阅读说明：本技术 利用周期性运动提供质子放射治疗的方法 (Method for providing proton radiation therapy using periodic motion ) 是由 斯图尔特·朱利安·斯维尔德洛夫 于 2019-04-26 设计创作，主要内容包括：本文中描述了用于根据确定的患者状态从连续旋转的台架朝向靶给送粒子束的技术。可以使用确定的患者状态和台架的识别的台架角度来向靶给送一组子束(例如,辐射剂量的图案)。粒子束可以在台架角度的范围旋转。可以在台架旋转的同时连续地给送上述一组子束。(Techniques for delivering a particle beam from a continuously rotating gantry toward a target according to a determined patient state are described herein. A set of beamlets (e.g., a pattern of radiation doses) may be delivered to the target using the determined patient state and the identified gantry angle of the gantry. The beam can be rotated through a range of gantry angles. The set of beamlets may be fed continuously while the gantry is rotating.)

1. A method of feeding a particle beam toward a target based on a periodic cycle, the method comprising:

determining a respiratory phase based on the periodic cycle;

identifying a current gantry angle of the particle beam;

dynamically selecting a pattern of beam spots based on the respiratory phase and the current gantry angle; and

determining a set of beamlets based on the pattern of beam spots; and

the group of beamlets is fed continuously using the particle beam.

2. The method of claim 1, wherein feeding the set of beamlets further comprises feeding the set of beamlets from a rotating gantry toward the target.

3. The method of claim 2, further comprising determining 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 method of feeding a particle beam at a specific gantry angle towards a moving target, wherein the particle beam is fed based on a set of control points, the method comprising:

identifying a layer of the target having a particular location within the target;

tracking movement of the target in an x-direction, a y-direction, and a z-direction;

identifying a physical location of the layer during a particular phase of a 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; and

delivering the predetermined radiation dose to the layer during the particular phase and at the particular gantry angle using the set of parameters.

5. The method of claim 4, further comprising iteratively traversing the plurality of target slices at respective respiratory phases and gantry angles until each target slice receives its respective predetermined dose.

6. The method of claim 4, wherein a radiation dose to be delivered at the physical location of the layer is different during different phases of a periodic cycle.

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

8. The method of claim 4, wherein the set of parameters includes a beam spot size.

9. The method of 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 has a particular coordinate position.

10. The method of claim 9, wherein a first beamlet of the plurality of beamlets has a first intensity for the layer at a first phase of the periodic cycle, a second beamlet of the plurality of beamlets has a second intensity for the layer at a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets has a third intensity for the second layer at the first phase of the periodic cycle.

11. The method of claim 4, wherein the periodic cycle is a respiratory breathing cycle.

12. A method of feeding a particle beam toward a target, the method comprising:

determining a current patient state of the 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.

13. The method of claim 12, further comprising iteratively traversing a range of a plurality of gantry angles in respective patient states until the target receives its predetermined dose.

14. The method of claim 13, further comprising determining an estimate of an actual expected dose received by the target by reconstructing the dose given for each of the range of the plurality of gantry angles.

15. The method of claim 14, further comprising determining the estimate using a weighted sum of the dose given for each of the range of the plurality of gantry angles.

16. The method of claim 12, wherein the current gantry angle is a center angle of the range of gantry angles.

17. The method of claim 12, further comprising:

determining a plurality of predefined beam spots in the target for the current gantry angle, wherein the plurality of predefined beam spots are configured as 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 the respective gantry angle to a beam spot farthest from the concentric axis; and

wherein delivering the predetermined radiation dose comprises delivering a plurality of sub-beams according to the spiral pattern of the plurality of predefined beam spots.

18. The method of claim 12, wherein the radiation dose comprises a plurality of beamlets, and wherein a first beamlet of the plurality of beamlets has a first intensity for the target in a first patient state of the periodic cycle and a second beamlet of the plurality of beamlets has a second intensity for the target in a second patient state of the periodic cycle.

19. The method according to claim 12, 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 a DVF, a low-dimensional representation of an image acquired using an imaging device, surface information, or a target location.

20. The method of claim 12, wherein the patient state is a respiratory phase calculated from a respiratory cycle.

Background

Radiation therapy or "radiotherapy" can be used to treat cancer or other diseases in mammalian (e.g., human and animal) tissues. One such radiation therapy technique is known as "gamma knife," by which a patient is irradiated with a large number of low intensity gamma rays that converge at a target region (e.g., a tumor) with high intensity and high accuracy. In another example, radiation therapy is provided using a linear accelerator ("linac"), whereby a target area is irradiated with high-energy particles (e.g., electrons, high-energy photons, etc.). In another example, radiation therapy is provided using a heavy charged particle accelerator (e.g., protons, carbon ions, etc.). The arrangement and dose of the radiation beam is precisely controlled to provide a prescribed dose of radiation to the target volume. The radiation beam is also typically controlled to reduce or minimize damage to surrounding healthy tissue, which may be referred to as "organs at risk" (OAR), for example. Radiation may be referred to as "prescribed" because physicians typically prescribe a predetermined dose of radiation to a target region, such as a tumor.

Typically, ionizing radiation in the form of a collimated beam is directed from an external radiation source towards the patient. Modulation of the radiation beam may be provided by one or more attenuators or collimators, for example multi-leaf collimators. The intensity and shape of the radiation beam can be adjusted by collimation to avoid damaging healthy tissue (e.g., OAR) adjacent to the target tissue by conforming the projection beam to the contour of the target tissue.

