Comunicazione
Innovative cone beam computed tomography orbit toward quantitative imaging.
Vanore I., Sarno A.
This work aims at investigating an innovative cone beam CT (CBCT) scanning geometry (ExoCT) for reduction of detected scatter and cone artifacts for improvement of accuracy and precision in quantitative evaluations. A CBCT scanner prototype was upgraded by permitting an oscillating trajectory and a tuneable beam collimation with the intent of reducing scatter and cone-related artifacts. In experimental studies on wax handmade phantom embodying different material inserts we found out that the ExoCT permits to improve accuracy in attenuation coefficients estimates up to 15% with respect to CBCT. A test on a Defrise phantom, with air gaps sandwiched between plastic discs showed that conspicuity of reconstructed images for remote portion of the FOV is preserved in ExoCT, with the visibility of quoted air gaps reduced in CBCT for large cone angles. Normalised noise power spectrum resulted 35% lower in ExoCT, this is mainly due to the minor amount of the detected scatter. Comparison between image quality of ExoCT and conventional CBCT showed that, in the first one, the reduction of cupping artifacts led to increase the accuracy in quantitative analysis.