System for delivering proton therapy using cyclical motion

Abstract

To provide techniques for delivering a particle beam from a continuously rotating gantry towards a target according to a determined patient state.SOLUTION: The determined patient state and an identified gantry angle may be used to deliver a set of beamlets (e.g., a pattern of radiation dose) to the target. The particle beam may rotate through a range of gantry angles. The set of beamlets may be delivered continuously while the gantry rotates.SELECTED DRAWING: Figure 9

Description

[Background technology]

[0001]

[0001] Radiation therapy, or "radiotherapy," is used to treat cancer and other diseases in mammalian (e.g., human and animal) tissues. One type of radiation therapy, known as a "gamma knife," uses multiple, low-intensity gamma rays that are focused with high intensity and precision on a target site, such as a tumor. Another example uses a linear accelerator ("linac") to deliver radiation therapy, bombarding a target area with high-energy particles (e.g., electrons, high-energy photons, etc.). Another example uses heavy charged particle accelerators (e.g., protons, carbon ions, etc.) to precisely control the placement and dose of the radiation beam to deliver a predetermined dose of radiation to the target area. Additionally, the radiation beam is typically controlled to reduce or minimize damage to surrounding healthy tissue (OARs, or "organ(s) at risk"). Radiation is sometimes referred to as "prescribed" because a physician typically prescribes a predefined amount of radiation to deliver to a target site, such as a tumor.

[0002]

[0002] Typically, a collimated beam of ionizing radiation is directed toward the patient from an external radiation source. Modulation of the radiation beam can be provided by one or more attenuators or collimators (e.g., multi-leaf collimators). The intensity and shape of the radiation beam can be adjusted by collimation to conform the projected beam to the profile of the target tissue, thereby avoiding damage to healthy tissue (e.g., OARs) adjacent to the target tissue.

[0003]

[0003] The treatment planning procedure involves using three-dimensional images of the patient to identify the target region (e.g., tumor) and identify critical organs near the tumor. Creating a treatment plan is a time-consuming process in which the planner attempts to adhere to various treatment objectives and constraints (e.g., DVH (Dose Volume Histogram) objectives and other constraints) while considering the importance (e.g., weighting) of each constraint to create a clinically acceptable treatment plan. This is a time-consuming trial-and-error process, and the process becomes more complex as the number of organs at risk (OARs) increases (e.g., approximately 13 for head and neck treatment) due to the various OARs. While OARs far from the tumor are more likely to be spared radiation, OARs close to or overlapping the target tumor may have difficulty avoiding radiation exposure during treatment.

[0004]

[0004] Typically, an initial treatment plan may be generated "offline" for each patient. The treatment plan may be developed well before radiation therapy is delivered, such as by using one or more medical imaging techniques. Imaging information may include, for example, X-rays, computed tomography (CT), nuclear magnetic resonance (MR), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and ultrasound images. A physician or other medical professional may use three-dimensional imaging information depicting the patient's anatomy to identify one or more target tumors, along with any nearby organs at risk. Using procedures, the medical professional may visualize the target tumor, which will receive a prescribed radiation dose. The medical professional may also visualize surrounding tissues, such as organs, that may be damaged by radiation therapy.

[0005]

[0005] Alternatively or additionally, automated tools (e.g., ABAS®, offered by Elekta AB, Sweden) can be used to identify or define the target tumor and organs at risk. A radiation therapy treatment plan ("treatment plan") can then be generated using optimization techniques based on clinical and dosimetric objectives and constraints (e.g., maximum, minimum, and average doses of radiation to the tumor and critical organs).

[0006]

[0006] The treatment planning procedure involves using three-dimensional images of the patient to identify the target region (e.g., tumor) and identify critical organs near the tumor. Image acquisition can occur immediately prior to initiating delivery of a specified radiation therapy fraction. Such imaging can provide information useful for locating the target region and identifying its motion. While such contemporaneous imaging is often referred to as "real-time," there is typically a latency or time delay between image acquisition and radiation therapy delivery.

[0007]

[0007] The treatment plan is then implemented by positioning the patient and administering the prescribed radiation treatments. The radiation treatment plan may include "fractioning," whereby, for example, a series of radiation treatment deliveries are provided over a predetermined period of time (e.g., 45 fractions, or some other sum of fractions) so that each treatment delivery contains a specific fraction of the prescribed total dose. During treatment, the position of the patient and the target area relative to the treatment beam is important because it determines whether the target area or healthy tissue is irradiated.

[0008]

[0008] In one approach, radiation therapy can be delivered using particles such as protons instead of electrons. This is commonly referred to as proton therapy. The advantage of proton therapy is that it provides excellent dose distribution with a minimal exit dose compared to other radiation therapies, such as X-ray therapy. This minimal exit dose significantly reduces the dose to organs at risk (OARs). Furthermore, the lower dose per treatment reduces the risk of side effects, potentially leading to improved quality of life during and after proton therapy.

[0009]

[0009] One approach to proton therapy is to use a broad proton beam, such as a broad Bragg peak, which provides a uniform beam with multiple energies. However, when treating patients using rotational therapy, a broad beam cannot always be realized. For example, a broad beam requires an ion beam compensator for each treatment field, customized for each patient. This means that multiple compensators must be used to treat a single patient, with one compensator required for every angle. For example, a different compensator must be used at least every four degrees. A 360-degree rotation of proton therapy requires 90 different ion compensators to stop and start treatment. Another problem with using a broad beam is that it can result in undesirable dose shaping at the proximal edge of the target tumor.

[0010] (Definition explanation)

[0010] A spot is a location configured to fit the diameter of the beamlet delivered to that location.

[0011]

[0011] A beamlet is a stream of particles having a nominal diameter delivered at a starting point and an end point with a given velocity.

[0012]

[0012] A line segment is configured to uniformly deliver multiple particles between a start position and an end position.

[0013] (overview)

[0013] In one approach, a method for delivering a particle beam from a continuously rotating gantry to a target, where the particle beam is composed of a plurality of beamlets and the target is moving according to a periodic cycle, includes determining the periodic cycle, identifying a corresponding radiation therapy treatment plan, selecting a set of beamlets for the periodic cycle corresponding to the gantry rotation angle, and optionally delivering the particle beam in a rotational pattern.

[0014]

[0014] This Summary is intended to provide an overview of the subject matter of the present patent application. It is not intended to be an exclusive, exhaustive description of the invention. The Detailed Description is included to provide further information regarding the present patent application. [Brief explanation of the drawings]

[0015]

[0015] [Figure 1] FIG. 1 illustrates a general example of such a system including a particle therapy system controller, according to one embodiment.

[0016]

[0016] [Figure 2] FIG. 2 illustrates a general example of a radiation therapy system, including a particle therapy system and an image acquisition device, according to one embodiment.

[0017]

[0017] [Figure 3] FIG. 3 shows an overview of a particle therapy system including a radiation therapy output configured to provide a proton therapy beam, according to one embodiment.

[0018]

[0018] [Figure 4] FIG. 4 illustrates typical radiation dose depths in human tissue for various types of particles, according to one embodiment.

[0019]

[0019] [Figure 5] FIG. 5 shows a schematic of a broadened Bragg Peak, according to one embodiment.

[0020]

[0020] [Figure 6] FIG. 6 shows an overview of an active scanning proton beam delivery system, according to one embodiment.

[0021]

[0021] [Figure 7A] [Figure 7B] 7A-7B show an overview of a spiral delivery path on a grid, according to one embodiment.

[0022]

[0022] [Figure 7C] FIG. 7C shows a spiral spot delivery path with different spot sizes, according to one embodiment.

[0023]

[0023] [Figure 8] FIG. 8 is a diagram illustrating an example of a patient's cyclic phases, according to one embodiment.