The treatment planning process may include using three-dimensional images of the patient to identify a target region (e.g., a tumor) and, for example, identify key organs near the tumor. Creation of a treatment plan can be a time consuming process in which the planner attempts to adhere to various treatment targets or constraints (e.g., Dose Volume Histogram (DVH) targets or other constraints), for example, 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), as the complexity of the process increases as the number of OARs increases (e.g., approximately 13 OARs for head and neck treatment). OARs that are far from the tumor may be more easily protected from radiation, but OARs that are close to or overlap the target tumor may be more difficult to not withstand radiation exposure during treatment.

Typically, for each patient, an initial treatment plan may be generated in an "off-line" manner. The treatment plan may be developed substantially prior to delivery of the radiation treatment, for example, using one or more medical imaging techniques. The imaging information may 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 health care provider, such as a physician, may use three-dimensional imaging information indicative of the patient's anatomy to identify one or more target tumors and organs-at-risk in the vicinity of the tumors. The healthcare worker can delineate the target tumor to receive the prescribed radiation dose using manual techniques, and the healthcare worker can similarly delineate nearby tissues, such as organs, at risk of radiation therapy injury.

Alternatively or additionally, automated tools (e.g., provided by Elekta AB, sweden) may be used) To aid in identifying or delineating the target tumor and organs at risk. A treatment plan for the radiation therapy ("treatment plan") can then be created using optimization techniques based on the clinically and dosimetrically measured targets and constraints (e.g., the maximum, minimum, and average doses of radiation to the tumor and critical organs).

The treatment planning process may include using a three-dimensional image of the patient to identify a target region (e.g., a tumor) and to identify key organs near the tumor. Image acquisition may be performed before the start of the delivery of the prescribed radiation treatment fraction. Such imaging may provide information that helps to identify the location of the target volume or helps to identify the motion of the target volume. Such contemporaneous imaging may be genetically referred to as "real-time," but typically there is a delay or time delay between the acquisition of the image and the delivery of the radiation therapy.

The treatment plan may then be performed later by positioning the patient and delivering the prescribed radiation treatment. The radiation therapy treatment plan may include a dose "split" whereby a series of radiation therapy deliveries are provided over a predetermined period of time (e.g., 45 splits or some other split total), such as a specified split including the total prescribed dose per treatment delivery. During treatment, the patient position or target position relative to the treatment beam is important because such a localized portion determines in part whether the target or healthy tissue is being irradiated.

In one approach, radiation therapy may be provided by using particles, such as protons, instead of electrons. This may be generally referred to as proton therapy. One significant known advantage of proton therapy is: proton therapy provides superior dose distribution with a very small exit dose compared to other forms of radiation therapy, such as X-ray therapy. Due to the extremely small exit dose, the dose to Organs At Risk (OAR) is significantly reduced. Further advantages include lower doses per treatment, which reduces the risk of side effects and may improve the quality of life during and after proton treatment.

One approach to providing proton therapy is to use a broad proton beam, such as a broadened bragg peak that provides a uniform beam with multiple energies. If a patient is to be treated using rotational therapy, this may not be done using a wide beam. For example, a wide beam requires an ion beam compensator for each treatment region that is customized for each patient. This means that one compensator is required for each angle, and therefore multiple compensators must be used to treat the patient. For example, a different compensator must be used at least every 4 degrees. The treatment must be stopped and started with 90 different ion compensators to provide 360 degrees of rotational proton radiation treatment. 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.

Definition of

The beam spot is a location configured as the diameter of the sub-beam to be fed to that location.

The beamlets comprise a stream of particles of a nominal diameter fed at a predetermined rate to a starting point and to an end point.

The line segment is configured to feed a plurality of particles uniformly between the start position and the end position.

SUMMARY

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

This summary is intended to provide an overview of the subject matter of the present patent application. And are not intended to provide an exclusive or exhaustive description of the invention. The detailed description is included to provide further information about the present patent application.

Drawings

Fig. 1 generally illustrates an example of a system according to an embodiment, such as may include a particle therapy system controller.

Fig. 2 generally illustrates an example of a radiation therapy system, such as may include a particle therapy system and an imaging acquisition device, according to an embodiment.

Fig. 3 generally illustrates a particle therapy system according to an embodiment, which may include a radiation therapy output configured to provide a proton therapy beam.

Fig. 4 generally illustrates radiation dose depth of various types of particles in human tissue according to an embodiment.

Fig. 5 generally illustrates a broadened bragg peak according to an embodiment.

Fig. 6 generally shows a diagram of an actively scanned proton beam delivery system in accordance with an embodiment.

Fig. 7A-7B generally illustrate a spiral feed path on a grid in accordance with an embodiment.

FIG. 7C illustrates a spiral beam spot feed path with different beam spot sizes, in accordance with an embodiment.

Fig. 8 shows an example periodic phase of a patient according to an embodiment.

Fig. 9 shows a graph illustrating the selection of radiation dose as a function of breathing cycle and gantry angle.

FIG. 10A illustrates arc angle target location intensities and Bragg peaks for various angles according to an embodiment.

FIG. 10B shows a composite target location intensity according to an embodiment.

Fig. 11 to 13 show flowcharts illustrating a technique for feeding a particle beam towards a target based on a periodic cycle according to an embodiment.

In the drawings, which are not necessarily drawn to scale, like reference numerals may depict like parts in different views. Like reference numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, and not by way of limitation, various embodiments discussed in the present document.

Detailed Description

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

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

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

One challenge arises when the patient is moving: accurately tracking targets, OARs or other objects. Movement may be classified as periodic (e.g., breathing or heartbeat) or aperiodic. Periodic breathing presents unique problems when the target for treatment is affected by patient movement. A set of phases of a periodic cycle may be defined, for example 8 or 16 unique phases within the periodic cycle. Other sets of phases may be used, for example anywhere from 2 to 20. The phase may represent positions through a periodic cycle, which are repeated with each repetition of the cycle.

