Radiotracer Decay - What's Left?

[Chyral]

Greetings all. I'm a just a chemist banging my head about some what seems to me as fundamentally a nuclear physics question, so please bear with me.

If you have a molecule bearing a radioactive atom, a PET radiotracer, say F-18 FDG or some such beast, and it decays (to O-18 correct?) what exactly happens to the entire molecule? Another way of putting it is: As the positron-neutrino pair is released, is the rest of the tracer molecule blown apart by kinetic energy from the decay event?
Or am I thinking too much in a classical sense and you are left with a molecule happily bearing O-18 rather than F-18?
And lastly, does the answer depend on what type of decay is occurring?

 

[malawi_glenn]

It depends on the electron configuration of the radioactive elements daugher.

You can look on wikipedia for example, on all decay modes. Then there are things like "Internal conversion", "electron capture"; which changes the electron configuration of the daugher atom.

 

[Chyral]

Thanks for the reply! So it looks like this was the wrong place to post (sorry about that). I have asked people here in radiochemistry and medical physics and I still am left without an answer, though. Oh well.

 

[imabug]

I'm not a radiochemist, but I believe that most of the time the daughter product dissociates from the tagged molecule/pharmaceutical (which remains intact)

 

[Barmecides]

If you have a molecule bearing a radioactive atom, a PET radiotracer, say F-18 FDG or some such beast, and it decays (to O-18 correct?) what exactly happens to the entire molecule? Another way of putting it is: As the positron-neutrino pair is released, is the rest of the tracer molecule blown apart by kinetic energy from the decay event?
Or am I thinking too much in a classical sense and you are left with a molecule happily bearing O-18 rather than F-18?
And lastly, does the answer depend on what type of decay is occurring?

Hello Chyral,

I would say that the recoiling of the nucleus is negligible (specially for F) wrt the energy of positron-neutrino pair. In some way, that's why you can do imaging.