[0024]

[0024] [Figure 9]FIG. 9 is a diagram showing the selection of the radiation dose according to the respiratory cycle and the gantry angle.

[0025]

[0025] [Figure 10A] FIG. 10A shows target location intensity and Bragg Peak for various degrees of arc angle, according to one embodiment.

[0026]

[0026] [Figure 10B] FIG. 10B illustrates composite target location intensities, according to one embodiment.

[0027]

[0027] [Figure 11] [Figure 12] [Figure 13] 11-13 are flow charts illustrating a technique for delivering a particle beam to a target on a periodic cycle, according to one embodiment.

[0028]

[0028] The drawings are not necessarily drawn to scale, and like numbers represent like components in different views. Like numbers with different letter suffixes represent different instances of similar components. The drawings illustrate various embodiments discussed herein by way of general illustration, not by way of limitation. DETAILED DESCRIPTION OF THE INVENTION

[0029]

[0029] The systems and methods described herein provide radiation therapy to a patient. The radiation therapy is delivered using a rotating gantry, e.g., a particle beam mounted on the gantry. The gantry can rotate continuously while the particle beam delivers multiple beamlets. The beamlets can be delivered to a target (e.g., a tumor, a portion of a tumor, or other spot) in a spiral pattern. In one example, rotating the gantry while delivering the particle beam can be inefficient (e.g., when dose and transmission information is planned every degree or every half degree). In other examples, rotating the gantry can introduce errors (e.g., when planning every few degrees, such as every 5 degrees or every 10 degrees). Performing rotational proton therapy has many advantages. First, instead of delivering undesirable incident doses at a few angles, the dose can be delivered from many angles.

[0030]

[0030] The systems and methods described herein address both of these issues by introducing a spiral pattern into the delivery of the beamlets. The spiral pattern can be planned and used at various angles, such as 5 degrees, 10 degrees, and 15 degrees. In one example, the spiral pattern can deliver the particle beam to the central portion of the target when the error is greatest and deliver the particle beam to the outer portion of the target when the error is smallest. The magnitude of the error depends on the difference between the actual gantry angle and the planned angle; for example, a larger angle difference results in a larger error, and a smaller angle difference results in a smaller error.

[0031]

[0031] In one embodiment, a spiral pattern for delivering particle beams to a target can reduce the time required to complete a radiation treatment. For example, beamlets delivered during a treatment may vary in size. Changing the size of the beamlets can disrupt the treatment, for example, by requiring more time and energy. Using a raster-type pattern, the beamlet size must be changed multiple times. Using a spiral pattern allows for a single change in beamlet size. For example, smaller beamlets can be used on the outer edge of the target and larger beamlets can be used on the inner edge of the target.

[0032]

[0032] One challenge is accurately tracking targets, OARs, and other objects when the patient is moving. Motion can be classified as either periodic (e.g., breathing or heartbeat) or non-periodic. Periodic breathing poses unique challenges when the therapeutic target is affected by patient movement. For example, 8 or 16 unique phases can be defined within a periodic cycle. Other sets of phases can be used, e.g., ranging from 2 to 20 phases. These phases represent positions throughout the periodic cycle that are repeated with each iteration of the cycle.

[0033]

[0033] The phases of a periodic cycle can be used to generate a radiation dose for treatment of a target in each phase. Treating a moving target involves using a phase that covers the correct area of ​​the target, but doing so results in a dose to normal healthy tissue and organs at risk. Non-rotating devices typically have a fixed angle for delivering particles to the target. One way to ensure a dose to a moving target is to pause delivery of the beam (e.g., "gate" the beam) when the target is not near its nominal position (usually "at rest" near the end of either expiration or inspiration). In this way, only one phase of the cycle is targeted, and only that phase is delivered.

[0034]

[0034] However, when using a non-rotating particle therapy system, multiple layers from fixed angles collectively cover the entire target. This can result in increased doses to healthy tissue and organs at risk, especially the skin around the entry point. Therefore, a rotating gantry can be used to avoid increased doses to the skin and other tissues in the delivery line between the beam emitter and the target. When using a rotating gantry to deliver particles, beam delivery typically cannot be paused without stopping the gantry or moving outside the angular range covered by the rotation. Solutions for non-rotating gantry systems that rely on stopping the beam do not work with a rotating gantry.

[0035]

[0035] The systems and methods described herein use a spiral delivery technique based on the patient's current phase and gantry angle (or range of gantry angles) to deliver doses during periodic cycle phase changes while the gantry is continuously rotating, without stopping the gantry.

[0036]

[0036] Instead of irradiating all layers of the tumor from each angle, one or two layers past or before the center of the target can be used. A layer includes the depth location to be targeted within the target. Particles can be delivered to the target from multiple angles, such as by continuously rotating the gantry. Because the target is in periodic cycling motion, which synchronizes with the patient's periodic breathing, a set of parameters corresponding to a given respiratory phase and particle delivery angle is used to deliver the dose to the intended part of the target.

[0037]

[0037] A database or other storage device can be used to store sets of parameters, each set including a specific breath phase, a specific gantry angle, and a specific particle dose. In one embodiment, the specific gantry angle can include a range of angles. For example, the sets of parameters correspond to 5-degree or 10-degree angle increments (e.g., 72 or 36 angles). Each of the multiple angles corresponds to a multiple phase of a cycle. For example, if a breath cycle has 8 phases and 36 angles (e.g., in a 10-degree range), a total of 288 radiation dose or beamlet sets are generated and stored. The dose and beamlet generation occurs before treatment. In another embodiment, 1152 radiation dose or beamlet sets are generated and stored for 16 phases and 72 angles (in a 5-degree range). During treatment, the current phase and gantry angle are identified and the corresponding radiation dose or beamlet set is selected.

[0038]

[0038] The cumulative dose to the target using a rotating gantry is equal to the weighted sum of all particle doses from each angle, taking into account the respiratory phase at each angle.

[0039]

[0039] 1 illustrates a general example of a system 100 including a particle therapy system controller, according to one embodiment. The system 100 may include a database or a hospital database. The particle therapy system controller may include a processor, a communication interface, or 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).

[0040]

[0040] In one example, the spot delivery module or beamlet module can be configured to plan beamlet size, target or spot location, etc. The beamlet module can be used to determine the ordering of beamlet delivery, for example, in a spiral pattern as described herein. The delivery ordering module can communicate with treatment planning software to plan the delivery of the beamlets. For example, the treatment planning software can be used to determine or plan gantry angle, gantry speed, beamlet size, spiral pattern (e.g., clockwise or counterclockwise), angular range of a particular spiral pattern (e.g., every 10 degrees of gantry rotation), etc.

[0041]

[0041] The processor may execute the plan, such as by communicating, via a communications interface, with a component used to execute the plan (e.g., a controller or component such as those described below with reference to FIG. 3). In one example, the communications interface may be used to retrieve stored information (e.g., patient information, past treatment information for the patient or other patients, treatment instructions, information about particular devices or components, etc.) from a database or hospital database.

[0042]

[0042] Figure 2 shows a general example of a radiation therapy system, including a particle therapy system and an image acquisition device, according to one embodiment. The particle therapy system includes an ion source, an accelerator, and a scanning magnet, each of which is described in more detail below with reference to Figure 3. The particle therapy system includes a gantry and a table, and the gantry may be attached to the table, may be affixed to the table, or is stable relative to the table. The table can support a patient. The gantry is a rotating gantry, and can rotate relative to (e.g., around) the table and can rotate relative to the patient (and the table or a portion of the table can rotate together with the gantry).

