CN107469239B - Computer-readable storage medium and radiation therapy planning system - Google Patents
Computer-readable storage medium and radiation therapy planning system Download PDFInfo
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- 238000003860 storage Methods 0.000 title claims abstract description 21
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- 238000013507 mapping Methods 0.000 claims abstract description 61
- 238000005457 optimization Methods 0.000 claims abstract description 49
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- 230000005855 radiation Effects 0.000 claims abstract description 14
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- 210000000920 organ at risk Anatomy 0.000 claims description 49
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- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/103—Treatment planning systems
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- A61N5/00—Radiation therapy
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- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1048—Monitoring, verifying, controlling systems and methods
- A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
- A61N2005/1054—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam using a portal imaging system
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- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
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Abstract
The present invention relates to a computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, is operative to perform a method of flux map optimization for generating a flux map for each field direction in a radiation treatment plan; the method comprises the following steps: establishing discretized discrete points on a plane perpendicular to the portal direction; mapping each organ sampling point in the field to the plane vertical to the field direction to form a corresponding mapping point; establishing a corresponding relation between each mapping point and each discrete point; determining an initial value for each discrete point according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source; forming an initial flux map according to the initial value of each discrete point; and carrying out flux optimization on the initial flux map to obtain an optimized flux map. The above-described traffic map optimization method can reduce the peaks and valleys of drastic changes in the optimized traffic map. The invention also provides a radiation therapy planning system.
Description
Technical Field
The present invention relates to the field of radiation therapy technology, and in particular, to a computer-readable storage medium and a radiation therapy planning system.
Background
The flux map refers to a distribution graph of flux (Fluence) obtained after a radioactive source passes through a multi-leaf grating. An optimization algorithm called flux map optimization is involved in radiotherapy planning such as intensity modulated radiotherapy, and the optimization algorithm has the effects that a flux map required to be used in dose calculation is directly optimized, so that a plan close to or meeting the requirements of a physicist or a doctor is obtained, and finally, the executable subfield shape and the hop count are obtained by segmenting through the approximately optimal flux map. After a traditional flux map optimization method optimizes a flux map, the obtained flux map may have peaks and valleys with drastic changes. For such a fluence map, a smaller opening is generated in the subsequent segmentation process, which is not favorable for dose calculation, and more sub-fields are generated without reducing the precision, thereby increasing the treatment execution time. If the number of the sub-fields is limited, more errors can be generated in the process of approximately dividing the flux map.
Disclosure of Invention
Based on this, there is a need for a computer-readable storage medium and a radiation therapy planning system that can reduce the peaks and valleys of the drastic changes in the optimized flux map.
A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, is operative to carry out a method of flux map optimization; the flux map optimization method is used for generating flux maps of all radiation field directions in a radiation treatment plan; the method comprises the following steps:
establishing discrete points on a plane perpendicular to the field direction;
mapping each organ sampling point in the field to the plane vertical to the field direction to form a corresponding mapping point;
establishing a corresponding relation between each mapping point and each discrete point;
determining an initial value for each discrete point according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source;
forming an initial flux map according to the initial value of each discrete point; and
and carrying out flux optimization on the initial flux map to obtain an optimized flux map.
When the flux map optimization method stored in the computer-readable storage medium forms the initial flux map, the initial value of each discrete point is determined according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and an illumination source, so that reasonable flux initial value distribution can be given. The initial flux map obtained by the initial value is relatively close to the ideal flux map, so that only small adjustment is carried out on the initial flux map in the subsequent flux optimization process of the flux map, and the peaks and the valleys of drastic change in the optimized flux map are indirectly reduced.
In one embodiment, the step of establishing discrete points on a plane perpendicular to the portal direction comprises: establishing a discretized grid on a plane perpendicular to the portal direction; and taking the grid nodes on the grid as the discrete points.
In one embodiment, the step of establishing the correspondence between each mapping point and each discrete point is to correspond each mapping point to a discrete point according to a distance between each mapping point and each discrete point.
In one embodiment, the step of determining an initial value for each discrete point according to the organ identifier of each mapping point corresponding to each discrete point and the distance of the organ from the illumination source comprises, for each discrete point:
determining the organ identification closest to the irradiation source according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source; and
determining an initial value of the discrete point according to an organ identifier nearest to the illumination source.
