HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH RSS TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JNM Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pain, F. Articles by Besret, L. Search for Related Content PubMed PubMed Citation Articles by Pain, F. Articles by Besret, L.

Arterial Input Function Measurement Without Blood Sampling Using a ß-Microprobe in Rats

¹ Unité Mixte de Recherche 8608, Institut de Physique Nucléaire, Université Paris XI, Orsay, France
² Commissariat à l’Energie Atomique, Direction des Sciences du Vivant, Departement de Recherche Medicale, Service Hospitalier Frédéric Joliot, Orsay, France
³ Unité de Recherche Associée 2210, Commissariat à l’Energie Atomique, Centre National de la Recherche Scientifique, Service Hospitalier Frédéric Joliot, Orsay, France
⁴ Isotopic Imaging Biochemical and Pharmacological Unit, Service Hospitalier Frédéric Joliot, Orsay, France

The evaluation of every new radiotracer involves pharmacokinetic studies on small animals to determine its biodistribution and local kinetics. To extract relevant biochemical information, time–activity curves for the regions of interest are mathematically modeled on the basis of compartmental models that require knowledge of the time course of the tracer concentration in plasma. Such a time–activity curve, usually termed input function, is determined in small animals by repeated blood sampling and subsequent counting in a well counter. The aim of the present work was to propose an alternative to blood sampling in small animals, since this procedure is labor intensive, exposes the staff to radiation, and leads to an important loss of blood, which affects hematologic parameters. Methods: Monte Carlo simulations were performed to evaluate the feasibility of measuring the arterial input function using a positron-sensitive microprobe placed in the femoral artery of a rat. The simulation results showed that a second probe inserted above the artery was necessary to allow proper subtraction of the background signal arising from tracer accumulation in surrounding tissues. This approach was then validated in vivo in 5 anesthetized rats. In a second set of experiments, on 3 rats, a third probe was used to simultaneously determine ¹⁸F-FDG accumulation in the striatum. Results: The high temporal resolution of the technique allowed accurate determination of the input function peak after bolus injection of ¹⁸F-FDG. Quantitative input functions were obtained after normalization of the arterial time–activity curve for a late blood sample. In the second set of experiments, compartmental modeling was achieved using either the blood samples or the microprobe data as the input function, and similar kinetic constants were found in both cases. Conclusion: Although direct quantification proved difficult, the microprobe allowed accurate measurement of arterial input function with a high temporal resolution and no blood loss. The technique, because offering adequate sensitivity and temporal resolution for kinetic measurements of radiotracers in the blood compartment, should facilitate quantitative modeling for radiotracer studies in small animals.

Key Words: arterial input function • ß-microprobe • ¹⁸F-FDG • rat • kinetic modeling

Related articles in JNM:

THIS MONTH IN JNM

JNM 2004 45: 8A-9A. [Full Text]  

This article has been cited by other articles:

				A. Desbree, M. Verdurand, J. Godart, A. Dubois, R. Mastrippolito, F. Pain, L. Pinot, T. Delzescaux, H. Gurden, L. Zimmer, et al. The Potential of a Radiosensitive Intracerebral Probe to Monitor 18F-MPPF Binding in Mouse Hippocampus In Vivo J. Nucl. Med., July 1, 2008; 49(7): 1155 - 1161. [Abstract] [Full Text] [PDF]

				L. Convert, G. Morin-Brassard, J. Cadorette, M. Archambault, M. Bentourkia, and R. Lecomte A New Tool for Molecular Imaging: The Microvolumetric {beta} Blood Counter J. Nucl. Med., July 1, 2007; 48(7): 1197 - 1206. [Abstract] [Full Text] [PDF]

				W. K. Schiffer, M. M. Mirrione, and S. L. Dewey Optimizing Experimental Protocols for Quantitative Behavioral Imaging with 18F-FDG in Rodents J. Nucl. Med., February 1, 2007; 48(2): 277 - 287. [Abstract] [Full Text] [PDF]

				J. Kim, P. Herrero, T. Sharp, R. Laforest, D. J. Rowland, Y.-C. Tai, J. S. Lewis, and M. J. Welch Minimally Invasive Method of Determining Blood Input Function from PET Images in Rodents J. Nucl. Med., February 1, 2006; 47(2): 330 - 336. [Abstract] [Full Text] [PDF]