(Solved): The following questions concern radiation dose and radiation therapy. 2 points A beam of 168-MeV ni ...

The following questions concern radiation dose and radiation therapy. 2 points A beam of 168-MeV nitrogen nuclei is used for cancer therapy. If this beam is directed onto a \( 0.200- \) \( \mathrm{kg} \) tumor and gives it a 2.00-Sv dose, how many nitrogen nuclei were stopped in the tumor? (Use an RBE of 20 for heavy ions.) Express your answer in scientific notation. 2 points Calculate the dose in \( \mathrm{mSv} \) to the chest of a patient given an \( x \)-ray under the following conditions. The \( x \) ray beam intensity is \( \backslash\left(1.50 \backslash\right. \) frack \( \left\{\mathrm{rm}\{\mathrm{W}\} \backslash \mathrm{rm}\{\mathrm{m}\}^{\wedge} 2\right\} \), the area of the chest exposed is \( 0.0750 \mathrm{~m}^{2}, 35.0 \% \) of the \( x \)-rays are absorbed in \( 20.0 \mathrm{~kg} \) of tissue, and the exposure time is \( 0.250 \mathrm{~s} \). 2 points A cancer patient is exposed to \( \gamma \) rays from a \( 5000-\mathrm{Ci} \) \( { }^{60} \mathrm{Co} \) transillumination unit for \( 32.0 \mathrm{~s} \). 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 \( 1.50 \mathrm{~kg} \). What is the dose, in rem, to the tumor, if the average \( \gamma \) energy per decay is \( 1.25 \mathrm{MeV} \) ? None of the \( \beta^{-1} \mathrm{~s} \) from the decay reach the patient.