A study of wavelet-based denoising and a new shrinkage function for low-dose CT scans
Sadegh Mohammadi, Th. Leventouri · Biomedical Physics & Engineering Express · 2019
Abstract Wavelet transformation is known as a strong method for signal and image processing tasks in the medical applications. We utilized this transformation to reduce the noise in low-dose x-ray computed tomography (CT) images. The CT images had been acquired with 75% less radiation dose compared to the normal dose scans. In this paper we propose a shrinkage function that outperforms the traditional ones and it doesn’t require any selected parameters, if it is tuned for the specific region of the patient volume. In addition, the denoising performances of combinations of wavelet orders, decomposition levels, and thresholding methods were investigated. The results revealed the best combination of wavelet order and decomposition level for low dose CT denoising.