بازسازي تصاوير برش نگاري رايانه اي به روش تكراري آماري-تركيبي

X-ray Computed Tomography (CT) is one of the most important medical imaging techniques, consisting of two main stages: data acquisition in the form of a sinogram and image reconstruction from this data. The choice of the appropriate reconstruction method not only impacts the final image quality but can also help reduce radiation dose and protect the patient. This study examines two image reconstruction methods: Filtered Back Projection (FBP) and Simultaneous Algebraic Reconstruction Technique (SART), each with its own unique features and advantages.The sinogram data for this study were simulated using the MCNPX software, and the image reconstruction process was carried out using MATLAB software. MATLAB is a suitable tool for these complex reconstructions due to its high computational power and capabilities in processing complex data.In this research, various phantoms, including contrast-detail, resolution, and point phantoms, were simulated under two radiation dose conditions: normal dose and low dose. To eva‎luate the quality of the reconstructed images, standard metrics such as Signal-to-Noise Ratio (SNR), Contrast-to-Noise Ratio (CNR), and Modulation Transfer Function (MTF) were used. These metrics directly assist in eva‎luating image clarity, detail preservation, and noise levels.The results indicate that under low-dose conditions, the SART method outperforms the FBP method. Under these conditions, SART was able to significantly improve image quality by reducing artifacts, enhancing SNR, and increasing CNR. This method has proven particularly effective in low-dose simulations, which typically lead to increased noise and artifacts.On the other hand, under normal-dose conditions, the FBP method demonstrated a good performance due to its faster image reconstruction and ability to preserve textural details. This characteristic is particularly important in clinical applications that require quick results. However, one drawback of the SART method is its longer computation time, which may be a limitation in certain clinical situations. Additionally, SART can sometimes cause changes in the image texture and excessive smoothing of details.The overall conclusion of this study suggests that under normal-dose conditions, the FBP method is more suitable due to its higher speed and ability to preserve image texture. In contrast, for low-dose conditions, where reducing artifacts and improving image quality are crucial, iterative methods like SART are more effective. These results can serve as a guide for selecting the appropriate reconstruction method based on different clinical needs and radiation conditions.

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