Reducing scatter and cone-beam artifacts in DE-CBCT

This study evaluates the feasibility of reducing scatter and cone beam artifacts in dual-energy CBCT (DE-CBCT) by using an axially collimated carbon nanotube (CNT) x-ray source array with interlaced spectral filters. A benchtop CBCT scanner with an energy integrating flat panel detector (FPD), a CNT x-ray source array, and a rotating gantry was used. X-ray photons from even-number focal spots were filtered by a low-energy (LE) filter, while those from the odd-number spots by a high-energy (HE) filter. The x-ray photons from each focal spot was confined by an external collimator to illuminate only a section of the object. DE-CBCT images were collected by cycling the eight beams sequentially during a full gantry rotation. An existing one-step materials decomposition and reconstruction method was modified for this specific imaging configuration. Phantom imaging studies showed significantly reduced cupping and cone beam artifacts, increased accuracy in material quantification, and enhanced image contrast compared to a regular DE-CBCT.