[0043]

[0043] The particle therapy system can communicate with a process control system, which is used to control the operation of the particle therapy system. The therapy control system can communicate with an image acquisition device (e.g., to receive images captured by the image acquisition device or from an image database) or can communicate with an oncology information system. The oncology information system can provide details of the treatment plan, such as those received from a treatment planning system, to the therapy control system. The therapy control system can use the treatment plan to control the particle therapy system (e.g., to operate the gantry, ion source, accelerator, scanning magnet, particle beam, etc.). The therapy control system can include, for example, beamlet intensity control, beamlet energy control, scanning magnet control, table control, gantry control, etc. In one example, beamlet intensity control and beamlet energy control can be used to activate beamlets of a specific size or to target a specific location. Scanning magnet control can be used to deliver beamlets according to the treatment plan, such as in a spiral pattern. Gantry control or table control can be used to rotate the gantry.

[0044]

[0044] The treatment planning software can include components such as a beamlet delivery and sequencing module that, for example, individually controls beamlets for spots or line segments. The treatment planning software is described in more detail above with reference to FIG. 1. The treatment planning software can access an image database to acquire images and store information. Once the treatment plan is complete, the treatment planning software sends the treatment plan to an oncology information system for communication with the treatment control system.

[0045]

[0045] 3 illustrates an embodiment of a particle therapy system 300 including a radiation therapy output configured to provide a proton therapy beam. The particle therapy system 300 includes an ion source 301, an injector 303, an accelerator 305, an energy selector 307, multiple bending magnets 309, multiple scanning magnets 311, and a snout 313.

[0046]

[0046] An ion source 301, such as a synchrotron (not shown), is configured to provide a stream of particles, such as protons. The stream of particles is delivered to an injector 303, which uses Coulomb forces to provide the charged particles with initial acceleration. The particles are further accelerated by an accelerator 305 to approximately 10% of the speed of light. Acceleration imparts energy to the particles, which determines the depth they travel within tissue. An energy selector 307 (e.g., range scattering) is used to select the energy of the protons delivered to the patient. In one embodiment, called passive scattering, an optional range modulator 308 (e.g., also called a ridge filter or range modulation wheel) can be used to spread the beam to match the tumor. After energy selection, a set of bending magnets 309 can be used to transport the proton stream to a hospital radiation therapy treatment room. Additionally, a scanning magnet 311 (e.g., an x-y magnet) is used to spread and trace the proton beam to match the exact shape of the tumor. The snout 313 or components of the snout 313 (e.g., a collimation device) are used to further shape the proton beam. In various embodiments, the particle stream may be composed of carbon ions, pions, or positively charged ions.

[0047]

[0047] Figure 4 shows a comparative illustration of the radiation dose depth of various particle types in human tissue. As shown, the relative penetration depth into human tissue of photons (e.g., X-rays), protons, and carbon ions is shown (e.g., delivered at distances below the surface, including all radiation doses, including secondary radiation and scattering). Each radiation dose is shown relative to the peak dose of a single-energy proton beam set at 100%.

[0048]

[0048] Monoenergetic (e.g., monoenergetic) proton beams exhibit a plateau region beginning at about 25%, gradually increasing to a tissue depth of about 10 cm, rapidly increasing to the Bragg Peak at 15 cm, and then advantageously dropping to zero at a short distance, at the end of the Bragg Peak no additional dose is delivered.

[0049]

[0049] The photon beam (e.g., labeled X-ray) shows an initial buildup due to electron scattering (e.g., the primary means by which X-rays deliver dose to tissue is through energy transfer to electrons within the tissue). After this, there is an exponential falloff, continuing past the distal end of the target (approximately 15 cm deep in the illustration). X-ray beams have the same entrance (skin) dose as proton beams. When normalized (e.g., scaled) to a depth of 15 cm, the X-ray dose is 40% of the proton dose, but X-rays achieve a peak dose of over 95% (close to 100%) at approximately 3 cm. When the X-ray data is renormalized to obtain 100% dose at 15 cm, the peak dose at approximately 3 cm is approximately 240%, resulting in dose being delivered to locations where it is not desired (e.g., in front of the target). Thus, with X-rays, a significant amount of dose is delivered in front of the target, and a significant amount is delivered past the target.

[0050]

[0050] Monoenergetic carbon beams exhibit a plateau region at lower entrance doses than proton beams. Carbon beams have sharper Bragg peaks and fall off more rapidly than proton beams, but carbon beams have tails (e.g., "spallation tails" where some carbon nuclei are fragmented into helium ions) that result in approximately 10% or less additional dose a few centimeters beyond the intended target. Carbon ion beams have less favorable entrance dose and skin dose than proton beams, but carbon ion beams deliver acceptable doses through the target.

[0051]

[0051] Figure 5 provides an illustration of the spread-out Bragg peak (SOBP). The SOBP shows the relative depth dose curves for a combination of proton beams of various initial energies, each with a spread in energy (e.g., variations in energy absorption in tissue). The desired result is a uniform dose across a target of a specific thickness. As shown, the target has 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 perfectly uniform (with a mean normalized to 100%). While this figure does not start at a depth of 0 cm and does not explicitly show the entrance (skin) dose, the nature of the entrance region of a proton beam results in a relatively flat depth-dose curve. Typically, the entrance (skin) dose will be approximately 70% of the target dose (e.g., shown at the right end of the x-axis). SOBP can be achieved in various ways, such as by modulating the energy (variable absorption) of a scattered proton beam using various devices (e.g., static ridge filters or dynamic range modulation wheels) or by selecting and using a single energy proton beam that is not scattered.

[0052]

[0052] Figure 6 shows a schematic diagram of a typical active scanning proton beam delivery system. As shown, a single-layer pencil beam scan is delivered, tracing a grid of spots on the patient in conjunction with the cross-sectional contour of the particle delivery. The incident monoenergetic proton beamlets have a predetermined amount of their energy absorbed by a range shifter (e.g., a range shifter plate in Figure 6), resulting in beamlets with the desired energy to achieve a predetermined depth relative to the patient's Bragg Peak for treating a predetermined layer. A magnetic scanner is capable of deflecting particles both vertically and horizontally. Adjusting the magnetic field strength controls the deflection perpendicular to the magnetic field and the incident beamlets. The speed at which the magnetic field strength is adjusted determines the scanning speed. For example, the combination of the proton beamlet strength and the scanning speed determines how much dose (e.g., particles per unit area) can be delivered to a specific area (e.g., "spot" in Figure 6) in a specific time period. In theory, the strengths of the magnetic fields could be adjusted independently of each other (similar to the children's toy "Etch a Sketch" offered by Spin Master™, Inc., Toronto, Canada, although the strength of the pencil beamlets is a variable not found in the toy). The most common scanning method is a raster scan, scanning quickly in one direction and slowly in the vertical direction, similar to how early televisions (e.g., cathode ray tubes (CRTs) using electrons instead of protons) were controlled, but any pattern can be scanned (as in the toy). By varying the strength of the scanning magnetic field and adjusting the intensity of the pencil beam in the meantime, a well-defined spot can be delivered.

[0053]

[0053] 7A-7B show an overview of a spiral delivery path on a grid, according to one embodiment. The spiral pattern shown in Figures 7A-7B can minimize errors due to gantry rotation. The illustrated spiral pattern improves target accuracy and reduces off-target radiation while the gantry is rotating, compared to a linear raster pattern.

[0054]

[0054] The systems and methods described herein optimize radiation dose when delivering protons to specific spots using proton arc therapy. When delivering to specific spots, the spiral pattern scanning described herein can minimize discrepancies between what was planned and what was actually delivered. If a spot away from the isocentric axis is not delivered with the gantry closest to the current planning angle, the actual spot location may end up far from the intended spot location, causing the overall beamlet trajectory to differ significantly from the expected trajectory. The use of spiral scanning minimizes errors in the actual spot location and minimizes discrepancies between the predicted and actual beamlet trajectories.

