Hi, The first thing come to my mind is vtkExtractVOI. If you can extract the slice(s) your are interested, then just build the histogram. -- View this message in context: http://vtk.1045678.n5.nabble.com/Histogram-for-dicom-slice-tp5736883p5736921.html Sent from the VTK - Users mailing list archive at Nabble.com.