Module 05a. Cardiovascular PET Tracers - Part a-Cardiovascular PET Tracers (Slides)

Cardiovascular PET Tracers (Slides)

Pdf Summary

PET (Positron Emission Tomography) tracers are chemical compounds with unstable atoms that can be used to explore processes or chemical reactions in the body. In cardiovascular PET imaging, these tracers are used to assess blood flow to the heart.<br /><br />There are several PET flow tracers available, including N13-Ammonia, Rubidium82 (Rb82), O15-Water, and F18-flurpiridaz. These tracers differ in their properties, such as photon energy, half-life, and positron range, which affects their spatial resolution and attenuation in the body.<br /><br />PET tracers decay by emitting a positron, which then annihilates with an electron, generating photons that are used to create images. PET imaging can quantify processes such as myocardial blood flow (MBF) and metabolism, allowing for the assessment of perfusion defects and the quantitation of various cardiac conditions.<br /><br />The accuracy of PET imaging relies on factors such as the extraction fraction (ExF) and retention fraction (RF) of the tracer, which determine how much of the tracer is taken up and retained by the myocardium. Tracers with high ExF and RF tend to have better contrast resolution of perfusion defects.<br /><br />PET tracers can be used in compartmental modeling to describe and quantify processes that vary over time. Compartmental modeling allows for the estimation of MBF and other parameters related to tracer movement in the body.<br /><br />Among the available PET tracers, Rb82 and N13-Ammonia are FDA-approved for clinical use. Rb82 is a potassium analog that is taken up by myocytes, while N13-Ammonia rapidly diffuses across membranes. These tracers have different strengths and weaknesses in terms of accuracy, spatial resolution, and detection of obstructive coronary artery disease.<br /><br />F18-flurpiridaz, another PET tracer, is currently being evaluated in clinical trials. It shows promising characteristics, including high accuracy for perfusion defects, but further research is needed to fully establish its efficacy.<br /><br />Overall, PET tracers provide significant advantages over SPECT imaging in terms of accuracy and diagnostic capabilities. However, each tracer has its limitations, and understanding these strengths and weaknesses is important for optimal use in patient-centered imaging.

Keywords

PET tracers

Positron Emission Tomography

cardiovascular PET imaging

N13-Ammonia

Rubidium82

O15-Water

F18-flurpiridaz

myocardial blood flow

perfusion defects

compartmental modeling