Technology and the irradiation chamber used by Scandinavian Clinics Estonia meets the requirements of the International Atomic Energy Agency. During 50 years of using gamma-radiation (Co-60isotope) for industrial purposes there haven’t been any incidents which have caused the elevated background radiation outside of irradiation chamber. Real tests carried out in United States demonstrated that such concrete chambers are resistant even to the plane crash.
It should also be emphasized that, unlike the nuclear fuel used in nuclear power plants, Co-60 isotope do not cause the secondary radiation, ie, the "Co-60 doesn’t make other objects to emit radiation".