Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7968869 | Journal of Radiation Research and Applied Sciences | 2018 | 6 Pages |
Abstract
In radiotherapy of head and neck cancer, the presence of high density materials modifies photon dose distribution near these high density materials during treatment. The aim of this study is to calculate the backscatter and attenuation effects of a healthy tooth, Amalgam, Ni-Cr alloy and Ceramco on the normal tissues before and after these materials irradiated by 6 and 15Â MV photon beams, respectively. All measurements were carried out in a water phantom with dimension of 50Â ÃÂ 50Â ÃÂ 50 cm3with an ionization chamber detector. Two points before and four points after the dental sample were considered to score the photon dose. The depth dose on the central beam axis was explored in a water phantom for source to surface distance (SSD) of 100Â cm in a 10Â ÃÂ 10Â cm2 field size. The percentage dose change was obtained relative to the dose in water versus depth of water, tooth, Amalgam, Ni-Cr alloy and Ceramco for the photon beams. The absolute dose (cGy) was measured by prescription of 100Â cGy dose in the water phantom at depth of 2.0 and 3.1Â cm for 6 and 15Â MV photons, respectively. At depth of 0.6Â cm, the maximum percentage dose increase was observed with values of 6.99% and 9.43%for Ni-Cr and lowest percentage dose increase of 1.49% and 2.63% are related to the healthy tooth in 6 and 15Â MV photon beams, respectively. The maximum absolute dose of 95.58Â cGy and 93.64Â cGy were observed at depth of 0.6Â cm in presence of Ni-Cr alloy for 6 and 15Â MV photon beams, respectively. The presence of dental restorations can cause backscattering dose during head and neck radiation therapy. Introduction of compositions and electron density of high density materials can improve the accuracy of dosimetric calculations in treatment planning systems to deliver the relevant dose to target organ and reduce the backscattering dose in healthy tissues in the surrounding of tooth.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Mona Azizi, Ali Asghar Mowlavi, Mahdi Ghorbani, Behnam Azadegan, Fatemeh Akbari,