Purpose: To analyze the biodistribution of Ga-DOTA-TATE in the normal tissues and uptake in benign, indeterminate, and malignant lesions in a population of patients with known neuroendocrine tumors (NET) using semiquantitative standardized uptake values (SUV) measurements.
Methods: One hundred four consecutively scanned patients (51 men and 53 women; mean age, 56.4 years) with confirmed diagnosis of NET underwent PET/CT 1 hour after administration of Ga-DOTA-TATE. SUVmean, and SUVmax were measured in 37 normal anatomical structures for each patient. Abnormal uptake was divided into benign, indeterminate, and malignant categories based on imaging characteristic, clinical follow-up, and pathology.
Results: High physiologic uptake (SUVmax > 7) was observed in spleen, renal parenchyma, adrenal glands, pituitary gland, stomach, and liver (in decreasing order). Moderate uptake (3.5-7) was present in the prostate, jejunum, pancreas, ileum, and salivary glands. Mild uptake (2-3.5) was present in the uterus, colon, thyroid, rectum, and skeleton. A total of 678 lesions (limited to 5 lesions with highest uptake per organ) were included in the analysis, including 127 benign and 54 indeterminate lesions. Uptake was significantly higher in malignant lesions than in benign lesions, but an overlap was noted between the groups.
Conclusions: Ga-DOTA TATE uptake in normal and abnormal structures is highly variable in patients with NET. SUV is a useful measure for characterizing benign versus malignant lesions. Anatomical and clinical correlation may be necessary to characterize foci of intermediate uptake.