Simulated superficial and deep tissue doses using niobium filtration for cephalometric radiography

Abstract

The effect of added niobum filtration 30 μm and 50μm on constant potential and conventional full-wave rectified cephalometric units was explored in terms of radiation dose. Water was used to simulate soft tissues to attenuate the X-ray beam. The addition of niobium 30μm and 50μm for each unit caused a reduction in the surface dose, but resulted in an increase in the dose deep to 8 cm of water. The more heavily filtered beam reduced the surface dose most for each operating potential, while, providing the highest deep dose through 8cm of water in each case. There was a comparatively strong linear association between half-value layer (HVL) and relative dose at both the zero and the 8cm thicknesses of water. The coefficients of determination (r2) and the significant probabilities of correlation coefficient (p) were 0.82 (p<0.0001) at the surface and 0.89 (p<0.0001) with 8cm of water.