.decimal CT QA software allows users to compare an actual “as-manufactured” range compensator to the expected device as it was designed by the treatment planning system. Users simply scan the compensators using their existing patient CT scanner and then import the resulting images into p.d. The software performs a density-weighted thickness determination along thousands of raylines for each compensator. By using CT imaging as opposed to standard optical or physical probing techniques, this software is able to detect errors in thickness, density, and surface shape, making this tool the most comprehensive commercial range compensator QA tool available.