Using the 50 kV INTRABEAM IORT system after breast-conserving surgery: tumor recurrence and organs at risk (OARs), such as the lung and heart, long-term complications remain the challenging problems for breast cancer patients. So, the objective of this study was to address these two problems with the help of high atomic number nanoparticles (NPs). A Monte Carlo (MC) Simulation type EGSnrc C++ class library (egspp) with its Easy particle propagation (Epp) user code was used. The simulation was validated against the measured depth dose data found in our previous study (Tegaw, et al 2020 Dosimetric characteristics of the INTRABEAM system with spherical applicators in the presence of air gaps and tissue heterogeneities, Radiat. Environ. Biophys. (10.1007/s00411-020-00835-0)) using the gamma index and passed 2%/2 mm acceptance criteria in the gamma analysis. Gold (Au) NPs were selected after comparing Dose Enhancement Ratios (DERs) of bismuth (Bi), Au, and platinum (Pt) NPs which were calculated from the simulated results. As a result, 0.02, 0.2, 2, 10, and 20 mg-Au/g-breast tissue were used throughout this study. These particles were not distributed in discrete but in a uniform concentration. For 20 mg-Au/g-breast tissue, the DERs were 3.6, 0.420, and 0.323 for breast tissue, lung, heart, respectively, using the 1.5cm-diameter applicator (AP) and 3.61, 0.428, and 0.335 forbreast tissue, lung, and heart using the 5cm-diameter applicator, respectively. DER increased with the decrease in the depth of tissues and increase in the effective atomic number (Z_eff) and concentration of Au NPs, however, there was no significant change as AP sizes increased. Therefore, Au NPs showed dual advantages such as dose enhancement within the tumor bed and reduction in the OARs (heart and lung).

使用 50 kV INTRABEAM保乳手术后的IORT系统：肿瘤复发和风险器官（OARs），如肺和心脏，长期并发症仍然是乳腺癌患者面临的挑战。因此，本研究的目的是在高原子序数纳米粒子 (NPs) 的帮助下解决这两个问题。使用了具有简单粒子传播 (Epp) 用户代码的蒙特卡洛 (MC) 模拟类型 EGSnrc C++ 类库 (egspp)。该模拟已针对我们之前研究中发现的测量深度剂量数据进行了验证（Tegaw, et al 2020 Dosimetric features of the INTRABEAM在存在气隙和组织异质性的情况下具有球形涂药器的系统，辐射。环境。生物物理学. (10.1007/s00411-020-00835-0)) 使用伽马指数并在伽马分析中通过了 2%/2 毫米的验收标准。在比较从模拟结果计算的铋 (Bi)、Au 和铂 (Pt) NPs 的剂量增强比 (DERs) 后，选择金 (Au) NPs。因此，在整个研究过程中使用了 0.02、0.2、2、10 和 20 mg-Au/g-乳房组织。这些颗粒不是分散分布的，而是以均匀的浓度分布的。对于 20 mg-Au/g-乳房组织，使用直径为 1.5 厘米的涂药器 (AP) 和 3.61、0.428 和 0.335 的乳房组织，乳房组织、肺、心脏的 DER 分别为 3.6、0.420 和 0.323，肺和心脏分别使用 5 厘米直径的涂药器。DER随着组织深度的减小和有效原子序数（Z _eff) 和 Au NPs 的浓度，然而，随着 AP 尺寸的增加，没有显着变化。因此，Au NPs 显示出双重优势，例如肿瘤床内的剂量增强和 OAR（心脏和肺）的减少。