Purpose: To evaluate head and neck IMRT plans with spatial dose‐volume histograms (DVHs) that have been calculated with a computational tool for DVH analysis. Method and Materials: A computational tool called HART (Histogram Analysis in Radiation Therapy) was developed for the efficient analysis of treatment plan DVHs. Notable functions include user‐defined DVH endpoints, an outcome analysis toolbox for biological endpoints such as tumor control probability (TCP) and normal tissue complication probability (NTCP) and a user‐friendly graphical interface. A recent addition to the HART package is the ability to calculate spatial DVHs in all three dimensions (xDVH, yDVH and zDVH). In this study, spatial DVHs in all three directions were extracted for ten head and neck IMRT plans and compared to conventional DVHs. Dose‐volume data was examined for all targets and 26 critical structures. Results: The attraction of the conventional DVH has been that it can summarize a 3‐D isodose distribution onto a 2‐D plot. Unfortunately, the cost of this transformation is the loss of spatial information. Spatial DVHs have been shown to provide information on the position of “hot” and “cold” spots in the dose distribution while still maintaining the simplicity of a 2‐D plot. This additional spatial data can then be used for correlation to complications in normal tissues. By automating the extraction and computation of all DVH data, it was shown that HART is a useful tool for the evaluation of IMRT treatment plans with spatial and conventional DVHs. Conclusion: Spatial DVHs can be used as a complementary tool to conventional DVHs in the evaluation of head and neck IMRT plans. Automating these computations with software such as HART allows for the routine clinical use of spatial DVHs.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging