Investigation of proper imaging conditions in the moving grid technique for a reduction of grid line artifacts

摘要

The most critical problem remaining as an obstacle for the successful use of antiscatter grids in digital X-ray imaging is probably the observation of grid line artifacts such as moir, patterns and shadows of the grid strips themselves in X-ray images, resulting in a risk of misdiagnosis by physicians. In this paper, in order to find a practical solution to the problem of grid line artifacts, we revisited the moving grid technique and investigated its proper imaging conditions. We implemented a simple and useful moving-grid analysis code, iTOM ((TM)) , and performed systematic simulations for a theoretical analysis. We also performed experiments and compared the results to the simulated ones to demonstrate the effectiveness of the code. According to our simulation and experimental results, the grid line artifacts can be effectively reduced when the grid moves with a large velocity or with specific velocities that reduce the coefficient of variation (CV), even with a small velocity. These velocities are determined by using the related parameters such as the grid pitch, the grid strip width, and the exposure time.