Is the physical decay correction of the (18)F-FDG input function in dynamic PET imaging justified?
In this theoretic note, the rationale for the physical decay correction of the (18)F-FDG input function in dynamic PET is investigated, using the Patlak equation as an example.


METHODS
The Patlak equation conventionally obtained when correcting the (18)F-FDG input function and correcting the tissue activity measurement for (18)F physical decay can also be derived from a 2-compartment analysis that does not conceptually involve any physical decay correction of the (18)F-FDG input function but accounts only for the physical decay of the trapped tracer.


RESULTS
We demonstrate that exactly the same equation can be derived from the 2 conceptual approaches, and hence each approach yields the correct uptake rate of the tracer.


CONCLUSIONS
No advantage in (18)F-FDG dynamic PET can be expected from using the concept of uncorrected data rather than that of decay-corrected data. Nevertheless, conceptually, we show that correcting the (18)F-FDG input function for radioactive decay cannot be justified and that this correction is not compatible with the calculation of patient radiation dose.
Laffon
Eric
E
Service de Médecine Nucléaire, CHU de Bordeaux, Pessac, France. elaffon@u-bordeaux2.fr
Barret
Olivier
O
Marthan
Roger
R
Ducassou
Dominique
D
D003593:Cytoplasm / Q000378:metabolism; D019788:Fluorodeoxyglucose F18 / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D049268:Positron-Emission Tomography / Q000379:methods*; D011851:Radioactivity; D013997:Time Factors
D019788:Fluorodeoxyglucose F18