Optimization Design Of Gantry For The Shanghai Advanced Proton Therapy

Proton therapy is the new large medical device for tumor treatment in the world,and the Gantry is characterized by large structure and high precision. Shanghai protontherapy demonstration plant is the comprehensive domestic independent research anddevelopment for proton therapy technology for the first time.the new type of Gantry isthe large precision mechanical structure with the rotation angle of180degrees,turning radius of5.4meters, weight162tons. As the first self-developed Gantry, it hasthe advanced structure and parameters, and are characterized by a big treament space,light weight, high cost performance, etc. But at the same time, due to the lack ofreferences, high rotation precision and complex construction design, higher costperformance must be obtained to adapt to the market competition, so it is verydifficult to design it.This paper introduces the overview of proton therapy technology, systematicallyintroduces the international development of Gantry at present and some calculationsand analysis during concept design stage.Purpose: in order to ensure the high cost performance of the structure design, thestructure must be optimized under the condition of guaranteeing the accuracy tosignificantly reduce the overall weight.Methods: this paper used the physical optimization, empirical design optimizationtopological optimization and size optimization technology to reduce the structureweight.Structure Optimization Theory: ESO(Evolutionary Structural Optimization)oftopology optimization,genetic algorithm, sequential quadratic programmingmethod,DOE(design of experiments)and RSM(response surface method) of sizeoptimization are put into use in this paper.Software used: Many software are integrated applied to finish this work, such asSolidworks,Ansys, Hyperworks,Optimus and etc.Result:After the optimization methods were applied into the main parts of theGantry, the total weight drops from240t to162t, and the isocenter accuracy still meets the sepecification.The application of structure optimization are firstly put into use in Gantry design,this work make a good result and will be applied into manufacturing in the future.