Research in the field of tomography focuses on the techniques for efficient and accurate reconstruction of an image from noisy image. Medical images have large variations, for which it should be dealt case wise. Reduction of noise in medical imaging is not an easy task. This motivated us to reconstruct new techniques that preserve the important features of medical images. Medical imaging is used for clinical diagnosis and computer aided surgery. A number of researchers have published image denosing literature from past many years but excellent noise reduction and image quality improvement is still a challenging area. In view of this, denoising techniques using window based multiwavelet transformation and thresholding, Modified Genetic algorithm were used. For image quality improvement, modified image quality enhancement techniques were used. These techniques improved the quality of an image compared to earlier techniques. Mainly this book is targeted for professionals, research scholars who would like to develop their ideas and work in the area of digital image processing, for denoising and image quality improvement.