Po‐Poster ‐ 21: On the use and sensitivity of dose‐functional volume histograms in radiation treatment planning
With the increased use of multi‐modality imaging in radiationoncology,dose functional volume histograms (DfVHs) have been introduced as a simple and insightful means of incorporating healthy and diseased tissue functional information in treatment evaluation. The DfVHs themselves may also be used to estimate radiobiological metrics such as the Equivalent Uniform Dose (EUD) or probability of tumor control and normal tissue damage. As the concepts of the DfVH and its utility in computing radiobiological metrics are still in development, the purpose of this work was to investigate the interpretation and sensitivities of DfVH curves and subsequently deduced radiobiological estimates by using mathematically defined and perturbed functional imagedata sets. Factors such as the signal to noise ratio of the functional image, the relationship between signal intensity of the functional image to the number of functional sub‐units in the voxel, and the extent of mis‐alignment of the functional image to the dose distribution all may affect the shape of the DfVH. As a consequence radiobiological metrics, such as the EUD, are also sensitive to these factors and caution is recommended when using these functions as a predictive measure of outcome. Despite this, the simplicity and relative robustness of the DfVH provides an efficient means of ranking the quality of competing treatment plans. This work was funded through a grant from the MDS‐Nucletron CCO Medical Physics Fund.