[0055]

[0055] FIG. 7C shows a spiral spot delivery path with different spot sizes, according to one embodiment.

[0056]

[0056] The trade-off between small and large spots is that delivering only small beamlets to a small spot can result in a significant radiation treatment time. Therefore, to reduce treatment time, it is recommended to deliver small beamlets to the outer edge / front of the tumor and large spots to the interior of the tumor. Changing spot size during delivery is time-consuming. By using the spiral delivery pattern shown in Figure 7C, only one spot size transition is required when moving from a set of small spots treating the outer edge of the tumor to a set of larger spots treating the inner tumor region. Similarly, only one spot size change is required when moving in the reverse direction, resulting in only two changes in the overall beam. In one embodiment, the spiral pattern is a two-dimensional spiral pattern, allowing the dose to be delivered to each layer of the target.

[0057]

[0057] In one example, beamlets are delivered to the edge of the arc range when the spiral is centered on the target. For example, in an arc from 0 to 10 degrees, the target can be planned as if the gantry were stationary at 5 degrees. In this example, the outer edge of the spiral occurs as the gantry approaches and moves away from 5 degrees, and the center of the spiral occurs as the gantry approaches and moves away from 0 degrees. For example, starting at 0 degrees, the spiral is drawn outward from the center of the target, ending near 5 degrees (at the outer point of the spiral). Then, in one example, as the gantry moves from 5 to 10 degrees, the spiral is reversed on the way back to the center of the target (e.g., moving clockwise from 0 to 5 degrees, then counterclockwise from 5 to 10 degrees, or vice versa). This process can be repeated at different angles, such as 10 to 20 degrees, and at different layers of the target until the dose is completed.

[0058]

[0058] FIG. 8 illustrates an example of a patient's cyclic phases, according to one embodiment. The cyclic respiratory cycle 800 is shown with eight phases (but may include other numbers, e.g., 16 phases). As an example, other patient state information can be used with the techniques described herein. For example, the patient state can be represented by respiratory phase, an approximation of respiratory phase, amplitude, deformation vector field (DVF), a low-dimensional representation of a DVF, a low-dimensional representation of an image acquired by an imaging device, surface information, target location, etc.

[0059]

[0059] The periodic breathing cycle 800 is represented by position over time and changing position based on movement of the lungs, throat, diaphragm, muscles, and other aspects of the respiratory system.

[0060]

[0060] Additionally, the current angle along with the direction of angular motion of the gantry is depicted in gantry angle 801. Gantry angle 801 represents the motion of the gantry over time, which, in conjunction with the periodic breathing cycle, is used to deliver a predetermined radiation dose to the patient.

[0061]

[0061] The periodic breathing cycle 800 is cyclical, with phases or states repeating over time. A plan for each phase or state of the cycle is developed to deliver a therapeutic dose to targets near or affected by movement within the cycle. For example, for each phase or state, a set of radiation doses or beamlets is generated at different gantry angles (e.g., every 10 degrees) as described herein.

[0062]

[0062] Detection and assignment of phases or states of the cycle 800 can be performed using imaging. For example, 4D CT or MRI can be used to identify each phase of the cycle for a patient. Once identified, a plan for the phase or state can be created for the specific patient (e.g., based on target size, target location in each phase, location of other tissues, etc.).

[0063]

[0063] FIG. 9 illustrates radiation dose selection as a function of respiratory cycle and gantry angle. Radiation dose selection involves determining the current phase or state of the respiratory cycle and identifying the current gantry angle. The radiation dose corresponding to these two variables can be stored, for example, in a system database, along with the radiation dose for each unique phase and gantry angle pair. In one example, the nearest gantry angle (e.g., rounded to the nearest 1 degree, 5 degrees, 10 degrees, etc.) can be used. The radiation dose can be specific to the patient target or target layer for the phase and gantry angle (or range). The specific dose is sent to the controller, which uses the gantry to deliver the dose.

[0064]

[0064] The dose can be delivered by a continuously rotating gantry. As the gantry rotates, the patient phase and gantry angle can change, allowing for other radiation doses to be used, for example, in 1-degree increments or 1-degree ranges. In one example, a radiation dose is specified for each 10-degree rotation. For example, the radiation dose can be used in the 0-10 degree range, generating a plan for a gantry position of 5 degrees (e.g., in the middle of the range). The displayed dose is delivered as the gantry rotates from 0 to 10 degrees, or changes with the change in phase (but using a 5-degree gantry angle throughout this range). The radiation dose is stored in a database, and a lookup involving the phase and gantry angle variables can be used to query for the corresponding gantry angle and patient condition.

[0065]

[0065] 10A shows target location intensity and Bragg Peaks for various arc angles, illustrating the different intensities and distances at which the particle beam penetrates depending on the angle of the gantry, according to one embodiment.

[0066]

[0066] Increasing the number of angles through which multiple doses are delivered to the target tumor results in fewer doses being delivered to areas of the body that are not the target tumor. By using more angles, statistical errors in stopping power and patient positioning errors are offset and reduced by averaging the overlapping doses. In this way, proton therapy becomes more robust by achieving good dose distribution even in the presence of errors in positioning and stopping power.

[0067]

[0067] The rotating gantry can compensate for the increased dose at the target center by using techniques such as "terminating" the spiral and planning it to restart at a location other than the target center on that plane. As shown in Figure 10A, varying penetration depth at different angles, terminating at a location other than the target center, can avoid overdosing the patient. A similar, but more precise, correction can be achieved by reducing the intensity of beamlets closer to the center along a line perpendicular to the isocentric line, along the direction of gantry travel.

[0068]

[0068] 10B shows composite target location intensity, according to one embodiment. In the composite image, overlap occurs between different angles, but the overlap is minimized by not all angles penetrating to the same depth in the target.

[0069]

[0069] Proton therapy using pencil beam scanning allows for the delivery of different energies, with the energy varying within a second. Pencil beam scanning enables intensity-modulated proton therapy (IMPT). Energy selection is crucial because it controls the depth of radiation treatment. Particle therapy inherently stops at a fixed depth for a specific energy. This allows for layered treatment depth within a tissue region. In each layer, the treatment outline is adapted to a specific region of tissue, allowing for different tumors to be treated, making it ideal for irregularly shaped tumors located near critical organs. When delivered from a rotating gantry, there is a limited time to deliver multiple energies to different layers. Energy selection at a given angle is important to control the depth at which the majority of the dose is delivered to the tumor. By judiciously selecting a very limited number of energies for each angle, this system achieves the desired total dose to the tumor and does so in a timely manner. By selecting energies delivered beyond the tumor midline from a fixed angle, this system ensures tumor coverage. What is clinically important is the total dose to the tumor from all angles.

[0070]

[0070] Accumulation of the actual delivered dose is important for adaptive therapy. In one embodiment, parameters are optimized to achieve the desired dose to the target and minimize the difference between the actual dose to the target and the predetermined dose to the target. This difference is due to motion, and the actual dose to normal tissue may differ (e.g., be larger) than the calculated dose. Knowing the actual dose distribution of the current session is important when dose delivery is interrupted. Upon treatment interruption, the dose is recalculated based on the amount administered before the session was interrupted. In one embodiment, a session is resumed after an interruption using techniques described herein (e.g., by determining the current respiratory phase and the current gantry angle).

[0071]

[0071] The dose distribution is recalculated based on the set of parameters and the previously administered dose. To determine the dose, the recalculation uses each gantry angle for particle delivery, the respiratory phase identity associated with each gantry angle, and a subset of images (e.g., 4D CT, MRI) for a particular respiratory phase. A sum of all doses delivered using these weighted terms is generated to determine the overall actual delivered dose. The actual dose may be an estimate.

