Fluorine-18 Undergoes Positron Emission with a Half-Life of 1

question 115

Multiple Choice

Fluorine-18 undergoes positron emission with a half-life of 1.10 × 10² minutes. If a patient is given a 248 mg dose for a PET scan, how long will it take for the amount of fluorine-18 to drop to 83 mg? (Assume that none of the fluorine is excreted from the body.)

• A) 99 minutes
• B) 1.7 × 10² minutes
• C) 1.3 × 10² minutes
• D) 3.0 × 10² minutes
• E) 2.1 × 10² minutes

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Definitions:

Ribosomes

Cellular structures responsible for protein synthesis in living organisms.

Nucleotides

Organic molecules that serve as the building blocks of nucleic acids, like DNA and RNA, each composed of a base, a sugar, and a phosphate group.

Rhizomes

A type of underground stem that sends out roots and shoots from its nodes, often used in plant reproduction.

Secondary Sex Characteristics

Physical features that emerge during puberty which are not directly involved in reproduction but distinguish the sexes.