Abstract：
Partial breast irradiation for the treatment of early-stage breast cancer patients can be performed by means of Intra Operative electron Radiation Therapy (IOeRT). One of the main limitations of this technique is the absence of a treatment planning system (TPS) that could greatly help in ensuring a proper coverage of the target volume during irradiation. An IOeRT TPS has been developed using a fast Monte Carlo (MC) and an ultrasound imaging system to provide the best irradiation strategy (electron beam energy, applicator position and bevel angle) and to facilitate the optimisation of dose prescription and delivery to the target volume while maximising the organs at risk sparing. The study has been performed in silico, exploiting MC simulations of a breast cancer treatment. Ultrasound-based input has been used to compute the absorbed dose maps in different irradiation strategies and a quantitative comparison between the different options was carried out using Dose Volume Histograms. The system was capable of exploring different beam energies and applicator positions in few minutes, identifying the best strategy with an overall computation time that was found to be completely compatible with clinical implementation. The systematic uncertainty related to tissue deformation during treatment delivery with respect to imaging acquisition was taken into account. The potential and feasibility of a GPU based full MC TPS implementation of IOeRT breast cancer treatments has been demonstrated in-silico. This long awaited tool will greatly improve the treatment safety and efficacy, overcoming the limits identified within the clinical trials carried out so far.
摘要：
用于治疗早期乳腺癌患者的部分乳房照射可以通过手术内电子放射治疗（IOeRT）进行。该技术的主要限制之一是缺乏治疗计划系统（TPS），该系统可以极大地帮助确保在辐照过程中对目标体积的适当覆盖。已使用快速蒙特卡罗（MC）和超声成像系统开发了IOeRTTPS，以提供最佳的辐照策略（电子束能量，涂药器位置和斜角），并促进剂量处方的优化和向目标体积的递送，同时最大限度地节省处于危险中的器官。这项研究是在计算机上进行的，利用乳腺癌治疗的MC模拟。基于超声的输入已用于计算不同辐照策略中的吸收剂量图，并且使用剂量体积直方图进行了不同选项之间的定量比较。该系统能够在几分钟内探索不同的光束能量和施加器位置，确定与临床实施完全兼容的总体计算时间的最佳策略。考虑了关于成像采集的治疗递送期间与组织变形相关的系统不确定性。已在计算机中证明了基于GPU的IOeRT乳腺癌治疗的完整MCTPS实施的潜力和可行性。这个期待已久的工具将大大提高治疗的安全性和有效性，克服了迄今为止进行的临床试验中确定的限制。
