title: Influence of metal of the applicator on the dose distribution during brachytherapy.
abstract: This study explores how the metal materials of the applicator influence the dose distribution when performing brachytherapy for cervical cancer. A pinpoint ionization chamber, Monte Carlo code MCNPX, and treatment planning system are used to evaluate the dose distribution for a single Ir-192 source positioned in the tandem and ovoid. For dose distribution in water with the presence of the tandem, differences among measurement, MCNPX calculation and treatment planning system results are <5%. For dose distribution in water with the presence of the ovoid, the MCNPX result agrees with the measurement. But the doses calculated from treatment planning system are overestimated by up to a factor of 4. This is due to the shielding effect of the metal materials in the applicator not being considered in the treatment planning system. This result suggests that the treatment planning system should take into account corrections for the metal materials of the applicator in order to improve the accuracy of the radiation dose delivered.
authors.affiliation: Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan, ROC.
authors.forename: Chin-Hui
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC; Department of Radiation Oncology, Koo Foundation Sun Yat-Sen Cancer Center, Taipei, Taiwan, ROC.
authors.forename: An-Cheng
authors.initials: AC
authors.lastname: Shiau
authors.affiliation: School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei, Taiwan, ROC.
authors.forename: Yi-Jen
authors.initials: YJ
authors.lastname: Liao
authors.affiliation: Department of Radiation Oncology, Saint Mary's Hospital Luodong, Yilan, Taiwan, ROC.
authors.forename: Hsin-Yu
authors.initials: HY
authors.lastname: Lin
authors.affiliation: Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan, ROC.
authors.forename: Yen-Wan Hsueh
authors.initials: YW
authors.lastname: Liu
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC; Biophotonics and Molecular Imaging Research Center, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Shih-Ming
authors.initials: SM
authors.lastname: Hsu
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation*; D006801:Humans; D019047:Phantoms, Imaging; D011874:Radiometry; D013193:Stainless Steel
chemical_list: D013193:Stainless Steel