Monte Carlo simulation and dosimetry verification of phantoms under LINAC with dynamic wedges

• Main Authors: Chen, Lu-Yu, 陳律宇
• Other Authors: Chang, Kwo-Ping
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/zyuwfh

碩士 === 慈濟技術學院 === 放射醫學科學研究所 === 102 === Abstract Dynamic wedges filter is commonly used in the radiotherapy. The Monte Carlo simulation is a recognized method for radiation dose verification. In Taiwan , there is lacking of basic simulation data and dose validation studies of dynamic wedge used in the treatment planning system. In this study, we have used the DYNJAWS component module in BEAMnrc code to perform Monte Carlo simulation and compared to the IBA water phantom and EBT2 films measurements. The phase space files of wedge dose distributions generated by the DYNJAWS were used as a source for DOSXYZnrc simulation in the phantom. We analyzed the dynamic wedge dose profiles and percentage depth dose, then we applied the DWs PHSP files to dose verification of a cylinder phantom. In the Monte Carlo simulation in BEAMnrc. The results showed that the measurement of dose distribution of the dynamic wedge with TPS calculations and Monte Carlo simulation data are in good agreements, which are further verified in those results for the home-made phantom. The TPS and Monte Carlo approximation surface dose of the skin incidence shows the TPS has overestimated the dose about 40%.This study has successfully simulated the dynamic wedges using the DYNJAW with STTs (Segment Treatment Tables) of TPS. Such approach can be used to derive accurately more basic dosimetry properties of the radiotherapy using dynamic wedges.