Abstract
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Objectives We wanted to establish the range of 68Ga DOTA TOC uptake in pancreatic neuroendocrine tumours (NET). This would allow differentiation between physiological uptake and tumour related somatostatin receptor (SST) expression in the pancreas (including the uncinate process).
Methods 115 68Ga DOTA TOC PET/CT studies were performed in order to detect or exclude SST-expressing malignancy. Histopathology confirmed NET of the pancreas in 14 patients who underwent surgery after positive 68Ga DOTA TOC PET/CT scan.
Results SUVmax (mean +/- standard deviation) values of 68Ga-DOTA-TOC were 33.2 +/- 15.1 in three NET of the uncinate process, 57.9 +/- 67.6 in three NET of pancreas body and 47.2 +/- 39.7 in nine NET of the pancreas cauda. Significant differences in SUVmax between nonmalignant and malignant tissue was found for the pancreas cauda (p<0.03). At a cut off value of 17.1 the specificity and sensitivity for differentiating tumors in the uncinate process were 92.0% and 100% (p<0.0001) and 92.5% and 88.9% (p<0.0001) for the cauda at a cut off value of 12.0, respectively. A cut off value of 14.4 was evaluated for the pancreas body, resulting in a specificity and sensitivity of 100% (p<0.0001), respectively.
Conclusions 68Ga DOTA TOC is an excellent tracer for the imaging of pancreatic NET expressing SST on the tumour cell surface. The noninvasive PET/CT approach by measurement of regional SUVmax offers important clinical information to distinguish between physiological and pathological somatostatin receptor expression, especially in the case of unclear anatomical correlation of the pancreas.