[0072]

[0072] When respiratory phase is taken into account, the administered dose can be determined based on a set of parameters including the administered dose corresponding to a respiratory phase and gantry angle pair. In one example, the set of gantry angles and respiratory phases can be used to index back to the dose calculation originally performed before treatment. The individual doses for a particular angle and respiratory phase combination can be summed to quickly obtain an approximate dose.

[0073]

[0073] The dose reconstruction for respiratory phases differs from the dose reconstruction for non-rotational delivery. In non-rotational delivery, multiple layers collectively cover the entire target. In rotational delivery, the multiple layers are one or two layers (e.g., one layer of each) that are just past the center of the target or just before the center of the target. Thus, the multiple layers shown in FIG. 10B represent a combination of layers aimed around the center of the target. Other embodiments may include layers aimed just before the center of the target.

[0074]

[0074] In one example, the dose is recalculated based on the actual parameters selected at each angle and respiratory phase. Using a continuously rotating gantry and based on respiratory phase, treatment may result in a dose to normal tissues (and organs at risk) that is not the same as any one of the set of parameters (for a given respiratory phase) or the weighted sum of the doses for all respiratory phases. The accumulation of the actual delivered dose is important for adaptive therapy, and the dose distribution of the current session is important when delivery is interrupted (e.g., continuing delivery from the angle where delivery was interrupted or resuming delivery at a later time or date is difficult without knowing the angle, phase, and actual delivered dose).

[0075]

[0075] In one example, the dose is calculated based on actual parameters incorporating respiratory phase identification using a subset of 4D CT images for that respiratory phase. For example, a quick approximation of the dose using actual parameters is generated using a set of gantry angles and respiratory phases to index back to the initial dose calculation performed before treatment and sum the individual doses delivered at a particular angle and respiratory phase combination. The total dose information can be used to refine or further plan the treatment as the patient's weight changes or the tumor shrinks (or grows).

[0076]

[0076] 11-13 are flow charts illustrating a technique for delivering a particle beam toward a target on a periodic cycle, according to one embodiment.

[0077]

[0077] 11 shows a method 1100 for delivering a particle beam toward a target based on a periodic cycle, which includes operation 1102 for determining a respiratory phase based on the periodic cycle. The periodic cycle may include, for example, a respiratory cycle having 8 or 16 respiratory phases. Method 1100 includes operation 1104 for identifying a current gantry angle of the particle beam.

[0078]

[0078] Method 1100 includes operation 1108 of dynamically selecting a pattern of spots based on the respiratory phase and the current gantry angle. Method 1100 includes operation 1110 of determining a set of energies (e.g., beamlets) for the respiratory phase based on the pattern of spots.

[0079]

[0079] The method 1100 includes operation 1112 of sequentially delivering a set of energies using a particle beam. The set of beamlets are delivered toward a target from a rotating gantry (e.g., a continuously rotating gantry). The method 1100 includes determining a radiation dose based on a selected set of parameters for a particular gantry position, at least one parameter being an angle and a respiratory phase.

[0080]

[0080] In one embodiment, the energy is determined based on the approximate radiation path length to the intended target layer, and the intensity of each beamlet is determined based on how much dose is provided to each spot. The energy selection may vary depending on the phase of respiration, such as when the radiation path length (or equivalent) changes, but the spot pattern remains substantially similar and has substantially similar intensity. Alternatively, the energy may remain the same but the spot pattern may change, such as due to lateral movement of the tumor relative to the central beam axis. The set of beamlets may include changes in energy and spot pattern while irradiating the target.

[0081]

[0081] 12 illustrates a method 1200 for delivering a particle beam at a specific gantry angle toward a moving target, where the particle beam is delivered based on a set of control points. Method 1200 includes an operation 1202 that identifies a layer for the target having a specific location within the target. In one embodiment, the set of parameters includes beam energy, and the beam energy travels to a predetermined depth within the target for the layer. In one embodiment, the set of parameters includes spot size.

[0082]

[0082] In one embodiment, the set of parameters includes a plurality of beamlets, each beamlet having a different intensity. The intensity includes a number of particles to be transmitted. In this embodiment, each beamlet has a specific coordinate location. Method 1200 further includes: a first beamlet of the plurality of beamlets having a first intensity for a layer of a first phase of the periodic cycle; a second beamlet of the plurality of beamlets having a second intensity for a layer of a second phase of the periodic cycle; and a third beamlet of the plurality of beamlets having a third intensity for a second layer of the first phase of the periodic cycle.

[0083]

[0083] Method 1200 includes an operation 1204 for tracking the movement of the target in the x, y, and z directions. Method 1200 includes an operation 1206 for identifying the physical location of the layer at a particular phase of a periodic cycle. In one example, the particular phase is a respiratory phase of a respiratory cycle.

[0084]

[0084] Method 1200 includes operation 1208 of selecting a set of parameters for delivering a predetermined radiation dose to a layer during a particular phase. In one embodiment, the selected set of parameters includes a particular gantry angle or a particular range of gantry angles. Method 1200 includes operation 1210 of delivering a predetermined radiation dose to a layer during a particular phase using the set of parameters. The predetermined radiation dose is delivered at a particular gantry angle.

[0085]

[0085] Method 1200 may include repeating across multiple target layers at each respiratory phase and gantry angle until each target layer receives its respective predetermined dose. Method 1200 may include verifying delivery of the radiation dose to each designated target layer or to the entire target. Verifying delivery of the radiation dose may include determining that the correct meter set was delivered. In another example, verifying delivery may include determining an estimate of the actual intended dose received by the target compared to the predetermined dose. The estimate of the actual intended dose may be determined using external measurements (e.g., 4D CT scans). Method 1200 may include providing different radiation doses at physical locations of the layers during different phases of a periodic cycle.

[0086]

[0086] 13 illustrates a technique 1300 for delivering a particle beam toward a target based on a periodic cycle, including operation 1302 of determining a current patient state of the patient. The current patient state is a phase of the periodic cycle. In one embodiment, the phase is a respiratory phase, and the periodic cycle is a respiratory cycle having 8 or 16 respiratory phases. In one embodiment, the patient state includes at least one of a respiratory phase, an approximation 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 by an imaging device, surface information, a target location, etc.

[0087]

[0087] The method 1300 includes an operation 1304 that identifies the current gantry angle.

[0088]

[0088] The method 1300 includes an operation 1306 for determining a radiation dose corresponding to the current patient condition and the current gantry angle.

[0089]

[0089] The method 1300 includes an operation 1308 of delivering a radiation dose to a target over a range of gantry angles that includes the current gantry angle, starting from a current patient state, for example, a 10 degree angular range with the current gantry angle at its center.

[0090]

[0090] Method 1300 may include iterating over multiple ranges of gantry angles for each patient state until the target receives its predetermined dose. In one embodiment, this operation includes determining an estimate of the actual intended dose received by the target by reconstructing the dose delivered for each of the multiple ranges of gantry angles. This operation may further include determining the estimate using a weighted sum of the dose delivered for each of the multiple ranges of gantry angles.

[0091]

[0091] The method 1300 further includes an operation of determining a plurality of predefined spots arranged in a spiral pattern within the target for the current gantry angle, including ordering the plurality of predefined spots within the spiral pattern from closest to an isocentric axis of each gantry angle to furthest from the isocentric axis. Delivering the predetermined radiation dose may include delivering a plurality of beamlets according to the spiral pattern of the plurality of predefined spots.

