MCNPX Simulation of Dosimetry From Grid Tpye Multi-Layer Pixel Collimator for Radiation Therapy Treatment
D Yoon1,2*, T Suh1,2*, (1) Department of Biomedical Engineering Research Institute of Biomedical Engineering Catholic Univ of Korea, Seoul,(2) Department of Biomedical Engineering Research Institute of Biomedical Engineering Catholic Univ of Korea, Seoul,SU-E-T-395 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
To develop grid type multi layer structure pixel collimator for radiation therapy treatment, feasibility of manufacture process and optimization of factors are essential using Monte Carlo simulation.
The present work is focused on a MCNP simulation of grid type pixel collimator(NxNxN) for radiation therapy. To realize actual pixel collimator hardware model, precise radiation shielding data and construction standard of collimator frame have been demanded. the pixel collimator cover which has opening type to radiation protection is defined as square with 1mm scale thickness. Frame window to fix several pixel collimators as grid type is constructed in simulation. If these pixel collimators arrange in window frame, it composes one of collimator layer which can be combined as multi layer. For these process, it is need to satisfy at least MLC quality assurance(QA). Furthermore, it is need to prove more than one specific advantage comparison with MLC. Radiation attenuation about layers, leakage radiation among pixels, model bulk, absorbed dose in EPID were calculated by using MCNP.
About pixel type collimator, the main research respects are accurate degree of attenuation, leakage radiation among pixel cover and influence of collimator frames. In case of 2MeV photon beams, quantitative attenuation measurement data and leakage estimation were calculated a similar level of MLC QA, optimal collimator frame size and structure are being constructed.
In this study we have developed a grid type pixel collimator for radiation therapy treatment using MCNP simulation based on multileaf collimator QA datas. This research has potential possibility of realization about actual new collimator as MCNP simulation data. Also in case of difficult pattern which has to consider intensity modulation like web, doughnut pattern, it was shown effective modulation