Assessment of tumor control probability for high-dose-rate interstitial brachytherapy implants

SummaryAimThe study was designed to propose a novel concept of biologically effective equivalent uniform dose to calculate tumor control probability for HDR implants.Materials and MethodsThe expression of biologically effective equivalent uniform dose was derived for non-uniform dose distribution in HDR implants using quality indices and voxel-based tumor control probability.ResultsThe results of this study show that high dose regions of the implant have higher tumor control probability. But these regions may also have a large number of normal cells and consequently may lead to severe normal tissue complications. If tumor coverage was not proper then the overall tumor control probability would be low and might result in tumor recurrence. Higher values of external volume index, dose non-uniformity ratio and overdose volume index were related to higher normal tissue complication rates outside and inside the implants.ConclusionThe present concept may provide an alternative approach to calculate tumor control probability for HDR implants.