Application of a test package in an intercomparison of the photon dose calculation performance of treatment planning systems used in a clinical setting

Background and purpose: Testing the performance of treatment planning syste ms by using the AAPM Task Group 23 test package is a useful approach, but h as its limitations. To be able to include technical developments, such as t he asymmetric collimator, it was decided to remeasure the AAPM data set on more modern radiotherapy equipment, to extend the test geometries, and to e valuate the use of the new package. Materials and methods: A coherent set of beam data of 6, 10 and 18 MV photo n beams was measured on two modern linear accelerators. These data served a s input data in seven commercially available treatment planning systems, wh ich were clinically in use in different radiotherapy departments. Next, a t est package was measured which included a missing tissue geometry and field s with asymmetrical collimator setting, with and without a wedge. Results: The absolute dose prediction from the different treatment planning systems in which the measured beam data were entered, was compared for all test points with the results of direct measurements. The criteria of accep tability were exceeded by some systems in cases of irregular field geometry and missing tissue geometry. The majority of the systems had difficulties with accurate dose calculation for asymmetrically wedged fields. Conclusions: The application of the new test package did not introduce insu perable difficulties and was highly appreciated by the participating centre s. Most systems performed reasonably well for the majority of the beam geom etries, with the exception of asymmetrically wedged beams. The extended tes t package is available for other users or user group, for the purpose of co mmissioning new treatment planning systems, or new releases of existing sys tems. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.