The paper presents the results of computational statistical experiment to estimate field radiation exposure on the soft tissue of the human body when external pressures are nondivergent narrow beam of gamma photon radiation. As an example, adopted the energy of a photon that enters 102 group energy axis constant laboratory ABBN. Given dose distribution in a cylinder diameter of 20 and a length of 10 centimeters. The method of statistical tests, known as Monte Carlo. Is used modify of the method with calculation the inverse functions. It is shown that the dose outside the beam ionization radiation load decreases by two orders, remains finite, that should be considered in therapeutic procedures, in which the total dose exceeds the lethal dose for a healthy bod

Keywords: gamma therapy, model analysis, Monte Carlo, radiation dose