Radiation treatment protocol optimization method and apparatus

Abstract

Embodiments of the present disclosure relate to radiation treatment plan optimization methods and apparatus. When optimizing a radiation treatment plan for a particular patient using a particular radiation treatment apparatus, and particularly when the optimization method includes direct aperture optimization, by one method, a control circuit can determine whether to apply field-specific asymmetry according to at least a first criterion, and upon determining to apply field-specific asymmetry, apply the field-specific asymmetry in establishing the multi-leaf collimator apertures with respect to the target projections.

Description

Technical Field

[0001] These teachings typically involve processing a patient's planned target volume with energy according to an energy-based treatment protocol, and in particular, optimizing the energy-based treatment protocol. Background Technology

[0002] The use of energy to treat disease encompasses the known areas of current technological efforts. For example, radiation therapy is a crucial component of many treatment protocols aimed at reducing or eliminating unwanted tumors. Unfortunately, the applied energy does not inherently distinguish between unwanted material and adjacent tissues, organs, etc., which are desired for, and even essential to, the patient's continued survival. Therefore, energy, such as radiation, is typically applied cautiously, with an attempt to at least confine the energy to a given target volume. So-called radiation treatment protocols are commonly used in the aforementioned areas.

[0003] Radiation treatment protocols typically include specified values ​​for each of a variety of treatment platform parameters during each of multiple consecutive radiation fields. Treatment protocols for radiation therapy are often automatically generated through a process known as optimization. As used herein, "optimization" will be understood as improving candidate treatment protocols, but it is not necessarily guaranteed that the optimized result is actually the only optimal solution. Such optimization typically involves automatically adjusting one or more physical treatment parameters (usually while simultaneously adhering to one or more corresponding constraints in these aspects), and mathematically calculating possible corresponding treatment outcomes (such as dose levels) to identify a given set of treatment parameters that represent a good trade-off between the expected therapeutic outcome and the avoidance of adverse side effects.

[0004] Direct aperture optimization is one method to achieve this optimization. It integrates the optimization of flux intensity and blade position in a multi-leaf collimator into a single iterative process. This method allows the physical parameters of radiation delivery to be directly customized to the desired dose distribution. Summary of the Invention

[0005] One aspect of the invention relates to a method for optimizing a radiation treatment regimen for a specific patient, the radiation treatment regimen using a specific radiation treatment apparatus, the method comprising, via control circuitry: determining whether to apply a field-specific asymmetry based on at least a first criterion; and, after determining that a field-specific asymmetry should be applied, applying the field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection.

[0006] Another aspect of the invention relates to an apparatus for optimizing a radiation treatment regimen for a specific patient, the radiation treatment regimen using a specific radiation treatment apparatus, the apparatus including control circuitry configured to: determine whether to apply a field-specific asymmetry based on at least a first criterion; and, after determining that a field-specific asymmetry should be applied, apply the field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection.

[0007] Another aspect of the invention relates to a non-transitory computer-readable medium for use in optimizing a radiation treatment regimen for a specific patient, the radiation treatment regimen using a specific radiation treatment apparatus, the non-transitory computer-readable medium storing instructions that, when executed on a processor, perform the following steps: determining whether to apply a field-specific asymmetry according to at least a first criterion; and, after determining that a field-specific asymmetry should be applied, applying the field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection. Attached Figure Description

[0008] The radiation treatment scheme optimization method and apparatus, which provide the following specific embodiments, can at least partially meet various needs, especially when studied in conjunction with the accompanying drawings, wherein:

[0009] Figure 1 Including block diagrams configured according to various embodiments of these teachings;

[0010] Figure 2 This includes flowcharts configured according to various embodiments of these teachings;

[0011] Figure 3 This includes schematic representations configured according to various embodiments of these teachings;

[0012] Figure 4 This includes schematic representations configured according to various embodiments of these teachings;

[0013] Figure 5 This includes schematic representations configured according to various embodiments of these teachings;

[0014] Figure 6 This includes decision trees configured according to various embodiments of these teachings; and

[0015] Figure 7 This includes diagrams configured according to various embodiments of the present invention.

