An isotope of Technetium, Technetium-99m (4399mTc^{99\text{m}}_{43}\text{Tc}4399mTc), is a pure gamma emitter widely used as a radioactive tracer in medical diagnostics, particularly for bone scans and cardiac perfusion imaging.
State two distinct reasons why a tracer that only emits gamma radiation is preferred for internal medical imaging over tracers that emit alpha or beta radiation.
A Technetium-99m tracer sample is prepared with an initial activity of 360 MBq360\text{ MBq}360 MBq. The half-life of Technetium-99m is 6.0 hours6.0\text{ hours}6.0 hours.
Calculate the number of Technetium-99m nuclei initially present in this tracer sample.
Calculate the time, in hours, required for the activity of the tracer to decrease to 1.5%1.5\%1.5% of its initial activity.
