PK and dosimetric results of CLR 124/125 for mice bearing orthotopic MDA-MB-231 tumors. (A) MIP of a decay-corrected imaging series of a representative mouse injected with CLR 124 and microPET/CT imaged at 0, 24, 48, 96, 120, and 144 h postinjection. (B) Summary results from the PK analysis showing the mean (±SD) concentration (percent ID/g) of CLR 124 within each ROI over time, (C) Summary results from the dosimetry analysis showing the mean (±SD) absorbed dose (Gy/MBq) of CLR 125 within each ROI. Consistent with the PK results, the dosimetry analysis showed that the tumor has the largest absorbed dose per injected activity while the “Rt femur BM,” which is generally the dose-limiting organ for CLR1404, appears to have the lowest. “Lt femur BM” appears to have a larger dose compared to “Rt femur BM” which is consistent with the PK results. Due to the prolonged retention within the blood of CLR1404, the lungs and heart have the largest doses compared to the other normal organs analyzed. CT, computed tomography; ID, injecting dose; Lt femur BM, left femur bone marrow; MIP, maximum intensity projections; PK, pharmacokinetic; ROI, region of interest; Rt femur BM, right femur bone marrow; SD, standard deviation.