Baldelli P, Taibi A, Tuffanelli A, Gambaccini M
Dipartimento di Fisca, Università di Ferrara and INFN, Sezione di Ferrara, via Paradiso 12, 44100 Ferrara, Italy.
Phys Med Biol. 2004 Sep 7;49(17):4135-46. doi: 10.1088/0031-9155/49/17/021.
Several techniques have been introduced in the last year to reduce the dose to the patient by minimizing the risk of tumour induced by radiation. In this work the radiological potential of dose reduction in quasi-monochromatic spectra produced via mosaic crystal Bragg diffraction has been evaluated, and a comparison with conventional spectra has been performed for four standard examinations: head, chest, abdomen and lumbar sacral spine. We have simulated quasi-monochromatic x-rays with the Shadow code, and conventional spectra with the Spectrum Processor. By means of the PCXMC software, we have simulated four examinations according to parameters established by the European Guidelines, and calculated absorbed dose for principal organs and the effective dose. Simulations of quasi-monochromatic laminar beams have been performed without anti-scatter grid, because of their inherent scatter geometry, and compared with simulations with conventional beams with anti-scatter grids. Results have shown that the dose reduction due to the introduction of quasi-monochromatic x-rays depends on different parameters related to the quality of the beam, the organ composition and the anti-scatter grid. With parameters chosen in this study a significant dose reduction can be achieved for two out of four kinds of examination.
在过去一年中，已经引入了几种技术，通过将辐射诱发肿瘤的风险降至最低来减少患者所受剂量。在这项工作中，评估了通过镶嵌晶体布拉格衍射产生的准单色光谱降低剂量的放射学潜力，并针对四项标准检查（头部、胸部、腹部和腰骶椎）与传统光谱进行了比较。我们使用Shadow代码模拟了准单色X射线，使用光谱处理器模拟了传统光谱。借助PCXMC软件，我们根据欧洲指南确定的参数模拟了四项检查，并计算了主要器官的吸收剂量和有效剂量。由于准单色层状光束固有的散射几何结构，在没有反散射栅格的情况下进行了模拟，并与有反散射栅格的传统光束模拟进行了比较。结果表明，引入准单色X射线导致的剂量降低取决于与光束质量、器官组成和反散射栅格相关的不同参数。在本研究中选择的参数下，四种检查中的两种可以实现显著的剂量降低。
