The fractal dimension (FD) image is generated by considering each pixel in the original CT image as a single fractal dimension estimated from its 7x7 neighbours. The FD generated image remarkably enhances the tissue texture, and the internal subtle structures become more obvious as compared to the original CT image. This could help the physician's eyes in better delineating the tumour from the surrounding normal tissue; furthermore, the mean Fractal Dimension value of the tumour region of interest can give an indication of tumour aggressiveness. See the following reference: O. S. Al-Kadi and D. Watson, “Texture Analysis of Aggressive and non-Aggressive Lung Tumor CE CT Images,” IEEE Transactions on Biomedical Engineering, vol. 55, pp. 1822-1830, 2008.