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BioMed Research International
Volume 2014, Article ID 946213, 11 pages
http://dx.doi.org/10.1155/2014/946213
Research Article

Dose Distributions of an 192Ir Brachytherapy Source in Different Media

1Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan
2School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei 110, Taiwan
3School of Medicine, Tzu Chi University, Hualian 970, Taiwan
4Department of Radiation Oncology, Buddhist Dalin Tzu Chi General Hospital, Chiayi 622, Taiwan
5Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 112, Taiwan
6Biophotonics and Molecular Imaging Research Center, National Yang-Ming University, Taipei 112, Taiwan

Received 23 January 2014; Accepted 12 March 2014; Published 7 April 2014

Academic Editor: Jack Yang

Copyright © 2014 C. H. Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study used MCNPX code to investigate the brachytherapy 192Ir dose distributions in water, bone, and lung tissue and performed radiophotoluminescent glass dosimeter measurements to verify the obtained MCNPX results. The results showed that the dose-rate constant, radial dose function, and anisotropy function in water were highly consistent with data in the literature. However, the lung dose near the source would be overestimated by up to 12%, if the lung tissue is assumed to be water, and, hence, if a tumor is located in the lung, the tumor dose will be overestimated, if the material density is not taken into consideration. In contrast, the lung dose far from the source would be underestimated by up to 30%. Radial dose functions were found to depend not only on the phantom size but also on the material density. The phantom size affects the radial dose function in bone more than those in the other tissues. On the other hand, the anisotropy function in lung tissue was not dependent on the radial distance. Our simulation results could represent valid clinical reference data and be used to improve the accuracy of the doses delivered during brachytherapy applied to patients with lung cancer.