In one embodiment, the step of determining the initial value of the discrete point according to the organ identifier closest to the illumination source comprises:
when the organ mark closest to the irradiation source is the target organ mark, the initial value of the discrete point is determined according to the target dose of the target organ;
when the organ nearest to the illumination source is identified as an organ-at-risk identification, the initial value of the discrete point is determined according to the upper dose and weight of the organ-at-risk.
In one embodiment, the step of determining an initial value for each discrete point according to the organ identifier of each mapping point corresponding to each discrete point and the distance of the organ from the illumination source comprises, for each discrete point:
determining the organ identification closest to the irradiation source according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source;
when the organ marker closest to the illumination source is a target organ marker:
determining initial values for the discrete points from the organ at risk and the target organ when an organ at risk is present within a preset range of distances from the target organ;
when no organs at risk exist within a preset distance range of a target organ, determining an initial value of the discrete point according to the target organ;
when the organ marker closest to the illumination source is an organ-at-risk marker:
when organ identification which is used for identifying the target organ does not exist in the discrete points, determining an initial value of the discrete points according to the organ at risk;
when an organ identifier, which is an identifier of a target organ, exists in the discrete points, an initial value of the discrete points is determined according to the target organ and the organ at risk.
In one embodiment, the step of establishing a correspondence between each mapping point and each discrete point further includes: labeling each discrete point;
the step of marking each discrete point comprises the steps of marking the organ identification of the mapping point corresponding to each discrete point and the distance between the organ and the irradiation source on the discrete point; or marking the organ identification of one organ closest to the irradiation source in the mapping points corresponding to the discrete points on the discrete points.
In one embodiment, the method further comprises the step of smoothing the optimized flux map.
In one embodiment, the step of smoothing the optimized flux map includes smoothing the optimized flux map according to a preset smoothing optimization model; the objective function of the preset smooth optimization model comprises a flux change penalty function and a smooth penalty function; the flux change penalty function is used for giving penalty brought by the change of the new flux value and the original flux value on each discrete point; the smooth penalty function is used for giving the penalty brought by the flux value difference on the adjacent discrete points.
A radiation treatment planning system comprising a memory and a processor; the memory includes a computer readable storage medium as in any preceding embodiment.
Drawings
FIG. 1 is a flow diagram of a method for traffic map optimization in one embodiment;
FIG. 2 is a macro diagram illustrating mapping points to discrete points according to an embodiment;
FIG. 3 is an enlarged view of a portion of FIG. 2;
FIG. 4 is a flowchart illustrating the operation of step S140 according to an embodiment;
fig. 5 is a flowchart illustrating the step S140 in another embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In one embodiment, the Radiation Therapy planning system can employ Radiation Therapy planning in modes including Intensity Modulated Radiation Therapy (MRT), Intensity Modulated Arc Radiation Therapy (IMAT), Tomotherapy (Tomotherapy), and the like, as well as mixed modes thereof. The radiation treatment planning system includes a memory and a processor. The memory includes a computer readable storage medium. A computer-readable storage medium has stored thereon a computer program which, when being executed by a processor, is operative to carry out a method of traffic map optimization. The flux map optimization method is used for generating flux maps in all radiation field directions in the radiation treatment plan. The flux map generated in the radiation therapy planning system can be used as reference information of a subsequent radiotherapy device. In one embodiment, the radiation treatment planning system and the radiation therapy device may be integrated into one system or may be two separate systems.
The flux map optimization method can be used to obtain a flux map for each portal direction. In the rotating intensity modulated radiation therapy (Arc) plan, all arcs can be discretized into one field direction every several degrees, the field directions with the same attributes, such as a gantry angle, a multi-leaf grating (collimat) angle and the like, are combined into one field direction, and then each field direction is processed by adopting the flux map optimization method in the embodiment of the invention.
Referring to fig. 1, a method for flux map optimization in one embodiment includes the steps of:
step S110, discrete points of discretization are established on a plane perpendicular to the portal direction.
