Formalism of the NanOx biophysical model for radiotherapy applications

Introduction: NanOx is a theoretical framework developed to predict cell survival ionizing radiation in the context of radiotherapy. Based on statistical physics, takes stochastic nature at different spatial scales fully into account. It extends concepts from microdosimetry nanodosimetry, and considers as well primary oxidative stress. This article presents detail general formalism behind NanOx. Methods: Cell death induction modeled through two types biological events: local lethal events, by inactivation nanometric sensitive targets, global represented toxic accumulation stress sublethal lesions. The model structured premises postulates, bases compliant with physics chemistry, simplifications approximations, which are required for its practical implementation. Results: Calculations performed showed that energy deposited penumbra ion tracks may be neglected low-energy ions encountered some radiotherapy techniques, such targeted radionuclide therapy. On other hand, hydroxyl radical concentration induced was shown larger low-LET decrease faster time compared photons. Starting model, an expression derived events track-segment approximation. Discussion: combines existing biophysical models innovative features consider effects all levels order estimate relative effectiveness ions. details about given this paper allow anyone implement modify it introducing approximations improve it, or even adapt medical applications.