Method and apparatus for delivering therapeutic radiation to a patient using field geometry based dose optimization

Abstract

The teachings provide for accessing optimization information (202), the optimization information (202) including at least one isocenter corresponding to a body contour of a particular patient (104), field geometry information of a particular radiation treatment platform (114), and dosimetric data. The optimization information can further include a model (104) for the body contour of the patient. A control circuit (101) optimizes a radiation treatment plan in accordance with the optimization information to provide an optimized radiation treatment plan (113), wherein a radiation dose level delivered to the particular patient (104) from a particular field (403, 405) is dependent on a relative volume size of a field path intersection, thereby reducing radiation dose delivery to healthy patient tissue in areas having relatively more overlapping fields (403, 405).

Description

Technical Field

[0001] These teachings generally involve irradiating the patient’s planned target volume according to the irradiation treatment plan, and more specifically involve optimizing the irradiation treatment plan. Background Technology

[0002] The use of radiation to treat medical conditions encompasses known existing technological fields. For example, radiation therapy is a crucial component of many treatment programs aimed at reducing or eliminating unwanted tumors. Unfortunately, the applied radiation itself cannot distinguish between unwanted material and adjacent tissues, organs, etc., necessary or even vital for the patient's continued survival. Therefore, radiation is typically applied cautiously, with an attempt to at least limit the radiation to a given target volume. So-called radiation treatment programs generally function in the aforementioned respects.

[0003] Radiation treatment plans typically include specified values ​​for each parameter among various treatment platform parameters during each of multiple consecutive fields. Treatment plans for radiation treatment phases are often generated through a so-called optimization process. As used herein, "optimization" will be understood as improving candidate treatment plans without necessarily ensuring that the result of optimization is actually a single optimal solution. Such optimization typically involves (usually while observing one or more corresponding limits in these aspects) automatically adjusting one or more treatment parameters and mathematically calculating possible corresponding treatment outcomes to identify a given set of treatment parameters that represents a good trade-off between desired therapeutic outcomes and the avoidance of undesirable side effects.

[0004] Unfortunately, the radiation therapy field setup specified by a given radiation treatment plan can sometimes deliver relatively high radiation doses to healthy tissue in areas where multiple field paths overlap. This problem can occur both in forward planning techniques and, to some extent, in backward planning techniques. Summary of the Invention

[0005] In a first aspect, the present invention provides a method as defined in claim 1. In a second aspect, the present invention provides an apparatus as defined in claim 11. Optional features are defined in the dependent claims. Attached Figure Description

[0006] The aforementioned needs are met at least in part by the provision of methods and apparatus that, particularly when studied in conjunction with the accompanying drawings, facilitate the generation of deliverable therapeutic radiation treatment plans as described in the following detailed description, in which:

[0007] Figure 1 Including block diagrams configured according to various embodiments of these teachings;

[0008] Figure 2 Includes flowcharts configured according to various embodiments of these teachings;

[0009] Figure 3 Includes schematic diagrams configured according to various embodiments of these teachings;

[0010] Figure 4 Includes schematic diagrams configured according to various embodiments of these teachings;

[0011] Figure 5 Including schematic diagrams configured according to various embodiments of these teachings; and

[0012] Figure 6 This includes schematic diagrams configured according to various embodiments of these teachings.

[0013] The elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the size and / or relative position of some elements may be exaggerated relative to other elements to aid in understanding the various embodiments of this teaching. Furthermore, common but well-known elements that are useful or necessary in commercially viable embodiments are often not described to facilitate a less obstructed view of these different embodiments of this teaching. Certain actions and / or steps may be described or depicted in a particular order of occurrence, and those skilled in the art will understand that such specificity regarding the order is not actually necessary. The terms and expressions used herein have the ordinary technical meaning consistent with those of those skilled in the art, unless otherwise specifically indicated herein. Unless otherwise specifically indicated, the word “or” as used herein should be interpreted as having a disjunctive paradigm rather than a conjunctive paradigm. Detailed Implementation

[0014] Generally, these different embodiments facilitate the use of a radiation treatment platform with a mobile radiation source during the radiation treatment phase and the use of an optimized radiation treatment plan to support the irradiation of treatment targets within a patient. By one method, these teachings specify access to optimization information via control circuitry. This optimization information may include, for example, at least one isocenter corresponding to the body contour of a particular patient, field geometry information for a particular radiation treatment platform, and / or dosimetry data. If necessary, the optimization information may also include a model of the body contour of a particular patient.

