Correction of scatter in computed tomography images of bone

A cylindrical aluminum/Plexiglas phantom representing trabecular bone surrounded by various amounts of cortical bone was constructed. Measurements of this phantom using a computed tomography scanner with a 1 2 5 I photon source demonstrated errors of 0% to 28% in the density of trabecular bone. Two contributing factors are identified: scatter and exponential edge‐gradient effect. A simple first‐order correction is developed to correct for the scatter‐induced error. Relative to the exponential edge‐gradient effect, which contributes up to 3.4% error over the range of cortical thicknesses measured, the correction procedure reduces the scatter‐induced error to a level of −0.66% to +0.61%. The consistency of the optimized correction parameters with the physical model as well as the effect of scatter measured by the same phantom on a GE 8800 scanner are shown.