The goal of this study was to develop new indices for effectively evaluating the dose coverage and homogeneity based on the target-volume dose-volume histogram (TV-DVH) of intensity-modulated radiotherapy treatment plans. A new coverage index and a new homogeneity index were developed by integrating a modified TV-DVH and by fitting a TV-DVH with a modified step function, respectively. The coverage index, named the I-index, indicates whether the dose coverage for the target volume is adequate based on user-defined criteria. A lower I-index indicates higher dose coverage of the tumor volume. The index for assessing dose homogeneity in a target volume, named the n-index, is more accurate than the conventional method in evaluating the dose homogeneity in a tumor volume. The baseline treatment plan for a target volume coverage and homogeneity is discussed. The proposed simple indices have been demonstrated to be effective in evaluating the dose coverage and homogeneity for TV-DVHs.

KeywordsCoverage index, Homogeneity index, Uniformity index, Target-volume DVH, Radiotherapy