SDAnext: an open-source MATLAB application for survival data analysis in radiobiology

Cell survival curves are a foundational tool in radiobiology and radiation research. We present SDAnext, an open-source MATLAB application providing an intuitive graphical user interface for survival data analysis. The software supports validated data import, fitting to widely used analytical models (Linear, Quadratic, Linear-Quadratic, Linear-Quadratic-Cubic, and Linear-Quadratic-Linear), and publication-ready visualization. SDAnext implements weighted least squares fitting with optional robust estimators, explicit handling of experimental uncertainties, automated model scanning with a goodness-of-fit ranking and bidirectional dose-survival evaluation. Derived radiobiological quantities, including α/β ratios with uncertainty propagation, are computed when applicable. A dedicated multi-session viewer enables cross-dataset comparisons and integrated relative biological effectiveness analysis, with explicit reference selection. The application can be used from MATLAB or as a standalone Windows executable (via MATLAB Runtime). This Technical Note describes the software architecture, input format and workflow, fitting and evaluation features, visualization tools and typical usage scenarios.