Question
(a) A cancer patient is exposed to γ rays from a 5000-Ci ${}^{60}\textrm{Co}$ transillumination unit for 32.0 s. The $\gamma$ rays are collimated in such a manner that only 1.00% of them strike the patient. Of those, 20.0% are absorbed in a tumor having a mass of 1.50 kg. What is the dose in rem to the tumor, if the average $\gamma$ energy per decay is 1.25 MeV? None of the $\beta$s from the decay reach the patient. (b) Is the dose consistent with stated therapeutic doses?
1. $158 \textrm{ rem}$
2. With a typical treatment protocol of up to 5 exposures, this dose will total 7.9 Sv which is almost the typical total dose for treatment of lung cancer.
Solution Video