The two most common evaluators for CT scan denoising are Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index (SSIM). This paper offers an alternative evaluator by utilizing of Natural Image Quality Evaluator (NIQE) assessment to determine the performance of denoising work on noise artefact. The noise artefact was obtained during the cancer screening process and had a particular noise density pattern across the image. NIQE is one of the blind image assessments which rely on the measurable deviation of image patch as a reference; it can determine the improved quality of denoising image. Due to the method of comparison in NIQE, the two parameters: patch size and sharpness threshold, will play an essential part in getting the score compared with the result from the other evaluators (PSNR and SSIM).