Study On Beam Weight And Orientation Optimization With Genetic Algorithms With Two Populations

Radiotherapy plays an important role in oncology, the main object of radiotherapy is that collect the radiation to the GTV(gross target volume), and make the normal tissue to get lowest dosage ,the three-dimensional conformal radiotherapy(3D-CRT) which the high-dose volume matches the targets volume can decrease the dosage of normal tissue, and in this condition, we can increase the clinical dosage , but 3D-CRT conforms only two dimensionally to the target projection in the plane perpendicular to the beam orientation, so that , intensity-modulated radiotherapy(IMRT) is the most advanced from of 3D-CRT,it can produce highly three-dimensionally conformal dose distributions to the target, however, IMRT as a new accurate radiotherapy technology, is so complicated that the difficult problems, including the optimization of beam's orientation and beam's weight.The conventional radiotherapy base on the experience to choose some parameters, it is not only lost many time but also get the incredible result. To save our clinical time and make out work effective, more and more science to study this problem, and the main optimize algorithms can summarize as follow: the programming quadratic programming, gradient programming, constrained simulated annealing and genetic algorithms are the typical ones. We choose the GAWTP (genetic algorithm with two populations) which has parallel, robust and global superiority to optimize the beam orientations and beam weights GAWTP is a powerful global optimization approach, it can provide an adaptive method of studding form the outside to solve the real problem, especially, it can also calculate the objective function fast, which is discontinuous, no differentiable, or highly nonlinear because its parallel, robust and global superiority.In this paper, the dose calculation model based on pencil beams was constructed three-dimensional convolution, and under this calculation model, we optimize the parameters in the same patient with different conditions, it can conclude that the GAWTP was an effective algorithm, It is not only protect on key apparatus but also give the GTV a high-dosage, and most important of all, it can decrease the clinical time. So, the algorithm can be satisfied the clinical requirement...