Article Text
Statistics from Altmetric.com
Imaging with positron emission tomography (PET) offers unrivalled sensitivity and specificity for research into biochemical pathways and pharmacological mechanisms in vivo. Cardiac and neurological research with PET has flourished over the past 20 years, but it is only more recently that cardiology has begun to benefit from the advantages provided by PET. From the physical point of view, scanning of the heart presents a challenge because of greater complications in correcting for photon attenuation and scattered radiation, and because of movement of the heart and lungs.
Unique features of PET
Positron annihilation/coincidence detection
Short physical half life/lower radiation dose to patients
Attenuation correction
Correction for partial volume effect
Capability of making absolute measurements of tracer concentration
Multiple physiological tracers
Methodological background
The success of PET is based on the properties of the isotopes used (table 1). Their short physical half lives make it possible to administer a tracer dose high enough to obtain useful data, but such that the radiation burden to the patient is acceptably low. Positron emitters do not exist in nature and they must be produced artificially by means of a particle accelerator (generally a cyclotron).1 Production of isotopes with the shortest half lives has to be carried out in the vicinity of the scanner and necessitates the installation of cyclotron and radiochemistry facilities. However, 18F compounds can be delivered from a relatively remote site of production. The commercial success of PET has been driven by 18F labelled fluorodeoxyglucose (FDG) which is used to measure glucose metabolism in tissues. Because of the longer half life of 18F (table 1), many centres rely on production from a centralised cyclotron, thus avoiding the expense of individual facilities. However, research centres aiming to derive most from the power of PET require on site production of a range of …