Question

1. positron emission tomography (pet) is an advanced medical scanning technique. fluorine - 18 is a commonly used isotope for pet scans. which equation shows positron emission by f - 18? a (\frac{18}{9}f

ightarrow\frac{14}{7}n+\frac{4}{2}he) b (\frac{18}{9}f
ightarrow\frac{18}{10}ne+\frac{0}{-1}e) c (\frac{18}{9}f+\frac{0}{-1}e
ightarrow\frac{18}{8}o) d (\frac{18}{9}f
ightarrow\frac{18}{8}o+\frac{0}{1}e) equation a equation b equation c equation d

Explanation:

Step1: Recall positron - emission concept

In positron emission, a proton in the nucleus is converted into a neutron, and a positron ($_{1}^{0}e$) and a neutrino are emitted. The mass number of the parent and daughter nuclei remains the same, and the atomic number of the daughter nucleus is one less than that of the parent nucleus.

Step2: Analyze each option

For option A, it shows alpha - decay ($_{2}^{4}He$ emission), not positron emission. For option B, it shows beta - minus decay ($_{ - 1}^{0}e$ emission). For option C, it shows electron capture. For option D, Fluorine - 18 ($_{9}^{18}F$) undergoes positron emission to form oxygen - 18 ($_{8}^{18}O$) with the emission of a positron ($_{1}^{0}e$).

Answer:

D. $_{9}^{18}F
ightarrow_{8}^{18}O + _{1}^{0}e$