Using the phases of the periodic cycle, a radiation dose can be generated for treatment of the target at each of the phases. Treating a moving target may use phasing to ensure complete coverage of the target, but doing so may result in the dose reaching normal healthy tissue or any organs at risk. The non-rotating device typically has a fixed angle to feed the particles to the target. One way to ensure that the dose is delivered to the moving target is to pause the delivery of the beam (e.g., "gate" the beam) when the target is not near its nominal (typically "stationary" near the end of expiration or inspiration). Thus, only one phase of the cycle is targeted and the dose is applied only during that phase.

However, when using a non-rotating particle therapy device, multiple layers from a fixed angle are focused to cover the entire target. This may result in increased dose to healthy tissue, organs at risk or particularly the skin around the entry point. Thus, a rotating gantry may be used to avoid increased dose to skin or other tissue residing in the feed line between the beam emitter and the target. When a rotating gantry is used and rotational feed of particles is provided, it is often not possible to pause the feed of the beam without stopping the gantry rotation or within the angular range covered by the rotation. Solutions that rely on non-rotating gantries to stop the beam are not compatible with rotating gantries.

The systems and methods described herein deliver dose 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 current phase of the patient and the gantry angle (or range of gantry angles).

Instead of attempting to deliver all layers of the tumor from each angle, one or two layers passing through or before the middle of the target may be used. The layer may include a depth location within the target to be targeted. Multiple angles of feeding the particles to the target may be used, for example by continuously rotating the gantry. Because the target is in periodic cyclical motion, and possibly periodic motion with the periodic breathing of the patient, a dose can be delivered to the desired portion of the target using a set of parameters corresponding to a given breathing phase and angle of delivery of the particles.

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

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

Fig. 1 generally illustrates an example of a system 100 according to an embodiment, which may include, for example, a particle therapy system controller. 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 feed controller may include a beamlet module for determining or planning spot feed (e.g., using the spot feed module) or line feed (e.g., using the line feed module).

In an example, the beam spot feed module or beamlet module may be configured to plan the size of the beamlets, the position of the target or beam spot, and the like. The beamlet module may be used to determine the feeding order of the beamlets, for example in a spiral pattern as described herein. The delivery sequence module may be in communication with treatment planning software for planning delivery of the beamlets. For example, the treatment planning software may be used to determine or plan gantry angles, gantry velocities, beamlet sizes, spiral patterns (e.g., clockwise or counterclockwise), angular amplitudes of particular spiral patterns (e.g., every ten degrees of gantry rotation), and so forth.

The processor may implement the plan, for example, by communicating with a means for implementing the plan (e.g., with a control device or means such as those described below with reference to fig. 3) via a communication interface or otherwise. In an example, the communication interface may be used to retrieve stored information (e.g., patient information, historical surgical information about the patient or other patients, surgical instructions, information about a particular device or component, etc.) from a database or hospital database.

Fig. 2 generally illustrates an example of a radiation therapy system 200 that can include, for example, a particle therapy system and an imaging acquisition device, in accordance with an 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 respect to fig. 3. The particle therapy system includes a gantry and a platform, where the gantry can be mounted on, attached to, or stabilized relative to the platform. The platform may 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).

The particle therapy system may be in communication with a therapy control system, which may be used to control the actions of the particle therapy system. The therapy control system may communicate with the imaging acquisition device (e.g., to receive images obtained by the imaging acquisition device or an imaging database) or with the oncology information system. The oncology information system may provide treatment plan details to the treatment control system, e.g., received from the treatment planning system. The treatment control system may use the treatment plan to control the particle therapy system (e.g., activation gantry, ion source, accelerator, scanning magnet, particle beam, etc.). For example, the treatment control system may include beamlet intensity control, beamlet energy control, scanning magnet control, stage control, gantry control, and the like. In an example, beamlet intensity control and beamlet energy control may be used to activate a beamlet of a particular size or to target a particular location. Scanning magnetic control may be used to deliver the beamlets, for example, in a spiral pattern, according to a treatment plan. Gantry control or platform control can be used to rotate the gantry.

The treatment planning software may include components such as beamlet delivery and sequencing modules with individual control of, for example, beamlet sequencing for beam spots or line segments. The treatment planning software is described in more detail above with respect to FIG. 1. The treatment planning software may access an imaging database to retrieve images or store information. When the treatment plan is complete, the treatment planning software may send the plan to the oncology information system for communication with the treatment control system.

Fig. 3 illustrates an embodiment of a particle therapy system 300, the particle therapy system 300 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 kissing protrusion 313.

An ion source 301, such as a synchrotron (not shown), may be configured to provide a stream of particles (e.g., protons). The particle stream is transported to an implanter 303, which implanter 303 uses coulombic forces to provide initial acceleration of the charged particles. The particles are further accelerated by accelerator 305 to approximately 10% of the speed of light. The acceleration provides energy to the particle, which determines the depth the particle can travel within the tissue. An energy selector 307 (e.g., range scatter) may be used to select the energy of the protons to be delivered to the patient. In an embodiment referred to as passive scattering, the beam may be broadened to fit the tumor with an optional range modulator 308 (e.g., also referred to as a ridge filter or range modulation wheel). After the energy is selected, the proton stream can be delivered to the treatment room of the hospital's radiation therapy using a set of bending magnets 309. In addition, a scanning magnet 311 (e.g., an x-y magnet) is used to spread or track the proton beam to an accurate image of the tumor shape. The proton beam may be further shaped using the kisses 313 or components of the kisses 313 (e.g. collimating means). In various embodiments, the particle stream may be composed of carbon ions, mesons, or positively charged ions.

