Journal of Medical Physics
ORIGINAL ARTICLE
Year
: 2010  |  Volume : 35  |  Issue : 2  |  Page : 81--87

Dose distribution near thin titanium plate for skull fixation irradiated by a 4-MV photon beam


Tomohiro Shimozato1, Keisuke Yasui2, Ryota Kawanami2, Kousaku Habara2, Yuichi Aoyama3, Katsuyoshi Tabushi1, Yasunori Obata1 
1 Department of Radiological Technology, Nagoya University School of Health Sciences, Higashi-ku, Nagoya, Aichi, Japan
2 Nagoya University Graduate School of Medicine, Higashi-ku, Nagoya, Aichi, Japan
3 Department of Radiotherapy, Nagoya University Hospital, Showa-Ku, Nagoya, Aichi, Japan

Correspondence Address:
Tomohiro Shimozato
Department of Radiological Technology, Nagoya University School of Health Sciences, 1-1-20 Daikou-minami, Higashi-ku, Nagoya, Aichi 461-8673
Japan

To investigate the effects of scattered radiation when a thin titanium plate (thickness, 0.05 cm) used for skull fixation in cerebral nerve surgery is irradiated by a 4-MV photon beam. We investigated the dose distribution of radiation inside a phantom that simulates a human head fitted with a thin titanium plate used for post-surgery skull fixation and compared the distribution data measured using detectors, obtained by Monte Carlo (MC) simulations, and calculated using a radiation treatment planning system (TPS). Simulations were shown to accurately represent measured values. The effects of scattered radiation produced by high-Z materials such as titanium are not sufficiently considered currently in TPS dose calculations. Our comparisons show that the dose distribution is affected by scattered radiation around a thin high-Z material. The depth dose is measured and calculated along the central beam axis inside a water phantom with thin titanium plates at various depths. The maximum relative differences between simulation and TPS results on the entrance and exit sides of the plate were 23.1% and − 12.7%, respectively. However, the depth doses do not change in regions deeper than the plate in water. Although titanium is a high-Z material, if the titanium plate used for skull fixation in cerebral nerve surgery is thin, there is a slight change in the dose distribution in regions away from the plate. In addition, we investigated the effects of variation of photon energies, sizes of radiation field and thickness of the plate. When the target to be irradiated is far from the thin titanium plate, the dose differs little from what it would be in the absence of a plate, though the dose escalation existed in front of the metal plate.


How to cite this article:
Shimozato T, Yasui K, Kawanami R, Habara K, Aoyama Y, Tabushi K, Obata Y. Dose distribution near thin titanium plate for skull fixation irradiated by a 4-MV photon beam.J Med Phys 2010;35:81-87


How to cite this URL:
Shimozato T, Yasui K, Kawanami R, Habara K, Aoyama Y, Tabushi K, Obata Y. Dose distribution near thin titanium plate for skull fixation irradiated by a 4-MV photon beam. J Med Phys [serial online] 2010 [cited 2022 Aug 10 ];35:81-87
Available from: https://www.jmp.org.in/article.asp?issn=0971-6203;year=2010;volume=35;issue=2;spage=81;epage=87;aulast=Shimozato;type=0