Abstract: ob＜x＞jective To investigate the predictive value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) parameters for interim treatment response in patients with diffuse large B-cell lymphoma (DLBCL) receiving R-CHOP chemotherapy. Methods 79 DLBCL patients who received R-CHOP chemotherapy were divided into complete response (CR) group and incomplete response (non-CR) group according to the interim treatment response. The differences of pre-treatment PET/CT quantitative parameters were compared between the two groups，and the PET/CT parameters with predictive value for the interim treatment response were searched. Results Among the 79 patients, 48 patients were included in CR group and 31 patients (PR 17 cases，SD 5 cases，PD 9 cases) were included in non-CR group. MTVmax，MTVsum，TLG max，TLGsum，Dmax，IPI，LDH，number of extranodal organ involvement and necrosis were significantly different between the two groups. The optimal cutoff values for MTVmax，MTVsum，TLGmax，TLGsum and Dmax to predict interim treatment response were 57.2cm3，45.3cm3，756.0g，1977.1g，6.6cm，respectively. Dmax had the highest efficacy. Multivariate analysis showed that Dmax and IPI were independent predictive indicators for interim treatment response. Conclusions 18F-FDG PET/CT parameters may be used as predictive factors for interim treatment response in DLBCL patients treated with R-CHOP，they can provide important information for the selection and timely adjustment of clincal treatment strategy.