Image quality improvement in a sparse-view cone-beam computed tomography using an anti-scatter grid

Abstract

Anti-scatter grids are known to suppress the scatter significantly thus improving contrast of image in radiography. However, its use in cone-beam CT for the purpose of improving contrast-to-noise ratio (CNR) has not been successful mainly due to increased noise related to Poisson statistics of photons. This paper proposes a sparse view cone-beam CT with the use of an anti-scatter grid to improve CNR. Compared to the conventional method, the proposed method reduces the number of projections and increases exposure in one projection to enhance image quality in terms of CNR without an additional cost of radiation dose. For image reconstruction from sparse-view data, a total-variation minimization algorithm was adopted. We conducted both simulation study and experiment to compare the resulting images by the conventional and the proposed methods quantitatively. The results showed that contrast and CNR by the proposed method have increased compared to the conventional method at the same or less total radiation dose condition and that the cupping artifact has been reduced as well. The proposed method can provide high quality image by using an anti-scatter grid with no additional radiation dose to the patient.