[0015] The control circuit can then optimize the radiation treatment plan for the specific patient and use the specific radiation treatment platform at least in part based on the aforementioned optimization information, thereby providing an optimized radiation treatment plan in which the radiation dose level delivered from a specific field to a specific patient depends on the relative volume of the field path intersection, thereby reducing the delivery of radiation dose to healthy patient tissues in areas with relatively more overlapping fields.

[0016] By means of a method, the aforementioned information regarding at least one isocenter corresponding to a body contour includes all isocenters corresponding to that body contour.

[0017] By means of a method, the aforementioned field geometry information at least partially represents the trajectory of the radiation source during the application of a radiation treatment program. These teachings are flexible in practice and will be adapted to, for example, field geometry information corresponding to one or more of the following: static pedestal field, arc field, field with stereotactic radiosurgery cone, static multileaf collimator field, and dynamic multileaf collimator field.

[0018] By one method, the aforementioned dosimetric data includes only at least one of depth-dose distribution data and depth-penumbra data, and other dosimetric data are thus utilized.

[0019] If necessary, these teachings will also adapt to configuring control circuitry to determine relative radiation dose levels based on the relative size of the intersecting volumes of field paths within healthy tissue. Furthermore, if necessary, the control circuitry can be configured to determine the aforementioned intersecting volumes at least in part based on a geometric solution of the common volume of the intersecting cylinders.

[0020] These instructions will guide the operation of the aforementioned specific radiation treatment platform in accordance with an optimized radiation treatment plan, in order to administer therapeutic radiation to specific patients.

[0021] With this configuration, at least the dose overdose of healthy tissue in areas of overlapping field pathways can be reduced.

[0022] These and other benefits will become clearer after a thorough review and study of the following detailed description. Refer now to the accompanying drawings, especially... Figure 1 An illustrative device 100 will be presented that is compatible with many of the teachings in these teachings.

[0023] In this particular example, the enabling device 100 includes a control circuit 101. As a “circuit”, the control circuit 101 therefore includes a structure that includes at least one (and typically many) conductive paths (such as paths made of conductive metals such as copper or silver) that transmit electricity in an ordered manner. These paths typically also include corresponding electrical components (whichever is passive (such as resistors and capacitors) and active (such as any of a variety of semiconductor-based devices) to allow the circuit to implement the control aspects of these teachings.

[0024] This type of control circuit 101 may include a fixed-purpose hardwired hardware platform (including, but not limited to, application-specific integrated circuits (ASICs) (which are integrated circuits designed specifically for a particular purpose rather than for general purposes), field-programmable gate arrays (FPGAs), etc.), or may include partially or fully programmable hardware platforms (including, but not limited to, microcontrollers, microprocessors, etc.). These architectural options of this type of structure are well known and understood in the art and do not require further description herein. The control circuit 101 is configured (e.g., by using corresponding programming that will be well understood by those skilled in the art) to perform one or more of the steps, actions, and / or functions described herein.

[0025] Control circuitry 101 is operatively coupled to memory 102. Memory 102 may be integrated into control circuitry 101 or may be physically separated from control circuitry 101 (wholly or partially) as needed. Memory 102 may also be local to control circuitry 101 (where, for example, both share a common circuit board, chassis, power supply, and / or housing), or may be partially or wholly remote to control circuitry 101 (where, for example, memory 102 is physically located in another facility, metropolitan area, or even country compared to control circuitry 101).

[0026] In addition to optimization information such as center position (multiple), field geometry information, and dose data, the memory 102 can also be used, for example, to non-transitory store computer instructions that, when executed by the control circuit 101, cause the control circuit 101 to operate as described herein. (As used herein, this reference to "non-transitory" will be understood to mean the non-transitory state of the stored content (and thus excludes the case where the stored content constitutes only a signal or wave), rather than the volatility of the storage medium itself; therefore, the memory 102 includes both non-volatile memory (such as read-only memory (ROM)) and volatile memory (such as dynamic random access memory (DRAM)).

