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 12.5% c 93.8% d 6.25%
To determine the percentage of Technetium-99m that will be left in the patient's body 12 hours later, we first need to determine how many half-lives have passed.
12 hours is equivalent to 12/6 = 2 half-lives.
Each half-life represents a reduction to half of the initial amount. Therefore, after 2 half-lives, the amount of Technetium-99m left in the body will be 1/2 * 1/2 = 1/4 of the initial amount.
This is equivalent to 1/4 * 100% = 25%.
Therefore, the answer is (a) 25.0%.