[0016] The elements in the accompanying drawings are illustrated for simplicity and clarity only and are not drawn to scale. For example, the size and / or relative positioning of some elements in the drawings may be exaggerated relative to other elements to aid in understanding the various embodiments of this teaching. Furthermore, common but well-understood elements that are useful or necessary in commercially viable embodiments are not typically depicted to facilitate less obstructed observation of these different embodiments of this teaching. Certain actions and / or steps may be described or depicted in a particular order, but those skilled in the art will understand that such specificity regarding the order is not actually necessary. Unless otherwise specified herein, the terms and expressions used herein have the ordinary technical meaning that those skilled in the art would typically assign to such terms and expressions. Unless otherwise expressly stated, the word "or" as used herein should be interpreted as having a disjunctive relationship rather than a parallel relationship. Detailed Implementation

[0017] Generally, these different embodiments can be employed when optimizing a radiation treatment protocol using a specific radiation treatment device for a particular patient, especially when the optimization method includes direct aperture optimization. One method allows control circuitry to determine whether to apply field-specific asymmetry based on at least a first criterion, and when it is determined that field-specific asymmetry should be applied, to apply it when establishing the multi-leaf collimator aperture relative to the target projection.

[0018] These teachings will support the aforementioned determination based on at least two criteria. As an illustrative example, this determination can be made based on a first criterion that includes the arc length and a second criterion that includes the angle of the multi-leaf collimator.

[0019] One method for determining the aforementioned determination may include: determining the application of field-specific asymmetry when the arc length of the radiation processing device exceeds 180 degrees, the plane angle of the multi-leaf collimator is less than 30 degrees, and the corresponding field aperture size completely surrounds the target volume rather than just a segmented field surrounding a portion of the target volume.

[0020] The aforementioned determination may include, in place of or in combination with the methods described above, determining whether to apply field-specific asymmetry, at least in part, based on whether the radiation processing scheme corresponds to a dual-field processing arrangement. If necessary, this determination may further include determining whether to apply field-specific asymmetry, also based on whether the corresponding field aperture size completely surrounds the target volume rather than merely surrounds a segmented field of the target volume.

[0021] By means of a method, when establishing an initial multi-leaf collimator aperture relative to a target projection, the aforementioned application of field-specific asymmetry may include modifying the original aperture adapted to the complete target projection by reducing the corresponding original aperture opening width by a modulation factor, and then offsetting the reduced aperture opening into the original target aperture. Alternatively, or in combination with the above method, the aforementioned application of field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection may include applying field-specific asymmetry on a field-by-field basis when establishing the multi-leaf collimator aperture relative to the target projection.

[0022] In one method, these teachings may include a non-transitory computer-readable medium having a computer program that itself includes instructions that, when executed by a computer, cause the computer to perform one or more of the operations, steps, or functions described herein, including determining whether to apply field-specific asymmetry according to at least a first criterion, and, after determining that field-specific asymmetry should be applied, applying field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection.

[0023] With this configuration, these teachings can be used, for example, to reduce manual adjustment work, avoid suboptimal solutions, and improve the modulation capability of multi-arc schemes.

[0024] These and other advantages become clearer through a comprehensive review and study of the following detailed description. See now the accompanying drawings, especially... Figure 1 First, an illustrative device 100 compatible with many of the teachings in these teachings will be presented.

[0025] In this particular example, the enabling device 100 includes a control circuit 101. As a “circuit”, the control circuit 101 therefore includes a structure comprising at least one (typically multiple) conductive paths (such as paths made of conductive metals such as copper or silver) that deliver power in an orderly manner, and the (multiple) paths typically also include corresponding electronic components (including passive (such as resistors and capacitors) and active (such as any of a variety of semiconductor devices)) to allow the circuit to implement the control aspects of these teachings.

[0026] Such control circuitry 101 may include a fixed-purpose hardwired hardware platform (including, but not limited to, application-specific integrated circuits (ASICs), which are integrated circuits designed for a specific purpose rather than a general purpose, field-programmable gate arrays (FPGAs), etc.), or may include a partially or fully programmable hardware platform (including, but not limited to, microcontrollers, microprocessors, etc.). These architectural options for such a configuration are well known in the art and need not be described further herein. This control circuitry 101 is configured (e.g., by using corresponding programming known to those skilled in the art) to perform one or more of the steps, actions, and / or functions described herein.

