Biodistribution of 18F-AlF-NOTA-octreotide in Different Organs and Characterization of Uptake in Neuroendocrine Neoplasms

The aims of this study were threefold: [1] to describe the biodistribution of 18F-AlF-NOTA-octreotide (18F-OC) in normal organs; [2] to evaluate the range of uptake of NEN and benign lesions using the maximum standardized uptake value (SUVmax); and [3] to compare the difference in 18F-OC uptake among tumors of different grades.This study included 162 patients (67 females and 95 males) who received 18F-OC positron emission tomography (PET)/computed tomography (CT), 128 of whom were diagnosed with neuroendocrine neoplasms (NENs). The SUVmax and SUVmean of 18F-OC were measured in 21 normal anatomical structures. We compared the differences among G1, G2, and G3 NENs, as well as between NENs and benign lesions.High physiological uptake of 18F-OC (SUVmax > 6.77) was detected in the spleen, adrenal gland, renal parenchyma, pituitary gland, and liver. Moderate uptake (SUVmax 3.00-6.77) was found in the uncinate process of the pancreas (PU), prostate, thyroid, and uterus. Mild uptake (SUVmax 1.34-3.00) was observed in the small intestine, pancreas (pancreas uptake except for the head of the pancreas), gallbladder, and transverse colon. The SUVmax of NENs was higher than that of benign lesions, including fractures, inflamed tissue, reactive hyperplasia, and degenerative disease. However, overlap was noted between the two groups. The SUVmax of 18F-OC uptake by tumors was significantly correlated with tumor grade in primary lesions and those of the lymph node, bone, and other sites (all P < 0.01).The results obtained from the majority of the samples in this study show the biodistribution of 18F-OC in normal organs and have significance as a reference. Although some benign lesions show variable uptake, the uptake by these lesions is still different from that of NENs. NENs of different grades have differences in 18F-OC uptake levels.