Effect of tubing length on the dispersion correction of an arterially sampled input function for kinetic modeling in PET.
OBJECTIVE
Arterial sampling with dispersion correction is routinely performed for kinetic analysis of PET studies. Because of the the advent of PET-MRI systems, non-MR safe instrumentation will be required to be kept outside the scan room, which requires the length of the tubing between the patient and detector to increase, thus worsening the effects of dispersion.


METHODS
We examined the effects of dispersion in idealized radioactive blood studies using various lengths of tubing (1.5, 3, and 4.5 m) and applied a well-known transmission-dispersion model to attempt to correct the resulting traces. A simulation study was also carried out to examine noise characteristics of the model. The model was applied to patient traces using a 1.5 m acquisition tubing and extended to its use at 3 m.


RESULTS
Satisfactory dispersion correction of the blood traces was achieved in the 1.5 m line. Predictions on the basis of experimental measurements, numerical simulations and noise analysis of resulting traces show that corrections of blood data can also be achieved using the 3 m tubing. The effects of dispersion could not be corrected for the 4.5 m line by the selected transmission-dispersion model.


CONCLUSIONS
On the basis of our setup, correction of dispersion in arterial sampling tubing up to 3 m by the transmission-dispersion model can be performed. The model could not dispersion correct data acquired using a 4.5 m arterial tubing.
aPET Imaging Centre, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London bRadiation Physics and Protection, Churchill Hospital, Oxford, UK.
Jim
J
O'Doherty
Anna
A
Chilcott
Joel
J
Dunn
D001158:Arteries / Q000378:metabolism*; D016477:Artifacts; D002138:Calibration; D004058:Diffusion; D006801:Humans; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D008954:Models, Biological; D049268:Positron-Emission Tomography / Q000295:instrumentation*