Objective To build a Monte Carlo model of a type of gamma knife independently produced in China, and prove the accuracy of this model and study dose field characteristics of the gamma knife.
Methods Monte Carlo model was built based on Monte Carlo N-Particle Transport Code, and the simulation result was verified by the experiment results.
Results Off Axis Ratio:the simulation result of Off Axis Ratios was in good agreement with the experiment results, the top dose rate platform decreased with the radium of the collimators reduced, penumbra decreased to some degree but not obviously; isodose curves:the dose gradient of the plane perpendicular to rotate axis was minimum.
Conclusions (1) The Monte Carlo model was accurate and effective. (2)The distance between the tumor and body surface, the size, shape of the tumor and the heterogeneity of exposure field need to be considered when the treatment plan is developed.
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