[0092]

[0092] The method 1300 may further include resuming delivery of the predetermined radiation dose at the particular gantry angle if delivery was interrupted at that angle. The irradiation may be resumed using the radiation dose corresponding to the particular gantry angle and the new patient condition.

[0093]

[0093] The radiation doses described herein include a plurality of beamlets, the plurality of beamlets including a first beamlet having a first intensity to a target at a first patient state of the periodic cycle and a second beamlet having a second intensity to a target at a second patient state of the periodic cycle. In one example, the patient state is a respiratory phase calculated from a respiratory cycle.

[0094]

[0094] Each of the non-limiting examples described herein may stand alone or may be combined with one or more of the other examples in various permutations or combinations.

[0095]

[0095] Example 1 is a method for delivering a particle beam toward a target based on a periodic cycle, the method comprising the steps of: determining a respiratory phase based on the periodic cycle; identifying a current gantry angle of the particle beam; dynamically selecting a spot pattern based on the respiratory phase and the current gantry angle; determining a set of beamlets based on the spot pattern; and continuously delivering the set of beamlets using the particle beam.

[0096]

[0096] In Example 2, the subject matter of Example 1 is such that delivering the set of beamlets includes delivering the set of beamlets from a rotating gantry toward the target.

[0097]

[0097] In Example 3, the subject matter of Example 2 includes determining a radiation dose based on a set of selected parameters for the current gantry angle, at least one parameter being an angle and a respiratory phrase.

[0098]

[0098] Example 4 is a method for delivering a particle beam based on a set of control points at a specific gantry angle toward a moving target, the method comprising the steps of identifying a layer of the target having a specific position within the target; tracking movement of the target in X, Y, and Z directions; identifying a physical position of the layer at a specific phase of a periodic cycle; selecting a set of parameters for delivering a predetermined radiation dose to the layer at the specific phase and specific gantry angle; and delivering the predetermined radiation dose to the layer at the specific phase and specific gantry angle using the set of parameters.

[0099]

[0099] In Example 5, the subject matter of Example 4 includes repeating across multiple target layers at each respiratory phase and gantry angle until each target layer receives its respective predetermined dose.

[0100]

[0100] In Example 6, the subject matter of Examples 4-5 includes different doses of radiation delivered to the physical locations of the layer at different phases of the periodic cycle.

[0101]

[0101] In Example 7, the subject matter of Examples 4-6 further includes the set of parameters including beam energy, the beam energy reaching a predetermined depth within the target relative to the layer.

[0102]

[0102] In Example 8, the subject matter of Examples 4-7 includes wherein the set of parameters includes a spot size.

[0103]

[0103] In Example 9, the subject matter of Examples 4 to 8 includes the set of parameters including a plurality of beamlets, each beamlet having a different intensity, the intensity being a number of particles transmitted, and each beamlet having a specific coordinate position.

[0104]

[0104] In Example 10, the subject matter of Example 9 includes a first beamlet of the plurality of beamlets having a first intensity for the layer in a first phase of the periodic cycle, a second beamlet of the plurality of beamlets having a second intensity for the layer in a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets having a third intensity for the second layer in the first phase of the periodic cycle.

[0105]

[0105] In Example 11, the subject matter of Examples 4-10 includes, wherein the periodic cycle is a breathing cycle of a respiratory system.

[0106]

[0106] Example 12 is a method for delivering a particle beam to a target, the method comprising the steps of 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 over a range of gantry angles starting from the current patient state and including the current gantry angle.

[0107]

[0107] In Example 13, the subject matter of Example 12 includes repeating through multiple ranges of gantry angles at each patient state until the target receives its predetermined dose.

[0108]

[0108] In Example 14, the subject matter of Example 13 includes determining an estimate of an actual intended dose received by the target by reconstructing a dose delivered for each of a plurality of ranges of gantry angles.

[0109]

[0109] In Example 15, the subject matter of Example 14 includes determining the estimate using a weighted sum of doses delivered for each of a plurality of ranges of gantry angles.

[0110]

[0110] In Example 16, the subject matter of Examples 12 to 15 includes the current gantry angle being a central angle of the range of gantry angles.

[0111]

[0111] In Example 17, the subject matter of Examples 12 to 16 includes a step of determining a plurality of predefined spots within the target for the current gantry angle, wherein the plurality of predefined spots are arranged in a spiral pattern, and a step of ordering the plurality of predefined spots within the spiral pattern from closest to an isocentric axis of each gantry angle to furthest from the isocentric axis, and the step of delivering the radiation dose includes delivering a plurality of beamlets according to the spiral pattern of the plurality of predefined spots.

[0112]

[0112] In Example 18, the subject matter of Examples 12 to 17 includes the radiation dose including a plurality of beamlets, a first beamlet of the plurality of beamlets having a first intensity to the target at a first patient state of the periodic cycle, and a second beamlet of the plurality of beamlets having a second intensity to the target at a second patient state of the periodic cycle.

[0113]

[0113] 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 approximation of the respiratory phase, an amplitude, a deformation vector field (DVF), a low-dimensional representation of a DVF, a low-dimensional representation of an image acquired by an imaging device, surface information, and a target location.

[0114]

[0114] In Example 20, the subject matter of Examples 12-19 includes wherein the patient condition is a respiratory phase calculated from a respiratory cycle.

[0115]

[0115] Example 21 is a system for delivering a particle beam toward a target based on a periodic cycle, the system having one or more processors coupled to a memory device and a memory device containing instructions that, when executed by the one or more processors, cause the system to perform the following method, the method including the steps of determining a respiratory phase based on the periodic cycle; identifying a current gantry angle of the particle beam; dynamically selecting a spot pattern based on the respiratory phase and the current gantry angle; determining a set of beamlets based on the spot pattern; and causing the particle beam to continuously deliver the set of beamlets.

[0116]

[0116] In Example 22, the subject matter of Example 21 is such that the step of delivering the set of beamlets includes delivering the set of beamlets from a rotating gantry towards the target.

[0117]

[0117] In Example 23, the subject matter of Example 22 includes the instructions further causing the one or more processors to perform a step of determining a radiation dose based on a set of selected parameters for the current gantry angle, at least one parameter being an angle and a respiratory phrase.

[0118]

[0118] Example 24 is a system for delivering a particle beam based on a set of control points at a specific gantry angle toward a moving target, the system having one or more processors coupled to a memory device and a memory device containing instructions that, when executed by the one or more processors, cause the system to perform the following method, the method including the steps of identifying a layer of the target having a specific position within the target; tracking movement of the target in X, Y, and Z directions; identifying a physical position of the layer at a specific phase of a periodic cycle; selecting a set of parameters for delivering a predetermined radiation dose to the layer at the specific phase and the specific gantry angle; and using the set of parameters to deliver the predetermined radiation dose to the layer at the specific phase and the specific gantry angle.

[0119]

[0119] In Example 25, the subject matter of Example 24 includes the instructions further causing the one or more processors to perform a step of iterating through multiple target layers at each respiratory phase and gantry angle until each target layer receives a respective predetermined dose.

[0120]

[0120] In Example 26, the subject matter of Examples 24-25 includes different doses of radiation delivered to the physical locations of the layer during different phases of the periodic cycle.

[0121]

[0121] In Example 27, the subject matter of Examples 24-26 further includes the set of parameters including beam energy, the beam energy reaching a predetermined depth within the target relative to the layer.

[0122]

[0122] In Example 28, the subject matter of Examples 24 to 27 includes wherein the set of parameters includes a spot size.

[0123]

[0123] In Example 29, the subject matter of Examples 24 to 28 includes the set of parameters including a plurality of beamlets, each beamlet having a different intensity, the intensity being a number of particles transmitted, and each beamlet having a specific coordinate position.

