Radiotherapy
Impacts of the composition and density of tissue on the dose distribution of implanted 125I seeds
Wu Ailin, Jiang Xiao, Wu Aidong, Zhu Lei, Yang Yidong, Liu Yunqin, Qian Liting
Published 2021-11-25
Cite as Chin J Radiol Med Prot, 2021, 41(11): 813-817. DOI: 10.3760/cma.j.issn.0254-5098.2021.11.003
Abstract
ObjectiveTo investigate the impacts of the composition and physical density of tissue on the dose distribution of implanted 125I seeds, in order to provide references for the clinical dose calculation and assessment of implanted radioactive particles.
MethodsThe OncoSeed 6711 physical model of 125I seeds was established using thes of twareegs_brachy and was validated through the calculation of dose rate constant and the radial dose function [g(r)] in water. Then, based on the element composition and physical density of different types of tissue, the g(r) and absorbed dose ratein water, prostate, breast, muscle, and bone were calculated.
ResultsThe calculated dose rate constant (0.950 cGy·h-1·U-1) and g(r)in water approached the values in related literature. The absorbed dose in bone was 6.042 times than that in water at a distance of 0.05 cm from the implanted source. The difference between the absorbed doses in breast and water was more than 10% at a distance of less than 1.7 cm from the implanted source. The difference between the absorbed doses in prostate/muscle and water was less than 5% at the same radial location.
ConclusionsThe dose distribution of 125I seeds in some types of human tissue is significantly different from that in water, which should be carefully considered in clinical dose calculation.
Key words:
Tissue composition; 125I seed; Monte Carlo; Brachytherapy; Dose distribution
Contributor Information
Wu Ailin
Department of Radiation Oncology, Anhui Provincial Cancer Hospital, First Affiliated Hospital of USTC, Division of Sciences and Medicine, University of Science and Technology of China, Hefei 230031, China
Jiang Xiao
School of Physics, University of Science and Technology of China, Hefei 230026, China
Wu Aidong
Department of Radiation Oncology, Anhui Provincial Cancer Hospital, First Affiliated Hospital of USTC, Division of Sciences and Medicine, University of Science and Technology of China, Hefei 230031, China
Zhu Lei
School of Physics, University of Science and Technology of China, Hefei 230026, China
Yang Yidong
School of Physics, University of Science and Technology of China, Hefei 230026, China
Liu Yunqin
Department of Radiation Oncology, Anhui Provincial Cancer Hospital, First Affiliated Hospital of USTC, Division of Sciences and Medicine, University of Science and Technology of China, Hefei 230031, China
Qian Liting
Department of Radiation Oncology, Anhui Provincial Cancer Hospital, First Affiliated Hospital of USTC, Division of Sciences and Medicine, University of Science and Technology of China, Hefei 230031, China
