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

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

Hossein Jadvar (Doctor) gives expert video advice on: How are radiopharmaceuticals made?; What are examples of radiopharmaceuticals?; Are there radiation risks of radiopharmaceuticals? and more...

The physical half life is defined by the amount of time for that radioactive element to decay to half of its original radioactivity. The physical half life for "f18", for example "nfdg" is 110 minutes. For technetium "99m" in some traces, for example, "mdp or system maybe that's 6 hours. The physical half life of "I131" which is used in radioiodine treatment of thyroid cancer, is 8 days.