Positron Emission Tomography Centre

Radiochemistry Tracers

Radiochemistry Tracers

A tracer is a radioactive substance given in extremely small quantities, so that it should not have any chemical or biochemical effect.

Oncology

Fluorodeoxyglucose

Fluorodeoxyglucose (FDG) is the mostly commonly used PET tracer, especially valuable in cancer diagnosis. FDG is available commercially and can be obtained in Newcastle either from IBA, Siemens or Erigal.

Fluorothymidine

Other 18F-labelled PET tracers which have been used in several PET facilities include fluorothymidine (FLT, a marker of cell proliferation)

Fluoride

Fluoride (F-, for bone scans)

Hypoxia

Fluorinated nitroimadazoles (markers of hypoxia).

Fluoroethylcholine

Changes in choline metabolism are often seen in tumours. Fluoroethylcholine (FEC) is a derivative of choline that may be useful in selected patients with prostate cancer, hepatocellular carcinoma, brain or gynaecological tumours. In the UK, this is currently produced by Erigal at their Sutton (Surrey) facility. The journey time to Newcastle is probably too long, for 18F-FEC to be available here.

Neuroscience

Alzheimer's disease

An important feature of Alzheimer's disease, is the presence of amyloid plaques within the brain. PET tracers are being developed in an attempt to map and quantify the presence of these plaques in patients suspected of having Alzheimer's disease. AV-45 is an 18F-labelled PET amyloid tracer and is currently being used in clinical trials in the USA.

Liver

Specific imaging agents for liver disease need to be developed. For a brief review on molecular, genetic and imaging techniques for HCV fibrosis evaluation refer to Ahmad-W et al. Virology Journal 8: 53-68 (2011). 

One approach, is to attach positron emitting isotopes, such as 18F, to peptides which are targeted against molecular features of the disease.