[0027] It should be understood that the control circuit 101 may include a single integrated platform, or may include multiple such circuits that cooperate with each other.

[0028] Control circuitry 101 is operatively coupled to memory 102. Memory 102 may be integrated into control circuitry 101 or physically ( wholly or partially) separated from control circuitry 101 as needed. Memory 102 may be located in the same location as control circuitry 101 (e.g., in this case, both share a circuit board, chassis, power supply, and / or enclosure), or it may be located partially or entirely remotely relative to control circuitry 101 (e.g., in this case, memory 102 is physically located in another facility, metropolitan area, or even country relative to control circuitry 101). Similar to control circuitry 101, memory 102 may comprise a monolithic structure or may comprise multiple memory platforms that collectively constitute the “memory” of this device 100.

[0029] In addition to information such as optimization information for a specific patient and information about a specific radiation processing platform, this memory 102 can also be used, for example, to non-transitory store computer instructions that, when executed by control circuitry 101, cause control circuitry 101 to behave as described herein. (As used herein, "non-transitory" will be understood to mean the non-transitory state of the stored content (and therefore does not include cases where the stored content merely constitutes a signal or wave), rather than the volatility of the storage medium itself, and therefore includes both non-volatile memory (such as read-only memory (ROM)) and volatile memory (such as dynamic random access memory (DRAM)).

[0030] Alternatively, control circuitry 101 may also be operatively coupled to user interface 103. User interface 103 may include any of a variety of user input mechanisms (such as, but not limited to, keyboards and keypads, cursor control devices, touch-sensitive displays, voice recognition interfaces, gesture recognition interfaces, etc.) and / or user output mechanisms (such as, but not limited to, visual displays, audio transducers, printers, etc.) to facilitate the receipt of information and / or instructions from the user, and / or to facilitate the provision of information to the user.

[0031] If needed, the control circuitry 101 can also be operatively coupled to a network interface (not shown). With this configuration, the control circuitry 101 can communicate with other components (including components inside and outside the device 100) via the network interface. Network interfaces (including wireless and non-wireless platforms) are well known in the art and will not be described further here.

[0032] By means of a method, computed tomography apparatus 106 and / or other imaging apparatus 107 known in the art can provide some or all of the desired patient-related imaging information.

[0033] In this illustrative example, control circuitry 101 is configured to ultimately output an optimized energy-based processing scheme (e.g., such as an optimized radiation processing scheme 113). Such an energy-based processing scheme typically includes specified values ​​for each of a variety of processing platform parameters during each of multiple consecutive radiation fields. In this case, the energy-based processing scheme is generated through an optimization process, examples of which will be provided further below.

[0034] In one method, control circuitry 101 can be operatively coupled to an energy-based processing platform 114, which is configured to, according to an optimized energy processing scheme 113, deliver energy to a processing volume 105 and one or more organs at risk (in... Figure 1 Therapeutic energy 112 is delivered to the corresponding patient 104 (represented by organs at risk 108 and 109, from the first to the Nth) in the process. These teachings are generally applicable to any of a wide variety of energy-based processing platforms / devices. In a typical application setting, the energy-based processing platform 114 will include an energy source, such as a radiation source 115 of ionizing radiation 116.

[0035] A method allows for the selective movement of the radiation source 115 along an arc-shaped pathway (wherein the pathway at least partially surrounds the patient during treatment administration) via a gantry. This arc-shaped pathway can be configured to form a complete or near-complete circle as needed. A method allows control circuitry 101 to control the movement of the radiation source 115 along the arc-shaped pathway, and correspondingly control when the radiation source 115 begins to move, stops moving, accelerates, decelerates, and / or the speed at which the radiation source 115 travels along the arc-shaped pathway.

[0036] As an illustrative example, radiation source 115 may include, for example, an X-ray source based on a radio frequency (RF) linear particle accelerator (a linear accelerator). A linear accelerator is a particle accelerator that greatly increases the kinetic energy of charged subatomic particles or ions by subjecting charged particles to a series of oscillating potentials along a linear beamline. This can be used to generate ionizing radiation (e.g., X-rays) 116 and high-energy electrons.