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

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

The photon beam (e.g., labeled as X-ray) is indicative of the initial accumulation due to electron scattering (e.g., the primary method of X-ray dosing tissue is by transfer of energy to electrons in the tissue). Followed by an exponential decay that continued beyond the distal edge of the target, which was at a depth of about 15cm in the figure. The X-ray beam has an incident (skin) dose setting that matches the incident (skin) dose of the proton beam. By normalizing (e.g., scaling) at a depth of 15cm, the dose induced 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 about 3 cm. If the X-ray data is renormalized to achieve a 100% dose at 15cm, the peak dose at a depth of about 3cm at the location of the undesired dose (e.g., before the target) will be about 240%. Thus, by x-ray, a significant amount of dose is delivered in front of the target and a significant amount of dose is delivered beyond the target.

The monoenergetic carbon beam shows a plateau region below the proton beam at the incident dose. The carbon beam has a sharp bragg peak that falls more steeply than the proton beam, but the carbon beam has a tail that exceeds the desired target by a few centimeters (e.g., referred to as a "spallation tail" where some of the carbon nuclei are fragmented into helium ions), with the tail having an additional dose of about 1.0% or less. Carbon ion beams have undesirable injection and skin doses compared to proton beams, but have non-negligible doses over target delivery.

Fig. 5 provides a graphical representation of a broadened bragg peak (SOBP). SOBP shows a relative depth dose curve of a set of proton beam combinations of different initial energies, each of which has some energy spread (e.g., variable absorption of energy in tissue). With the expected result of a uniform dose for a target of a particular thickness. As shown, the target is shown as having a proximal depth of about 10cm, a distal depth of about 13cm, and a target thickness of about 3 cm. Within the target, the dose was fairly uniform (with average normalization to 100%). The figure does not start at 0cm depth and also does not explicitly show the injected (skin) dose, but the injected region of the proton beam is characterized by a relatively flat depth dose profile. Typically, the injected (skin) dose will be about 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.

Figure 6 provides an illustration of a diagrammatic representation of a typical actively scanned proton beam delivery system. As shown, a single layer pencil beam scan is being delivered, in which a beam spot grid is delineated on the patient in conjunction with the contour of the cross-sectional area to which the particles are to be delivered. The incoming monoenergetic proton beamlets have a specified amount of monoenergetic proton beamlet energy absorbed by the range shifter (which is, for example, a range shifter plate in fig. 6), resulting in beamlets having the desired energy to achieve a bragg peak at a determined depth in the patient to treat a specified layer. A magnetic scanner having the ability to deflect particles in both 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 intensity of the proton beamlets in combination with the scan rate determines how much dose can be delivered to a particular area (e.g., a "beam spot" in fig. 6) within a particular amount of time (e.g., particles/unit area). In theory, the magnetic field strength can be adjusted independently of each other (to resemble Spin Master by Toronto, Canada^TMProviding a child's toy "Etch a"in a specific manner; where pencil beam intensity as a variable is not available in the child's toy). The most common scanning scheme is to scan quickly in one direction and more slowly in the vertical direction in a raster fashion, similar to earlier television control schemes (e.g., Cathode Ray Tubes (CRTs) using electrons instead of protons), but can scan arbitrary patterns (similar to the aforementioned toys). The delivery of different beam spots is achieved by increasing the scanning magnetic field strength and suppressing the pencil beam intensity between increments.

Fig. 7A-7B generally illustrate a spiral feed path on a grid in accordance with an embodiment. The spiral pattern shown in fig. 7A to 7B minimizes errors generated by the rotating gantry. The helical pattern shown improves target accuracy and reduces radiation outside the target as compared to a linear grating pattern when the gantry rotates.

The systems and methods described herein use proton arc therapy to optimize the radiation dose when delivering protons to certain beam spots. When delivered to certain beam spots, the difference in planned content from what is actually delivered using the helical pattern scanning described herein can be minimized. Unless a beam spot further from the isocenter is fed when the gantry is closest to the currently planned angle, the resulting actual beam spot position may be far from the intended beam spot position, and the overall trajectory of the beamlets will be significantly different from the intended trajectory. Using helical scanning can minimize errors in the actual beam spot position and minimize the difference between the intended and actual trajectories of the beamlets.

FIG. 7C illustrates a spiral beam spot feed path with different beam spot sizes, in accordance with an embodiment.

The trade-off between a small beam spot and a large beam spot is that only a small sub-beam needs to be delivered to the small beam spot for an excessive amount of time to deliver the radiation therapy. Therefore, to reduce time, it is preferable to feed small beamlets to the outer edge/outside of the tumor and larger beam spots to the inside of the tumor. Changing the beam spot size during feeding is a time consuming activity. By using the spiral feed pattern shown in fig. 7C, there may be as few as one beam spot size transition as going from a set of smaller beam spots at the outer edge of the treated tumor to a set of larger beam spots at the inner region of the treated tumor. Similarly, when going from a larger set of beam spots treating the inner region of the tumor to a smaller set of beam spots treating the outer edge of the tumor, there may be as few as one beam spot size transition, resulting in the entire beam changing through both beam spot sizes. In an example, the spiral pattern may be a two-dimensional spiral pattern as each layer of the target delivers a dose.

