ABSTRACT
An important component of radiation therapy is the creation of a patient's treatment plan, including calculation of the dose distribution to be deposited. The problem of comparing calculated and/or measured dose distributions scales in complexity with the dimensionality of the distributions being evaluated. Though qualitative in nature, visual comparison allows for fast identification of gross differences in the dose distributions, which is useful for both treatment planning and quality assurance tasks. One of the most straightforward means of quantitatively comparing two dose distributions is by computing the dose difference. The concept of distance-to-agreement was developed as a means for comparing dose distributions in regions characterized by large dose gradients. Gamma is the minimum Euclidean distance between points in the evaluated and reference dose distributions calculated in the normalized dose difference–distance space. Target coverage is a useful metric in radiation therapy treatment planning because it indicates the percent volume of a target region-of-interest that receives prescription dose.
