基于时域有限差分法(FDTD)对PET回旋加速器内部束流测量探头的热传导过程进行了数值模拟。定义了运动和固定两种探头测量模式, 在辐射散热的条件下, 分别研究了3种探头材料(铜、钽、钨)在两种模式下的表面最高温度和尾部温度随功率加载时间的变化。研究表明：运动模式下, 3种探头材料没有明显的优劣, 探头速度选为10 mm/s较为合适；固定模式下, 由于铜材料具有高黑度、高热导率的优点, 是设计探头的最佳材料。

The thermal transport process of measuring probes within PET cyclotron is simulated based on finite difference time domain(FDTD) method. For both dynamic and static measurement modes, the highest surface temperature and back-end temperature for three probes of different materials(Cu, Ta, W) are obtained with the variation of power load time under thermal irradiation condition. The results show that there is no obvious difference among the three materials and the speed of probes should be 10 mm/s in dynamic mode. However, in static mode, copper turns out to be the best material for probe design due to its advantages such as high blackness and high thermal conductivity.