Figure 8.

SPECT/CT monitoring of fractionated anti-HER2-DOTA-PRIT treatment. The imaging field-of-view was limited to the caudal half of the animal (midline to tail) to center on the tumor (white arrow). The bladder is indicated when appropriate by a yellow arrow. (A) Representative SPECT/CT images of BT-474 tumor-bearing animals 24 h p.i. of cycle 1 ¹⁷⁷Lu-DOTA-Bn (55.5 MBq, 300 pmol) pretargeted with either control IgG-DOTA-PRIT or anti-HER2-DOTA-PRIT (from left to right: coronal and transverse slices through center of tumor, maximum intensity projection (MIP)). For the IgG-DOTA-PRIT mouse, the tumor ROI was 0.46 ± 0.33 MBq/cc (mean ± SD), with min-max of 0.00-2.92 MBq/cc. For the anti-HER2-DOTA-PRIT mouse, the tumor ROI was 5.24 ± 2.87 MBq/cc (mean ± SD), with min-max of 0.069-19.75 MBq/cc. (B) Representative serial SPECT/CT MIP images of a BT-474 tumor-bearing animal undergoing fractionated anti-HER2-DOTA-PRIT (left), taken 24 h p.i. of each cycle of radioactive injection. The image-derived region-of-interest (ROI) values for tumor uptake at 24 h p.i. of cycle 1, 2, or 3 ¹⁷⁷Lu-DOTA-Bn (55.5 MBq, 300 pmol) are presented as MBq/cc (mean ± SD).