[0037] A typical energy-based treatment platform 114 may also include one or more support devices 110 (such as a treatment table) to support the patient 104 during treatment; one or more patient fixation devices 111; a gantry or other movable mechanism to allow selective movement of the radiation source 115; and one or more energy shaping devices (e.g., beamforming devices 117, such as secondary collimators, multi-leaf collimators, etc.) to provide selective energy shaping and / or energy modulation as needed.

[0038] In a typical application setting, this document assumes that the patient support device 110 can be selectively moved in any direction (i.e., any X, Y, or Z direction) during an energy-based treatment session via control circuitry 101. Since the foregoing elements and systems are well understood in the art, further elaboration of these aspects is not provided herein unless relevant to this description.

[0039] See now Figure 2 The process 200 will be described, which can be executed, for example, in conjunction with the application setup described above (more specifically via the aforementioned control circuitry 101). Generally, this process 200 can be used to facilitate the generation of an optimized radiation treatment scheme 113, thereby facilitating the treatment of a specific patient 104 with therapeutic radiation 112 using a specific radiation treatment platform 114 according to the optimized radiation treatment scheme 113.

[0040] In this illustrative example, the term process 200 can be used when optimizing a radiation treatment regimen for a specific patient 104 using a specific radiation treatment device 114.

[0041] At box 201, control circuitry 101 determines whether to apply a specific field asymmetry based on at least a first criterion. A "field" refers to a specific area or volume on the patient's body that is targeted and exposed to a controlled dose of radiation. Typically, a field is defined by spatial coordinates and geometric parameters that delineate the area to be treated, including the size, shape, and angle of the incident radiation beam. Fields can be shaped using various methods, such as multi-leaf collimators, custom baffles, or other beam-shaping devices. Many radiation treatment protocols offer multiple fields to accommodate different angles at which the radiation beam is aimed at the target volume.

[0042] As used in this article, "field-specific asymmetry" will be understood as a lateral offset of the beamforming aperture relative to the target volume projection.

[0043] These teachings will support a wide variety of criteria that will be applied in the foregoing aspects. For example, one approach is that the first criterion could be arc length. Another example is that the first criterion could include the angle of a multi-leaf collimator.

[0044] These teachings will also support determining whether to apply field-specific asymmetry based on at least the first and second criteria (e.g., arc length and multi-leaf collimator angles mentioned above).

[0045] As an illustrative example of the aforementioned determination, determining whether to apply field-specific asymmetry according to at least the first criterion may include: determining to apply field-specific asymmetry when the arc length of the radiation processing device exceeds 180°, the plane angle of the multi-leaf collimator is less than 30°, and the corresponding field aperture size completely surrounds the target volume rather than just a segmented field surrounding a portion of the target volume.

[0046] As another illustrative example in this regard, determining whether to apply field-specific asymmetry based on at least a first criterion may include: determining whether to apply field-specific asymmetry based at least in part on whether the radiation processing scheme corresponds to a dual-field processing arrangement. Alternatively, the foregoing may include: further determining whether to apply field-specific asymmetry based on whether the corresponding field aperture size completely surrounds the target volume rather than merely surrounds a segmented field of the target volume.

[0047] At block 204, after determining to apply field-specific asymmetry, control circuit 101 can apply field-specific asymmetry when establishing the multi-leaf collimator aperture relative to the target projection. For example, control circuit 101 can modify the original aperture adapted to the complete target projection by reducing the corresponding original aperture opening width by a modulation factor, and then offsetting the reduced aperture opening inside the original target aperture. In one method, control circuit 101 can apply field-specific asymmetry on a field-by-field basis when establishing the multi-leaf collimator aperture relative to the target projection.

[0048] If necessary, these teachings will support the use of the resulting optimized radiation treatment protocols to administer therapeutic radiation to specific patients using specific radiation treatment devices.

[0049] More details consistent with these teachings will now be presented. It should be understood that the specific details in these examples are intended to be illustrative and not to suggest any particular limitations on these teachings.