The beam axis view (BEV) is assumed to stand at the source position and view the field along the central axis of the beam. The BEV plane is a plane perpendicular to the field direction. If the field direction is represented by the direction of the central axis of the beam, the BEV plane is a plane perpendicular to the field direction, which is a plane substantially perpendicular to the central axis of the beam. In one embodiment, the BEV plane may be disposed between the radiation source and the isocenter plane. In one embodiment, the BEV plane may be disposed in the plane of the multileaf grating. The discretized discrete points can be arranged in any manner, such as regularly arranged points or randomly arranged points, and the regular arrangement can be uniform arrangement or non-uniform arrangement.
Step S120, mapping each organ sampling point in the field direction to the plane perpendicular to the field direction to form a corresponding mapping point.
The organ sampling points in the field direction may be mapped onto a plane perpendicular to the field direction in a direction opposite to the beam direction. The organ sampling points can be selectively set according to requirements, for example, sampling is performed on each organ by using a sampling method, so that each organ sampling point is obtained. The organ sampling points may be evenly distributed or randomly distributed points. In the present application, the sampling method is not limited, and the sampling methods corresponding to the organs may be the same or different, and the present application is not limited.
Step S130, establishing a corresponding relationship between each mapping point and each discrete point.
And corresponding each mapping point to a corresponding discrete point according to a preset rule.
Step S140, determining an initial value for each discrete point according to the organ identifier of each mapping point corresponding to the discrete point and the distance from the organ to the radiation source.
And determining the adaptive field dose according to the organ identification of each mapping point corresponding to each discrete point and the distance between the organ and the irradiation source, thereby setting a more reasonable flux initial value distribution for each discrete point. The dose of the sampling point is in a direct proportion relation with the flux value of the corresponding discrete point, and the larger the dose of the sampling point is, the larger the flux value of the discrete point is. The flux value at a discrete point may be several times or a fraction of the dose calculated at the corresponding sampled point.
Step S150, an initial flux map is formed from the initial values of the discrete points.
And step S160, optimizing the initial flux map to obtain an optimized flux map.
The flux optimization process can be performed on the initial flux map by using an optimization model known to those skilled in the art to obtain an optimized flux map.
When the initial flux map is formed, the flux map optimization method determines an initial value for each discrete point according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and an irradiation source, so that reasonable flux initial value distribution can be given. The initial value in the above optimization method is already close to the ideal dose requirement, compared to the conventional way of giving zero initial value for each discrete point, so that the obtained initial flux map is already relatively close to the ideal flux map. Therefore, in the subsequent flux optimization process of the flux map, only minor adjustment is carried out on the initial flux map, so that the peaks and the valleys of drastic changes in the optimized flux map are indirectly reduced. Therefore, a smaller opening is not generated in the subsequent segmentation process, which is beneficial to dose calculation. Moreover, on the premise of not reducing the precision, the number of the generated sub-fields can be reduced, thereby shortening the treatment execution time. If the number of the sub-fields is limited, the error generated in the process of approximately dividing the flux map is small, and the improvement of the precision is facilitated.
In one embodiment, step S110 includes the step of creating a discretized grid on a plane perpendicular to the field direction, the grid nodes on the grid being discrete points, the grid being a uniform grid, a non-uniform grid, or a randomly discrete grid, etc., such that the grid nodes thereof assume a uniform, non-uniform, or random state.
In one embodiment, in step S130, each mapping point is mapped to a discrete point (or a grid node) according to a distance between each mapping point and each discrete point. For example, mapping points are mapped to neighboring flux points on a near basis. Specifically, mapping points can be mapped to four adjacent discrete points according to a rule of proximity, so that the finally obtained flux map is ensured to be as close to the ideal flux map as possible. In this embodiment, the distance between the four discrete points and the mapping point may not be limited, and the mapping point may be only required to be mapped to the preset 4 adjacent discrete points according to the distance. In other embodiments, mapping points may be mapped to adjacent one, two or more discrete points on a near basis. In the correspondence process, the distance between the mapping point and the discrete point may be defined, for example, the mapping point is corresponded to all discrete points within a preset distance range. In another embodiment, the mapping point may also be mapped to the nearest one of the discrete points.
