Objective:To analyze the therapeutic effect and safety of simultaneous integrated boost intensity-modulated radiotherapy for lung cancer brain metastases.Methods:A total of 300 patients with lung cancer brain metastases admitted to the Department of Oncology, Qingdao Municipal Hospital from March 2021 to March 2023 were selected as the study objects. The patients were divided into control group ( n=150) and study group ( n=150) by random number table method. The control group received sequential three-dimensional conformal radiotherapy, while the study group received simultaneous integrated boost intensity-modulated radiotherapy. The short-term and medium-term efficacy, target dose, and adverse reactions were compared between the two groups. Results:The short-term and medium-term total effective rates of the study group were 73.33% (110/150) and 88.67% (133/150), respectively, which were higher than those of the control group [51.33% (77/150) and 71.33% (107/150) ] ( χ2=15.46, P<0.001; χ2=14.08, P<0.001). The D min in gross tumor planning target volume and whole brain clinical planning target volume of the study group were (23.78±1.11) and (58.46±0.55) Gy, respectively, which were higher than those in the control group [ (16.67±1.08) and (53.44±0.74) Gy], with statistically significant differences ( t=56.22, P<0.001; t=66.68, P<0.001). The D mean in gross tumor planning target volume and whole brain clinical planning target volume of the study group were (44.12±0.87) and (62.19±0.57) Gy, respectively, which were higher than those in the control group [ (37.55±0.89) and (57.78±0.82) Gy], with statistically significant differences ( t=64.65, P<0.001; t=54.08, P<0.001). The total incidence of adverse reactions was 30.67% (46/150) in the study group and 36.67% (55/150) in the control group, with no significantly significant difference ( χ2=1.20, P=0.271) . Conclusion:Compared with sequential three-dimensional conformal radiotherapy, simultaneous integrated boost intensity-modulated radiotherapy has better short-term and medium-term efficacy in patients with lung cancer brain metastases. Target dose can be increased without increasing adverse reactions.