To detect the prognostic significance of interim F-FDG PET/CT SUV(standard uptake value) reduction(△SUV_(max)) associated with Ki67 in patients with diffuse large B cell lymphoma(DLBCL).47 DLBCL patients underwent PET/CT before initiation and after 2-4 cycles of chemotherapy were included.The SUV_(max)of the dominant lesions were calculated.Ki67 positive indices were provided by enzyme-labeled immunohistochemistry.SPSS17.0 was used for statistical analysis.ASUV_(max) of different groups were compared by t test.Receiver-operator characteristic analysis was performed to determine the optimal cutoff values.KaplanMeier analyses of PFS(Progression-free survival) were compared using log-rank test.The average of △SUV_(max)and △SUV_(max)%were 11.53 and 69.10%,respectively.The optimal cutoff values of △SUV_(max)x and △SUV_(max)%were 11.45 and 82.92%,respectively.Higher △SUV_(max) and △SUV_(max)%indicated longer PFS(p < 0.001).The optimal cutoff value of Ki67 was 55%.Ki67>55%was revealed to be an indicator of shorter PFS(p = 0.019).Either △SUV_(max)≤11.45 or Ki67>55%was defined as an indicator to poor outcome and scored 1 point.The PFS rate was 100%in patients scored 0 point,yet 0%in patients scored 2 points.PFS tended to be shorter along with the score getting higher(p = 0.006).△SUV_(max) and Ki67 positive index were both of significance in DLBCL prognosis.The prognostic value may be confirmed when △SUV_(max) was accordant with Ki67. To detect the prognostic significance of interim F-FDG PET / CT SUV (standard uptake value) reduction associated with Ki67 in patients with diffuse large B cell lymphoma (DLBCL) .47 DLBCL patients underwent PET / CT before initiation and after 2-4 cycles of chemotherapy were included. The SUV_ (max) of the dominant lesions were calculated. Ki67 positive indices were provided by enzyme-labeled immunohistochemistry. PSS 17.0 was used for statistical analysis. ASUV_ (max) of different groups were compared by t test. Receiver-operator characteristic analysis was performed to determine the optimal cutoff values. Kaplan Meier analyzes of PFS (Progression-free survival) were compared using log-rank test. The average of △ SUV_ (max) and △ SUV_ (max)% were 11.53 and 69.10% respectively.The optimal cutoff values ​​of △ SUV_ (max) x and △ SUV_ (max)% were 11.45 and 82.92%, respectively.Higher △ SUV_ (max) and △ SUV_ (max) % indicated longer PFS (p <0.001). The optimal cutoff value of Ki67 was 55%. Ki67> 55% was re Either ΔSUV_ (max) ≤11.45 or Ki67> 55% was defined as an indicator to poor outcome and scored as 1 point. The PFS rate was 100% in patients scored 0 point, yet 0% in patients scored 2 points. PFS tended to be shorter along with the score getting higher (p = 0.006). △ SUV_ (max) and Ki67 positive index were both of significance in DLBCL prognosis.The prognostic value may may confirmed when △ SUV_ (max) was accordant with Ki67.