In an example, the beamlets may be fed at the edges of an arc range while spiraling in the center of the target. For example, in an arc from 0 degrees to 10 degrees, the target may be planned to be at rest at 5 degrees as if the gantry. In this example, the outside of the helix occurs as the gantry approaches and departs by 5 degrees, while the center of the helix occurs as the gantry departs by 0 degrees and as the gantry approaches by 10 degrees. For example, starting at 0 degrees, the helix may start at the center of the target and spiral outward until ending around 5 degrees (at the outward point of the helix). Then, in an example, the spiral may be reversed on the way back to the target center as the gantry moves from 5 to 10 degrees (e.g., from 0 to 5 degrees clockwise, then from 5 to 10 degrees counterclockwise, or vice versa). This process may be repeated on a different layer of the target at another arc, e.g., from 10 to 20 degrees, etc., until the dose is complete.

Fig. 8 shows an example periodic phase of a patient according to an embodiment. The periodic breathing cycle 800 is illustrated with 8 phases (but may include other numbers (e.g., 16 phases). 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 location, and so forth.

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

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

The periodic breathing cycle 800 is periodic and the phase or state may repeat over time. A plan for each phase or state of the cycle can be developed for delivering a therapeutic dose to a nearby or cycle-shift affected target. For example, as described herein, for each phase or state, a radiation dose or group of beamlets may be generated for a different gantry angle (e.g., every 10 degrees).

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

Fig. 9 shows a graph illustrating the selection of radiation dose as a function of breathing cycle and gantry angle. The selection of the radiation dose may include determining a current phase or state of the breathing cycle and identifying a current gantry angle. The radiation doses corresponding to these two variables may be stored in a database of the system, for example with radiation doses for each unique pair of phases and gantry angles. In an example, an approximate gantry angle (e.g., rounded to the nearest 1, 5, 10 degrees) may be used. The radiation dose can be specific to the target or layers of the target of the patient for both phase and gantry angle (or range). The specific dose may be sent to the controller to administer the dose using the gantry.

The dose may be administered by continuously rotating the gantry. The patient phase and gantry angle can change with gantry rotation, e.g., every angle or a range of angles, and other radiation doses can be used. In an example, the radiation dose is identified every 10 degrees of rotation. For example, the radiation dose may be used from 0 degrees to 10 degrees, where the plan is generated from 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 phase change (but this range always uses a gantry angle of 5 degrees). The radiation dose may be stored in a database, where a look-up of variables including phase and gantry angle is used for querying the corresponding gantry angle and patient state.

FIG. 10A illustrates arc angle target location intensities and Bragg peaks for various angles 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.

Increasing the number of angles at which multiple doses can be provided to a target tumor allows any given area of the body that is not the 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.

The rotating gantry can compensate for the increased dose at the target center by using techniques such as planning the spiral to "end" and restarting somewhere other than the target center on the plane. As shown in fig. 10A, different angles produce different penetration depths, and by ending the different penetration depths at not exactly the center of the target, overdosing of the patient can be avoided. Reducing the intensity of the beamlets along a line perpendicular to the isocenter and near the center along the direction of motion of the gantry may provide similar and more accurate compensation.

FIG. 10B shows a composite target location intensity 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.

Proton arc therapy using pencil beam scanning delivery provides the ability to deliver different energies, where the change in energy may occur in less than a second. Pencil beam scanning enables Intensity Modulated Proton Therapy (IMPT). The selection of energy is very important because it controls the depth of treatment of the radiation therapy. Particle therapy inherently stops at a specific depth for a specific energy. This allows the depth of treatment to enter the tissue region to be stratified. For each layer, the contour of the treatment may conform to a particular tissue region; allowing the profile to be tailored to the tumor variations layer by layer, which is ideal for irregularly shaped tumors near the organs at risk. When feeding from a rotating gantry, the time for feeding to different layers using multiple energies is limited. The choice of energy at a given angle is important because it controls the depth to which the majority of the dose is delivered into the tumor. The system is able to achieve the desired total dose to the tumor for each angle by judiciously selecting a very limited number of energies and in time. The system can ensure complete irradiation of the tumor by selecting the energy delivered from a given angle beyond the midline of the tumor. Of clinical significance is the total dose to the tumor from all angles.

Accumulation of the actual dose delivered is important for adaptive therapy. In an example, parameters are optimized to achieve a desired dose to the target and to minimize a difference between an actual dose to the target and a prescribed dose to the target. The difference may be due to motion, and the actual dose to normal tissue may be different from (e.g., greater than) the calculated dose. When there is a break in the delivered dose, it is important to know the actual dose distribution of the current course of treatment. At the time of the interruption of the treatment, the dose may be recalculated based on the amount of dose delivered prior to the interruption of the treatment session. In an example, the therapy session can be restarted after the interruption (e.g., by identifying a current respiratory phase and a current gantry angle) using the techniques described herein.

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

In the case of considering the respiratory phase, the delivered dose may be determined based on a set of parameters including the delivered dose corresponding to the paired respiratory phase and gantry angle. In an example, a set of gantry angles and respiratory phases can 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 fast approximation of the dose.

The respiratory phase dose reconstruction may be different from the non-rotational delivered dose reconstruction. For non-rotational feed, multiple layers are gathered to cover the entire target. For rotary feed, the layer may be just beyond the middle of the target or just one or two layers (e.g., one layer of each) just prior to the middle of the target. Thus, the layers shown in FIG. 10B show combinations of layers that are directed just beyond the middle of the target. Other examples may include layers directly preceding the middle of the target.

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 respiratory phases, treatment may result in a dose to normal tissue (and organs at risk) that is different from the dose of any one of the sets of parameters (for a given respiratory phase), nor a weighted sum of the doses for all respiratory phases. Accumulation of the actual dose delivered may be important for adaptive therapy, and the current course dose distribution may be important in the case of an interruption in delivery (e.g., continuing delivery from the point of view of the interruption in delivery or resuming at a later time or date, which may be more difficult without knowledge of the angle and phase and the delivered dose actually delivered).

