Response to doxorubicin at 72 h is revealed with [¹¹C]-AnxA5-ST but not [¹⁸F]-FDG or [¹¹C]-mTrx-GFP-ST.

Representative MIP and transaxial images of radioactivity (summed over 35–55 min) after tail vein injection in mice with FaDu xenografts of A) [¹¹C]-AnxA5-ST or B) [¹¹C]-mTrx-GFP-ST, 72 h after treatment with a single dose of doxorubicin (5 mg/kg). Also shown are representative images of [¹⁸F]-FDG, at C) baseline or, alternatively, D) after treatment with doxorubicin and 90 min after the image with [¹¹C]-AnxA5-ST in A). E) Time activity curves of single tumors showing uptake of [¹¹C]-AnxA5-ST (solid triangles and squares) or [¹⁸F]-FDG (lines) before (solid triangle and dashed line) or after doxorubicin treatment (solid squares and solid line). F) Corresponding experiments showing a comparison between of [¹¹C]-mTrx-GFP-ST (empty triangles and squares) and [¹⁸F]-FDG (lines) tumor uptake in the same mouse before (empty triangles and dashed line) or after doxorubicin treatment (empty squares and solid line).