A Preliminary Study On The PET / CT Imaging Of A Novel Molecular Probe With ⁶⁸ Ga Marking

Project Ⅰ 68Ga-BNOTA-PRGD2 PET/CT for Preoperative Grading in Gliomas: A Comparison Study with 18F-FDG PET/CTObjective:Classification and treatment strategy of gliomas remain to be optimized. The Arg-Gly-Asp (RGD) peptide specifically recognizes the integrin, which is over expressed on glioma cells. The aim of this study was to compare18F-FDG PET/CT with 68Ga-BNOTA-PRGD2 PET/CT for gliomas grading.Methods:Twenty-nine patients with gliomas were included in this study. The standardized uptake value (SUVmax) and tumor to normal tissue (T/N) ratios were measured. Spearman correlation test was used to calculate the correlation coefficient with pathological grade. Receiver operating characteristic (ROC) curve analyses were performed to assess the value for tumor grading. And the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were compared for 18F-FDG PET/CT and 68Ga-BNOTA-PRGD2 PET/CT.Results:Pathology reports revealed 7 low-grade (WHO grade Ⅰ or Ⅱ) gliomas (LGGs) and 22 high-grade (WHO grade Ⅲ and Ⅳ) gliomas (HGGs). All 68Ga-BNOTA-PRGD2 PET/CT parameters showed the ability to differentiate between LGGs and HGGs (P=0.04 and P=0.014 for SUVmax and T/N ratio separately). The FDG PET/CT parameters didn’t show differentiates the LGGs and HGGs (P=0.129 and P=0.067 for SUVmax and T/N ratio separately). On the ROC analysis, 68Ga-BNOTA-PRGD2 PET/CT showed higher area under curve in tumor grade than FDG PET/CT (0.883 vs 0.795,0.812 vs 0.805 for SUVmax and T/N ratio separately). According to the cut-off determined from ROC analysis, the sensitivity for FDG PET/CT (86.4%,90.9% for SUVmax and T/N ratio separately) was higher in predicting tumor grade than the 68Ga-BNOTA-PRGD2 PET/CT (77.3%,72.7%), but FDG PET/CT showed lower specificity (71.4%,71.4%) than the 68Ga-BNOTA-PRGD2 PET/CT (85.7%,100%). Linear regression analysis revealed significant correlation of SUVmax and T/N Ratio both for 18F-FDG (SUVmax: r 0.64, P< 0.001; T/N:r = 0.72, P< 0.001) and 68Ga-BNOTA-PRGD2 (SUVmax: r 0.74, P< 0.001; T/N:r = 0.55, P= 0.002) between the WHO grade respectively.Conclusions:68Ga-BNOTA-PRGD2 PET/CT imaging is a noninvasive modality that is useful in determining a tumor area as well as improving preoperative grading for gliomas.Project Ⅱ Potential Applications of Using 68Ga-Evans Blue PET/CT in the Evaluation of Lymphatic DisorderObjetive:Potentials of 68Ga-NEB as a PET tracer in the evaluation of a variety of lymphatic drainage disorders were analyzed.Methods:68Ga-NEB was injected subcutaneously, and the PET/CT images were acquired in 13 patients with different suspected lymphatic drainage abnormality. The 68Ga-NEB PET/CT findings were compared with 99mTc-SC lymphoscintigraphy.Results:68Ga-NEB activity could be clearly observed in the lymphatic route on the PET/CT images from all the patients. In 5 (38.5%) of 13 patients tested,68Ga-NEB PET/CT provided more information than the 99mTc-SC lymphoscintigraphy.Conclusions:68Ga-NEB PET/CT can be used as an alternative of 99mTc-SC lymphoscintigraphy in the evaluation of lymphatic disorders, which enables fast results and might be more accurate than the conventional 99mTc-SC lymphoscintigraphy.Project III Pilot Study of 68Ga-DOTATATE PET/CT for evaluation of Small Cell Lung CancerObjective:Small cell lung cancer (SCLC) is prone to metastatic dissemination and the tumor stage has great impact on its treatment. So far, no standard procedure has been established for this tumor type. SCLC expresses high level of somatostatin receptor (SSTR), which may allow it to be imaged by the tracer 68Ga-1,4,7,10-tetraazacyclododecane-N,N’,N",N "’-tetraacetic-acid-D-Phe1,Tyr3-octr eotate (68Ga-DOTATATE). We thus compared the detection efficiency of the SCLC lesions between 68Ga-DOTATATE with 18F-FDG. Methods:A total of 12 patients diagnosed with SCLC by biopsies underwent both68Ga-DOTATATE PET/CT and 18F-FDG PET/CT scan. The PET/CT images of each PET tracer were evaluated for primary and distance lesions. Other imaging (such as post PET/CT, CT or MRI) or further information from clinical follow-up results provided the reference standards.Results:Both68Ga-DOTATATE PET/CT and 18F-FDG PET/CT detected the primary tumors in all of the 12 patients. For the detection of bone lesions,6 of 12 patients who showed positivity by 68Ga-DOTATATE PET/CT imaging, but 2 of these 6 patients were negative by 18F-FDG PET/CT imaging. Statistically significant differences were found in bone lesions (P= 0.001) between68Ga-DOTATATE and18F-FDGscan. However, no statistical differences were found in primary lesion (P=0.052) or lymph nodes (P=0.387) for 68Ga-DOTATATE and for 18F-FDG.Conclusion:68Ga-DOTATATE is sensitive for detecting SCLC bone lesions and providing important supplemental information to that of 18F-FDG for staging.