In an embodiment, after step S130, a step of labeling each discrete point is further included. Specifically, the organ identification of the mapping point corresponding to each discrete point and the distance of the organ from the irradiation source are marked on the discrete points. The organ identification is used to identify the type of the organ. The organ mark can be directly a character mark or a corresponding symbol, a pattern mark and the like. In one embodiment, the distance of each organ corresponding to each mapping point from the illumination source is taken as its Z-axis coordinate during the labeling process. Therefore, in step S140, an initial value of the flux value may be determined according to the organ identifier at each mapping point and its corresponding Z-axis coordinate.
In one embodiment, the marked schematic can be output to a display interface for viewing by an operator. When output, only the marked organ identification may be displayed, and not the distance of the organ from the illumination source, as shown in fig. 2. Fig. 2 is a macroscopic view diagram formed after mapping each mapping point to a discrete point in an embodiment. As can be seen in fig. 2, the target detection sites include target organs (PTV) and Organs At Risk (OAR). Fig. 3 is an enlarged view of a portion 20 of fig. 2. In fig. 3, the solid circles are target organ markers, the dashed circles are organs at risk markers, and the triangles are discrete points. According to the principle of proximity, each mapping point can be mapped to four adjacent discrete points, so that only target organ identifiers exist on part of the discrete points, such as the four discrete points on the left side in fig. 3; part of discrete points, namely target organ marks and organs at risk marks, such as two discrete points at the upper right in the figure 3; while partial discrete points only present the organs-at-risk identification as the lower right two discrete points in fig. 3. In other embodiments, the organ identifier of only one organ closest to the irradiation source among the mapping points corresponding to the discrete points may be marked on the discrete points.
In an embodiment, in step S140, the determining an initial value of each discrete point according to the flow shown in fig. 4 specifically includes:
and step S210, determining the organ identifier closest to the irradiation source according to the organ identifier of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source.
And comparing the distances from the organs in the mapping points corresponding to the discrete points to the irradiation source to determine the organ identifier closest to the irradiation source, so as to determine the organ corresponding to the organ identifier as the organ with the largest beam influence.
Step S220, determining an initial value of the discrete point according to the organ identifier closest to the illumination source.
Specifically, when the determined organ identifier is the target organ identifier, the initial value of the discrete point is determined according to the target dose of the target organ. The target dose may be a specific value or a range of values having an upper and lower limit, which is set by the user. For example, the initial value of the discrete points is set equal to the ratio of the target dose to the number of fields of the target organ. Herein, the number of shots is the sum of the number of shots in all the shot directions.
When the determined organ identity is a critical organ identity, initial values of discrete points are determined based on the upper dose and weight of the critical organ. The upper limit dose represents the upper limit of the dose that the organ at risk can bear, and is set by a user; the weights represent the relative importance of the corresponding organs. For example, the initial value of the scatter point is set to be less than or equal to the ratio of the upper dose to the number of fields at the organ at risk. By setting the initial value of the discrete points to be less than or equal to the ratio of the upper dose to the number of fields of the organ at risk, it is possible to protect the organ at risk within the allowable range.
In an embodiment, in step S140, the determining an initial value of each discrete point according to the flow shown in fig. 5 specifically includes:
step S310, according to the organ mark of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source, determining the organ mark nearest to the irradiation source.
When determining that the organ identifier closest to the irradiation source is the target organ identifier, executing step S320; when it is determined that the organ identifier closest to the illumination source is the organ-at-risk identifier, step S330 is performed.
Step S320, determining whether there is an organ at risk in a preset distance range of the target organ.
The preset distance range may be set as desired, e.g., determined according to the importance of the organ at risk, etc. When the organs at risk exist in the preset distance range of the target organs, step S340 is executed, otherwise step S350 is executed.
In step S340, initial values of discrete points are determined from the organs at risk and the target organs.
Specifically, initial values of discrete points are determined from the organs at risk and the target organs in combination. In one embodiment, the importance of each organ at risk may be defined. In one embodiment, the importance of the corresponding organ may be determined based on the organ identifier, for example, the organ identifier may be liver, spleen, stomach, spine, etc., and the importance of these organs is high. When the degree of importance of the organ at risk is high, the initial value of the discrete point is set to be less than or equal to the ratio of the upper limit dose of the organ at risk to the number of fields, so that the organ at risk is protected. When the critical procedure for the organ is low, then the initial value of the discrete points can be set equal to the ratio of the target dose to the number of fields for the target organ. In other embodiments, when the organ at risk is of lesser importance, protection of the organ at risk may also be achieved by appropriately lowering the initial values of the discrete points. The level of significance of the organ at risk may be predefined such that the level of significance of the organ at risk may be known when the organ at risk identification is obtained.