In an example, the dose may be calculated based on the identified actual parameters in conjunction with the respiratory phase and using a subset of the 4D CT images for that respiratory phase. For example, a set of gantry angles and respiratory phases can be used to generate a fast approximation of the dose using actual parameters to review the dose calculations initially performed prior to treatment, and to sum the individual doses given a particular angle and respiratory phase combination. The total dose information may be used to modify the treatment plan or to further plan the treatment as the patient changes weight or the tumor shrinks (or grows).

Fig. 11 to 13 show flowcharts illustrating a technique for feeding a particle beam towards a target based on a periodic cycle according to an embodiment.

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

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. Technique 1100 includes an operation 1110 of determining a set of energies (e.g., beamlets) for a respiratory phase based on a pattern of beam spots.

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

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 differ based on the breathing phase, e.g. when (the equivalent of) the radiation path length is varied, while the beam spot patterns may remain substantially similar and have substantially similar intensities. Or the energy may remain the same while the beam spot pattern varies with intensity variations caused, for example, by lateral movement of the tumor relative to the central beam axis. The set of beamlets may include a change in energy or a change in beam spot pattern over time as it is fed to the target.

Fig. 12 illustrates a technique 1200 for feeding a particle beam toward a moving target at a particular gantry angle, where the particle beam is fed based on a set of control points. Technique 1200 includes an operation 1202 of identifying a layer of the target having a particular location within the target. In an example, the set of parameters includes a beam energy that travels for the layer to a predetermined depth in the target. In an example, the set of parameters includes a beam spot size.

In an example, the 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 particular coordinate position. The technique 1200 may also include wherein a first beamlet of the plurality of beamlets has a first intensity for the layer in the first phase of the periodic cycle, a second beamlet of the plurality of beamlets has a second intensity for the layer in the second phase of the periodic cycle, and a third beamlet of the plurality of beamlets has a third intensity for the second layer in the first phase of the periodic cycle.

Technique 1200 includes an operation 1204 that tracks movement of the target in the x-direction, the y-direction, and the z-direction. The technique 1200 includes an operation 1206 of identifying a physical location of a layer during a particular phase of a periodic cycle. In an example, the particular phase is a respiratory phase of a respiratory tract respiratory cycle.

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

The technique 1200 may include iteratively traversing the plurality of target slices at respective respiratory phases and gantry angles until each target slice has received its respective predetermined dose. The technique 1200 may include verifying the delivery of radiation dose to each of the designated target layers or to the target as a whole. Verifying the delivery of the radiation dose may include determining that the correct metrology setting (meterset) has been delivered. In another example, verifying the delivery may include determining an estimated amount of the actual expected dose received by the target as compared to the prescribed dose. External measurements (e.g., 4D CT scans) may be used to determine an estimate of the actual expected dose. The technique 1200 may include delivering different radiation doses at physical locations of the layer during different phases of the periodic cycle.

Fig. 13 shows a technique 1300 for delivering a particle beam toward a target based on a periodic cycle, 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 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 using an imaging device, surface information, a target location, and the like.

The technique 1300 includes an operation 1304 of identifying a current gantry angle.

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

The technique 1300 includes operation 1308: a radiation dose is delivered to the target, beginning at the current patient state and throughout a range of gantry angles that includes the current gantry angle. For example, the range of gantry angles can include a 10 degree range, where the center angle is the current gantry angle.

The technique 1300 may include iteratively traversing a range of multiple gantry angles at various patient states until the target has received its predetermined dose. In an example, the operations can include determining an estimated amount of actual expected dose received by the target by reconstructing a given dose for each of a range of a plurality of gantry angles. The method may also include determining an estimate using a weighted sum of the given dose for each of a range of the plurality of gantry angles.

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 as a spiral pattern. The method may include ordering a plurality of predefined beam spots in a spiral pattern in an order from a beam spot closest to a concentric axis for a respective gantry angle to a beam spot farthest from the concentric axis. Delivering the predetermined radiation dose may include delivering a plurality of sub-beams according to a spiral pattern of a plurality of predefined beam spots.

The technique 1300 may also include resuming the delivery of the predetermined radiation dose at the particular gantry angle when the delivery at the particular gantry angle is interrupted. The delivery may be restarted with a radiation dose corresponding to the particular gantry angle and the new current patient state.

The radiation dose described herein may include a plurality of sub-beams. The plurality of beamlets may include a first beamlet having a first intensity for the target in a first patient state of the periodic cycle and a second beamlet having a second intensity for the target in a second patient state of the periodic cycle. In an example, the patient state may be a respiratory phase calculated from a respiratory cycle.

Each of the non-limiting examples described in this document can exist independently, or can be combined in various permutations or with one or more of the other examples.

Example 1 is a method of feeding a particle beam toward a target based on a periodic cycle, the method comprising: determining a respiratory phase based on the periodic cycle; identifying a current gantry angle of the particle beam; dynamically selecting a pattern of beam spots based on a respiratory phase and a current gantry angle; and determining a set of beamlets based on the pattern of beam spots; and continuously feeding the set of beamlets using a particle beam.

In example 2, the subject matter of example 1 includes, wherein feeding the set of beamlets further comprises feeding the set of beamlets from a rotating gantry towards a target.

In example 3, the subject matter of example 2 includes: a radiation dose is determined based on a set of selected parameters for a current gantry angle, wherein at least one parameter is an angle and a respiratory phase.

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

In example 5, the subject matter of example 4 includes: the plurality of target slices are iteratively traversed at respective respiratory phases and gantry angles until each target slice has received its respective predetermined dose.

In example 6, the subject matter of examples 4 to 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.

