1. A method for deriving the amount of dense tissue from a digital mammographic image representation comprising: (1) determining a region of interest in said image, (2) computing for each pixel in each location (x,y) in said region of interest a value h int (x,y) representing the amount of dense tissue below said pixel as h int ( x , y ) = 2 μ fat ( E ) - μ int ( E ) ( Log ( p ( x , y ) ) - Log ( p fat ) ) wherein p(x,y) represents the pixel value of a pixel at location (x,y) in said digital mammographic image, p fat is a reference fat pixel value, μ fat ,μ int are the linear attenuation coefficients of fat tissue and dense tissue as a function of E and E is the mono-energetic energy value of the x-ray source at image recording, in which E and p fat are derived from said digital mammographic image representation, and (3) from h int , deducing a breast classification value representative of the amount of dense tissue is deduced.