Step S350, determining an initial value of the discrete point according to the target organ.
The steps for determining the initial values of the discrete points according to the target organs have been described in the previous embodiments, and are not described herein.
Step S330, determining whether an organ identifier, which is an identifier of the target organ, exists in the discrete point.
When there is an organ identity that is the target organ identity, step S360 is performed, otherwise step S370 is performed.
Step S360, determining initial values of discrete points according to the target organs and the organs at risk.
When an organ marker exists that is a target organ marker, the initial value of the scatter point is set equal to the ratio of the upper dose to the number of fields for the organ at risk. By setting the initial value of the discrete points equal to the ratio of the upper dose of the organ at risk to the number of fields, the organ at risk can be protected within the allowable range and the target organ can be treated by radiation. In another embodiment, the initial values of the discrete points may also be determined taking into account the upper dose and weight of the organ at risk.
In step S370, initial values of discrete points are determined from the organ at risk.
When there is no organ marker present for the target organ marker, the initial value of the scatter point is set to be less than or equal to the ratio of the upper dose to the number of fields for the organ at risk. In one embodiment, the initial values of the discrete points may be determined based on the upper dose and weight of the organ at risk. In one embodiment, the initial value of the discrete point may be set to zero, thereby avoiding unnecessary exposure of the organ at risk.
By the method, the organ type with the largest beam influence is considered when the initial value is selected, so that reasonable flux initial value distribution is given, and finally the obtained initial flux map is close to an ideal flux map. In addition, the descending speed of the optimization objective function can be accelerated, the number of optimization iterations is reduced, and the optimization time is shortened.
In an embodiment, the above-mentioned flux map optimization method further includes a step S170 of performing a smoothing process on the optimized flux map, as shown in fig. 1. In this embodiment, by independently separating the smoothing processing from the flux optimization of the flux map, the problem of poor optimization effect caused by non-uniform dimensions can be avoided.
In an embodiment, a preset smooth optimization model is adopted to perform smoothing processing on the optimized flux map. The objective function of the preset smooth optimization model comprises a flux change penalty function and a smooth penalty function. The sum of the flux change penalty function and the smoothness penalty function forms the objective function. The flux change penalty function is used for giving penalty brought by the change amount of the new flux value and the original flux value on each discrete point; the smooth penalty function is used for giving the penalty brought by the flux value difference on the adjacent discrete points.
In one embodiment, the objective function of the preset smooth optimization model is as follows:
wherein, (. is) a flux change penalty function for giving a new flux value f at the ith grid nodeiAnd the original flux value
The penalty due to the variation of (a), e.g. (x) ═ x)2. K is a change penalty coefficient;
is a smooth penalty function for representing the flux value at a plurality of adjacent discrete points
Penalty by difference, e.g.
(a1，a2，……，an) ∈ N denotes the labels of a plurality of adjacent discrete points, N is the set of all adjacent discrete points, in this embodiment, a common optimization method of quadratic function can be used for optimization, for example, a BFGS solution method is used to perform a plurality of iterative optimizations on the objective function, the number of iterations can be determined according to the finally required precision, for example, 20 iterative optimizations are performed on the objective function.
In the traditional flux map optimization process, the smoothing processing of the flux map is added into the flux optimization. Due to the fact that the flux change punishment and the smoothness punishment are different in dimension, the optimization effect is obviously affected by the two coefficients. By adopting the method for optimizing the flux map in the embodiment, the smooth punishment of the flux map is independent of the flux optimization process, so that the problem that the optimization effect is influenced due to different dimensions can be effectively solved.
