Cardiac Positron Emission Tomography

Chapter 11


Cardiac Positron Emission Tomography





1. What is positron emission tomography (PET)?


    A positron, as its name implies, is a positively charged particle that is ejected from the nucleus of an unstable atom. It is identical in mass to an electron. Strictly speaking, it is “antimatter” and very shortly after leaving the nucleus it collides with an electron in what is called an annihilation reaction. This reaction generates two 511 keV gamma photons that are emitted almost diametrically opposite from each other. The energy of these photons is captured by a special (PET) scanner and through a sophisticated network of electronics as well as computer software and hardware, it is transformed into an image.


2. Which are the two most common PET radiopharmaceuticals used for myocardial perfusion imaging (MPI)?


    Rubidium-82 (Rb-82) and nitrogen-13 (N-13) ammonia.


3. What are the characteristics of Rb-82?


    Rb-82 is a monovalent cation analog of potassium. It is commercially available as a strontium-82 generator. Its physical half-life is 75 seconds. It is extracted with high efficiency by myocardial cells through the Na+,K+-ATPase pump. The adult radiation dose from a Rb-82 MPI varies from 1.75 to 7.5 mSv (Fig. 11-1).



4. What are the characteristics of N-13 ammonia?


    N-13 Ammonia is an extractable myocardial perfusion tracer which, due to its 10 minute half-life, requires an on-site cyclotron. It is retained in myocardial tissue as N-13 glutamine by the action of glutamine synthetase. The adult radiation dose from an N-13 ammonia MPI is approximately 1.4 mSv.

Stay updated, free articles. Join our Telegram channel

Jun 5, 2016 | Posted by in CARDIOLOGY | Comments Off on Cardiac Positron Emission Tomography

Full access? Get Clinical Tree

Get Clinical Tree app for offline access