[0050] In typical existing direct aperture optimization methods, establishing the processing field and its aperture (including collimator angles and the rectangular field size defined by the positions of secondary collimators X1, X2, Y1, Y2 (and / or multi-collimator aperture dimensions)) usually requires user expertise to achieve good final solution quality. Achieving useful results can become even more difficult when the target volume exceeds the maximum available blade modulation range of a single field.

[0051] In many typical existing direct aperture optimization methods, blade aperture optimization is often based solely on independent two-dimensional target injection maps. In particular, this optimization occurs without using information about the number of arc fields, their gantry rotation range, and / or collimator angles. For single-field or multi-field arc settings, the corresponding results may not be optimal. Therefore, iterative fine-tuning of the field aperture in each arc field setting may be necessary to improve protocol quality for a given patient model geometry.

[0052] This invention provides a method for creating an initial blade configuration for each firing field to iteratively optimize direct aperture. The initial blade aperture configuration for each firing field can be created such that it depends on the overall arc firing field setup. This method can be based on defining a field-of-view specific asymmetry in the X (blade) direction when locating / guiding the initial blade aperture relative to the target projection. The aperture adapted to the full target projection (referred to herein as the target-adapted aperture) can be modified by first reducing the aperture opening width by the desired modulation factor and then offsetting the result to the interior of the target-adapted aperture.

[0053] Figures 3-5The illustration shows an example of asymmetric blade aperture initialization in the aforementioned dual-field scenario. Figure 3 The illustration shows the patient treatment volume 105, which appears on either side of the organ at risk 108 in this field of view. Figure 4 The field 1, initialized to the right of the target volume 105 projection, is presented, while Figure 5 The field 2, initialized to the left of the target volume 105 projection, is presented.

[0054] One method allows the target projection to be confined within a given aperture for each radiation field. During the direct aperture optimization iteration, the blades can be moved to any position within the aperture. The relative initial blade aperture positions can be defined for each radiation field and applied equally to all control points within that field. (Control points are specific locations or angles at which the radiation beam is turned on or off during processing. Control points are typically used to aid in beam shaping and to optimize dose distribution to target the tumor while protecting surrounding healthy tissue.)

[0055] Figure 6 The diagram illustrates a method for finding relevant asymmetries via a decision tree 600.

[0056] At box 601, a determination is made as to whether the scheme presents a dual-field design. A scheme can be identified as a dual-field design when it comprises a pair of arcs that share a common arc span, treatment table angle, isocenter, and similar field apertures (defined by the collimator angle and the X1, X2, Y1, Y2 rectangles). In this case, their blade apertures can be initialized to the left (first arc) and right (second arc). Accordingly, the multi-leaf collimator blades align their movement directions in both fields and allow the same X-range of movement, differing only in their initial blade positions.

[0057] When the aforementioned is true, at box 602, a determination is made regarding whether the field aperture is full-size (and therefore not a segmented field). This determination essentially quantifies the situation if the field aperture in a dual-field setup already has left and right segmentation. Any additional left and right blade positioning can only be applied as needed via box 603 using asymmetric initialization, where the aperture can be biased toward either side of the corresponding target projection (and typically both sides are used simultaneously in a dual-field scenario).

[0058] When the dual-field determination at box 601 yields a false result, the applicant has determined that, for arcs outside the dual-field, asymmetrically positioned blade apertures can serve as a good starting point for iterative direct aperture optimization, thereby producing high target dose homogeneity in bilateral cases and avoiding critical organs or normal tissues that may be present at the isocenter. However, for the asymmetric aperture to function as intended in this setting, the arc should be long (e.g., at least half an arc or longer) and the collimator angle should be small so that the beam can sweep across the entire target volume during gantry rotation. (In this application setting, "small" can, for example, mean an angle less than 10 degrees, less than 20 degrees, less than 30 degrees, less than 40 degrees, or any value within that range as needed.) The "Is the arc long?" decision box 604 and the "Is the collimator angle small?" decision box 605 in decision tree 600 check these conditions. When these conditions are not met, the blade can be initialized as the center of the target projection (multiple) as shown in box 606. Arc length and collimator angle can also be continuously quantized and normalized to the range [0, 1], and asymmetric quantities can be used as continuous functions of arc length and collimator angle if needed.

