Simplification for measuring input function of FDG PET: investigation of 1-point blood sampling method.
The current method for quantitative FDG PET study requires application of multiple arterial blood sampling for measuring the input function, but the procedure is invasive and complicated. The purpose of this study was to establish a 1-point blood sampling technique that gives data comparable with the data of more elaborate serial arterial sampling.


METHODS
We established a time point for 1-point arterial sampling that exhibited the highest correlation between plasma radioactivity at the time point and the real integrated value (IV) of the measured input function obtained by multiple arterial sampling in 120 patients and the smallest coefficient of variation of the real IV divided by plasma radioactivity at the time point in 120 patients. Scaling factors for estimation at each sampling point were determined, and a reference table was established to make the supposed input function.


RESULTS
The optimal time for 1-point arterial sampling was 12 min after FDG injection. A good correlation was observed between the real IVs and those estimated from 1-point arterial blood sampling at 12 min using the supposed input function (n = 120; P < 0.001). The time point at which the difference between values of arterial and venous blood disappeared was 40 min after FDG injection. The percentage errors of IV estimation by 1-point sampling were 1.70% (n = 120) for arterial blood at 12 min and 3.64% (n = 10) for venous blood at 40 min.


CONCLUSIONS
We conclude that the simplified 1-point sample method works in a manner that is comparable with serial arterial sampling and should be useful for clinical PET.
Wakita
K
K
Clinical PET Center, Nishijin Hospital, Kyoto, Japan.
Imahori
Y
Y
Ido
T
T
Fujii
R
R
Horii
H
H
Shimizu
M
M
Nakajima
S
S
Mineura
K
K
Nakamura
T
T
Kanatsuna
T
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001800:Blood Specimen Collection / Q000379:methods; D001927:Brain Diseases / Q000097:blood / Q000000981:diagnostic imaging*; D001932:Brain Neoplasms / Q000097:blood / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000097:blood / Q000493:pharmacokinetics; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000097:blood / Q000493:pharmacokinetics; D012044:Regression Analysis; D015203:Reproducibility of Results; D014055:Tomography, Emission-Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18