A cancer treatment called the gamma knife (see Insight 29.1, Biological and Medical Application of Radiation) uses focused 60Co sources to treat tumors. Each 60Co nucleus emits two gamma rays, of energy 1.33 MeV and 1.17 MeV, in quick succession. Assume that of the total gamma-ray energy is absorbed by a tumor. Further assume that the total activity of the 60Co sources is 1.00 mCi, the tumor’s mass is 0.100 kg, and the patient is exposed to the gamma radiation for an hour. Determine the effective radiation dose received by the tumor. (Since the 60Co half-life is 5.3 years, changes in its activity during treatment are negligible.)