[0124]

[0124] In Example 30, the subject matter of Example 29 includes a first beamlet of the plurality of beamlets having a first intensity for the layer in a first phase of the periodic cycle, a second beamlet of the plurality of beamlets having a second intensity for the layer in a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets having a third intensity for the second layer in the first phase of the periodic cycle.

[0125]

[0125] In Example 31, the subject matter of Examples 24-30 includes, wherein the periodic cycle is a breathing cycle of a respiratory system.

[0126]

[0126] Example 32 is a system for delivering a particle beam toward a target, the system having one or more processors coupled to a memory device and a memory device containing instructions that, when executed by the one or more processors, cause the system to perform the following method, the method comprising the steps of 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 over a range of gantry angles starting from the current patient state and including the current gantry angle.

[0127]

[0127] In Example 33, the subject matter of Example 32 includes the instructions further causing the one or more processors to perform the step of iterating through multiple ranges of gantry angles at each patient state until the target receives its predetermined dose.

[0128]

[0128] In Example 34, the subject matter of Example 33 includes the instructions further causing the one or more processors to perform a step of determining an estimate of the actual intended dose received by the target by reconstructing the dose delivered for each of a plurality of ranges of gantry angles.

[0129]

[0129] In Example 35, the subject matter of Example 34 includes the instructions further causing the one or more processors to perform a step of determining the estimate using a weighted sum of doses delivered for each of a plurality of ranges of gantry angles.

[0130]

[0130] In Example 36, the subject matter of Examples 32 to 35 includes the current gantry angle being a central angle of the range of gantry angles.

[0131]

[0131] In Example 37, the subject matter of Examples 32 to 36 is such that the instructions further cause the one or more processors to perform the steps of determining a plurality of predefined spots within the target for the current gantry angle, wherein the plurality of predefined spots are arranged in a spiral pattern, and ordering the plurality of predefined spots within the spiral pattern from closest to an isocentric axis of each gantry angle to furthest from the isocentric axis, and the step of delivering the radiation dose includes delivering a plurality of beamlets according to the spiral pattern of the plurality of predefined spots.

[0132]

[0132] In Example 38, the subject matter of Examples 32 to 37 includes the radiation dose including a plurality of beamlets, a first beamlet of the plurality of beamlets having a first intensity to the target at a first patient state of the periodic cycle, and a second beamlet of the plurality of beamlets having a second intensity to the target at a second patient state of the periodic cycle.

[0133]

[0133] In Example 39, the subject matter of Examples 32 to 38 includes the patient condition including at least one of a respiratory phase, an approximation of the respiratory phase, an amplitude, a deformation vector field (DVF), a low-dimensional representation of the DVF, a low-dimensional representation of an image acquired by an imaging device, surface information, and a target position.

[0134]

[0134] In Example 40, the subject matter of Examples 32-39 includes wherein the patient condition is a respiratory phase calculated from a respiratory cycle.

[0135]

[0135] Example 41 is a machine-readable medium including instructions for delivering a particle beam toward a target based on a periodic cycle, which, when executed by one or more processors, causes the one or more processors to perform operations including determining a respiratory phase based on the periodic cycle; identifying a current gantry angle of the particle beam; dynamically selecting a spot pattern based on the respiratory phase and the current gantry angle; determining a set of beamlets based on the spot pattern; and causing the particle beam to continuously deliver the set of beamlets.

[0136]

[0136] In Example 42, the subject matter of Example 41 is such that the step of delivering the set of beamlets includes delivering the set of beamlets from a rotating gantry toward the target.

[0137]

[0137] In Example 43, the subject matter of Example 42 includes the instructions further causing the one or more processors to perform a step of determining a radiation dose based on a set of selected parameters for the current gantry angle, at least one parameter being an angle and a respiratory phrase.

[0138]

[0138] Example 44 is a machine-readable medium containing instructions for delivering a particle beam based on a set of control points toward a moving target at a specific gantry angle, which instructions, when executed by one or more processors, cause the one or more processors to perform operations including identifying a layer of the target having a specific position within the target; tracking movement of the target in X, Y, and Z directions; identifying a physical position of the layer at a specific phase of a periodic cycle; selecting a set of parameters for delivering a predetermined radiation dose to the layer at the specific phase and specific gantry angle; and using the set of parameters to deliver the predetermined radiation dose to the layer at the specific phase and specific gantry angle.

[0139]

[0139] In Example 45, the subject matter of Example 44 includes the instructions further causing the one or more processors to perform a step of repeating on multiple target layers at each respiratory phase and gantry angle until each target layer receives a respective predetermined dose.

[0140]

[0140] In Example 46, the subject matter of Examples 44-45 includes different doses of radiation delivered to the physical locations of the layer at different phases of the periodic cycle.

[0141]

[0141] In Example 47, the subject matter of Examples 44-46 includes the set of parameters including beam energy, the beam energy reaching a predetermined depth within the target relative to the layer.

[0142]

[0142] In Example 48, the subject matter of Examples 44 to 47 includes wherein the set of parameters includes a spot size.

[0143]

[0143] In Example 49, the subject matter of Examples 44 to 48 includes the set of parameters including a plurality of beamlets, each beamlet having a different intensity, the intensity being a number of particles transmitted, and each beamlet having a specific coordinate position.

[0144]

[0144] In Example 50, the subject matter of Example 49 includes a first beamlet of the plurality of beamlets having a first intensity for the layer in a first phase of the periodic cycle, a second beamlet of the plurality of beamlets having a second intensity for the layer in a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets having a third intensity for the second layer in the first phase of the periodic cycle.

[0145]

[0145] In Example 51, the subject matter of Examples 44-50 includes, wherein the periodic cycle is a respiratory cycle of the respiratory system.

[0146]

[0146] Example 52 is a machine-readable medium containing instructions for delivering a particle beam toward a target, which, when executed by one or more processors, cause the one or more processors to perform operations including 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 over a range of gantry angles starting from the current patient state and including the current gantry angle.

[0147]

[0147] In Example 53, the subject matter of Example 52 includes the instructions further causing the one or more processors to perform a step of iterating through multiple ranges of gantry angles at each patient state until the target receives its predetermined dose.

[0148]

[0148] In example 54, the subject matter of example 53 includes the instructions further causing the one or more processors to perform a step of determining an estimate of the actual intended dose received by the target by reconstructing the dose delivered for each of a plurality of ranges of the gantry angle.

[0149]

[0149] In example 55, the subject matter of example 54 includes the instructions further causing the one or more processors to perform a step of determining the estimate using a weighted sum of doses delivered for each of a plurality of ranges of the gantry angle.

[0150]

[0150] In Example 56, the subject matter of Examples 52 to 55 includes the current gantry angle being a central angle of the range of gantry angles.

[0151]

[0151] In Example 57, the subject matter of Examples 52 to 56 is such that the instructions further cause the one or more processors to perform the steps of determining a plurality of predefined spots within the target for the current gantry angle, wherein the plurality of predefined spots are arranged in a spiral pattern, and ordering the plurality of predefined spots within the spiral pattern from closest to an isocentric axis of each gantry angle to furthest from the isocentric axis, and the step of delivering the radiation dose includes delivering a plurality of beamlets according to the spiral pattern of the plurality of predefined spots.

[0152]

[0152] In Example 58, the subject matter of Examples 52 to 57 includes the following: the radiation dose includes a plurality of beamlets, a first beamlet of the plurality of beamlets has a first intensity to the target at a first patient state of the periodic cycle, and a second beamlet of the plurality of beamlets has a second intensity to the target at a second patient state of the periodic cycle.

