PARAMETRIC IMAGING OF ACETYLCHOLINESTERASE ACTIVITY WITH PET: EVALUATION OF DIFFERENT METHODS

C-11-labeled N-methyl-4-piperidin acetate ([11C]MP4A) is used for the quantitative measurement of acetylcholinesterase activity with positron emission tomography (PET). In this study, two new methods, i.e. simplified ridge regression with spatial constraint (SRRSC) and its generalized formulation (GRRSC), are evaluated to quantify, without arterial measurements, [11C]MP4A images at pixel level. Their performance is assessed against state of art quantification methods for [11C]MP4A by Monte Carlo simulations. Although characterized by a little bias, GRRSC emerges as the most reliable and computationally efficient algorithm to generate parametric images of [11C]MP4A when an arterial input function is not available.