在進行MRI （magnetic resonance imaging）超導主磁體的設計時常采用優(yōu)化設計的方法，將各設計參數(shù)看作連續(xù)變量處理，但實際上很多參數(shù)是離散變量，為了更符合工程實際，將超導MRI 主磁體的設計作為一個含有離散變量的全局優(yōu)化問題。建立了適用于多種超導MRI 主磁體結(jié)構的數(shù)學模型，包括設計變量、目標函數(shù)、約束條件等，選用了適用于MRI 超導主磁體優(yōu)化設計的含有離散變量的模擬退火算法進行設計。算例結(jié)果表明，本文選取的數(shù)學模型和優(yōu)化算法是有效的，能夠達到超導MRI 主磁體設計的要求。
關鍵字：磁共振成像；超導主磁體；離散優(yōu)化；模擬退火
Abstract: Optimization design is often used in the design of MRI superconducting main magnet, where all variables are treated as continuous ones. According to the fact that not all variables are continuous, here the design problem is seen as a global optimization problem with discrete variables. A mathematical model is built including the definition of variables, objective function and constraints. A simulated annealing algorithm suitable for the
optimization of mixed integer non-linear programming problems is used to design MRI SC main magnet. An example is given to illustrate the effectiveness of the mathematical model and the optimization algorithm.
Key words: MRI; superconducting main magnet; discrete optimization; simulated annealing