In vitro Dosimetric Study of Biliary Stent Loaded with Radioactive 125I Seeds

作者：Lihong Yao, Junjie Wang, Charles Shang, Ping Jiang, Lei Lin, Haitao Sun, Lu Liu, Hao Liu, Di He, Ruijie Yang · 发表于：Chinese Medical Journal · 年份：2017 · DOI：10.4103/0366-6999.204936 · 被引用次数：11 · 研究领域：Gallbladder and Bile Duct Disorders、Radiation Dose and Imaging、Organ Transplantation Techniques and Outcomes

BACKGROUND: A novel radioactive 125I seed-loaded biliary stent has been used for patients with malignant biliary obstruction. However, the dosimetric characteristics of the stents remain unclear. Therefore, we aimed to describe the dosimetry of the stents of different lengths - with different number as well as activities of 125I seeds. METHODS: The radiation dosimetry of three representative radioactive stent models was evaluated using a treatment planning system (TPS), thermoluminescent dosimeter (TLD) measurements, and Monte Carlo (MC) simulations. In the process of TPS calculation and TLD measurement, two different water-equivalent phantoms were designed to obtain cumulative radial dose distribution. Calibration procedures using TLD in the designed phantom were also conducted. MC simulations were performed using the Monte Carlo N-Particle eXtended version 2.5 general purpose code to calculate the radioactive stent's three-dimensional dose rate distribution in liquid water. Analysis of covariance was used to examine the factors influencing radial dose distribution of the radioactive stent. RESULTS: The maximum reduction in cumulative radial dose was 26% when the seed activity changed from 0.5 mCi to 0.4 mCi for the same length of radioactive stents. The TLD's dose response in the range of 0-10 mGy irradiation by 137Cs γ-ray was linear: y = 182225x - 6651.9 (R2=0.99152; y is the irradiation dose in mGy, x is the TLDs' reading in nC). When TLDs were irradiated by different en...