Sabbaghizadeh Rahim, Shamsudin Roslinda, Deyhimihaghighi Najmeh, Sedghi Arman
Physics Department, Faculty of Science and Technology, National University of Malaysia, Bangi, Selangor, Malaysia.
Departments of Physics, University Putra Malaysia, UPM Serdang, Selangor, Malaysia.
PLoS One. 2017 Jan 6;12(1):e0168737. doi: 10.1371/journal.pone.0168737. eCollection 2017.
In the present study, the normoxic polyacrylamide gelatin and tetrakis hydroxy methyl phosphoniun chloride (PAGAT) polymer gel dosimeters were synthesized with and without the presence of silver (Ag) nanoparticles. The amount of Ag nanoparticles varied from 1 to 3 ml with concentration 3.14 g/l, thus forming two types of PAGAT polymer gel dosimeters before irradiating them with 6 to 25 Gy produced by 1.25-MeV 60Co gamma rays. In this range, the predominant gamma ray interaction with matter is by Compton scattering effect, as the photoelectric absorption effect diminishes. MRI was employed when evaluating the polymerization of the dosimeters and the gray scale of the MRI film was determined via an optical densitometer. Subsequent analyses of optical densities revealed that the extent of polymerization increased with the increase in the absorbed dose, while the increase of penetration depth within the dosimeters has a reverse effect. Moreover, a significant increase in the optical density-dose response (11.82%) was noted for dosimeters containing 2 ml Ag nanoparticles.
在本研究中，合成了常氧聚丙烯酰胺明胶和四羟甲基氯化磷（PAGAT）聚合物凝胶剂量计，分别有无银（Ag）纳米颗粒存在的情况。Ag纳米颗粒的量在1至3毫升之间变化，浓度为3.14克/升，从而在使用1.25兆电子伏60Co伽马射线产生的6至25戈瑞对其进行辐照之前，形成了两种类型的PAGAT聚合物凝胶剂量计。在此范围内，随着光电吸收效应减弱，伽马射线与物质的主要相互作用是康普顿散射效应。在评估剂量计的聚合情况时采用了磁共振成像（MRI），并通过光密度计测定MRI胶片的灰度。随后对光密度的分析表明，聚合程度随吸收剂量的增加而增加，而剂量计内穿透深度的增加则有相反的效果。此外，对于含有2毫升Ag纳米颗粒的剂量计，观察到光密度 - 剂量响应有显著增加（11.82%）。
