A Negative Correlation Between Blood Glucose Level and ⁶⁸ Ga-DOTA-TOC Uptake in the Pancreas Uncinate Process

⁶⁸ Ga-DOTA-TOC uptake in the pancreas uncinate process is often found due to physiologic expression of somatostatin receptors (SSTR). We investigated the association of physiologic ⁶⁸ Ga-DOTA-TOC uptake in the pancreas uncinate process with blood glucose level.

⁶⁸ Ga-DOTA-TOC PET scans acquired from 44 patients (male:female = 20:24, age = 50.8 ± 14.8y [mean ± SD]) were retrospectively analyzed. The blood glucose level (BGL) was examined before ⁶⁸ Ga-DOTA-TOC injection. Patients diagnosed with diabetes mellitus and patients with BGL over 200 mg/dl were excluded. ⁶⁸ Ga-DOTA-TOC uptake was measured by the maximum standardized uptake values (SUVmax). Additionally, SSTR-positive volume (SV) in the pancreas uncinate process was measured with two different thresholds: by SUV cutoff of 2.5 (SV_2.5) and 40% of SUVmax (SV_40%). These measurements on ⁶⁸ Ga-DOTA-TOC PET were correlated with BGL.

The mean of SUVmax of the pancreas uncinate process was 6.51 ± 2.04. SV_2.5 was 17.81 ± 7.14 cm³, and SV_40% was 18.20 ± 8.83 cm³. A significant negative correlation was found between SUVmax of the pancreas uncinate process and BGL (r = -0.37, p = 0.01). The ratio between SUVmax of the pancreas uncinate process and SUVmean of the pancreas body also showed a significance negative correlation with BGL (r = -0.40, p = 0.01). SV_2.5 (r = 0.27, p = 0.07) and SV_40% (r = -0.151, p = 0.32) were not significantly correlated with BGL.

Physiologic ⁶⁸ Ga-DOTA-TOC uptake in the pancreas uncinate process was negatively correlated with BGL. Our results suggested that glycemia could affect physiologic uptake of ⁶⁸ Ga-DOTA-TOC.