Toward real-time Monte Carlo simulation using a commercial cloud computing infrastructure.
Toward real-time Monte Carlo simulation using a commercial cloud computing infrastructure.
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DOI：
10.1088/0031-9155/56/17/n02
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发表时间：
2011-09-07
影响因子：
3.5
通讯作者：
Xing L
中科院分区：
文献类型：
--
作者：
Wang H;Ma Y;Pratx G;Xing L
蒙特卡罗(MC)方法是模拟非均匀介质中光子和电子输运的金标准，但其计算成本限制了其在临床上的常规应用。云计算是一种高性能计算的新方法，它的计算资源是从第三方按需分配的，用于放射治疗中的超高速MC计算。我们在一个商业云环境中部署了EGS5 MC包。从一台可以访问互联网的本地计算机启动，一个python脚本将分配一个远程虚拟集群。握手协议指定主节点和工作节点。最初将EGS5二进制文件和模拟数据加载到主节点上。然后，通过消息传递接口(MPI)在独立的工作节点之间分发模拟，并将结果聚集在本地计算机上以供显示和数据分析。对高能电子和光子的铅笔束和宽束所描述的方法进行了评估。基于云的MC模拟的输出与单线程实现产生的输出相同。对于100万个电子，在本地计算机上需要2.58小时的模拟可以在有100个节点的云上3.3分钟内执行，速度提高了47倍。模拟时间与并行节点的数量成反比。对于大型模拟，并行化开销也可以忽略不计。云计算代表了超级计算技术中最重要的最新进展之一，并为实质性改进MC模拟提供了一个有前途的平台。除了显著提高速度外，云计算还为高性能并行计算构建了一层抽象层，这可能会改变执行剂量计算和完成放射治疗计划的方式。
Monte Carlo (MC) methods are the gold standard for modeling photon and electron transport in heterogeneous medium; however, their computational cost prohibits their routine use in the clinic. Cloud computing, wherein computing resources are allocated on-demand from a third party, is a new approach for high performance computing and is implemented to perform ultra-fast MC calculation in radiation therapy. We deployed the EGS5 MC package in a commercial cloud environment. Launched from a single local computer with Internet access, a python script allocates a remote virtual cluster. A handshaking protocol designates master and worker nodes. The EGS5 binaries and the simulation data are initially loaded onto the master node. The simulation is then distributed among independent worker nodes via the Message Passing Interface (MPI), and the results aggregated on the local computer for display and data analysis. The described approach is evaluated for pencil beams and broad beams of high-energy electrons and photons. The output of the cloud-based MC simulation is identical to that produced by the single-threaded implementation. For 1 million electrons, a simulation that takes 2.58 hour on a local computer can be executed in 3.3 minutes on the cloud with 100 nodes, a 47x speed-up. Simulation time scales inversely with the number of parallel nodes. The parallelization overhead is also negligible for large simulations. Cloud computing represents one of the most important recent advances in supercomputing technology and provides a promising platform for substantially improved MC simulation. In addition to the significant speed up, cloud computing builds a layer of abstraction for high performance parallel computing, which may change the way dose calculations are performed and radiation treatment plans are completed.