Send to

Choose Destination
Nucl Med Biol. 2012 Oct;39(7):1081-6. doi: 10.1016/j.nucmedbio.2012.04.005. Epub 2012 May 16.

Ex vivo and in vivo evaluation of the norepinephrine transporter ligand [11C]MRB for brown adipose tissue imaging.

Author information

PET Center, Department of Diagnostic Radiology, Yale University, New Haven, CT 06520, USA.



It has been suggested that brown adipose tissue (BAT) in humans may play a role in energy balance and obesity. We conducted ex vivo and in vivo evaluation using [(11)C]MRB, a highly selective NET (norepinephrine transporter) ligand for BAT imaging at room temperature, which is not achievable with [(18)F]FDG.


PET images of male Sprague-Dawley rats with [(18)F]FDG and [(11)C]MRB were compared. Relative [(18)F]FDG or [(11)C]MRB retention at 20, 40 and 60 min post-injection was quantified on awake rats after exposing to cold (4°C for 4h) or remaining at room temperature. Rats pretreated with unlabeled MRB or nisoxetine 30 min before [(11)C]MRB injection were also assessed. The [(11)C]MRB metabolite profile in BAT was evaluated.


PET imaging demonstrated intense [(11)C]MRB uptake (SUV of 2.9 to 3.3) in the interscapular BAT of both room temperature and cold-exposed rats and this uptake was significantly diminished by pretreatment with unlabeled MRB; in contrast, [(18)F]FDG in BAT was only detected in rats treated with cold. Ex vivo results were concordant with the imaging findings; i.e. the uptake of [(11)C]MRB in BAT was 3 times higher than that of [(18)F]FDG at room temperature (P=0.009), and the significant cold-stimulated uptake in BAT with [(18)F]FDG (10-fold, P=0.001) was not observed with [(11)C]MRB (P=0.082). HPLC analysis revealed 94%-99% of total radioactivity in BAT represented unchanged [(11)C]MRB.


Our study demonstrates that BAT could be specifically labeled with [(11)C]MRB at room temperature and under cold conditions, supporting a NET-PET strategy for imaging BAT in humans under basal conditions.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center