Monte Carlo calculation of beam quality correction for solid-state detectors and phantom scatter correction at 137Cs energy

Beam quality correction k(QQ0) (r), which reflects the absorbed energy dependence of the detector, is calculated for solid-state detector materials diamond, LiF, Li2B4O7, and Al2O3 for the Cs-137 RTR brachytherapy source using the Monte Carlo-based EGSnrc code system. The study also includes calculation of detector-specific phantom scatter corrections k(phan) (r) for solid phantoms such as PMMA, polystyrene, RW1, solid water, virtual water, and plastic water. Above corrections are calculated as a function of distance r along the transverse axis of the source. k(QQ0) (r) is about unity for the Li2B4O7 detector. LiF detector shows a gradual decrease in k(QQ0) (r) with r (decrease is about 2% over the distance range of 1-15 cm). Diamond detector shows a gradual increase in k(QQ0) (r) with r (about 3% larger than unity at 15 cm). In the case of Al2O3 detector, k(QQ0) (r) decreases with r steeply (about 14% over the distance range of 1-15 cm). The study shows that some solid-state detectors demonstrate distance-dependent k(phan) (r) values, but the degree of deviation from unity depends on the type of solid phantom and the detector.