Pharmacokinetics and Biodistribution of ⁸⁶Y-Trastuzumab for ⁹⁰Y Dosimetry in an Ovarian Carcinoma Model: Correlative MicroPET and MRI

Longitudinal microPET coronal slice images of ⁸⁶Y-trastuzumab (A), excess unlabeled trastuzumab (B), ⁸⁶Y-trastuzumab on nontumor-bearing mice (C), ⁸⁶Y-HuM195 (D), and free ⁸⁶Y (E). Numbers in upper left corner of each panel indicate time after injection (in hours). Black arrows indicate mAb accumulation at confirmed tumor sites. White arrows indicate injection site.

(A) High-resolution transverse MR image slices, registered to corresponding microPET slices. Contours depicting outer periphery of mouse and also collection of tumor nodules near spleen are shown. (B) Two transverse MR slices, obtained on small-animal (4.7 T) scanner, are shown. Two slices are taken at different transaxial positions. Slice on left is through spleen (yellow contour), kidneys (blue), and tumor nodules (orange). Slice on right is posterior to left slice and depicts multiple small tumor nodules in mesentery.

(A) Time–activity curve over injection site. Relative activity concentrations were determined by drawing ROIs on microPET image sets. Data are corrected for acquisition time, physical decay, and background. Error bars represent SE. (B) Time–activity curves for blood (triangles) and tumor (squares). Open symbols represent relative activity concentration (e.g., pharmacokinetics) derived from repeated microPET imaging. Activity concentrations (%IA/g) in dissected tissue (solid symbols) were used to quantitate image-based relative concentrations. Error bars represent combined standard uncertainty. Lines show fits used for cumulated activity calculations.