A straightforward estimation of cardiac substructure exposure for clinical practice: example of breast rotational intensity modulated radiation therapy

Abstract

Introduction. Mean heart dose (MHD) is the most widely used dosimetric parameter for cardiac sparing during treatment planning. Specific cardiac substructure exposure could be more clinically important, but MHD cannot provide the radiation oncologist with precise insight at the substructural level. Materials. We propose a straightforward method for estimating cardiac substructure exposure based on linear regressions between mean dose delivered to cardiac substructures and MHD. We focused on breast irradiation with intensity modulated radiation therapy as an application example. Correlations between mean dose to cardiac substructures and MHD were statistically significant and usually moderate (r > 0.5) or strong (r > 0.7), allowing the use of such linear regression models to estimate cardiac substructure exposure from MHD for clinical practice. Conclusion. This method can be extrapolated to other clinical situations for daily practice, albeit with some restrictions.