Inveon pet small animal scanners

Mice were implanted with β-estradiol pellets on the rear flank and MCF-7tumors on the axillary thorax and allowed to grow as described above. The mice (n = 3) were injected intratumorally with 3 × 10⁹ pfu of AdSSTR2-yCD or with saline, followed by i.v. injection of ⁶⁴Cu-CB-TE2A-Y3-TATE two days later (4.1 MBq (110 µCi); 125 ng). One group of saline injected mice received a co-injection of ⁶⁴Cu-CB-TE2A-Y3-TATE and 200 µg of Y3-TATE to serve as a block. Four hours after injection, the mice were anesthetized with 1–2% isoflurane, positioned supine, and imaged on microPET FOCUS 220 or Inveon PET small animal scanners (Siemens Medical Solutions, Malvern, PA). The PET acquisition times were 10 min and CT images were obtained using a MicroCAT II System (ImTek, Inc., Knoxville, TN). The images were reconstructed with an Ordered-Subset Estimation Maximization (OSEM) algorithm which included corrections for scatter and attenuation. Regions of interest were drawn to encompass the entire tumor to determine the maximum activity concentration (nCi/cc) in the tumor. To calculate the standardized uptake values (SUVs), the nCi/cc was divided by the nCi injected (decay corrected to the scan start time) and multiplied by the mouse weight.