An embodiment of the present invention also provides a computer-readable storage medium having a computer program stored thereon. The computer program, when executed by a processor, may be adapted to perform a method of flux map optimization as described in any of the previous embodiments.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, is operative to perform a method of flux map optimization; the flux map optimization method is used for generating flux maps of all radiation field directions in a radiation treatment plan; the method comprises the following steps:
establishing discrete points on a plane perpendicular to the field direction;
mapping each organ sampling point in the field to the plane vertical to the field direction to form a corresponding mapping point;
establishing a corresponding relation between each mapping point and each discrete point;
determining an initial value for each discrete point according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source;
forming an initial flux map according to the initial value of each discrete point; and
carrying out flux optimization on the initial flux map to obtain an optimized flux map;
the step of determining an initial value for each discrete point based on the organ identity of each mapping point corresponding to the discrete point and the distance of the organ from the illumination source comprises, for each discrete point:
determining the organ identification closest to the irradiation source according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source; and
determining an initial value of the discrete point according to an organ identifier nearest to the illumination source.
2. The computer-readable storage medium of claim 1, wherein the step of establishing discrete points on a plane perpendicular to the portal direction comprises: establishing a discretized grid on a plane perpendicular to the portal direction; and taking the grid nodes on the grid as the discrete points.
3. The computer-readable storage medium of claim 1, wherein the step of establishing the correspondence between each mapping point and each discrete point is to map each mapping point to a discrete point according to a distance between each mapping point and each discrete point.
4. The computer-readable storage medium of claim 1, wherein the step of determining the initial value of the discrete point based on the organ identity closest to the illumination source comprises:
when the organ mark closest to the irradiation source is the target organ mark, the initial value of the discrete point is determined according to the target dose of the target organ;
when the organ nearest to the illumination source is identified as an organ-at-risk identification, the initial value of the discrete point is determined according to the upper dose and weight of the organ-at-risk.
5. The computer-readable storage medium of claim 1, wherein the step of determining an initial value for each discrete point based on the organ identification of its corresponding mapped point and the distance of the organ from the illumination source comprises, for each discrete point:
determining the organ identification closest to the irradiation source according to the organ identification of each mapping point corresponding to the discrete point and the distance between the organ and the irradiation source;
when the organ marker closest to the illumination source is a target organ marker:
determining initial values for the discrete points from the organ at risk and the target organ when an organ at risk is present within a preset range of distances from the target organ;
when no organs at risk exist within a preset distance range of a target organ, determining an initial value of the discrete point according to the target organ;
when the organ marker closest to the illumination source is an organ-at-risk marker:
when organ identification which is used for identifying the target organ does not exist in the discrete points, determining an initial value of the discrete points according to the organ at risk;
when an organ identifier, which is an identifier of a target organ, exists in the discrete points, an initial value of the discrete points is determined according to the target organ and the organ at risk.
6. The computer-readable storage medium of claim 1, wherein the step of establishing a correspondence between each mapping point and each discrete point is further followed by: labeling each discrete point;
and the step of marking the discrete points comprises the step of marking the organ identification of the mapping point corresponding to each discrete point and the distance of the organ from the irradiation source on the discrete points.
7. The computer-readable storage medium of claim 1, wherein the step of establishing a correspondence between each mapping point and each discrete point is further followed by: labeling each discrete point;
and the step of marking the discrete points is to mark the organ identification of the organ closest to the irradiation source in the mapping points corresponding to the discrete points on the discrete points.
8. The computer-readable storage medium of claim 1, wherein the method further comprises the step of smoothing the optimized traffic map.
9. The computer-readable storage medium of claim 8, wherein the step of smoothing the optimized flux map comprises smoothing the optimized flux map according to a preset smoothing optimization model; the objective function of the preset smooth optimization model comprises a flux change penalty function and a smooth penalty function; the flux change penalty function is used for giving penalty brought by the change of the new flux value and the original flux value on each discrete point; the smooth penalty function is used for giving the penalty brought by the flux value difference on the adjacent discrete points.
10. A radiation treatment planning system comprising a memory and a processor; wherein the memory comprises the computer-readable storage medium of any one of claims 1 to 9.
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| CN105413068A (en) * | 2015-12-31 | 2016-03-23 | 上海联影医疗科技有限公司 | Optimization method for solving flux map and radiotherapy equipment |
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| EP3075416A1 (en) * | 2015-04-02 | 2016-10-05 | RaySearch Laboratories AB | System and method for determining a radiation treatment plan and a radiation treatment machine |
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