Kinetic analysis in human brain of [11C](R)-rolipram, a positron emission tomographic radioligand to image phosphodiesterase 4: A retest study and use of an image-derived input function

►Binding of [11C](R)-rolipram to phosphodiesterase 4 can be reliably quantified in human brain using a two-tissue compartment model and a Logan plot. ►[11C](R)-rolipram binding has a moderate test-retest variability of about 15%. ►An image-derived input function method, using the PET blood pool of carotid arteries, gives almost identical distribution volumes to those obtained with invasive arterial blood sampling. ►This image input method allows not only the estimation of the whole-blood time activity curve, like all the methods described in the literature up to now, but also the estimation of the parent concentration in plasma.