Estimate the Primary Electron Beam Parameters of Individual Linear Accelerator by Using Monte Carlo Methods

Objective To estimate the primary electron beam parameters (PEB), including energy, sigma and angular divergence, of the individual linear accelerator by using Monte Carlo method.

Methods  A model of treatment head and a standard field were built by BEAMnrc, and the dose distribution was simulated in water phantoms by DOSXYZnrc to obtain the percentage depth dose curve and off-axis ratio. By debugging parameters mentioned above until the simulation and measurement results could match.

Results The simulation and measurement results could achieve the best match when the parameters mentioned above were 6.2 5MeV, 0.95 mm and 0.1°respectively.

Conclusions The PEB of a linear accelerator could have a significant impact on the output beam characteristics. Monte Carlo estimating was one of the most crucial steps of establishing an individual linear accelerator model.