[0059] When the aforementioned determination establishes a dual-field situation, or when the arc is very long and the collimator angle is very small, as described above in box 602, it can be determined whether the field aperture is full-size (and not a segmented field). If the result is not true, center initialization can be performed at box 606. If the result is true, asymmetric initialization can be performed at box 603.

[0060] If needed, these teachings will also support adjusting blade positioning asymmetry based on the average X-symmetry of the target-fit blade aperture. The higher the X-symmetry of the target-fit blade aperture, the greater the blade positioning asymmetry will be to offset this symmetry. If the target-fit blade aperture is already sufficiently asymmetric, for example, if the field aperture cuts off one side of the target volume, then adding additional asymmetry through blade positioning may be less necessary or unnecessary.

[0061] Figure 7 A graph is presented illustrating the asymmetry in the increase of the centroid relative to the target fitting aperture in the X direction (averaged within the firing field). This graph presents a graphical representation of the continuous form of the rules / decision discussed above with respect to box 602.

[0062] These teachings offer numerous benefits. As a first example, these methods can reduce the manual tuning work required to identify and determine the optimal field aperture. As a second example, these teachings help avoid suboptimal solutions resulting from less useful field apertures that are difficult to handle using current iterative direct aperture optimization techniques (e.g., dual-field systems with equivalent field apertures, and X-symmetric field apertures where the optimal solution is clearly X-asymmetric). As a third example, these teachings can improve the modulation capability of multi-arc schemes by incorporating coordination between field apertures into the direct aperture optimization step. This may be particularly important for radiation processors whose field apertures can, in most cases, encompass the entire target volume.

[0063] The following terms provide further details on these teachings (where it should be understood that any of these terms may be combined with one or more of the other terms as needed). Clause 1. A method for optimizing a radiation treatment protocol for a specific patient, the radiation treatment protocol using a specific radiation treatment device, the method comprising: via control circuitry: determining whether to apply a field-specific asymmetry based on at least a first criterion; and, after determining that a field-specific asymmetry should be applied, applying the field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection.

[0064] Clause 2. The method according to Clause 1, wherein the first criterion includes one of the following: arc length; multi-leaf collimator angle.

[0065] Clause 3. The method according to Clause 1, wherein determining whether to apply field-specific asymmetry based on at least a first criterion includes: determining whether to apply field-specific asymmetry based on at least a first criterion and a second criterion.

[0066] Clause 4. The method according to Clause 3, wherein the first criterion includes arc length and the second criterion includes multi-leaf collimator angle.

[0067] Clause 5. The method according to Clause 1, wherein determining whether to apply field-specific asymmetry according to at least a first criterion includes: determining to apply field-specific asymmetry when the arc length of the radiation processing device exceeds 180 degrees, the plane angle of the multi-leaf collimator is less than 30 degrees, and the corresponding field aperture size completely surrounds the target volume rather than just a segmented field surrounding a portion of the target volume. Clause 6. The method according to Clause 1, wherein applying field-specific asymmetry when establishing an initial multi-leaf collimator aperture relative to a target projection comprises modifying the original aperture adapted to the complete target projection by reducing the corresponding original aperture opening width by a modulation factor and then offsetting the reduced aperture opening into the original target aperture.

[0068] Clause 7. The method according to Clause 1, wherein optimizing the radiation treatment scheme includes using direct aperture optimization.

[0069] Clause 8. The method according to Clause 1, wherein applying field-specific asymmetry when establishing the multi-leaf collimator aperture relative to the target projection includes: applying field-specific asymmetry on a field-by-field basis when establishing the multi-leaf collimator aperture relative to the target projection.

[0070] Clause 9. The method according to Clause 1, wherein determining whether to apply field-specific asymmetry based on at least a first criterion comprises: determining whether to apply field-specific asymmetry based at least in part on whether the radiation treatment scheme corresponds to a dual-field treatment arrangement.

[0071] Clause 10. The method according to Clause 9, wherein determining whether to apply field-specific asymmetry further comprises: determining whether to apply field-specific asymmetry based on whether the corresponding field aperture size completely surrounds the target volume rather than just a portion of the target volume of the segmented field.

