n13

n13 commonly denotes nitrogen-13 (13N), a radioactive isotope of nitrogen with atomic number 7 and mass number 13. It is produced in nuclear reactions, most often by irradiating natural carbon targets with protons in a cyclotron via the 12C(p,n)13N reaction. Nitrogen-13 decays by positron emission to carbon-13 with a half-life of about 9.97 minutes. Because of its short half-life and positron emission, 13N is used in positron emission tomography (PET) imaging, where it is often incorporated into radiopharmaceuticals such as [13N]ammonia for tracing nitrogen metabolism and evaluating tissue blood flow.

In practical medical imaging, 13N-labeled ammonia is prepared under radiopharmaceutical conditions and administered to patients for dynamic cardiac PET studies to assess myocardial perfusion. The rapid decay requires on-site production or rapid transport from a nearby facility, and imaging is conducted soon after synthesis. Safety, regulatory approvals, and specialized radiochemistry workflows govern the use of 13N tracers in clinical settings.

Beyond nitrogen-13, the notation “n13” or “N13” can serve as a generic designation in various contexts, including catalog numbers, model identifiers, or coding schemes. Its exact meaning is context-dependent and not unique to a single entity, so additional information is typically needed to determine what a specific instance of “n13” refers to.