Diagnostic Value Of^99mTc-RGD-BBN SPECT For BI-RADS Category4C Breast Lesions

Objective: This study aimed to explore the screen performance of single photonemission computed tomography (SPECT) using a new radiotracer99mTc-RGD-BBNfor BI-RADS category4C breast tumors.Method:31female patients who were scheduled for breast tissue biopsy withsuspicious breast lesions on MRI findings (BI-RADS category4C) were included.The mean age was59±10years old and average weight was58.8±13.6kg. Therewas no any previous history of breast, neither in pregnancy and lactation. All patientshad inconclusive MRI reports. All of the patients were administrated with99mTc-RGD-BBN SPECT scan in the week before surgery. Breast SPECT wasperformed at4h after administration of99mTc-RGD-BBN (11.1MBq/kg). The imageswere interpreted independently by two experienced nuclear medicine physicians usinga3-piont system. For a semi-quantitative analysis, ROIs were drawn manually overthe area of intense uptake or abnormal findings on MRI if no obvious uptake ontomography images. Then, T/N ratios in maximum ROI were calculated. A fraction ofthe samples were analyzed immunohistochemically to evaluate integrin αvβ3andGRPR expression. A final diagnosis was made by histopathology of the specimensobtained by the surgical procedure. T/N ratios of breast lesions with different degreesof expression integrin αvβ3and GRPR were compared using variance analysis.Results: No serious adverse events were reported in any of the patients duringthe study. Among the31breast lesions,22were diagnosed as malignant and9werebenign. The mean T/N ratio of malignant lesions was significantly higher than benignlesions with a statistic significance (3.15±0.88vs.1.90±0.87, p<0.01). The optimalcutoff values and ROC areas for SPECT visual and semiquantative analysis werevisual score2and T/N ratio2.15. The empirical ROC areas of them were0.811and0.848respectively.11malignant lesions were found with dual αvβ3and GRPR expression (GRPR+/αvβ3+),6malignant lesions with only GRPR positive expression(GRPR+/αvβ3-),5malignant lesions and3benign lesions with only integrin αvβ3positive expression (GRPR-/αvβ3+).Conclusion:99mTc-RGD-BBN SPECT showed an excellent ability to identifybenign lesions and avoid unnecessary surgical biopsy.