Available in LEADTOOLS Medical Imaging toolkits.
LUT Encoding: VOI LUT
L_DicomGetWindowCount
L_DicomGetVOILUTCount
L_DicomGetWindow
L_DicomSetWindow
L_DicomDeleteWindow
L_DicomGetVOILUT
L_DicomSetVOILUT
L_DicomGetVOILUTData
L_DicomDeleteVOILUT