Technetium-99m is a radioactive isotope commonly used in medicine as a radioactive tracer. A radioactive tracer is an isotope injected into the body to help create images for diagnosis of health problems. Technetium-99m has a half-life of 6 hours. If a patient receives a dose of technetium-99m one morning, about what percentage of the technetium-99m will be left in the patient's body 12 hours later?
a
25.0%
b
6.25%
c
12.5%
d
93.8%
The half-life of Technetium-99m is 6 hours, which means that after 6 hours, half of the Technetium-99m will have decayed. After another 6 hours (12 hours total), another half of the remaining Technetium-99m will have decayed.
So, after 12 hours, there will be (1/2) * (1/2) = 1/4 = 25% of the original Technetium-99m left in the patient's body.
Therefore, the correct answer is a) 25.0%.