# Nitrogen-13

Source: https://nuclide.cc/isotopes/n-13/  
Nuclide record `n-13` (Isotope). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

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.

It 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.

Alongside 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.

## Fields

- Kind: Isotope
- Status: approved
- Last checked: 2026-09-22
- Also known as: 13N
- Tags: positron emitter; ultra-short-lived; cardiac perfusion

## Sources

- FDA label: Ammonia N 13 Injection (initial approval 2007): https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/022119s001lbl.pdf
- PMC: reliable production of large quantities of [13N]ammonia: https://pmc.ncbi.nlm.nih.gov/articles/PMC10254488/

## Connected records

- technologies: [Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211)](https://nuclide.cc/technologies/cyclotron-isotope-production/), [PET (positron emission tomography)](https://nuclide.cc/technologies/pet/)
- indications: [Cardiac sarcoidosis](https://nuclide.cc/indications/cardiac-sarcoidosis/), [Coronary artery disease](https://nuclide.cc/indications/coronary-artery-disease/)
- drugs: [Ammonia N-13](https://nuclide.cc/drugs/n-13-ammonia/), [Flurpiridaz F-18](https://nuclide.cc/drugs/f-18-flurpiridaz/), [Rubidium Rb-82 chloride](https://nuclide.cc/drugs/rb-82-chloride/)
- institutions: [American Society of Nuclear Cardiology](https://nuclide.cc/institutions/asnc/)
- companies: [IONETIX](https://nuclide.cc/companies/ionetix/)
- fronts: [Cardiac imaging](https://nuclide.cc/fronts/f-cardiac-imaging/)

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JSON: https://nuclide.cc/api/v1/entities/n-13.json