Analysis of [15O]CO2
Inhaled [15O]CO2 is converted to [15O]H2O in the lungs (West and Dollery, 1962) by carbonic anhydrase (CA):
This reaction is reversible, but since there is much more water in the body than carbon dioxide, practically all 15O is labelling water. The reaction rate of carbonic anhydrase is only limited by the diffusion rate of the substrates, and equilibrium is thus instant as compared to the time-resolution of PET.
Therefore [15O]CO2 can be used in quantification of blood flow with the same analysis methods that are used with [15O]H2O PET.
Notice that 11C and 15O labeled CO2 are completely different tracers.
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Created at: 2009-04-24
Updated at: 2017-09-07
Written by: Vesa Oikonen