Abstract
PURPOSE: Neuroendocrine tumors (NETs) can be classified into three grades based on the malignancy index identified via histological and pathological diagnosis, and (111)In-pentetreotide single photon emission computed tomography (SPECT) is effective for diagnosis. Therefore, this study aimed to distinguish between NET grade 1 (G1) and NET grade 2 (G2) based on the change in standardized uptake value (SUV) 4 and 24 h after injection in pancreatic and gastrointestinal NETs. METHODS: Twenty-two patients underwent (111)In-pentetreotide SPECT and were definitively diagnosed with pancreatic or gastrointestinal NETs. The volume of interest were set in the tumor areas 4 and 24 h after injection, and SUV(max) and SUV(mean) were calculated. The ⊿tumor SUV (24 h-4 h) was calculated for each G1 and G2 by subtracting the SUV 4 h from SUV 24 h. RESULTS: The ⊿tumor SUV(max) (24 h-4 h) was 19.35 ± 23.26 in G1 and - 13.30 ± 20.26 in G2, and the ⊿tumor SUV(mean) (24 h-4 h) was 7.64 ± 15.58 in G1 and - 8.89 ± 15.45 in G2. The ⊿tumor SUV(max) (24 h-4 h) and ⊿tumor SUV(mean) (24 h-4 h) were higher in G1 compared to G2 (p < 0.05). CONCLUSION: The ⊿tumor SUV (24 h-4 h) in patients with pancreatic/gastrointestinal NET on (111)In-pentetreotide SPECT images were higher in G1 compared to G2. The ⊿tumor SUV (24 h-4 h) for pancreatic and gastrointestinal NETs may predict the malignancy grade, as determined by histological and pathological diagnosis.