| BackgroundThyroid Cancer（TC）is one of the most common endocrine malignancies.In recent years,the incidence of TC has been on the rise,and the onset age has been younger.More than 90% of thyroid cancers are differentiated thyroid cancers,among which patients with iodine-refractory differentiated thyroid cancer do not benefit from131 I treatment.RGD polypeptide is a hot target of tumor molecular probe imaging in recent years,which can specifically identify integrins and their ligands that are highly expressed on neovascular epidermal cells of malignant tumors.Therefore,radionuclide labeled RGD molecular probe can efficiently and specifically detect tumors and metastatic lesions,and can be applied in the diagnosis and treatment of thyroid cancer.ObjectiveFor patients with iodine-refractory differentiated thyroid cancer（RAIR-DTC）,131 I cannot play its due role in diagnosis and treatment,so it is necessary to seek new methods for diagnosis and treatment of these patients.The purpose of this study was to investigate the diagnosis of recurrence/metastasis of RAIR-DTC by 99 m Tc-3PRGD2SPECT/CT imaging and its influencing factors,and to compare it with 18F-FDG PET/CT examination method,and to explore the application of 99 m Tc-3PRGD2SPECT/CT imaging in iodide refractory differentiated thyroid cancer.Meterials and Methods24 patients with RAIR-DTC who were admitted to our hospital from October2019 to December 2020 with suspected recurrence/metastasis were enrolled and underwent 99 m Tc-3PRGD2 SPECT/CT imaging.The influencing factors,predictive value of positive results,sensitivity and specificity of imaging were analyzed,and the efficacy of targeted drugs was evaluated.Clinical diagnosis was made on the basis of clinical data such as follow-up serology and imaging examination,and the relationship between T/N value and clinical diagnosis was analyzed.Nine patients who underwent 18F-FDG PET/CT examination at the same time were analyzed,and the sensitivity and specificity of the two methods were compared,so as to study the difference between the two methods in the diagnosis of recurrence/metastasis.ResultsIn 24 patients,135 lesions were detected by 99 m Tc-3PRGD2 SPECT/CT imaging,most of which were lung lesions（69.6%）.The T/N value of the lesion was not related to the location of the lesion（P=0.071>0.05）,but was significantly related to the size of the lesion（correlation coefficient was 0.425,P=0.01 < 0.05）.The optimal cut-off value for positive and negative 99 m Tc-3PRGD2 SPECT/CT imaging was 2.434,and the sensitivity,specificity,accuracy,positive predictive value and negative predictive value were 81.6%,96%,89.6%,94.2% and 86.7%,respectively,by ROC operating curve analysis.The T/N value of thyroid cancer in the group with clinical diagnosis of recurrence/metastasis was higher than that in the group without recurrence/metastasis,and the difference was statistically significant（P=0.001 < 0.05）.There was statistical difference in T/N value of lesions in different TG level groups（P=0.018 < 0.05）.There was no significant correlation between T/N value and TG level（correlation coefficient was 0.236,P=0.362 > 0.05）,and no significant correlation between T/N value and TG dynamic change trend（correlation coefficient was 0.259,P=0.257 >0.05）.The size of the lesion（F=22.472,P=0.009 < 0.05）and the T/N value（F=27.762,P=0.002 < 0.05）were statistically different before and after treatment in the patients treated with targeted drugs.The sensitivity and specificity of 18F-FDG PET/CT imaging in the diagnosis of recurrence/metastasis were 94.7% and 84.2% in 9 RAIR-DTC received 18F-FDG PET/CT scan at the same time.The sensitivity and specificity of 99 m Tc-3PRGD2SPECT/CT imaging in diagnosis of recurrence/metastasis were 89.5% and 89.5%,respectively.There was no significant correlation between T/N value and SUVmax（correlation coefficient was 0.273,P= 0.368> 0.05）.ConclusionsIn the diagnosis and treatment of iodide refractory differentiated thyroid cancer,the sensitivity and specificity of 99 m Tc-3PRGD2 SPECT/CT imaging and 18F-FDG PET/CT in the diagnosis of recurrence and/or metastasis were similar.The increased uptake of 99 m Tc-3PRGD2 indicated active proliferation of vascular endothelial cells in the target lesion,which was complementary to 18F-FDG and had different advantages.99mTc-3PRGD2 SPECT/CT imaging can be used in the diagnosis and treatment of RAIR-DTC,to locate and diagnose the recurrence/metastasis of thyroid cancer,and to evaluate the efficacy of tumor angiogenesis targeting drugs,so as to help the clinical development of individualized treatment programs,so as to maximize the benefits of patients. |
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