CN104268437A - Method for quickly optimizing intensity-modulated sub-fields through grouping - Google Patents

Abstract

The invention discloses a method for quickly optimizing intensity-modulated sub-fields through grouping. The method for quickly optimizing intensity-modulated sub-fields through grouping solves the problems that the prior art needs multiple iterations, and the time is long. The method for quickly optimizing intensity-modulated sub-fields through grouping includes steps that (1) determining a blade needed for forming a field according to the anatomic relationship between the three-dimensional shape of a target region and the related organ at risk, and grouping the blade for forming the field; (2) using a simulated annealing method to judge the blade of each group. The method for quickly optimizing intensity-modulated sub-fields through grouping includes that grouping the blade before performing the simulated annealing, and using a CPU core to carry out optimal computation on each group; judging each sub-group through an independent target function, changing the blade position in the sub-group, calculating the target function, and judging whether the blade change can be accepted according to a solution accepting method. The method for quickly optimizing intensity-modulated sub-fields through grouping reduces the optimizing time based on reducing the sub-field number and monitor unit number and improving the implementation efficiency; the waste is lowered by means of the computation ability of the multi-core CPU.

Description

A kind of method realizing rapid Optimum tune hadron open country with hiving off

Technical field

The present invention relates to a kind of method realizing rapid Optimum tune hadron open country with hiving off.

Background technology

By adjustment intensity of beam distribute realize ideal dosage distribution, be called tune strong technology.Adjusting strong technology to be the most important developing direction of contemporary radiotherapy technology, is the core of radiotherapy technology, effectively can improve the cure rate of tumour and improve the quality of life of patient.Current tune mainly contains by force following several mode: MLC static intensity modulating, MLC dynamically adjust by force, arc adjusts strong, step-by-step movement Tomotherapy.MLC static intensity modulating method mainly contains substep reverse optimization method and direct Ziye optimization (DAO) two kinds.When plan quality is suitable, direct Ziye optimization method obviously can reduce Ziye number and machine jumping figure, improve efficiency of the practice.But algorithm optimization needs successive ignition, the time is longer, and counting yield is low.

The CPU production commercial cities such as Intel, AMD have employed multi-core technology to promote cpu performance, even propose group concept of core CPU.This means, give full play to the performance of multi-core CPU, the mode that program just must adopt multi-thread concurrent to calculate, traditional serial program greatly will waste the arithmetic capability of multi-core CPU; So cannot be applied to preferably in existing intensity modulated radiation therapy technology.

Summary of the invention

The object of the present invention is to provide a kind of method realizing rapid Optimum tune hadron open country with hiving off, solving prior art optimization needs successive ignition, the problem that the time is longer.

To achieve these goals, the technical solution used in the present invention is as follows:

Realizing the method that rapid Optimum adjusts hadron open country with hiving off, comprising the following steps:

(1) according to the direction of irradiation field, anatomy relationship between the 3D shape of target area and relevant crisis organ, determine forming the blade needed for launched field, then the blade for the formation of launched field is hived off;

(2) simulated annealing method is adopted to judge the blade of each group respectively;

Simulated annealing method in described step (2), comprises the following steps:

A, initialization: initialization temperature T, initial solution state S, the iterations of each T value is L;

B, to K=1,2,3 ... L, performs C to E and walks;

C, generation new explanation S ';

D, calculating increment △ F=F (S ')-F (S), wherein F (S) is evaluation function;

If E △ F < 0, then accept S ' as new current solution, otherwise accept S ' as new current solution using probability exp (-△ F/T);

F, T reduce gradually, repeat B to E, try to achieve some current solutions newly, judge whether all current solutions newly meet end condition, if then output meets the current solution of end condition as optimum solution, terminate program; Wherein, the T limit is tending towards 0;

Described evaluation function is as follows:

$O\left(I\right)=\underset{j}{\mathrm{\&Sigma;}}{\mathrm{\&omega;}}_j\underset{k\&Element;\mathrm{\&omega;}}{\mathrm{\&Sigma;}}{(I_k{d_k}^d-{d_k}^p)}^2$

Wherein, j is the numbering of histoorgan profile; ω is institutional framework weight; I is the intensity of pen bundle; d _k ^dthe dosage calculated, d _k ^pbe prescribed dose, subscript k is volume elements ordinal number.

