Speed-up of Monte Carlo simulation with object description by using maximum rectangular region in diagnosis and radiation therapy

在SPECT、PET诊断或放射治疗中，光子输运模拟是检验散射和吸收校正方法不可缺少的技术。为了加快光子输运模拟的速度，我们提出了一种最大区域（最大矩形区域）内的目标描述方法，并与传统的目标描述方法进行了计算时间的比较。在这项研究中，详细的MRR扩展到三个维度。并通过对两种模型的仿真结果，与VB和八叉树方法进行了比较。这种对象描述方法可以比八叉树方法获得更大的区域。在通过MRR表达式获得的模拟结果中，计算时间能够比使用诸如VB和八叉树的常规表达式更短。

The photon transportation simulation which uses a Monte Carlo method is an indispensable techinique for examining the scatter and absorption correction methods in diagnosis with SPECT and PET or radiation therapy. We have developed a method for object description in maximum regions (maximum rectangular regions : MRRs) to speed up photon transportation simulation, and compared the calcuylation time with that of conventional object description methods. In this research details of the expansion of MRR to three dimensions are developed. Moreover, the effectiveness of proposed method was compared with the VB and octree method in the results of simulations of two kinds of phantoms. This object description method could secure larger areas than the octree method. In the simulation result obtained by MRR expression, the calculation time was able to made shorter than with conventional expressions such as by VB and octree.