In example 7, the subject matter of examples 4 to 6 includes wherein the set of parameters includes a beam energy that travels to a predefined depth for the layer in the target.

In example 8, the subject matter of examples 4 to 7 includes, wherein the set of parameters includes a beam spot size.

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 a number of particles fed and each beamlet has a particular coordinate position.

In example 10, the subject matter of example 9 includes wherein a first beamlet of the plurality of beamlets has a first intensity for the layer in a first phase of the periodic cycle, a second beamlet of the plurality of beamlets has a second intensity for the layer in a second phase of the periodic cycle, and a third beamlet of the second plurality of beamlets has a third intensity for the second layer in the first phase of the periodic cycle.

In example 11, the subject matter of examples 4 to 10 includes, wherein the periodic cycle is a respiratory tract breathing cycle.

Example 12 is a method of feeding a particle beam toward a target, the method comprising: determining a current patient state of the patient; identifying a current gantry angle; determining a radiation dose corresponding to a current patient state and a current gantry angle; and delivering a 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.

In example 13, the subject matter of example 12 includes iteratively traversing a range of a plurality of gantry angles at various patient states until the target receives its predetermined dose.

In example 14, the subject matter of example 13 includes determining an estimate of an actual expected dose received by the target by reconstructing the dose given for each of a range of a plurality of gantry angles.

In example 15, the subject matter of example 14 includes determining the estimate using a weighted sum of the dose given for each of a range of a plurality of gantry angles.

In example 16, the subject matter of examples 12 to 15 includes wherein the current gantry angle is a center angle of a range of gantry angles.

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

In example 18, the subject matter of examples 12-17 includes wherein the radiation dose includes a plurality of beamlets, and wherein a first beamlet of the plurality of beamlets has a first intensity for the target in a first patient state of the periodic cycle and a second beamlet of the plurality of beamlets has a second intensity for the target in a second patient state of the periodic cycle.

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 a DVF, a low dimensional representation of an image acquired using an imaging device, surface information, or a target location.

In example 20, the subject matter of examples 12 to 19 includes wherein the patient state is a respiratory phase calculated from a respiratory cycle.

Example 21 is 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 storage device, the storage device containing instructions that when executed by the one or more processors cause the system to: determining a respiratory phase based on the periodic cycle; identifying a current gantry angle of the particle beam; dynamically selecting a pattern of beam spots based on a respiratory phase and a current gantry angle; and determining a set of beamlets based on the pattern of beam spots; and causing the particle beam to continuously feed the set of beamlets.

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.

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 a current gantry angle, wherein the at least one parameter is an angle and a respiratory phase.

Example 24 is a system for feeding a particle beam at a particular gantry angle toward a moving target, wherein the particle beam is fed 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: identifying a layer of the target having a particular location within the target; tracking movement of the target in the x-direction, y-direction, and z-direction; identifying a physical location of the layer during a particular phase of the periodic cycle; selecting a set of parameters to deliver a predetermined radiation dose to the layer during a particular phase and at a particular gantry angle; and using the set of parameters to deliver a predetermined radiation dose to the layer during a particular phase and at a particular gantry angle.

In example 25, the subject matter of example 24 includes wherein the instructions further cause the one or more processors to iteratively traverse the plurality of target slices at respective respiratory phases and gantry angles until each target slice receives its respective predetermined dose.

In example 26, the subject matter of examples 24 to 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.

In example 27, the subject matter of examples 24 to 26 includes, wherein the set of parameters includes a beam energy traveling to a predetermined depth for the layer in the target.

In example 28, the subject matter of examples 24 to 27 includes, wherein the set of parameters includes a beam spot size.

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 a number of particles fed and each beamlet has a particular coordinate position.

In example 30, the subject matter of example 29 includes wherein a first beamlet of the plurality of beamlets has a first intensity for the layer in a first phase of the periodic cycle, a second beamlet of the plurality of beamlets has a second intensity for the layer in a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets has a third intensity for the second layer in the first phase of the periodic cycle.

In example 31, the subject matter of examples 24 to 30 includes, wherein the periodic cycle is a respiratory tract breathing cycle.

Example 32 is a system to feed 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: determining a current patient state of the patient; identifying a current gantry angle; determining a radiation dose corresponding to a current patient state and a current gantry angle; and delivering a 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.

In example 33, the subject matter of example 32 includes wherein the instructions further cause the one or more processors to iterate through a range of the plurality of gantry angles in the respective patient states until the target receives its predetermined dose.

In example 34, the subject matter of example 33 includes wherein the instructions further cause the one or more processors to determine an estimated amount of actual expected dose received by the target by reconstructing the dose given for each of a range of a plurality of gantry angles.

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 dose given for each gantry angle in the range of the plurality of gantry angles.

In example 36, the subject matter of examples 32 to 35 includes, wherein the current gantry angle is a center angle of a range of gantry angles.

In example 37, the subject matter of examples 32 to 36 includes 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 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 the concentric axis for the respective gantry angle to a beam spot farthest from the concentric axis; and wherein delivering the radiation dose comprises delivering the plurality of sub-beams according to a spiral pattern of a plurality of predefined beam spots.

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 for the target in a first patient state of the periodic cycle and a second beamlet of the plurality of beamlets has a second intensity for the target in a second patient state of the periodic cycle.

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 a DVF, a low-dimensional representation of an image acquired using an imaging device, surface information, or a target location.

In example 40, the subject matter of examples 32 to 39 includes wherein the patient state is a respiratory phase calculated from a respiratory cycle.