[0027] Alternatively, the control circuitry 101 may also be operatively coupled to the user interface 103. The 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 converters, printers, etc.) to facilitate receiving information and / or instructions from the user and / or providing information to the user.

[0028] If necessary, 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 (internal and external to device 100) via the network interface. Network interfaces, including both wireless and non-wireless platforms, are well known in the art and require no further explanation here.

[0029] By means of a method, computed tomography apparatus 106 and / or other imaging apparatus 107 known in the art can acquire some or all of any desired patient-related imaging information.

[0030] In this illustrative example, control circuitry 101 is configured to ultimately output an optimized radiation processing plan 113. This radiation processing plan 113 typically includes specified values ​​for each parameter among various processing platform parameters during each of multiple consecutive fields. In this case, radiation processing plan 113 is generated through an optimization process. Various automated optimization processes specifically configured to generate such radiation processing plans are known in the art. Since this teaching is not overly sensitive to any particular choice of these aspects, further elaboration of these aspects is not provided herein except where particularly relevant to the details of this specification.

[0031] In one method, control circuitry 101 is operatively coupled to a radiation treatment platform 114, which is configured to deliver therapeutic radiation 112 to a corresponding patient 104 according to an optimized radiation treatment plan 113. These teachings are generally applicable to any of a wide variety of radiation treatment platforms / devices. In a typical application setup, radiation treatment platform 114 will include a radiation source 115 that can be selectively moved along an arcuate path via a gantry. The arcuate path may comprise a complete or near-complete circle, depending on the desired outcome. In one method, control circuitry 101 controls the movement of radiation source 115 along the arcuate path and can accordingly control when radiation source 115 begins to move, stops moving, accelerates, decelerates, and / or the speed at which radiation source 115 travels along the arcuate path.

[0032] Radiation source 115 may include, for example, an X-ray source based on a radio frequency (RF) linear particle accelerator (linac-based), such as the Varian TrueBeam or Halcyon linear accelerator. A linac 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, which can be used to generate ionizing radiation (e.g., X-rays) 116 and high-energy electrons.

[0033] A typical radiation treatment platform 114 may also include one or more support devices 110 (such as a treatment bed) for supporting the patient 104 during the treatment phase, one or more patient fixation devices 111, a gantry or other movable mechanism allowing selective movement of the radiation source 115, and / or one or more beamforming devices 117 (such as jaws, multi-leaf collimators, etc.) to provide selective beamforming and / or beam modulation as needed. In a typical application setting, it is assumed herein that the patient support device 110 can be selectively controlled by control circuitry 101 to move in any direction (i.e., any X, Y, or Z direction) during the radiation treatment phase. Since the foregoing elements and systems are well known in the art, detailed descriptions of these aspects are not provided herein except where relevant to the description.

[0034] For reference Figure 2 The process 200, which may be implemented, for example, in conjunction with the above-described application setup (and more particularly via the above-described control circuit 101), will be described. Generally, the process 200 facilitates the use of a radiation treatment platform (114) with a mobile radiation source (115) and an optimized radiation treatment plan (113) to support the irradiation of the treatment target (105) within the patient (104) during the radiation treatment phase.

[0035] In box 201, the process 200 has access to optimization information 202. By one method, the optimization information 202 includes information about the relative positioning of at least one isocenter corresponding to the body contour of a particular patient 104, field geometry information and / or dosimetry data for a particular radiation treatment platform 114. In many application settings, the optimization information 202 may also include a model of the body contour of a particular patient 104.

[0036] Those skilled in the art of radiation therapy know that the isocenter is the spatial point through which the center of the radiation beam passes, especially when the beam is moving relative to the patient. In many cases, the isocenter is a spatial point relative to the radiation treatment platform around which the radiation source rotates via a gantry. In a typical application setup, the isocenter will be located within the treatment volume 105 (e.g., more or less at the center of volume 105). It should be noted that the process 200 will adapt multiple isocenters corresponding to the patient's body contours in appropriate application settings.

