Field output correction factors and perturbation factor analysis for novel SunSILICON and SunSILICON P silicon diode...

Field output factor measurements of clinical linear accelerators require detector-specific corrections, due to the introduction of fluence perturbation effects by non-water-equivalent components of applied detectors.

This study aims to determine field output correction factors for novel shielded and unshielded silicon diode detectors in high energy photon fields. Special emphasis is placed on understanding the influence of perturbation factors and evaluating the suitability of these detectors across a wide range of field sizes.

Field output correction factors for the silicon diodes SunSILICON and SunSILICON P were determined through experimental measurements conducted at four distinct sites. Monte Carlo-based models of the diode detectors were developed to calculate field output correction factors using the EGSnrc code system. In addition, these silicon diode models enabled a detailed analysis of perturbation factors for field sizes from 0.6 cm up to 40 cm.

Experimentally determined and Monte Carlo calculated field output correction factors are in good agreement for the detectors investigated. The perturbation factor analysis demonstrated a strong field size dependence of the fluence perturbation factor for silicon.

This is the first study to systematically characterize the SunSILICON diode detector family using both simulation and measurement. The findings confirm that both shielded and unshielded designs are suitable for clinical dosimetry in photon beams, requiring only minor corrections. The shielding of the SunSILICON P diode enables accurate field output factor measurements across a broad range of field sizes, establishing its utility in modern radiotherapy applications.