RT Journal Article SR Electronic T1 microPET-Based Biodistribution of Quantum Dots in Living Mice JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1511 OP 1518 DO 10.2967/jnumed.107.040071 VO 48 IS 9 A1 Schipper, Meike L. A1 Cheng, Zhen A1 Lee, Sheen-Woo A1 Bentolila, Laurent A. A1 Iyer, Gopal A1 Rao, Jianghong A1 Chen, Xiaoyuan A1 Wu, Anna M. A1 Weiss, Shimon A1 Gambhir, Sanjiv S. YR 2007 UL http://jnm.snmjournals.org/content/48/9/1511.abstract AB This study evaluates the quantitative biodistribution of commercially available CdSe quantum dots (QD) in mice. Methods: 64Cu-Labeled 800- or 525-nm emission wavelength QD (21- or 12-nm diameter), with or without 2,000 MW (molecular weight) polyethylene glycol (PEG), were injected intravenously into mice (5.55 MBq/25 pmol QD) and studied using well counting or by serial microPET and region-of-interest analysis. Results: Both methods show rapid uptake by the liver (27.4–38.9 %ID/g) (%ID/g is percentage injected dose per gram tissue) and spleen (8.0–12.4 %ID/g). Size has no influence on biodistribution within the range tested here. Pegylated QD have slightly slower uptake into liver and spleen (6 vs. 2 min) and show additional low-level bone uptake (6.5–6.9 %ID/g). No evidence of clearance from these organs was observed. Conclusion: Rapid reticuloendothelial system clearance of QD will require modification of QD for optimal utility in imaging living subjects. Formal quantitative biodistribution/imaging studies will be helpful in studying many types of nanoparticles, including quantum dots.