Radioactivity is really important for making blood flow studies more accurate. We use special techniques like Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) to do this.

Here’s How It Helps:

1. Radioactive Tracers:

   • Doctors inject small amounts of special radioactive materials (like $^{18}$F or $^{99m}$Tc) into a patient's blood.
   • These materials give off gamma rays, which special machines can pick up.

2. Better Sensitivity:

   • Using radioactive methods, we can notice changes in blood flow that are as small as 2%.
   • This means we can find problems, like reduced flow or blockages, much earlier than other methods would allow.

3. Precise Measurements:

   • We can measure blood flow with an accuracy of ±5%.
   • For example, getting more precise measurements of blood flow in heart conditions can help doctors treat patients more effectively, possibly improving outcomes by 25% when they act quickly.

In summary, radioactivity helps us understand heart health better. It makes medical tests more accurate and can really improve how we diagnose and treat patients.