Title: Normal biodistribution and tumor uptake of 68Ga DOTATATE PET / CT in the clinical setting: normal background activity, and organ specific tumor characterization of metastatic lesions.
Abstract: 3031 Introduction: 68Ga DOTATATE PET / CT has demonstrated higher sensitivity and lesion detectability compared to 111In octreoscan for suspected neuroendocrine tumors. 68Ga DOTATATE PET / CT acquisition parameters have traditionally been chosen to mimic those for FDG PET / CT, without consideration for physical differences in 68Ga compared to 18F. Significant differences also exist in the 68Ga DOTATATE PET / CT injected dose, normal biodistribution, tumor uptake and tumor distribution. Both physical and biological differences can influence lesions detectability. For example, the lower administered activity and the higher background activity in the liver could obscure detection of hepatic metastases, commonly present in neuroendocrine malignancies. The purpose of this study is to determine radiotracer specific properties of 68Ga DOTATATE with respect to radiotracer normal biodistribution, tumor uptake, and location of metastases. Methods: After 68Ga DOTATATE administration (5.7 + 0.5 mCi) and uptake time (63.1 + 4.7) minutes, PET / CT imaging was performed in patients referred for known or suspected neuroendocrine tumors (n=50; M=29, F =21). Normal background organ uptake and their background noise levels were quantified with both SUVmean,, SUV max (mean+1std). Focal tumor abnormalities were confirmed by retrospective review of clinical reports, identified using a semi-automated program (MIM software), and quantified using imaging metrics including RECIST 1.1, modified PERCIST, and recorded as SUVmean, SUVmax (mean+1std). Tumor to background ratio (TBR) is reported for SUVmax of both the tumor and the background. Results: Normal background SUVmean measured: blood pool (1.06+0.35), brain (0.11+0.05), liver (5.01+1.44), lung (0.30+0.15), muscle (0.67+0.216), spleen (17.1+6.97), and T12 bone marrow (1.11+0.36). Of the 50 patients, 18 were normal, and 32 had focal disease. Of the 101 lesions, the most frequent site was the liver (43/101), which showed very high tumor uptake SUVmax (41.2+38.9; median 25.3; range=10.9-223.4). The TBR for hepatic lesions (mean=6.4+8.0; range=1.6-48.6; median 3.6) was significantly lower (P
Publication Year: 2019
Publication Date: 2019-05-01
Language: en
Type: article
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Cited By Count: 1
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