Further, described step (1) must meet in isocentric overall width minimum value each group of blade Leafs:

$\left\{\begin{array}{c}{w}_{\min }=C\&CenterDot;r\\ \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_i\&GreaterEqual;W_{\min }\end{array}\right.$

In formula, r is the width of photon beam dosage nuclear scattering, and C is for considering the revised width redundancy factor of pencil-beam, and i is the sequence number of blade, δ _ibe the i-th blade at isocentric width, w _minfor blade is in isocentric overall width minimum value.

Again further, when described step C produces new explanation, each Leaf quantity N that hives off is identical, selects a blade in each hiving off to carry out position change, adjacent hive off in the blade sequence number difference that changes for there is position be the quantity N of blade of hiving off.

The present invention compared with prior art, has the following advantages and beneficial effect:

The present invention adopts and hived off to blade before simulated annealing, is then optimized calculating with a CPU core respectively to each group; Each hive off with one independently objective function judge, change the position of Leaf of hiving off, calculate objective function, whether the rule that accepts according to separating judges that this blade changes and can be accepted.Thus decrease the optimization time ensureing to reduce Ziye number and machine jumping figure, on the basis of improving efficiency of the practice; Make use of the arithmetic capability of multi-core CPU simultaneously, reduce waste.

Accompanying drawing explanation

Fig. 1 is that blade of the present invention hives off schematic diagram.

Fig. 2 is embodiments of the invention dose volume histogram.

Fig. 3 is schematic flow sheet of the present invention.

Embodiment

Below in conjunction with drawings and Examples, the invention will be further described, and embodiments of the present invention include but not limited to the following example.

Embodiment

As shown in Figure 3, a kind of method realizing rapid Optimum tune hadron open country with hiving off, is specifically implemented as follows:

According to the direction of irradiation field, the 3D shape of target area and the relevant anatomy relationship jeopardized between organ, determine forming the blade needed for launched field, then hived off by the blade for the formation of launched field, launched field outer leafs is not done to consider, the blade such as, forming launched field in Fig. 1, Fig. 1 is numbered 5 ~ 24.Each group is optimized calculating with a CPU core respectively, the each group of use one independently objective function judge, change the position of group's Leaf, calculate objective function, the rule that accepts according to separating judges whether the change of this blade can be accepted, and is then specifically adopt simulated annealing method to judge the blade of each group respectively.

Wherein, the quantity of hiving off not is get The more the better, decides according to the quantity of CPU core and blade gains in depth of comprehension width in waiting.Described step (1) must meet in isocentric overall width minimum value each group of blade Leafs:

$\left\{\begin{array}{c}{w}_{\min }=C\&CenterDot;r\\ \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_i\&GreaterEqual;W_{\min }\end{array}\right.$

In formula, r is the width of photon beam dosage nuclear scattering, and C is for considering the revised width redundancy factor of pencil-beam, and i is the sequence number of blade, δ _ibe the i-th blade at isocentric width, W is that blade is in isocentric overall width minimum value.

According to actual conditions, illustrating below is initialised the blade in Fig. 1 is divided into 4 to hive off, and namely the value of N is 5.First blade that hives off is numbered 5-9; Second blade that hives off is numbered 10-14; 3rd blade that hives off is numbered 15-19; 4th blade that hives off is numbered 20-24.

Described simulated annealing method, comprises the following steps:

A, initialization: initialization temperature T, initial solution state S, the iterations L of each T value;

B, to K=1,2,3 ... L, performs C to E and walks;

C, generation new explanation S ';

D, calculating increment △ F=F (S ')-F (S), wherein F (S) is evaluation function;

If E △ F < 0, then accept S ' as new current solution, otherwise accept S ' as new current solution using probability exp (-△ F/T);

F, T reduce gradually, repeat B to E, try to achieve some current solutions newly, judge whether all current solutions newly meet end condition, if then export current solution as optimum solution, terminate program; Wherein, the T limit is tending towards 0;

Described evaluation function is as follows: $O\left(I\right)=\underset{j}{\mathrm{\&Sigma;}}{\mathrm{\&omega;}}_j\underset{k\&Element;\mathrm{\&omega;}}{\mathrm{\&Sigma;}}{(I_k{d_k}^d-{d_k}^p)}^2$

Wherein, j is the numbering of histoorgan profile; ω is institutional framework weight; I is the intensity of pen bundle; d _k ^dthe dosage calculated, d _k ^pbe prescribed dose, subscript k is volume elements ordinal number.

