Correction of scatter in CBCT with a new grid design.


This study aims at developing a simple and rapid Compton scatter correction approach for cone-beam CT (CBCT) imaging.
Approach:
In this work, a new Compton scatter estimation model is established based on two distinct CBCT scans: one measures the full primary and scatter signals without anti-scatter grid (ASG), and the other measures a portion of primary and scatter signals with ASG. To accelerate the entire data acquisition speed, a half anti-scatter grid (h-ASG) that covers half of the full detector surface is proposed. As a result, the distribution of scattered X-ray photons could be estimated from a single CBCT scan. Physical phantom experiments are conducted to validate the performance of the newly proposed scatter correction approach.
Main Results:
Results demonstrate that the proposed half grid approach can quickly and precisely estimate the distribution of scattered X-ray photons from only one single CBCT scan, resulting in a significant reduction of shading artifacts. In addition, it is found that the h-ASG approach is less sensitive to the grid transmission fractions, grid ratio and object size, indicating a robust performance of the new method.
Significance:
In the future, the Compton scatter artifacts can be quickly corrected using a half grid in CBCT imaging.