Small, medium and large optical cone beam CT

摘要

The reconstructed profile for a 9.6 cm outer diameter PFA teflon cylinder filled with a nigrosin dye solution is presented in figure 2. Three profiles from reconstructions with 0percent, 40percent and 100percent of measured stray light corrections are presented. No correction for stray light results in a bowed profile with a minimum along the diameter. This is consistent with an apparent "beam-hardening" artifact due to scattered light. Reconstructing with the measured stray light corrections generated the opposite trend in the profile. Through iteration, an attenuation of approx40percent of the measured value resulted in the most uniform profiles. Corrections for wall reflections had a small effect on the profile shape and magnitude. But wall reflection corrections were sensitive for introducing high contrast artifacts at the cylinder walls. The relatively large noise present in the highest resolution reconstruction is attributed to the poor optical uniformity of the sample of PFE teflon tubing available for this scan.