Ammonia (N-13)

13NH3 is a PET tracer used for studies of myocardial perfusion imaging. It is produced in a cyclotron by proton irradiation of the enriched water of the oxygen-16. Ammonia (N-13) is administered intravenously, at a dose of 10-20 mCi (370-740 Mbq) in adults; its physical half-life is 10 minutes.

Extraction and retention 

Ammonia, at physiological pH, is found in its cationic form, 13NH4+ (ammonium ion); it is, therefore, probable that it passes the cell membrane of the myocyte through the sodium-potassium pump active transport mechanism. Inside the cell, it is then converted, together with glutamic acid, into glutamine (N-13).

Physics and imaging technology: nuclear medicine
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Article information

rID: 73988
System: Cardiac
Synonyms or Alternate Spellings:

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