1. A method for improving quality in a positron emission tomography image, comprising: masking a background in the positron emission tomography image, wherein masking generates a new set of input data for the positron emission tomography image; normalizing a pixel in the new set of input data for the positron emission tomography image to correct for a background noise; determining a reference region in the positron emission tomography image; enhancing a contrast of the pixel in the new set of input data for the positron emission tomography image as a function of the reference region; and applying a multivariate analysis method on the new set of input data for the positron emission tomography image.