Ex vivo biodistribution

For ex vivo biodistribution analysis, mice were euthanized following the imaging procedure on day 6 post dosing. Blood was collected via cardiac puncture into counting tubes. Tumors and select normal tissues (spleen, heart, lungs, stomach, intestine (small), liver, kidneys, and bone (femur)) were then excised and placed into counting tubes. The weight of each sample (blood, tumor, or tissues) was measured and recorded. Values for ⁸⁹Zr 511 keV photons were then determined in counts per minute (cpm) by measuring samples using an automatic gamma counter (Wizard 2470, PerkinElmer). Samples from some studies were weighed and counted using an Hidex Automatic Gamma Counter (Hidex, Finland). The %ID values for individual samples collected were calculated relative to the 511 keV photons count value for a dose-standard from injected material prepared on the day of dosing and measured on day 6 post dosing:

Subsequently, the %ID/g values were derived using the weight of the individual samples and the ratio of tissue (or tumor)-to-blood %ID/g values was calculated for each sample.