Isotope notation

Dr Daniel J Bell et al.

When employing formal scientific isotope notation, an isotope is usually expressed in longhand as the name of the chemical element, followed immediately by a dash, and then the mass number (A), i.e. "element-A". When abbreviated, the element's symbol is used, prefixed by a superscripted mass number, above a subscripted atomic number. In everyday practice the atomic number can usually be omitted, as it same for all the isotopes of any one element. 

However we have decided on Radiopaedia to deviate from standard scientific practice for reasons of simplicity, and to not use superscripts for this purpose. 

Instead we ask that for an isotope of element unobtainium (symbol Un), which has 23 neutrons, one writes unobtainium-23, and thereafter abbreviate it as Un-23. We ask for the sake of uniformity across the site that you do not write 23Un.

Correct usage:

  • fluorine-18, e.g. fluorine-18 PET-CT
  • F-18 e.g. F-18 PET-CT

NB: preferred style for hybrid imaging on Radiopaedia is joining the two modalities by a hyphen "-", not using a "/", a space, or running the two modalities together

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Article information

rID: 68239
Synonyms or Alternate Spellings:
  • Isotopes' notation

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