| The precision and calculation speed of the algorithm are two important factors to three-dimensional planning system, which are also closely related to the quality and efficiency of radiation therapy.Monaco is a commercial treatment planning system developed by Elekta corporation, which contains XVMC and PB algorithm. This thesis aims at comparing the differences between XVMC and PB algorithm in calculation accuracy and efficiency. In order to achieve this goal, we selected two representative chest tumor--Lung cancer and colorectal cancer for studying, and each diseases chosen twelve patients for comparing. After doing CT simulation positioning and target delineation, we designed PB and XVMC plans for each patient by using different algorithm of Monaco treatment planning system. Two sets of plans were compared in terms of conformity index, homogeneity index of target volume and receiving dose to critical organs by analyzing the dose volume histogram; To compare the precision of the algorithm,we used film to analyzed the deviation between plans and measured doses. In addition, we discuss the way of how to improving plan efficiency.Through a series of comparative analysis, the study concluded that: The doses calculated by PB algorithm was higher than that by XVMC algorithm no matter for organs at risk or target, and there exist a statistical significant between two algorithms. what’s more, those differences are bigger in those areas which shows higher density in-homogeneity and low density.At the same time,the author concluded that XVMC is more closer to the measured dose,which means XVMC algorithm is more accurate;and manual optimization method can improve the efficiency of clinical physical division of work.In conculsion, in order to ensure radiotherapy precision and improve the efficiency of clinical work, the author recommend XVMC algorithm for dose calculation and suggest that experienced physical trainer with the method of manual optimization plan optimization. |
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