Before the use of technetium-99m, patients with high risk coronary artery disease were evaluated using thallium-201 which has a half-life of 73.00 hours. If a person is exposed to 5.000 μg of thallium-201, how many hours would it take to reach 10.00 % of its original mass?

Question

Quizplus · Accepted Answer

To find the time it takes for a substance to decay to 10% of its original mass, we can use the half-life formula: $t = \frac{\ln(\frac{final\ mass}{initial\ mass})}{\ln(0.5)} \times half\ life$. Plugging in the values, $t = \frac{\ln(0.1)}{\ln(0.5)} \times 73.00$ hours. This calculation results in approximately 242.5 hours, which matches option B.

Before the Use of Technetium-99m, Patients with High Risk Coronary