Typical X-ray imaging systems for diagnosing chest diseases include general X-ray radiography, which can acquire one cross-sectional image and computed tomography (CT) based on 360-degree projection data and the reconstruction process. In particular, X-ray imaging systems are widely used to detect chest nodules or masses. In recent years, the use of an X-ray-based imaging system has become essential in the field of diagnostic medicine. In conclusion, the applicability of the NLM noise reduction algorithm to CDT X-ray images using limited projection data was demonstrated. In particular, the performance of the NLM algorithm showed superior results to those obtained with the conventional filtering methods. When the similarity evaluation parameters were measured, we proved that 11%–53% better values were derived compared with the noisy image in the NLM algorithm. As a result, we confirmed that the coefficient of variation of the noise level was improved about 9.74 times compared with the noisy image when the NLM noise reduction algorithm was applied to the CDT X-ray image. Conventional filtering methods were used in the comparison group to analyze the efficiency of the NLM algorithm. The NLM noise reduction algorithm was modeled as a method for obtaining weights based on the similarity of the neighboring set of pixels. For quantitative evaluation, a reference image was obtained using the full radiation dose, and a noisy image was obtained using the minimum radiation dose to increase the amount of noise. CDT X-ray images using a human phantom were generated employing the filtered back-projection reconstruction method with a projection angle of ± 36. The aim of this study is to model the non-local means (NLM)-based algorithm, which is known to be very effective in removing noise from X-ray images, and to confirm its applicability in the CDT system. In these CDT X-ray images, noise reduction methods using software that reduce the accuracy of lesion detection are essential. As a method for diagnosing chest lesions, a chest digital tomosynthesis (CDT) X-ray imaging system based on projection data using a limited angle has been widely used in the medical field since its development.

Siberean moise magnet