PT - JOURNAL ARTICLE AU - Greuter, Henri N.J.M. AU - Boellaard, Ronald AU - van Lingen, Arthur AU - Franssen, Eric J.F. AU - Lammertsma, Adriaan A. TI - Measurement of <sup>18</sup>F-FDG Concentrations in Blood Samples: Comparison of Direct Calibration and Standard Solution Methods DP - 2003 Dec 01 TA - Journal of Nuclear Medicine Technology PG - 206--209 VI - 31 IP - 4 4099 - http://tech.snmjournals.org/content/31/4/206.short 4100 - http://tech.snmjournals.org/content/31/4/206.full SO - J. Nucl. Med. Technol.2003 Dec 01; 31 AB - Objective: The purpose of this study was to compare the accuracy and reliability of 2 well counter methods for measuring the activity concentration of 18F-FDG in blood samples. Methods: Three to 5 blood samples from 154 patient studies were weighed and measured in a well counter. The 18F-FDG activity concentration was derived using, first, a direct calibration factor to convert measured well counter readings into activity concentration and, second, a comparison of measured counts with those of a specified standard solution. Results: The ratio between the activity concentration results of the 2 methods was 0.996 ± 0.033, indicating that the methods provided equal results. Conclusion: Because the standard solution method is more prone to human error, less reproducible, and more labor intensive, preference should be given to the direct calibration method.