A 60Co source with activity 2.6 x 10-4Ci is embedded in a tumor that has mass 0.500 kg. The source emits γ photons with average energy 1.25 MeV. Half the photons are absorbed in the tumor, and half escape.
(a) What energy is delivered to the tumor per second?
(b) What absorbed dose (in rad) is delivered per second?
(c) What equivalent dose (in rem) is delivered per second if the RBE for these γ rays is 0.70?
(d) What exposure time is required for an equivalent dose of 200rem?