[0037] The aforementioned field geometry information can vary with the needs and / or opportunities presented by the physical characteristics of a given radiation processing platform 114. In many cases, generally speaking, during the application of radiation processing program 113, the field geometry information at least partially represents the trajectory of radiation source 115. More specifically, the field geometry information may correspond to at least one, more, or all of the following: a static gantry field, an arc field, a field with a stereotactic radiosurgery cone, a static multi-leaf collimator field, and a dynamic multi-leaf collimator field. (As used herein, the expression “field” will be understood to include both “field” and “subfield,” wherein either or both may be used depending on the processing platform and / or processing mode itself.)

[0038] The aforementioned dosimetric data may also vary depending on the needs and / or opportunities to characterize a given application setting. In one approach, the dosimetric data may be limited in scope and include only one or both of depth-dose distribution data and depth-penumbra data. In such cases, the optimization information 202 does not include other dose data to be utilized by the control circuitry 101 / process 200.

[0039] In optional box 203, if needed, control circuitry 101 can determine the weights of the fields in the field geometry information, thereby facilitating control of the amount of radiation dose delivered at each field and / or the use of some or all of these weights when optimizing radiation treatment.

[0040] In optional box 204, if necessary, control circuit 101 can determine the relative radiation dose level based on the relative size of the intersecting volumes of field paths within healthy tissue (such as the organs at risk 108, 109 described above). By one method, control circuit 101 can determine such intersecting volumes at least in part based on the geometric solution of the common volume of the intersecting cylinders.

[0041] In any case, at block 205, control circuitry 101 optimizes, at least in part, a radiation treatment plan for a specific patient 104 using a specific radiation treatment platform 114 based on optimization information 202 to provide an optimized radiation treatment plan 113, wherein the radiation dose level delivered from a specific field to a specific patient 104 depends on the relative volume size of the field paths intersecting, thereby reducing radiation dose delivery to healthy patient tissues in areas with relatively more overlapping fields.

[0042] The process 200 may include, as shown in optional box 206, operating a specific radiation treatment platform 114 in accordance with an optimized radiation treatment plan 113 to apply radiation to a specific patient 104.

[0043] Therefore, these teachings permit the delivery of different doses of radiation in different fields to help minimize the risk of organs being exposed to inappropriate doses, a risk that might occur in other protocols due to overlapping fields. In these respects, Figure 3 A simple illustrative example is provided in which each of a plurality of arcs (some of which are indicated by reference numeral 301) is shown as consisting of a plurality of fields (some of which are indicated by reference numeral 302). In this illustrative example, the length of each field 302 represents a dose level, for the purpose of illustrating that each arc 301 consists of fields with selectively varying dose levels. In this example, these levels are adjusted at least in part based on the overlap between the fields. Generally, fields indicating higher dose levels are those that overlap little with other fields, while fields indicating lower dose levels overlap with other fields to a variable degree.

[0044] Some illustrative examples will now be provided. It should be understood that these examples are intended for illustrative purposes, and the details of these examples are not intended to imply any particular limitation on these teachings.

[0045] refer to Figure 4 In this example, the radiation processing platform 114 includes a collimator 401, which is a portion of a beamforming device 117. The collimator 117 may include, for example, a stereotactic radiosurgery cone, a static multi-leaf collimator, a dynamic multi-leaf collimator, or other methods as needed. At a first position indicated by reference numeral 402, the device generates a first radiation field 403. This first radiation field 403 includes a processing volume 105 within its range. After moving counterclockwise to a position indicated by reference numeral 404, the device now generates a second radiation field 405. This second radiation field 405 also includes a processing volume 105 within its range.

[0046] The figure shows that reference numeral 406 indicates the volume in which the two radiation fields 403 and 405 overlap within the patient 104. These teachings help to reduce the delivered dose of a given subfield in such a volume, thereby minimizing irradiation of non-target tissues (including, of course, organs at risk).

