{"entity":{"id":"n-13","kind":"isotope","name":"Nitrogen-13","aka":["13N"],"tldr":"A radioactive gas-forming isotope with a ten-minute lifetime, turned into ammonia and injected to map blood flow to the heart muscle on a PET scan.","summary":"Nitrogen-13 decays by pure positron emission with a 9.97-minute half-life. Its main clinical use is as ammonia N-13 injection, an FDA-approved PET myocardial perfusion agent (initial US approval 2007) used at rest and under pharmacological stress to evaluate suspected or existing coronary artery disease; it clears the blood with a biological half-life of under three minutes and is trapped in viable myocardium as glutamine.\n\nIt is made on a cyclotron via the 16O(p,α)13N reaction, typically by irradiating a dilute ethanol-in-water target, with the proton beam degraded to avoid co-producing oxygen-15 by the competing 16O(p,pn)15O channel. Because the ten-minute half-life is even shorter than fluorine-18's, N-13 ammonia must be made on site or very close to the scanner, which historically limited it to centres with an in-house cyclotron; compact superconducting mini-cyclotrons introduced in the 2010s and 2020s have made single-site N-13 ammonia production more practical for community cardiac PET programmes.\n\nAlongside 82Rb and 15O-water, 13N-ammonia is one of only a small number of PET perfusion tracers, and one of only two (with 82Rb) that carry FDA approval for that indication in the United States.","status":"approved","asOf":"2026-09-22","links":[{"label":"FDA label: Ammonia N 13 Injection (initial approval 2007)","url":"https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/022119s001lbl.pdf"},{"label":"PMC: reliable production of large quantities of [13N]ammonia","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC10254488/"}],"tags":["positron emitter","ultra-short-lived","cardiac perfusion"],"related":[],"indications":[],"sections":[],"technologies":["pet","cyclotron-isotope-production"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"symbol":"13N","element":"Nitrogen","massNumber":13,"halfLife":"9.97 minutes","emissions":["β+ 100% (max 1.19 MeV)","annihilation γ 511 keV"],"emissionClass":"positron","use":"imaging","production":"Cyclotron: 16O(p,α)13N, typically on a dilute ethanol-in-water liquid target, with proton energy degraded to suppress the competing 16O(p,pn)15O reaction.","supply":"research-only","supplyNote":"The 9.97-minute half-life requires production essentially at the scanner; compact on-site mini-cyclotrons have widened access beyond large academic centres but supply remains site-by-site rather than distributed.","chelators":[],"pairedWith":[],"since":1970},"route":"/isotopes/n-13/","neighbours":{"technology":[{"id":"cyclotron-isotope-production","kind":"technology","name":"Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211)","route":"/technologies/cyclotron-isotope-production/"},{"id":"pet","kind":"technology","name":"PET (positron emission tomography)","route":"/technologies/pet/"}],"indication":[{"id":"cardiac-sarcoidosis","kind":"indication","name":"Cardiac sarcoidosis","route":"/indications/cardiac-sarcoidosis/"},{"id":"coronary-artery-disease","kind":"indication","name":"Coronary artery disease","route":"/indications/coronary-artery-disease/"}],"drug":[{"id":"n-13-ammonia","kind":"drug","name":"Ammonia N-13","route":"/drugs/n-13-ammonia/"},{"id":"f-18-flurpiridaz","kind":"drug","name":"Flurpiridaz F-18","route":"/drugs/f-18-flurpiridaz/"},{"id":"rb-82-chloride","kind":"drug","name":"Rubidium Rb-82 chloride","route":"/drugs/rb-82-chloride/"}],"institution":[{"id":"asnc","kind":"institution","name":"American Society of Nuclear Cardiology","route":"/institutions/asnc/"}],"company":[{"id":"ionetix","kind":"company","name":"IONETIX","route":"/companies/ionetix/"}],"section":[{"id":"f-cardiac-imaging","kind":"section","name":"Cardiac imaging","route":"/fronts/f-cardiac-imaging/"}]}}