Study On Hybrid Multi-objective Gradient Algorithm For Inverse Planning Of IMRT

As one of the core modules on radiation treatment planning system(TPS/RTS), optimization algorithm has been concerned very much. It is very important to develop inverse planning system in intensity modulated radiation therapy (IMRT) for seeking a high-speed and precise optimization algorithm.Aimming at the multi-objective characteristic of target volume, normal tissue and organ at risk on inverse planning of IMRT, based on the research of theory and method of multi-objective optimization, dose calculation, intelligent algorithm, This thesis develop a multi-objective gradient algorithm for the inverse planning module in the IMRT PST .The multi-objective genetic algorithm is combined with gradient algorithm, the hybrid multi-objective gradient algorithm is formed by real number. Test functions are used to analyze the efficiency of the algorithm. Under the simulation case of water phantom, the algorithm is applied to inverse planning process of IMRT. The objective functions of (planning target volume) PTV and (normal tissue) NT are based on the average dose distribution. Comparising with other optimization algorithms, the result shows that the hybrid multi-objective gradient algorithm can considerably save the computational time with a good Pareto frontier, and can meet the requirements of practical application.