Department of Medical Physics and Medical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Radiation Oncology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
Med Phys. 2021 Mar;48(3):1417-1426. doi: 10.1002/mp.14697. Epub 2021 Feb 1.
Intraoperative radiotherapy (IORT) technique is an advanced radio therapeutic method used for delivery of a single high-dose radiation during surgery while removing healthy tissues from the radiation field. Nowadays, growing attention is being paid to IORT for its low-energy (kilovoltage) delivery as it requires less radiation protection, but suffers several disadvantages, including high-dose delivery and prolonged treatment time. The application of nanoparticles with high atomic number and high attenuation coefficients in kilovoltage energy may help overcome the mentioned shortcomings. This study was designed to investigate and quantify the mean dose enhancement factor (DEF) in the presence of nanoparticles using IORT method.
Bismuth oxide nanoparticles (Bi O NPs), both in sheet and spherical formats, were synthesized using a novel hydrothermal method and characterized with x-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis. Genipin-gelatin gel dosimeter (GENIPIN) was produced in three batches of pure with sheet and with spherical nanoparticles in concentration of 46.596 µg/ml, and irradiated with 50 kV x-rays.
Samples were scanned by a spectrophotometer, which indicated a DEF of 3.28 0.37 and 2.50 0.23 for sheet and spherical NPs, respectively. According to the results of this study, GENIPIN is a suitable dosimeter for the evaluation of three-dimensional dose distribution in the presence Bi O NPs.
As a result, IORT along with Bi O NPs has the potential to reduce treatment time and/or normal tissue dose; moreover, it could provide localized dose enhancement.
术中放射治疗（IORT）技术是一种先进的放射治疗方法，用于在手术过程中单次给予高剂量辐射，同时将健康组织从辐射场中移除。如今，由于其低能（千伏）输送需要较少的辐射防护，因此越来越关注 IORT，但它也存在一些缺点，包括高剂量输送和延长治疗时间。在千伏能量下应用高原子序数和高衰减系数的纳米粒子可能有助于克服上述缺点。本研究旨在研究并量化存在纳米粒子时使用 IORT 方法的平均剂量增强因子（DEF）。
采用新型水热法合成了片状和球形氧化铋纳米粒子（BiO NPs），并通过 X 射线衍射（XRD）、透射电子显微镜（TEM）和 Brunauer-Emmett-Teller（BET）分析对其进行了表征。采用基因蛋白-明胶凝胶剂量计（GENIPIN），分别以纯片和纯球形纳米粒子的形式，在浓度为 46.596 µg/ml 下，制备了三个批次的 GENIPIN，并采用 50 kV X 射线进行了照射。
用分光光度计对样品进行了扫描，结果表明片状和球形 NPs 的 DEF 分别为 3.28 ± 0.37 和 2.50 ± 0.23。根据本研究的结果，GENIPIN 是评估存在 BiO NPs 时三维剂量分布的合适剂量计。
因此，IORT 联合 BiO NPs 有可能降低治疗时间和/或正常组织剂量；此外，它还可以提供局部剂量增强。
