Technetium-99m has a half-life of 6 hours. What percentage of an injected dose remains after 24 hours?
Correct answer D. 6.25%
Explanation
Number of half-lives = 24/6 = 4, so the fraction of technetium-99m remaining is (1/2)⁴ = 1/16 = 6.25% of the injected dose.
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