Figure 3. Autoradiography of [¹⁸F]FEDL distribution after intravenous administration and HIP/PAP expression.

(A) H&E stained section and (B) color-coded autoradiographic image of [¹⁸F]FEDL-derived radioactivity distribution in an adjacent section obtained from the same tissue block including: pancreas, spleen and intestine and a small orthotopic pancreatic carcinoma lesion outlined by the dotted lines (bar: 5 mm) and indicated by the arrows; a blue dotted line outlines the area shown at ×15 higher magnification in panel (C) IHC of HIP/PAP and (D) autoradiography of [¹⁸F]FEDL-derived radioactivity distribution. High level of [¹⁸F]FEDL radioactivity is seen in the peritumoral pancreatic tissue, but not in the tumor lesion. (E) A scatter plot and linear regression analysis of relationship between the magnitude of HIP/PAP expression (IHC densitometry, ROD) and [¹⁸F]FEDL accumulation in peritumoral pancreatic tissue (autoradiography, PSL/mm²); an almost linear relationship is observed (r = 0.88).