Linear regression analysis between mRNA expression values measured by mRNA probe B for mGluR1 gene and average 2-tissue-compartment model/VT values of 18F-FIMX. VT of cerebellum, right-most data point, was calculated from 210 min of image acquisition. Linear regression shown in this graph, which includes cerebellum, has R2 of 0.992 and x-intercept of 0.5 mL·cm−3, which corresponds to VND of 18F-FIMX. When cerebellum is removed, R2 becomes 0.648 and x-intercept decreases to 0.3 mL·cm−3.