In recent years,several RGD(Arg-Gly-Asp)-based radiotracers have already been successfully tested in human for the visualization of integrin αvβ3,demonstrating its feasibility in tumor diagnosis.In this paper,we evaluated the 99mTc-3P4-RGD2 single photon emission computed tomography/computerized tomography(SPECT/CT)in patients suffering from space occupying disease of esophagus.40 patients(34 males and 6 female;mean age: 58.3 years) with a suspected space occupying lesion of esophagus were included,thus finally obtaining their definite pathologic diagnosis(malignant,n=32;benign,n=8).All patients underwent endoscopic,barium esophagography and SPECT/CT imaging preoperatively.The chest SPECT was performed at 4 h after administration of99mTc-3P4-RGD2 with a dose of 939±118 MBq.The diagnosis precision,sensitivity and specificity among these methods were compared.The relationship between radioactive uptake and clinical pathological stage of esophageal carcinoma was discussed by calculating the tumor to normal esophagus(T/N).Meanwhile,the integrin αvβ3 expression was assessed immunohistochemically in postoperative esophageal tissues.31 patients were diagnosed as esophageal carcinoma;and 1,leiomyosarcoma;and 6.leimyoma;and 2,esophageal tuberculosis.The accuracy,sensitivity and specificity of barium esophagography,endoscopic and SPECT/CT imaging are 92.5/93.8/87.5%,97.5/96.9/100%,and 90/90.6/87.5%,respectively.Abnormal accumulation of radiotracer in 29 malignant lesions is observed.The SPECT/CT imaging displayed the region of radioactive uptake and lesions matched extremely with the T/N ratio from 1.31 to 2.79(mean 2.04).A case with pulmonary metastases and a case with mediastinal lymph node metastases were found which were missed by barium esophagography and endoscopic.The99mTc-3P4-RGD2 uptake of the esophageal carcinoma masses had no relevance to the tumor pathologic classification(P>0.05).There was a significant positive correlation between T/N ratio and positive cell percentage of integrin αvβ3(r=0.976),demonstrating the certain clinical potential in the diagnosis of esophageal carcinoma. Several recent RGD (Arg-Gly-Asp) -based radiotracers have been successfully tested in human for the visualization of integrin αvβ3, demonstrating its feasibility in tumor diagnosis. In this paper, we evaluated the 99mTc-3P4-RGD2 single photon emission computed tomography / computerized tomography (SPECT / CT) in patients suffering from space occupying disease of esophagus. 40 patients (34 males and 6 female; mean age: 58.3 years) with a suspected space occupying lesion of esophagus were included, thus finally obtaining their definite pathologic diagnosis (malignant, n = 32; benign, n = 8). All patients underwent endoscopic, barium esophagography and SPECT / CT imaging preoperatively.The chest SPECT was performed at 4 h after administration of99mTc-3P4-RGD2 with a dose of 939 ± 118 MBq. The diagnosis precision, sensitivity and specificity among these methods were compared. The relationship between radioactive uptake and clinical pathological stage of esophageal carcinoma was discussed by calculatin g the tumor to normal esophagus (T / N) .Meanwhile, the integrin αvβ3 expression was assessed immunohistochemically in postoperative esophageal tissues.31 patients were diagnosed as esophageal carcinoma; and 1, leiomyosarcoma; and 6. leimyoma; and 2, esophageal tuberculosis. The accuracy, sensitivity and specificity of barium esophagography, endoscopic and SPECT / CT imaging were 92.5 / 93.8 / 87.5%, 97.5 / 96.9 / 100%, and 90 / 90.6 / 87.5%, respectively.Abnormal accumulation of radiotracer in 29 malignant lesions is observed. SPECT / CT imaging displayed the region of radioactive uptake and lesions matched with the T / N ratio from 1.31 to 2.79 (mean 2.04). A case with pulmonary metastases and a case with mediastinal lymph node metastases were found which were missed by barium esophagography and endoscopic.The99mTc-3P4-RGD2 uptake of the esophageal carcinoma masses had no relevance to the tumor pathologic classification (P> 0.05). There was a significant positive correlation between T / N ratio and positive cel l perCentage of integrin αvβ3 (r = 0.976), demonstrating the certain clinical potential in the diagnosis of esophageal carcinoma.