[0072] Clause 11. An apparatus for optimizing a radiation treatment regimen for a specific patient, the radiation treatment regimen using a specific radiation treatment apparatus, the apparatus comprising: control circuitry configured to: determine whether to apply a field-specific asymmetry based on at least a first criterion; and, after determining that a field-specific asymmetry should be applied, apply the field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection.

[0073] Clause 12. The apparatus according to Clause 11, wherein the first criterion includes one of the following: arc length; multi-leaf collimator angle. Clause 13. The apparatus of Clause 11, wherein the control circuit is configured to determine whether to apply a field-specific asymmetry based on at least a first criterion by: determining whether to apply a field-specific asymmetry based on at least a first criterion and a second criterion.

[0074] Clause 14. The apparatus according to Clause 13, wherein the first criterion includes arc length and the second criterion includes multi-leaf collimator angle. Clause 15. The apparatus of Clause 11, wherein the control circuitry is configured to determine whether to apply field-specific asymmetry by operating according to at least a first criterion: when the arc length of the radiation processing apparatus exceeds 180 degrees, the plane angle of the multi-leaf collimator is less than 30 degrees, and the corresponding field aperture size completely surrounds the target volume rather than just a segmented field surrounding a portion of the target volume. Clause 16. The apparatus of Clause 11, wherein the control circuit is configured to apply field-specific asymmetry when establishing an initial multi-leaf collimator aperture relative to a target projection by modifying the original aperture adapted to the complete target projection by reducing the corresponding original aperture opening width by a modulation factor and then offsetting the reduced aperture opening into the original target aperture. Clause 17. The apparatus of Clause 11, wherein the control circuit is configured to apply field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection by applying field-specific asymmetry on a field-by-field basis when establishing a multi-leaf collimator aperture relative to a target projection. Clause 18. The apparatus of Clause 11, wherein the control circuitry is configured to determine whether to apply field-specific asymmetry by operating according to at least a first criterion: at least in part based on whether the radiation processing scheme corresponds to a dual-field processing arrangement. Clause 19. The apparatus of Clause 18, wherein the control circuit is further configured to determine whether to apply field-specific asymmetry by: further determining whether to apply field-specific asymmetry based on whether the corresponding field aperture size completely surrounds the target volume rather than just surrounds a portion of the target volume of a segmented field. Clause 20. A non-transitory computer-readable medium for use in optimizing a radiation treatment protocol for a specific patient, the radiation treatment protocol using a specific radiation treatment apparatus, the non-transitory computer-readable medium storing instructions that, when executed on a processor, perform the following steps: determining whether to apply a field-specific asymmetry according to at least a first criterion; and, after determining that a field-specific asymmetry should be applied, applying the field-specific asymmetry when establishing a multi-leaf collimator aperture relative to a target projection.

[0075] Those skilled in the art will recognize that various modifications, alterations, and combinations can be made to the embodiments described above without departing from the scope of the invention, and such modifications, alterations, and combinations should be considered to be within the scope of the inventive concept.

Claims

1. A method for optimizing a radiation treatment regimen for a specific patient, the radiation treatment regimen using a specific radiation treatment device, the method comprising: By controlling the circuit: Determine whether to apply field-specific asymmetry based on at least the first criterion; After determining which field-specific asymmetry to apply, apply the field-specific asymmetry when establishing the multi-leaf collimator aperture relative to the target projection.

2. The method of claim 1, wherein the first criterion comprises one of the following: Arc length; Multi-leaf collimator angle.

3. The method of claim 1, wherein determining whether to apply a field-specific asymmetry based at least on a first criterion comprises: Whether to apply field-specific asymmetry is determined based on at least the first and second criteria.

4. The method of claim 3, wherein the first criterion includes arc length, and the second criterion includes multi-leaf collimator angle.

5. The method of claim 1, wherein determining whether to apply a field-specific asymmetry based on at least a first criterion comprises: When the arc length of the radiation processing device exceeds 180 degrees, the plane angle of the multi-leaf collimator is less than 30 degrees, and the corresponding field aperture size completely surrounds the target volume rather than just a segmented field surrounding a portion of the target volume, it is determined that a field-specific asymmetry should be applied.

