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In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected
photons are scattered within the body, resulting in the scatter component. Scattered radiation can significantly deteriorate
image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement and
non-measurement-based methods have been proposed in the past. Both methods can reduce scatter artifacts in
images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter
component correction. Therefore, we employed a measurement-based method to correct for the scatter component of
inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo
simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary
modulator, which has a checkerboard pattern, was used to modulate primary radiation. Cylindrical phantoms of variable
size were used to quantify imaging performance. For scatter estimation, we used Discrete Fourier Transform filtering.
The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter
components were accurately removed using a primary modulator. When the results acquired with scatter correction and
without correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher
than that obtained without correction, and the average root mean square error (RMSE) with the correction was 38.00%
better than that without correction. In the subtraction study, the average CNR with correction was 2.04 (aluminum
subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the
correction. The analysis demonstrated the accuracy of scatter correction and the improvement of image quality using a
primary modulator and showed the feasibility of introducing the primary modulation technique into dual energy
subtraction. Therefore, we suggest that the scatter correction method with a primary modulator is useful for the DEDR
system.
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