Dose response explorer: an integrated open-source tool for exploring and modelling radiotherapy dose-volume outcome relationships

Radiotherapy treatment outcome models are a complicated function of treatment, clinical and biological factors. Our objective is to provide clinicians and scientists with an accurate, flexible and user-friendly software tool to explore radiotherapy outcomes data and build statistical tumour control or normal tissue complications models. The software tool, called the dose response explorer system ( DREES), is based on Matlab, and uses a named-field structure array data type. DREES/Matlab in combination with another open-source tool ( CERR) provides an environment for analysing treatment outcomes. DREES provides many radiotherapy outcome modelling features, including ( 1) fitting of analytical normal tissue complication probability ( NTCP) and tumour control probability ( TCP) models, ( 2) combined modelling of multiple dose-volume variables ( e. g., mean dose, max dose, etc) and clinical factors ( age, gender, stage, etc) using multi-term regression modelling, ( 3) manual or automated selection of logistic or actuarial model variables using bootstrap statistical resampling, ( 4) estimation of uncertainty in model parameters, ( 5) performance assessment of univariate and multivariate analyses using Spearman's rank correlation and chi-square statistics, boxplots, nomograms, Kaplan-Meier survival plots, and receiver operating characteristics curves, and ( 6) graphical capabilities to visualize NTCP or TCP prediction versus selected variable models using various plots. DREES provides clinical researchers with a tool customized for radiotherapy outcome modelling. DREES is freely distributed. We expect to continue developing DREES based on user feedback.