Monte Carlo Evaluation of Gamma Knife Dose Profile in Real Brain Phantom

Aghaebrahimian, Ali and Alamatsaz, Mohammad Hassan (2016) Monte Carlo Evaluation of Gamma Knife Dose Profile in Real Brain Phantom. Iranian Journal of Medical Physics, 13 (1). pp. 1-7.

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Introduction The Gamma Knife system is designed solely for non-invasive treatment of brain disorders, and it benefits from stereotactic surgical techniques. Dose calculations required in the system are performed by GammaPlan code; in this code, brain tissue is considered uniform. In the present study, we evaluated the effect of Gamma Knife system on the obtained dose through simulating a real human brain phantom. Materials and Methods In this study, a Monte Carlo simulation code (MCNPX2.7) was employed to simulate Gamma Knife system. Brain tissue equivalent Snyder phantom and combinations were considered according to International Commission on Radiological Units (ICRU)-44 report. Results To ensure accuracy of the simulations, patient�s head was modeled by a spherical water phantom. At this point, the dosimetry parameters were compared with those obtained by the Monte Carlo code EGS4 and good consistency was observed (less than 7 difference). At the next stage, the above dosimetry parameters were compared with those obtained experimentally by polystyrene phantom and EDR2 dosimetry film and improved consistency was detected (less than 0.5 difference). Finally, the Snyder phantom, as the human brain, was simulated. The Full Width at Half Maximum (FWHM) and penumbra decreased by 4.7 and 18, respectively. Moreover, an isocenter dose reduction of 30-40, compared to the water phantom, was noted. Conclusion The calculation of the real phantom showed that water and polystyrene could function similarly, while evaluating dosimetry parameters in the Gamma Knife system; thus, water and polystyrene are not appropriate phantom matters for this purpose.

Item Type: Article
Subjects: WN Radiology . Diagnostic Imaging
Divisions: Journals > Iranian J Medical Physics
Depositing User: ijmp ijmp
Date Deposited: 24 Sep 2017 14:22
Last Modified: 24 Sep 2017 14:22

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