Design and research of an improved radiosurgical collimator

In this paper, a new collimator based on Hygeia GMX-1 cobalt (60Co) radiosurgery system was designed and analyzed using the Monte Carlo simulation program GEANT4. The results of EBT3 film measurements showed that the field penumbra of the improved collimator was reduced by 17.6% and the absorbed dose rate was 2.12 times higher, while the source activity, source axis distance and field size remained unchanged. The collimator has significant advantages in the two key technical parameters of absorbed dose rate and penumbra.