Denoising of iodine-131 images using a median filter

In this study, we have compared the performance of a plus-shape and a square-shape median filter for 131I whole-body images and found the filter with optimum parameter that improves 131I image quality acceptable to nuclear medicine physicians. Materials and methods A total of 150 whole-body 131I images were exported in DICOM format. These images were converted into PNG format and processed with a plus-shape and a square-shape median filter, with each shape mask having sizes of 3, 5, 7, and 9 pixels. The quality of the processed images was assessed by visual assessment by two nuclear medicine physicians and also quantitatively by evaluating metrics: mutual information, mean square error, peak signal-to-noise ratio, and difference entropy. Nuclear medicine physicians assigned a score to each image on the scale 1 (lowest) to 5 (highest) for image quality on the basis of the noise removal, smoothness, and edge information available in the image. Student’s t-test was carried out to find the significant difference in the image quality (α=0.05) between the processed images with square-shape and cross-shape mask with the same pixel size. All experiments including statistical analysis were conducted using R installed on a personal computer. Results Both median filters improved the image quality of 131I images. The plus-shape median filter was found to show better performance in comparison with the square-shape median filter (P
Source: Nuclear Medicine Communications - Category: Nuclear Medicine Tags: ORIGINAL ARTICLES Source Type: research