Kinetic model analysis for absorbed dose calculation applied to brain in [¹⁸F]-fluorodeoxyglucose positron emission tomography imaging.

A kinetic model analysis has been proposed to assess absorbed dose to an arbitrary tissue in [¹⁸F]-fluorodeoxyglucose ([¹⁸F]-FDG) positron emission tomography (PET) imaging, whose efficiency is demonstrated in physiological brain, by comparing calculated estimates with human literature data. First, an analytic solution for the tissue [¹⁸F]-FDG time-activity curve has been derived from kinetic model analysis, assuming reversible radiotracer trapping. Then, integrating this solution from the time of tracer administration to infinity yielded analytic solutions for cumulated activity (and hence for the ratio of cumulated/injected activity) and the percentage of tracer uptake for an arbitrary tissue. Calculated estimates from these analytic solutions for the whole gray and white matter have been found in very good agreement with human literature data: 7.55 versus 6.57 (±1.51) MBq·hour (per unit of administered activity of 37 MBq), 0.204 versus 0.220 (±0.090) hour, and 6.25% versus 6.90%, respectively. This study concludes that the proposed kinetic model analysis has proven effective in assessing absorbed dose to human brain in [¹⁸F]-FDG PET imaging, under physiological conditions. This study suggests that this model could be further developed to assess absorbed dose to other tissues, either healthy or pathological, and also it could be further considered by involving other PET tracer features.