Objective To prepare 99 Tcm-HYNIC-c( isoDGRKy) as a SPECT/CT imaging molecu-lar probe targeting integrin αvβ3 , and evaluate its biodistribution and feasibility on SPECT/CT imaging for integrinαvβ3-positive tumor in U87MG human glioma xenograft mouse models. Methods The bifunctional chelator HYNIC was conjugated to c( isoDGRKy) , and tricine and TPPTS were used as coligands for 99 Tcm labeling to prepare 99 Tcm-HYNIC-c( isoDGRKy) . The radiochemical purity and stability of the product were measured. The expression of integrin αvβ3 and binding affinity ( half maximal inhibitory concentration, IC50 ) of c ( isoDGRKy ) was detected in U87MG cells by cell experiments in vitro. Biodistribution and SPECT/CT imaging of 99 Tcm-HYNIC-c( isoDGRKy) including blocking experiments were performed respec-tively in nude mice bearing U87MG human glioma xenografts. Results The radiochemical purity of 99 Tcm-HYNIC-c( isoDGRKy) was over 99%, and was still over 99% after 4 h incubation in saline at room temper-ature. Flow cytometry assay showed that U87MG cells were integrinαvβ3-positive ( expressive rate:70%) . The IC50 of c(isoDGRKy) was 6.67×10-8 mol/L. Biodistribution results showed 99Tcm-HYNIC-c(isoDGRKy) with a rapid clearance from blood was excreted mainly via the kidneys. The 99 Tcm-HYNIC-c( isoDGRKy) uptake values in U87MG tumors were (7.31±1.42) and (1.09±0.11) %ID/g at 15 and 45 min post-injection re-spectively, and tumor-to-muscle ratio reached 5.01±1.47 at 15 min post-injection. The tumors were clearlyvisualized with low background from 0.5 to 1 h post-injection in tumor bearing mice. In the blocking experi-ment, the tumor was barely visualized after co-injection of excess cold c(RGDfK) peptide with 99Tcm-HYNIC-c(isoDGRKy). Conclusions 99Tcm-HYNIC-c(isoDGRKy) may be easily and steadily prepared. It may be a RGD-like promising SPECT/CT imaging probe for integrinαvβ3-positive tumor.

Objective:To compare the diagnostic values of different diagnostic criteria of prostate specific membrane antigen (PSMA) PET/CT for primary prostate cancer (PCa).Methods:From May 2019 to May 2021, 2-(3-(1-carboxy-5-((6- 18F-fluoro-pyridine-3-carbonyl)-amino)-pentyl)-ureido)-pentanedioic acid ( 18F-DCFPyL) PET/CT images of 78 patients (age: (68.5±1.4) years) with clinically suspected PCa in Shanxi Bethune Hospital were retrospectively collected and blind diagnosed by the three criteria of SUV max, PSMA reporting and data system (PSMA-RADS) score and molecular imaging PSMA (miPSMA) score. The diagnostic efficacy for PCa, the correlation between the diagnostic results and disease risk, and the consistency of the diagnostic results of the three criteria were compared. Delong test, Spearman rank correlation analysis, and intra-class correlation coefficient (ICC) were used to analyze data. Results:The sensitivities of SUV max, PSMA-RADS score and miPSMA score for PCa were all 93.75%(60/64) and the specificities were 12/14, 10/14 and 12/14 respectively; AUCs of the three criteria were 0.951, 0.862 and 0.951, with no significant difference between SUV max and miPSMA score ( z=0.00, P=1.000), while there were significant differences between PSMA-RADS score and SUV max or miPSMA score ( z values: 2.71, 2.93, P values: 0.007, 0.030). There were positive correlations between the diagnostic results of the three criteria and the disease risk (International Society of Urological Pathology (ISUP) grading: rs values: 0.66, 0.62, 0.63, all P<0.001; D′Amico grouping: rs values: 0.67, 0.64, 0.67, all P<0.001). The diagnostic results of the three criteria were highly consistent (ICC=0.941, 95% CI: 0.903-0.967). Conclusion:The SUV max and miPSMA score have higher diagnostic efficiency and correlation of disease risk, which are more suitable for clinical application.