A new optimization of dose distribution for intracavitary radiation therapy by simulated annealing

An optimization method for dose distribution in a remote afterloading system (RALS) using simulated annealing has been proposed. In intracavitary radiotherapy it is necessary to irradiate tumor volumes with a higher dose than the lethal dose of the tumor cell. At the same time, it is necessary to reduce the absorbed dose of critical organs as much as possible. However, the tumors and the critical organs are close to each other in a patient body; hence, it is difficult to realize the optimum dose plan. The proposed method yields the solution to this problem. The irradiation time of each source is optimized by minimizing the difference between a prescribed dose distribution and the calculated dose distribution. Simulation results showed that the method worked fairly well in obtaining the optimum dose distribution