Figure 1. The energy-dependent hypothesis of apoptosis induction.

A. Schematic representation of different paths in the space of control parameters (kV, T) used in our experiments. Here, we assumed that the energy of each photon (ε) generated by the X-ray source increases along with the voltage setting (kV) whereas its current (j) remains fixed. Thus, the total exposure (E) at which an embryo is subjected at any given time is proportional to kV x T. Three different scenarios are denoted and were tested: (Scenario A) E increases a as result of augmenting the energy of the photon ε and, therefore, kV while maintaining the exposure time (T) constant; (B) E increases by augmenting T while keeping a constant value for kV; and (C) E remains constant throughout all states analyzed as a result of increasing the exposure time (T) while diminishing kV accordingly. Each colored line represents a different total exposure, also named “dose”, E. The dotted line indicates a hypothetical threshold level below which there is not an observable effect of radiation in a biological system. B. Summary of the experimental conditions to be analyzed in order to evaluate the scenarios discussed above.