3 ms·
Where does the electron come from, the body? Or is it generated in pairs with the positron or something?
by heavyset_go 3y ago
Where does the electron come from, the body? Or is it generated in pairs with the positron or something?
- deleted 3y ago[deleted]
- eigenket 3y agoYeah, the positron hits an ambient electron from somewhere in the environment, in a PET scan this is usually inside the body.
- bonzini 3y ago... which is why it's called ionizing radiation, removing an electron (or adding it in the case of beta decay) turns neutral atoms into ions.
- eigenket 3y agoIn general yes. In this specific case not entirely, because once the radiating nucleus has undergone positron emission it has turned one of its protons into a neutron, which means it now needs one less electron in order to form a neutral atom. The "spare" electron can wander off and replace (eventually, on average) the electron that gets annihilated by the positron.