FIGURE 7. Imaging D₂R and HSV1-tk PET reporter genes in same animal. Mouse carrying C6-stb-tk+ tumor (right) and D₂R tumor (left) was imaged by microPET for HSV1-tk reporter gene expression (using FPCV) and D₂R reporter gene expression (using FESP). Both images are displayed using same global maximum to allow direct comparison. Quantitative scale is shown at right. Images shown were reconstructed with MAP reconstruction algorithm. Highly specific localization of FPCV and FESP was observed in tumors expressing HSV1-tk and D₂R genes, respectively.