[0153]

[0153] In Example 59, the subject matter of Examples 52 to 58 includes the patient condition including at least one of a respiratory phase, an approximation of the respiratory phase, an amplitude, a deformation vector field (DVF), a low-dimensional representation of the DVF, a low-dimensional representation of an image acquired by an imaging device, surface information, and a target position.

[0154]

[0154] In Example 60, the subject matter of Examples 52-59 includes wherein the patient condition is a respiratory phase calculated from a respiratory cycle.

[0155]

[0155] Example 61 is at least one machine-readable medium comprising instructions that, when executed by a processing circuit, cause the processing circuit to perform operations to implement any of Examples 1 to 60.

[0156]

[0156] Example 62 is an apparatus having means for carrying out any one of Examples 1 to 60.

[0157]

[0157] Example 63 is a system that implements any of Examples 1 to 60.

[0158]

[0158] Example 64 is a method of carrying out any of Examples 1 to 60.

[0159]

[0159] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings are shown for purposes of illustration and show specific embodiments in which the present disclosure may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. Furthermore, the inventors also contemplate examples using any combination or permutation of those elements (or one or more aspects thereof) shown or described with respect to a particular example (or one or more aspects thereof), or with respect to any other example (or one or more aspects thereof) shown or described herein.

[0160]

[0160] In the event of a conflict in methodology between this specification and a document incorporated by reference, the methodology used in this specification will control.

[0161]

[0161] The terms "a" or "an" are used herein, as is common in patent documents, to include one or more elements, regardless of other instances or usages of "at least one" or "one or more." The term "or" is used herein to refer to a non-exclusive "or," such that "A or B" includes "A but not B," "B but not A," or "A and B," but unless otherwise stated, "A or B" also includes "A but not B," "B but not A," or "A and B." The terms "including" and "in which" are used herein as the plain-English equivalents of the terms "comprising" and "wherein," respectively. Also, in the following claims, the terms "including" and "comprising" are open-ended, i.e., systems, devices, articles, compositions, formulations, and processes that include an element in addition to the elements recited after such term in a claim are deemed to be within the scope of that claim. Moreover, in the following claims, the terms "first," "second," "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[0162]

[0162] Embodiments of the methods described herein may be implemented, at least in part, by a machine or computer. Some embodiments may include a computer-readable or machine-readable medium encoded with instructions operable to configure an electronic device to perform the methods described in the above embodiments. Implementations of such methods may include code, such as microcode, assembly language code, high-level language code, etc. Such code may include computer-readable instructions for performing various methods. This code may constitute part of a computer program product. Furthermore, in one embodiment, the code may be tangibly stored, during execution or at other times, on one or more volatile, non-transitory, or non-volatile tangible computer-readable media. Examples of these tangible computer-readable media include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks, digital video disks), magnetic cassettes, memory cards, memory sticks, random access memory (RAM), read-only memory (ROM), etc.

[0163]

[0163] The above description is illustrative, not limiting. For example, the above-described examples (or one or more aspects thereof) can be used in combination with each other. Those skilled in the art will be able to utilize other embodiments upon reviewing the above description. The Abstract is provided to comply with 37 CFR §1.72(b) to enable the reader to quickly grasp the nature of the technical disclosure. It is submitted with the understanding that it will not be used to limit the interpretation or meaning of the claims. Additionally, the above Detailed Description may group together various features to streamline the disclosure. This should not be construed as intending that any unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Accordingly, the following claims are incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as an independent embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. 1. A system for delivering a particle beam at a moving target at a specific gantry angle based on a set of control points, comprising: The system comprises: a rotatable gantry; a particle therapy system including a radiation therapy output mounted to the gantry and configured to provide a particle beam; an image capture device; one or more processors coupled to a memory device; a memory device containing instructions that, when executed by the one or more processors, cause the system to perform a method: The method comprises: Identifying a layer of the target having a particular location within the target; tracking X, Y, and Z movement of the target; Identifying the physical location of the layer at a particular phase of a periodic cycle; selecting a set of parameters for delivering a predetermined radiation dose to the layer at the particular phase and particular gantry angle; delivering the predetermined radiation dose to the layer at the particular phase and the particular gantry angle using the set of parameters; have A system characterized by:

2. 10. The system of claim 1, The instructions further cause the one or more processors to repeatedly deliver the particle beam at a plurality of target layers at each respiratory phase and gantry angle until each target layer receives a respective predetermined dose. A system characterized by:

3. 3. The system according to claim 1, wherein: The physical location of the layer receives different amounts of radiation during different phases of the periodic cycle. A system characterized by:

4. 4. The system according to claim 1, wherein: The set of parameters includes a beam energy, the beam energy reaching a predetermined depth within the target relative to the layer. A system characterized by:

5. 5. The system according to claim 1, wherein: The set of parameters includes a spot size A system characterized by:

6. 6. The system according to claim 1, The set of parameters includes a plurality of beamlets, each beamlet having a different intensity, the intensity being a number of particles transmitted, and each beamlet having a specific coordinate position. A system characterized by:

7. 7. The system of claim 6, a first beamlet of the plurality of beamlets having a first intensity for the layer in a first phase of the periodic cycle; a second beamlet of the plurality of beamlets having a second intensity for the layer during a second phase of the periodic cycle; a third beamlet of the plurality of beamlets having a third intensity for a second layer in the first phase of the periodic cycle; A system characterized by:

8. 8. The system according to claim 1, wherein: The periodic cycle is the respiratory cycle of the respiratory system. A system characterized by:

9. 1. A system for delivering a particle beam toward a target, comprising: The system comprises: a rotatable gantry; a particle therapy system including a radiation therapy output mounted to the gantry and configured to provide a particle beam; an image capture device; one or more processors coupled to a memory device; a memory device containing instructions that, when executed by the one or more processors, cause the system to perform a method: The method comprises: determining a current patient status for a patient; Identifying a current gantry angle; determining a radiation dose corresponding to the current patient condition and the current gantry angle; delivering the radiation dose to the target over a range of gantry angles starting from the current patient state and including the current gantry angle; and The patient state includes at least one of a respiratory phase, an approximation 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 by an imaging device, surface information, and a target location. A system characterized by:

10. 10. The system of claim 9, The instructions further cause the one or more processors to repeat delivery of the particle beam over a range of gantry angles for each patient state until the target receives the predetermined dose. A system characterized by:

11. 11. The system of claim 10, The instructions further cause the one or more processors to determine an estimate of the actual intended dose received by the target by reconstructing the delivered dose for each of a plurality of ranges of gantry angles. A system characterized by:

12. 12. The system of claim 11, The instructions further cause the one or more processors to determine the estimate using a weighted sum of the doses provided for each of a plurality of ranges of gantry angles. A system characterized by:

13. 13. The system according to any one of claims 9 to 12, The current gantry angle is the center angle of the range of the gantry angles. A system characterized by:

14. 14. The system according to any one of claims 9 to 13, The instructions cause the one or more processors to: For the current gantry angle, determining a plurality of predefined spots within the target, the plurality of predefined spots being arranged in a spiral pattern; ordering the plurality of predefined spots within the spiral pattern from closest to an isocentric axis of a respective gantry angle to furthest from the isocentric axis; Further, The step of delivering the radiation dose includes delivering a plurality of beamlets according to the spiral pattern of the plurality of predefined spots. A system characterized by:

15. 15. The system according to any one of claims 9 to 14, the radiation dose comprises a plurality of beamlets; A first beamlet of the plurality of beamlets has a first intensity on the target at a first patient state of the periodic cycle, and a second beamlet of the plurality of beamlets has a second intensity on the target at a second patient state of the periodic cycle. A system characterized by:

16. In the system according to any one of claims 9 to 15, The patient state is a respiratory phase calculated from a respiratory cycle. A system characterized by:

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