硼中子俘获治疗(BNCT)蒙特卡罗剂量计算软件系统MCDB (Monte Carlo dosimetry code for brain)已经开发成功。它包括医学前处理、剂量计算和后处理。前处理把CT、MRI图像数据自动转化为剂量计算的输入文件，剂量计算基于蒙特卡罗(MC)方法，后处理是确定照射方向和照射时间。为了提高剂量计算的精度和缩短计算时间，MCDB发展了针对体素模型的快速粒子径迹算法，构造材料矩阵和计数矩阵，程序实现了MPI并行化。通过一个病例，MCDB完成了从CT、MRI提取数据、剂量计算和后处理的全过程。计算取得了与MCNP程序一致的结果，串行计算速度较MCNP提高3倍以上，并行效率可以达到90 %，完全满足临床对计算精度和计算时间的要求。

MCDB is developed for boron neutron capture therapy (BNCT). This system consists of a medical pre-processor, a dose computation and a post-processor. MCDB automatically produces the input file from CT and MRI image data. In Monte Carlo dose calculation, several accelerated measures, such as the fast track technique, mesh tally matrix and material matrix, are developed. In this paper, we proposed a real model simulated by MCNP and MCDB, respectively. The almost same results as MCNP are achieved. MCDB is faster in computational speed than MCNP.