PT  - JOURNAL ARTICLE
AU  - Eric Laffon
AU  - Olivier Barret
AU  - Roger Marthan
AU  - Dominique Ducassou
TI  - Is the Physical Decay Correction of the <sup>18</sup>F-FDG Input Function in Dynamic PET Imaging Justified?
AID  - 10.2967/jnmt.108.060350
DP  - 2009 Jun 01
TA  - Journal of Nuclear Medicine Technology
PG  - 111--113
VI  - 37
IP  - 2
4099  - http://tech.snmjournals.org/content/37/2/111.short
4100  - http://tech.snmjournals.org/content/37/2/111.full
SO  - J. Nucl. Med. Technol.2009 Jun 01; 37
AB  - In this theoretic note, the rationale for the physical decay correction of the 18F-FDG input function in dynamic PET is investigated, using the Patlak equation as an example. Methods: The Patlak equation conventionally obtained when correcting the 18F-FDG input function and correcting the tissue activity measurement for 18F physical decay can also be derived from a 2-compartment analysis that does not conceptually involve any physical decay correction of the 18F-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. Conclusion: No advantage in 18F-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 18F-FDG input function for radioactive decay cannot be justified and that this correction is not compatible with the calculation of patient radiation dose.