Abstract: A method for analysing a sample comprising a first material and a second material of generally different densities and having a junction therebetween, the method comprising defining a region of interest in a cross sectional image of at least a portion of the sample that includes said junction, determining a density profile of the sample within the region of interest and crossing the junction, determining a representative density of said second material, and analysing said sample using said junction used to distinguish said first and second materials.