Assertion: fluorine's compound | /r/ObjectUse | used in scanning
Facets:
value: often
type: TEMPORAL
Source sentences:
text: Compounds containing fluorine-18, a radioactive isotope that emits positrons, are often used in positron emission tomography (PET) scanning, because the isotope's half-life of about 110 minutes is usefully long by positron-emitter standards.