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.
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.
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.
Aghaebrahimian, A., & Alamatsaz, M. H. (2016). Monte Carlo Evaluation of Gamma Knife Dose Profile in Real Brain Phantom. Iranian Journal of Medical Physics, 13(1), 1-7. doi: 10.22038/ijmp.2016.7139
Ali Aghaebrahimian; Mohammad Hassan Alamatsaz. "Monte Carlo Evaluation of Gamma Knife Dose Profile in Real Brain Phantom". Iranian Journal of Medical Physics, 13, 1, 2016, 1-7. doi: 10.22038/ijmp.2016.7139
Aghaebrahimian, A., Alamatsaz, M. H. (2016). 'Monte Carlo Evaluation of Gamma Knife Dose Profile in Real Brain Phantom', Iranian Journal of Medical Physics, 13(1), pp. 1-7. doi: 10.22038/ijmp.2016.7139
Aghaebrahimian, A., Alamatsaz, M. H. Monte Carlo Evaluation of Gamma Knife Dose Profile in Real Brain Phantom. Iranian Journal of Medical Physics, 2016; 13(1): 1-7. doi: 10.22038/ijmp.2016.7139