Multiple-source models for electron beams of a medical linear accelerator using BEAMDP computer code

The aim of this work was to develop multiple-source models for electron beams of the
NEPTUN 10PC medical linear accelerator using the BEAMDP computer code.
Background: One of the most accurate techniques of radiotherapy dose calculation is the
Monte Carlo (MC) simulation of radiation transport, which requires detailed information of
the beam in the form of a phase-space file. The computing time required to simulate the
beam data and obtain phase-space files from a clinical accelerator is significant. Calculation
of dose distributions using multiple-source models is an alternative method to phase-space
data as direct input to the dose calculation system.
Materials and methods: Monte Carlo simulation of accelerator head was done in which a
record was kept of the particle phase-space regarding the details of the particle history.
Multiple-source models were built from the phase-space files of Monte Carlo simulations.
These simplified beam models were used to generate Monte Carlo dose calculations and to
compare those calculations with phase-space data for electron beams.
Results: Comparison of the measured and calculated dose distributions using the phasespace
files and multiple-source models for three electron beam energies showed that the
measured and calculated values match well each other throughout the curves.
Conclusion: It was found that dose distributions calculated using both the multiple-source
models and the phase-space data agree within 1.3%, demonstrating that the models can be
used for dosimetry research purposes and dose calculations in radiotherapy