Objective To monitor and evaluate the synergistic antitumor effects of programmed death-1(PD-1)checkpoint inhibitor combined with radiation therapy through whole-body dynamic 18 F-Fluorodeoxy glucose positron emission computed tomography(18F-FDG PET/CT)and Patlak multi-parametric analysis.Methods B16F10 mel-anoma dual-tumor mouse model was established and randomly divided into control,PD-1 monoclonal antibody,ra-diation-only,and combination groups(n=6).Whole-body 18F-FDG PET/CT imaging was performed before and 24 hours post-treatment.The changes of maximum standardized uptake value(SUVmax)and metabolic rate of FDG(MRFDG)changes were analyzed and compared.Mice were then euthanized,tumors excised and underwent histo-pathology with HE,CD8,Ki-67 staining to assess immune infiltration and proliferation.Distal tumor volumes were monitored during treatment.Results At 24 hours post-treatment,in the primary tumors,SUVmax and MRFDG values increased compared to pre-treatment in the control group(P＜0.000 1),while they decreased in the combination treatment group(P＜0.000 1),with statistically significant differences.In the distal tumors,SUVmax and MRFDG values increased compared to pre-treatment in the control group,PD-1 monoclonal antibody group,and radiothera-py-alone group.The SUVmax differences were statistically significant in the control group before and after treatment(P＜0.000 1).MRFDG values in the distal tumors showed statistically significant differences in all three groups(P＜0.01 or P＜0.000 1).In the combination treatment group,SUVmax and MRFDG values in the distal tumors de-creased significantly compared to pre-treatment(P＜0.000 1).Post-treatment comparison of SUVmax and MRFDG values in the distal tumors showed that statistically significant differences in SUVmax and MRFDG values were observed among all groups except between the radiotherapy-alone and PD-1 monoclonal antibody groups(all P＜0.05).Im-munohistochemistry results showed that the mean absorbance value of CD8 T lymphocytes in the distal tumor was significantly higher than that in the other three groups(P＜0.001);the mean absorbance value of Ki-67 immuno-histochemistry in the distal tumor proliferation index was significantly lower than that in the other three groups(P＜0.001).Conclusion The synergistic effects of combined treatment reduced distal tumor growth.Whole-body 18F-FDG PET/CT Patlak multi-parametric imaging can monitor the synergistic effects of PD-1 antibody and radiotherapy in B16F10 melanoma,providing reliable imaging parameters for optimizing combinatorial therapies.

Background Although current evidence suggests a link between outdoor air pollution and depressive symptoms, the effect of solid fuel use (a significant indoor air pollutant) on depressive symptoms in China's rural middle-aged and elderly population remains poorly understood. Objective To explore the association between solid fuel use for cooking and depressive symptoms among middle-aged and elderly people in rural areas of China, and to provide a basis for the prevention and control of depressive symptoms among residents in rural areas. Methods Data were obtained from the 2020 China Family Panel Studies (CFPS), depressive symptoms were assessed using 8-item Center for Epidemiologic Studies Depression Scale (CES-D), and cooking fuel type was self-reported. Subsequently, two-level binary unconditional logistic regression models were fitted to assess the impact of solid fuel use for cooking on depressive symptoms. Results A total of 7991 participants aged 45 years and older [mean age (58.52±9.18) years] were included in the study, with a mean CES-D score of 6.07±4.48 and a mean positive depressive symptoms rate of 34% (40.54% in the solid fuel group and 30.81% in the clean fuel group, χ²=74.40, P<0.001). After controlling for potential confounding covariates, rural middle-aged and elderly residents in the solid fuel group had a higher risk of reporting depressive symptoms than those in the clean fuel group (OR=1.36, 95%CI: 1.20-1.54), an association that was unaffected by participant characteristics and was positive across age and gender groups. Conclusion There is a positive association between solid fuel use for cooking and depressive symptoms in middle-aged and elderly people in rural areas of China. It is recommended that rural areas promote the upgrading of stoves through the installation of ventilation equipment or the switch from solid cooking fuel to clean fuel. This approach is directed toward reducing exposure to household air pollution, alleviating the prevalence of depression among middle-aged and elderly residents in vast rural areas, and enhancing their mental health.