TSPO and steatosis: Xie et al. applied N-benzyl-N-methyl-2-[7,8-dihydro-7-(2-[18F]fluoroethyl)-8-oxo-2-phenyl-9H-purin-9-yl]acetamide ([18F]FEDAC), a specific positron emission tomography (PET) radiotracer for TSPO imaging, to quantify the expression level of TSPO in a methionine- and choline-deficient diet-fed mouse model and found that the uptake of [18F]FEDAC significantly elevated from simple steatosis to the NASH state [5].