In order to make to be independent of each other between each group, need to avoid choosing the interactive situation of the adjacent blade that hives off, the mode adopted selects a pair blade in each group to carry out position change, adjacent hive off in the blade sequence number difference that changes for there is position be the quantity N of blade of hiving off, the space requirement of hiving off can be made so minimum, such as, when the 1 selection blade 6 that hives off changes, corresponding other three blade numberings of hiving off are then 11,16,21.

End condition has: circulating temperature T is less than setup parameter value, iteration number of success reaches setup parameter value, target function value is less than setup parameter value etc.

The present invention is applied to personal computer (CPU4 core dominant frequency 3.0GHz, internal memory 4G, operating system win7), do the typical nasopharyngeal carcinoma of an example and adjust strong case, making of 7 directions (frame angle is respectively 0 °, 52 °, 104 °, 156 °, 208 °, 260 °, 312 °) fixing open country adjusts strong plan to test, show that the dose volume histogram of plan is shown in Fig. 2, solid line is the dose volume histogram of lower each organ of not hiving off, the dose volume histogram of each organ when round dot is point 4 groups.As can be seen from the figure to hive off and basically identical regardless of the effect of optimization obtained under public sentiment condition, but when launched field is divided into two groups, optimization efficiency improves 1.5 times, when being divided into 3 groups, efficiency improves 2.2 times, is divided into 4 groups to be that efficiency improves 3.1 times.Thus illustrate that relatively existing its efficiency of method of the present invention obviously increases, and be increase substantially, effectively shorten and adjust the strong time.

According to above-described embodiment, just the present invention can be realized well.What deserves to be explained is; under prerequisite based on said structure design, for solving same technical matters, even if some making on the invention are without substantial change or polishing; the essence of the technical scheme adopted is still the same with the present invention, therefore it also should in protection scope of the present invention.

Claims (3)

1. realizing the method that rapid Optimum adjusts hadron open country with hiving off, it is characterized in that, comprise the following steps:

(1) according to the direction of irradiation field, anatomy relationship between the 3D shape of target area and relevant crisis organ, determine forming the blade needed for launched field, then the blade for the formation of launched field is hived off;

(2) simulated annealing method is adopted to judge the blade of each group respectively;

Simulated annealing method in described step (2), comprises the following steps:

A, initialization: initialization temperature T, initial solution state S, the iterations of each T value is L;

B, to K=1,2,3 ... L, performs C to E and walks;

C, generation new explanation S ';

D, calculating increment △ F=F (S ')-F (S), wherein F (S) is evaluation function;

If E △ F < 0, then accept S ' as new current solution, otherwise accept S ' as new current solution using probability exp (-△ F/T);

F, T reduce gradually, repeat B to E, try to achieve some current solutions newly, judge whether all current solutions newly meet end condition, if then output meets the current solution of end condition as optimum solution, terminate program; Wherein, the T limit is tending towards 0;

Described evaluation function is as follows:

$O\left(I\right)=\underset{j}{\mathrm{\&Sigma;}}{\mathrm{\&omega;}}_j\underset{k\&Element;\mathrm{\&omega;}}{\mathrm{\&Sigma;}}{(I_k{d_k}^d-{d_k}^p)}^2$

Wherein, j is the numbering of histoorgan profile; ω is institutional framework weight; I is the intensity of pen bundle; d _k ^dthe dosage calculated, d _k ^pbe prescribed dose, subscript k is volume elements ordinal number.

2. a kind of method realizing rapid Optimum tune hadron open country with hiving off according to claim 1, it is characterized in that, described step (1) must meet in isocentric overall width minimum value each group of blade Leafs:

$\left\{\begin{array}{c}{w}_{\min }=C\&CenterDot;r\\ \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;}}_i\&GreaterEqual;W_{\min }\end{array}\right.$

In formula, r is the width of photon beam dosage nuclear scattering, and C is for considering the revised width redundancy factor of pencil-beam, and i is the sequence number of blade, δ _ibe the i-th blade at isocentric width, w _minfor blade is in isocentric overall width minimum value.

3. a kind of method realizing rapid Optimum tune hadron open country with hiving off according to claim 1 and 2, it is characterized in that, when described step C produces new explanation, each Leaf quantity N that hives off is identical, select a blade in each hiving off to carry out position change, adjacent hive off in the blade sequence number difference that changes for there is position be the quantity N of blade of hiving off.