[Evaluation of radiation treatment effectiveness using the rated standard dose (RSD) under different irradiation...

In the evaluation of efficacy or while comparing various irradiation schemes with the help of the RSD concept one should consider the effect of various conditions of patient's irradiation (energy, a field size, dose rate, etc.) on the biological efficacy of absorbed energy. The radiobiological effect of various irradiation schemes should be evaluated by a common scale, therefore factors altering dose biological efficacy should be considered within the limits of the same RSD formula. In our opinion, there is no sense in individualizing the evaluation of an effect of the dose rate on the biological efficacy of radiotherapy as a separate RSD formula. The incorporation in the RSD formula of an empirical expression of RBE dependence on the dose rate within the range of 0.13-300 Gy/hr. and factors of the dependence of dose biological efficacy on its spatial distribution (energy, a field size) gives an opportunity not only to consider more correctly changes in patient's irradiation from session to session but also makes it possible to apply it to fractionated and protracted irradiation schemes.