[0047] A method, either replacing or combining with the aforementioned method, is now referred to. Figure 5 These teachings also support the use of depth-dependent doses. Specifically, as shown in graph 502, the dose in this particular subfield is depth-dependent, such that the dose decreases with increasing depth. (Here, "depth" refers to the distance the subfield travels through the patient's body 104.) In this configuration, this approach helps to avoid over-irradiation of healthy tissues.

[0048] Alternatively, either in place of or in combination with the aforementioned methods, these teachings would support the reduction of delivered dose as the penumbra width increases at target depth. (Figure 503 depicts penumbra width as a function of depth.) This approach reduces the subtle, indistinct dose shaping associated with a wide penumbra.

[0049] In light of the above, these teachings will support the following calculations for each field angle in each field.

[0050] First, control circuitry 101 determines a relative intersecting volume I shared with at least one other region. (In fact, in typical application settings, such intersecting volume I may be at least partially shared with multiple other regions.) This can be achieved by using, for example, a piecewise model to determine the exact volume. Alternatively, this can be achieved by approximating the volume using a simplified geometric solution to the common volume of the intersecting cylinders (this approach is at least applicable to a single isocentric setting with cones). The target volume is then subtracted from volume I.

[0051] The control circuit 101 then determines the depth d of the target volume 105. (In some application settings, simply determining the depth to the isocenter is acceptable.)

[0052] Using depth-dose distribution data (such as curve 502 above), control circuit 101 can find the relative dose level D at depth d. 深度 Furthermore, using penumbra data (such as curve 503 above), control circuit 101 can locate the relative penumbra width P at depth d. 深度 Then, control circuit 101 can calculate the dose to be delivered in the subfield in any of a variety of ways. A useful example is as follows:

[0053] Relative delivery dose = 1 – I × (1 – D) 深度 )×(1–P 深度 ).

[0054] If necessary, these teachings will be adapted to apply experimental weights to D. 深度 and P 深度 One or both. Such experimental weights can be computationally determined, for example, by iterating over each weight and various target volume locations within the patient 104 while observing the steepness of the dose drop at the boundary of the target volume 105. For example, the steepness can be observed by generating a dose-volume histogram for the target volume 105 using complete spatial dose distribution data. The weight that results in the steepest dose drop for a representative set of target volume locations can be used as a constant weight to determine the aforementioned relative dose to be delivered.

[0055] Figure 6Illustrative examples are provided where these teachings can be applied to application setups using multiple isocenters. Specifically, these teachings can specify enabling dose rate modulation for arc field setups based on multiple isocenters. Multiple isocenters can be used to treat multiple lesions or cover a single lesion with a large and / or complex shape. Similarly, these teachings can specify determining the intersection volume size by sampling a volume segment model of the field path.

[0056] As a concrete illustrative example, these teachings can be used to support processing planning and application using a sector SRS setup. Specifically, the user or device creates an arc field or trajectory field setup during the processing planning phase. For this example, it is assumed that the fields in the field setup significantly overlap within healthy, non-target tissue. The user or device then uses an SRS cone or a static or dynamic multi-leaf collimator to define the field collimation. The latter may include, for example, selecting the SRS cone size, assembling the multi-leaf collimator onto the structure, assembly and shielding techniques, VMAT optimization, and so on.

[0057] The user or device then applies the aforementioned dynamic dose rate training. While this training will adapt to human activity in these areas, it will also adapt to environments with, for example, VMAT optimizers that integrate dynamic dose rate techniques into the optimized VMAT field. In this configuration, the device can populate instrument set weights into the control points of the processing field containing dynamic dose rate data. The device can then calculate the dose distribution for the treatment plan, and optionally, the user can evaluate the dose distribution and approve the treatment plan or make further adjustments as needed.

[0058] Those skilled in the art will recognize that these teachings can be used in conjunction with optimized inverse programming techniques, such as volume modulated arc therapy (VMAT) or intensity modulated radiation therapy (IMRT). For example, these teachings can be combined with optimized inverse programming techniques in a manner that the corresponding instrument conditioning weights primarily follow the dose delivery constraints defined by the process 200.

