What is 'effective half life' in relation to radionuclides?

What is 'effective half life' in relation to radionuclides?

I mentioned a physical half life of the radionuclides for some of the major radionuclides that we use in nuclear medicine. However, the effective half life can be quite shorter than what I mentioned before, because it also takes into consideration the biological half life of the radiotracer, which is dictated by the physiological processes in the human body. Therefore, the effective half life is the more important term in comparison to the physical half lives that we talked about, taking into consideration the physiology and chemistry of the particular radiotracer, and are generally much shorter than the physical half lives.