A novel technique to suppress grid line artifacts

Abstract

It has been established that coarse strip density, air-interspace grid systems can suppress scatter in general radiography and in mammography more effectively than conventional high strip density grids. However, such systems have never gained clinical acceptance due to the large distance the grid needs to move to suppress gridline artifacts and due to their corresponding bulk. We present a novel technique for suppressing grid lines using an x-ray exposure wave form with a soft start and soft stop. The wave form is achieved by varying the x-ray tube current during the exposure. We derive the conditions that the time dependence of the x-ray exposure output needs to meet to suppress gridline artifacts with only a modest grid movement. The technique allows for the design of compact coarse strip density grid systems. We present experimental results that demonstrate the feasibility of the technique.

Design and evaluation of a grid reciprocation scheme for use in digital breast tomosynthesis

“…21 Much like the flat-field correction method presented here, the tube output must closely and reproducibly be synchronized with grid motion for artifact removal to be consistent. Gauntt and Barnes explain that even with their novel technique, GLA presence is never exactly zero.…”

“…Gauntt and Barnes explain that even with their novel technique, GLA presence is never exactly zero. 21 Because of the possibility of inconsistency from one acquisition to the next, post-acquisition image filtering was considered. Marayuma and Yamamoto proposed a median filtering method for smoothing grid lines in x-rays films.…”

Grid artifact reduction for direct digital radiography detectors based on rotated stationary grids with homomorphic filtering

“…In practical applications for a fixed N, the grid frequency should satisfy the relationship f 1 > c 0 /N from Eq. (6). Hence, we should impose an additional constraint on f 1 in the optimization problem of Eq.…”

“…They also derived the grid shadow profiles for moving and stationary grids and suggested an artifact suppression technique for moving grids. 6 For a compact design of the radiography imaging system, however, using a stationary grid is attractive, 7 and then analog filters can remove the grid artifact components as described by McGillem and Riemer 8 if scanning technologies such as film digitizers are employed.…”

A new stationary gridline artifact suppression method based on the 2D discrete wavelet transform

“…Numerous approaches have been undertaken to suppress the gridline artifacts in x-ray images. [7][8][9][10][11][12][13][14][15][16][17][18] Some researchers have reported methods that avoid gridline artifacts by adjusting some of the physical modules during the x-ray projection and detection process in the imaging system. [7][8][9][10][11] These methods are limited in some specific situations because of the induced system architecture complexity.…”