6. The method of claim 1, wherein applying a field-specific asymmetry when establishing the initial multi-leaf collimator aperture relative to the target projection comprises: The original aperture that is adapted to the complete target projection is modified by the following operation: the corresponding original aperture opening width is reduced by a modulation factor, and then the reduced aperture opening is offset into the original target aperture.

7. The method of claim 1, wherein optimizing the radiation treatment scheme includes using direct aperture optimization.

8. The method of claim 1, wherein applying field-specific asymmetry when establishing the multi-leaf collimator aperture relative to the target projection comprises: When establishing the multi-leaf collimator aperture relative to the target projection, field-specific asymmetry is applied on a field-by-field basis.

9. The method of claim 1, wherein determining whether to apply a field-specific asymmetry based on at least a first criterion comprises: Whether to apply field-specific asymmetry is determined at least in part based on whether the radiation treatment scheme corresponds to a dual-field treatment arrangement.

10. The method of claim 9, wherein determining whether to apply a field-specific asymmetry further comprises: The application of field-specific asymmetry is determined based on whether the corresponding field aperture size completely surrounds the target volume rather than just a portion of it.

11. An apparatus for optimizing a radiation treatment regimen for a specific patient, the radiation treatment regimen using a specific radiation treatment apparatus, the apparatus comprising: Control circuit, the control circuit being configured to: Determine whether to apply field-specific asymmetry based on at least the first criterion; After determining which field-specific asymmetry to apply, apply the field-specific asymmetry when establishing the multi-leaf collimator aperture relative to the target projection.

12. The apparatus of claim 11, wherein the first criterion comprises one of the following: Arc length; Multi-leaf collimator angle.

13. The apparatus of claim 11, wherein the control circuitry is configured to determine whether to apply a field-specific asymmetry based on at least a first criterion by: Whether to apply field-specific asymmetry is determined based on at least the first and second criteria.

14. The apparatus of claim 13, wherein the first criterion includes arc length and the second criterion includes multi-leaf collimator angle.

15. The apparatus of claim 11, wherein the control circuitry is configured to determine whether to apply a field-specific asymmetry based on at least a first criterion by: When the arc length of the radiation processing device exceeds 180 degrees, the plane angle of the multi-leaf collimator is less than 30 degrees, and the corresponding field aperture size completely surrounds the target volume rather than just a segmented field surrounding a portion of the target volume, it is determined that a field-specific asymmetry should be applied.

16. The apparatus of claim 11, wherein the control circuitry is configured to apply a field-specific asymmetry when establishing an initial multi-leaf collimator aperture relative to a target projection by: The original aperture that is adapted to the complete target projection is modified by the following operation: the corresponding original aperture opening width is reduced by a modulation factor, and then the reduced aperture opening is offset into the original target aperture.

17. The apparatus of claim 11, wherein the control circuitry is configured to apply a field-specific asymmetry when establishing the multi-leaf collimator aperture relative to the target projection by: When establishing the multi-leaf collimator aperture relative to the target projection, field-specific asymmetry is applied on a field-by-field basis.

18. The apparatus of claim 11, wherein the control circuitry is configured to determine whether to apply a field-specific asymmetry based on at least a first criterion by: Whether to apply field-specific asymmetry is determined at least in part based on whether the radiation treatment scheme corresponds to a dual-field treatment arrangement.

19. The apparatus of claim 18, wherein the control circuitry is further configured to determine whether to apply a field-specific asymmetry by: The application of field-specific asymmetry is determined based on whether the corresponding field aperture size completely surrounds the target volume rather than just a portion of it.

20. A non-transitory computer-readable medium for optimizing a radiation treatment regimen for a specific patient, the radiation treatment regimen using a specific radiation treatment apparatus, the non-transitory computer-readable medium storing instructions that, when executed on a processor, perform the following steps: Determine whether to apply field-specific asymmetry based on at least the first criterion; After determining which field-specific asymmetry to apply, apply the field-specific asymmetry when establishing the multi-leaf collimator aperture relative to the target projection.

Images