-beams according to the spiral pattern of the plurality of predefined beam spots.

18. The system of claim 12, wherein: The radiation dose comprises a plurality of beamlets, wherein a first beamlet of the plurality of beamlets has a first intensity with respect to the target in the periodically cycled first patient state, and a second beamlet of the plurality of beamlets has a second intensity with respect to the target in the periodically cycled second patient state.

19. The system of claim 12, wherein: The patient state includes at least one of respiratory phase, amplitude, deformation vector field, low dimensional representation of an image acquired using an imaging device, surface information, or target position.

20. The system of claim 19, wherein: The deformation vector field comprises a low dimensional representation of the deformation vector field.

21. The system of claim 12, wherein: The patient state is a respiratory phase calculated based on the respiratory cycle.

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