Comparison of Diagnostic Sensitivity and Quantitative Indices Between 68Ga-DOTATOC PET/CT and 111In-Pentetreotide SPECT/CT in Neuroendocrine Tumors: a Preliminary Report
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In-pentetreotide has been used for neuroendocrine tumors expressing somatostatin receptors. Recently, 68Ga-DOTATOC PET has been used with the advantage of high image quality. In this study, we compared quantitative indices between 111In-pentetreotide SPECT/CT and 68Ga-DOTATOC PET/CT.
Thirteen patients diagnosed with neuroendocrine tumors were prospectively recruited. Patients underwent 111In-pentetreotide scans with SPECT/CT and 68Ga-DOTATOC PET/CT before treatment. The number and location of lesions were analyzed on both imaging techniques to compare lesion detectability. Additionally, the maximal uptake count of each lesion and mean uptake count of the lungs were measured on both imagings, and target-to-normal lung ratios (TNR) were calculated as quantitative indices.
Among 13 patients, 10 exhibited lesions with increased uptake on 111In-pentetreotide SPECT/CT and/or 68Ga-DOTATOC PET/CT. Scans with SPECT/CT detected 19 lesions, all of which were also detected on PET/CT. Moreover, 16 additional lesions were detected on PET/CT (6 in the liver, 9 in the pancreas and 1 in the spleen). PET/CT exhibited a significantly higher sensitivity than SPECT/CT (100 % vs. 54 %, P < 0.001). TNR was significantly higher on PET/CT than on SPECT/CT (99.9 ± 84.3 vs. 71.1 ± 114.9, P < 0.001) in spite of a significant correlation (r = 0.692, P = 0.01).
Ga-DOTATOC PET/CT has a higher diagnostic sensitivity than 111In-pentetreotide scans with SPECT/CT. The TNR on PET/CT is higher than that of SPECT/CT, which also suggests the higher sensitivity of PET/CT. 111In-pentetreotide SPECT/CT should be used carefully if it is used instead of 68Ga-DOTATOC PET/CT.
KeywordsNeuroendocrine tumors 68Ga-DOTATOC 111In-pentetreotide Positron emission tomography Single-photon emission-computed tomography
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (no. NRF-2014M2A2A6049855)
Conflict of Interest
Inki Lee, Jin Chul Paeng, Soo Jin Lee, Chan Soo Shin, Jin-Young Jang, Gi Jeong Cheon, Dong Soo Lee, June-Key Chung and Keon Wook Kang declare that they have no conflict of interest.
This prospective study was approved by the Institutional Review Board at Seoul National University Hospital (IRB no. 1404-095-573), and all procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards
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