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Positron Emission Tomography (PET) at the Biological Imaging Centre

PET Overview

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Quad-HIDAC PET scanner [+]
Quad-HIDAC PET scanner
  
Positron emission tomography (PET) is one type of nuclear imaging that utilises short-lived positron-emitting isotopes to allow visualisation and quantification of biological processes or drug kinetics. Positron-emitting isotopes such as [15O] (t1/2=2 min), [11C] (t1/2=20 min), [18F] (t1/2=109 min), [124I] (t1/2= 4.2 days) can be incorporated into many compounds of biological interest to produce a radiotracer/radioligandsuch as [18F] fluorodeoxyglucose, [11C] raclopride and [15O]H2O for PET studies.

A PET study begins with the injection or inhalation of a radiotracer followed by scanning. When the radiotracer decays, it emits a positron that travels a short distance and annihilates with an electron. Annihilation produces two 511 keV photons, which propagate in nearly opposite directions and can be detected within a short time window (the coincidence time window; ~10 ns). Many such events are summed to provide the distribution of the radiotracer. Radiotracer transport, washout and retention can be monitored by PET; if calibrated, PET images can yield quantitative estimates of the amount of radiotracer in specific parts of the body. Additional information of blood radioactivity levels or radioactivity in 'reference regions' enable calculation of exchange rate constants/parameters such as receptor binding potential that correlate with various physiological or pharmacological processes.



Application of PET to Study Biology of Small Animals

New developments in detector technologies have led to the commercialisation of dedicated small animal scanners. It is now possible to perform PET studies in animal models, thus, bridging the gap between in vitro science and clinical studies. The potential of this technology to study biology is huge and we are only beginning to realise this. Several of the radiotracers employed clinically can be used to study the biology of animal models and effects of therapy. In addition the PET is well suited to in vivo functional genomic studies. Application in each setting (transgenics, tumour models, lesioned rodents) requires a level of ex vivo validation to appreciate the relationship between the PET imaging parameter and ex vivo biochemistry/genetics.



PET Image Gallery

•  3-D volume-rendered PET images of [18F]FDG uptake [+]
3-D volume-rendered PET images of [18F]FDG uptake
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3-D volume-rendered PET images of [18F]FDG uptake


•  PET Imaging of bone turnover with [18F] [+]
PET Imaging of bone turnover with [18F]
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PET Imaging of bone turnover with [18F]
MAP Volume-rendered Volume-rendered


• PET Imaging of D2 receptor with [11C]Raclopride [+]
PET Imaging of D2 receptor with [11C]Raclopride
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Pet Imaging of D2 receptor with [11C]Raclopride


• MRI and FDG-PET co-registration
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Whole body [+]
Whole body MRI and FDG-PET co-registration
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Brain [+]
Brain MRI and FDG-PET co-registration
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