Purpose: To compare the quality of IMRT plans optimized with biologically (EUD) based versus dose‐volume based objectives in a commercial treatment planning system in the treatment of head and neck cancers. Method and Materials: EUD‐based optimization was utilized in the Philips Pinnacle P3IMRT treatment planning system (licensed for Biological Evaluation) to obtain intensity‐modulated radiation therapy plans for five head and neck cancer patients. These plans were evaluated against IMRT plans optimized with conventional dose‐volume objectives. Each patient had twenty‐six organs‐at‐risk (OAR) contoured within the head and neck region. The plans were compared by examining dose‐volume histograms, dosimetric indices and biological endpoints. Dosimetric indices included mean, minimum and maximum doses, as well as target conformality, dose uniformity and the generalized EUD. Biological endpoints included tumor control probability (TCP), normal tissue complication probability (NTCP) and uncomplicated tumor control probability (P+). Results: Preliminary results show that the EUD‐based optimization in P3IMRT is capable of improving the sparing of OAR while maintaining target coverage. The biologically‐based optimization resulted in greater dose inhomogeneity and less conformality than the dose‐volume based optimization plans. It was also shown that plans optimized with EUD‐based objectives could obtain similar target coverage as the dose‐volume optimized plans but with fewer parameters. Conclusion: The P3IMRT biologically‐based optimization of head and neck IMRT plans resulted in equivalent target coverage while increasing the sparing of normal tissues compared to dose‐volume based optimization. This system can increase the efficiency of obtaining plans of equivalent or better quality by utilizing fewer parameters and has the potential of being incorporated into routine clinical use.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging