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How many atoms of carbon-11 were injected into the subject?How many molecules of cocaine?Why are they not same

Cocaine binds to and inhibits the dopamine reuptake transporter that controls dopaminergic neurotransmission, thus raising extracellular dopamine in the striatum, the principal brain area containing dopamine nerve terminals. PET images of a human brain taken 10 minutes after intravenous injection of 10 mCi of carbon-11 labeled cocaine ([11C]cocaine) prepared in high specific radioactivity (1 Ci/micromol at the time of injection) showed that the concentration of radioactivity in striatum was 0.8 microCi per cubic centimeter (cc), while the concentration in cerebellum (a brain region that lacks dopamine nerve terminals) was 0.5 microCi per cc. Assume that 1 cc = 1 mL, that a state of equilibrium between bound and free cocaine exists at 10 min, that the half-life of Carbon11 is exactly 20 min, and that Avogadro’s Number is exactly 6 x 10^23.

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1. because they arnt