Sample preparation techniques for radiometabolite analysis of positron emission tomography radioligands; trends, progress, limitations and future prospects

Radiometabolite corrected arterial plasma input function is essential for quantitative measurement of the brain binding of positron emitting radioligands and drugs that have no suitable reference region in brain. Various sample preparation techniques have been successfully applied for extraction of radioligands and their metabolites from biological samples. Nevertheless, there is room for improvements of these techniques with regard to sample volume, selectivity and sensitivity, sample preparation time and simplicity (eg potential utility to handle whole-blood samples). The present review purports to give a brief overview of current applications, advances, limitations and future prospective uses of sample preparation, radiometabolite analysis and plasma protein binding methods in conjunction with positron emission tomography studies.