[0059] Those skilled in the art will recognize that various modifications, alterations, and combinations can be made to the above embodiments without departing from the scope of the invention. Therefore, such modifications, alterations, and combinations are considered to be within the scope of the concept of the invention.

Claims

1. A method for providing an optimized radiation treatment plan, comprising: By controlling the circuit: Access optimization information, the optimization information including: - Corresponding to at least one isocenter for the body contour of a specific patient; - Field geometry information for a specific radiation processing platform; and - Dosimetric data, wherein the dosimetric data includes only depth-penumbra data, or the depth-penumbra data and depth-dose distribution data, and excludes other dosimetric data; and The radiation treatment plan for the specific patient using the specific radiation treatment platform is optimized, at least in part, based on the optimization information, to provide an optimized radiation treatment plan in which the radiation dose level delivered from the specific field to the specific patient depends on the relative volume of the field paths intersecting, thereby reducing the delivery of radiation dose to healthy patient tissues in areas with relatively more overlapping fields.

2. The method of claim 1, wherein the field geometry information at least partially represents the trajectory of the radiation source during the application of the radiation treatment plan.

3. The method of claim 1 or 2, wherein the control circuit is configured to determine weights for the fields in the field geometry information to control the amount of radiation dose delivered at each field, and the control circuit is configured to use the weights when optimizing the radiation treatment plan.

4. The method according to claim 1 or 2, wherein the at least one isocenter corresponding to the body contour comprises: Multiple isocenters corresponding to the body contour.

5. The method according to claim 1 or 2, wherein the field geometry information corresponds to at least one of the following: a static gantry field, an arc field, a field with a stereotactic radiosurgery cone, a static multi-leaf collimator field, or a dynamic multi-leaf collimator field.

6. The method of claim 1 or 2, wherein the control circuit is configured to determine a relative radiation dose level based on the relative size of the intersecting volumes of field paths within healthy tissue.

7. The method of claim 6, wherein the control circuit is further configured to determine the intersecting volume based at least in part on a geometric solution of the common volume of the intersecting cylinders.

8. The method of claim 1 or 2, wherein the optimization information further includes a model of the body contours of the particular patient.

9. An apparatus for providing an optimized radiation treatment plan, comprising: The control circuit is configured as follows: Access optimization information, the optimization information including: - Corresponding to at least one isocenter for the body contour of a specific patient; - Field geometry information for a specific radiation processing platform; and - Dosimetric data, wherein the dosimetric data includes only depth-penumbra data, or the depth-penumbra data and depth-dose distribution data, and excludes other dosimetric data; and Based at least in part on the optimization information, the radiation treatment plan for the specific patient using the specific radiation treatment platform is optimized to provide an optimized radiation treatment plan, wherein the radiation dose level delivered from the specific field to the specific patient depends on the relative volume size of the field paths intersecting, thereby reducing the delivery of radiation dose to healthy patient tissues in areas with relatively more overlapping fields.

10. The apparatus of claim 9, wherein the field geometry information at least partially represents the trajectory of the radiation source during the application of the radiation treatment plan.

11. The apparatus of claim 9 or 10, wherein the control circuitry is further configured to determine weights for the fields in the field geometry information to control the amount of radiation dose delivered at each field, and the control circuitry is configured to use the weights when optimizing the radiation treatment schedule.

12. The apparatus of claim 9 or 10, wherein the at least one isocenter corresponding to the body contour comprises: Multiple isocenters corresponding to the body contour.

13. The apparatus of claim 9 or 10, wherein the field geometry information corresponds to at least one of the following: a static gantry field, an arc field, a field having a stereotactic radiosurgery cone, a static multi-leaf collimator field, or a dynamic multi-leaf collimator field.

14. The apparatus of claim 9 or 10, wherein the control circuit is further configured to determine a relative radiation dose level based on the relative size of the intersecting volumes of field paths within healthy tissue.

15. The apparatus of claim 14, wherein the control circuit is further configured to determine the intersecting volume based at least in part on a geometric solution of the common volume of the intersecting cylinders.

16. The apparatus of claim 9 or 10, wherein the optimization information further includes a model of the body contours of the particular patient.

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