Purpose: To characterize a commonly occurring increased uptake by the uncinate process of the pancreas at PET/CT using 68Ga-DOTA-d-Phe1-Tyr3-octreotide (68Ga-DOTA-TOC). This tracer has replaced 111In pentetreotide (OctreoScan®) for somatostatin receptor scintigraphy at our laboratory.
Methods: Fifty of our first 74 PET/CT examinations with 68Ga-DOTA-TOC could be evaluated in retrospect. None of these patients had surgery or showed any pathology in the pancreas head at the concomitant CT.
Results: Thirty-five of the 50 examinations (70%) showed an uptake by the uncinate process sufficiently intense to be interpreted as pathologic and simulating a tumor. Mean SUVmax was 9.2. Mean SUVmean using an isoactivity cut-off of >75% and >50% was 7.8 and 6.0, respectively. Volume calculations of the uncinate process activity using these definitions gave 0.9 mL and 4.2 mL, respectively.
Conclusion: There is a frequent physiological uptake of 68Ga-DOTA-TOC by the pancreas uncinate process. This may be caused by an accumulation of pancreatic polypeptide-containing cells expressing somatostatin receptors. If there is a normal finding at concomitant diagnostic CT, this uptake should be regarded as physiological.
From the Departments of *Radiology, †Nuclear Medicine, and ‡Neuroradiology, Karolinska University Hospital Solna, Stockholm, Sweden.
Received for publication July 28, 2011; revision accepted December 21, 2011.
Conflict of interest and sources of funding: none declared.
Reprints: Hans Jacobsson, MD, PhD, Department of Radiology, Karolinska University Hospital Solna, SE-171 76 Stockholm, Sweden. E-mail: email@example.com.