System and a method of directly optimizing static-state intensity-modulated sub-field shapes and machine hop count thereof

Abstract

The invention discloses a system and a method of directly optimizing static-state intensity-modulated sub-field shapes and machine hop count thereof. The system comprises an input module, a data processing module, an optimizing module and an optimized result output module. According to requirements of radiotherapy plan constitutors, the system and the method automatically build corresponding objective functions, regulation of the sub-filed shapes is conducted through the genetic algorithm, optimization of sub-field weight is conducted through the conjugate gradient algorithm, the genetic algorithm and the conjugate gradient algorithm are alternated for optimization, and finally, the sub-filed shapes meeting requirements and the corresponding machine pop count weight of the sub-field shapes are obtained. By means of the method, each sub-filed shape in each radiation field direction, meeting the requirements, and the machine pop count of each sub-field shape can be rapidly obtained, and the optimized result is a sub-field array which can be directly implemented. The system and the method not only can effectively solves the precision problem existing in a traditional method, but also are simple to operate, and can improve plan drawing-up efficiency and plan implementation efficiency.

Description

technical field [0001] The invention relates to a system and method for minimizing the number of subfields and the total number of machine jumps corresponding to the multi-leaf grating when the multi-leaf grating is used for intensity modulation in precise radiotherapy. Background technique [0002] The general steps to obtain the implementable sub-field shape and the number of machine hops in static intensity-modulated radiotherapy are to first obtain the optimal intensity that satisfies the expected dose distribution in each direction by means of optimization algorithm optimization, and then perform sub-field segmentation on the optimized intensity , converted into subfields that can be implemented by MLC, this method is called "two-step method" for short. Since the intensity distribution optimization does not consider some constraints contained in the multi-leaf grating itself, these restrictions are only considered in the sub-field segmentation, so the sub-field segmenta...

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Problems solved by technology

Long-term clinical application shows that the defects of the "two-step method" can be summarized as follows: (1) The number of subfields in each irradiation field is large, and the total number of irradiation jumps (MU) is often the number of conventional / conformal irradiation fields; times, this situation will not only increase the irradiation time, but also increase the probability of leakage, head scattering and tongue-groove effects; (2) some small, irregularly shaped sub-fields may be generated, and these sub-fields During the implementation of the field, there are large errors and low ray utilization rate, which may affect the accuracy of the patient's exposure dose; (3) When converting the ideal intensity distribution into an executable intensity distribution, the two intensities will have differences, which often lead to poor plan quality, and plans that already meet clinical requirements may no longer meet

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