Monitor unit calculations using a 3D computerised treatment planning system: verification in an anthropomorphic phantom

The aim of this work was to assess the monitor unit calculation accuracy of a new 3D computer planning system in a volume containing significant lung heterogeneity. An anthropomorphic phantom drilled to accommodate a cylindrical ionisation chamber was used for measurements. Results were also compared to an older 2D system and a manual calculation method. Only a slight improvement was achieved with the new system and an energy dependence was evident. This type of test is recommended before implementing a new 3D planning system. Copyright (1999) Australasian Physical and Engineering Sciences in Medicine and the College of Biomedical Engineers