Example 41 is a machine-readable medium comprising instructions for feeding a particle beam toward a target based on a periodic cycle, the instructions, when executed by one or more processors, cause the one or more processors to: determining a respiratory phase based on the periodic cycle; identifying a current gantry angle of the particle beam; dynamically selecting a pattern of beam spots based on a respiratory phase and a current gantry angle; determining a set of beamlets based on the pattern of beam spots; and causing the particle beam to continuously feed the set of beamlets.

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.

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 a current gantry angle, wherein the at least one parameter is an angle and a respiratory phase.

Example 44 is a machine-readable medium comprising instructions for delivering a particle beam at a particular gantry angle toward a moving target, wherein the particle beam is delivered based on a set of control points, the instructions, when executed by one or more processors, cause the one or more processors to: identifying a layer of the target having a particular location within the target; tracking movement of the target in the x-direction, y-direction, and z-direction; identifying a physical location of the layer during a particular phase of the periodic cycle; selecting a set of parameters to deliver a predetermined radiation dose to the layer during a particular phase and at a particular gantry angle; and using the set of parameters to deliver a predetermined radiation dose to the layer during a particular phase and at a particular gantry angle.

In example 45, the subject matter of example 44 includes wherein the instructions further cause the one or more processors to iteratively traverse the plurality of target slices at respective respiratory phases and gantry angles until each target slice receives its respective predetermined dose.

In example 46, the subject matter of examples 44 to 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.

In example 47, the subject matter of examples 44-46 includes, wherein the set of parameters includes beam energy traveling to a predetermined depth for the layer in the target.

In example 48, the subject matter of examples 44-47 includes, wherein the set of parameters includes a beam spot size.

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 a number of particles fed and each beamlet has a particular coordinate location.

In example 50, the subject matter of example 49 includes wherein a first beamlet of the plurality of beamlets has a first intensity for the layer in a first phase of the periodic cycle, a second beamlet of the plurality of beamlets has a second intensity for the layer in a second phase of the periodic cycle, and a third beamlet of the plurality of beamlets has a third intensity for the second layer in the first phase of the periodic cycle.

In example 51, the subject matter of examples 44-50 includes, wherein the periodic cycle is a respiratory tract breathing cycle.

Example 52 is a machine-readable medium comprising instructions for delivering a particle beam toward a target, the instructions, when executed by one or more processors, cause the one or more processors to: determining a current patient state of the patient; identifying a current gantry angle; determining a radiation dose corresponding to a current patient state and a current gantry angle; and delivering a 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.

In example 53, the subject matter of example 52 includes wherein the instructions further cause the one or more processors to iterate through a range of the plurality of gantry angles in the respective patient states until the target receives its predetermined dose.

In example 54, the subject matter of example 53 includes wherein the instructions further cause the one or more processors to determine an estimated amount of actual expected dose received by the target by reconstructing the dose given for each of a range of a plurality of gantry angles.

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 dose given for each gantry angle in the range of the plurality of gantry angles.

In example 56, the subject matter of examples 52 to 55 includes wherein the current gantry angle is a center angle of a range of gantry angles.

In example 57, the subject matter of examples 52 to 56 includes 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 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 the concentric axis for the respective gantry angle to a beam spot farthest from the concentric axis; and wherein delivering the radiation dose comprises delivering the plurality of sub-beams according to a spiral pattern of a plurality of predefined beam spots.

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 for the target in a first patient state of the periodic cycle and a second beamlet of the plurality of beamlets has a second intensity for the target in a second patient state of the periodic cycle.

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 a DVF, a low dimensional representation of an image acquired using an imaging device, surface information, or a target location.

In example 60, the subject matter of examples 52 to 59 includes wherein the patient state is a respiratory phase calculated from a respiratory cycle.

Example 61 is at least one machine readable medium comprising instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement any of examples 1 to 60.

Example 62 is an apparatus comprising means for implementing any of examples 1 to 60.

Example 63 is a system to implement any of examples 1 to 60.

Example 64 is a method to implement any of examples 1 to 60.

The foregoing detailed description includes references to the accompanying drawings, which form a part hereof. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples. Such examples may include elements other than those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof) with respect to a particular example (or one or more aspects thereof) or with respect to other examples (or one or more aspects thereof) shown or described herein.

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

As is common in patent documents, in this document, the terms "a" or "an" are used to include one or more than one, independently of any other instances or usages of "at least one" or "one or more". In this document, unless otherwise indicated, the term "or" is used to indicate nonexclusivity, such 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 respective terms "comprising" and "in which". Furthermore, in the following claims, the terms "comprising" and "including" are open-ended, that is, a system, apparatus, article, composition, formulation, or process that includes an element other than the elements in the claims that follow such term is considered to be within the scope of the claims. Furthermore, in the appended claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

The method examples described herein may be machine or computer-implemented at least in part. Some examples may include a computer-readable or machine-readable medium encoded with instructions operable to configure an electronic device to perform a method as described in the above examples. Implementations of such methods may include code, such as microcode, assembly language code, higher level language code, and the like. Such code may include computer readable instructions for performing various methods. The code may form part of a computer program product. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, e.g., during execution or at other times. Examples of such tangible computer-readable media may include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic tapes, memory cards or sticks, Random Access Memories (RAMs), Read Only Memories (ROMs), and the like.

The above description is intended to be illustrative and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used, for example, by one of ordinary skill in the art after reviewing the above description. The abstract is provided to comply with 37c.f.r. § 1.72(b), to enable the reader to quickly ascertain the nature of the technical disclosure. The summary is submitted with the following understanding: the abstract is not intended to interpret or limit the scope or meaning of the claims. Moreover, in the foregoing detailed description, various features may be grouped together to streamline the disclosure. This should not be interpreted as implying that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that these embodiments may 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.