Question

# Painful bone metastases are common in advanced prostate cancer. Physicians often order treatment with strontium-89 (89Sr), a radionuclide with a stron

Normal distributions

Painful bone metastases are common in advanced prostate cancer. Physicians often order treatment with strontium-89 (89Sr), a radionuclide with a strong affinity for bone tissue. A patient is given a sample containing 4 mCi of $$\displaystyle{89}^{{{S}{r}}}$$.
If 20% of the $$\displaystyle{89}^{{{S}{r}}}$$ remains in the body after 90 days, write a function of the form $$\displaystyle{Q}{\left({t}\right)}={Q}{0}{e}^{{−{k}{t}}}$$ to model the amount Q(t) of radioactivity in the body t days after the initial dose.
b. what is the biological half-life of $$89^{Sr}$$ under this treatment? Round to the nearest tenth of a day.

a. $$\displaystyle{Q}{\left({t}\right)}={Q}{o}{e}^{{-{0.017882}{t}}}$$