PET with [11C]PMP has shown 19 – 39 % inhibition of cortical AChE activity following donepezil treatment in AD patients [70, 71] whereas 28 – 39 % AChE inhibition has been observed after donepezil and rivastigmine in the frontal temporal and parietal regions of AD patients using [11C]MP4A PET [72, 73]. This evidence concerns the gene ACHE and Alzheimer disease.