Objectives: To evaluate the outcome of Rotating Gamma Knife radiosurgery in treating brain metastases of non-small cell lung cancer patients at the Nuclear Medicine and Oncology Center, Bach Mai Hospital. Patients and methods: Clinical interventional trial, no control group. From July 2007 to July 2011, the authors enrolled 60 non-small cell lung cancer patients (confirmed histopathology) with one to three tumors diagnosed brain metastases. Diameter of lesions were less than 30mm on the magnetic resonance imaging films. All the patients were undergone radiosurgery by Rotating Gamma Knife and are being follow-up up to now. Prescribed doses were stratified as 18 Gy and 24 Gy for tumor whose size 20 mm and 20-30 mm in diameter, respectively. Results: Clinical response rates are 58,4 percent
60,0 percent
63,3 percent and tumor response rates are 53,4 percent
60,0 percent
61,6 percent at three months, six months and nine months after radiosurgery, respectively. Tumor control rates are 93,5 percent at one year after treatment. The patients in group classified as a single brain metastasis, less than 20 mm in diameter get the better outcome than the other (84,0 percent vs 45,7 percent
75,7 percent vs 39,1 percent), p0,05. In conclusion: Rotating Gamma Knife surgery is an effective method for treating brain metastases of non-small cell lung cancer patients. It controls tumor, minimizes clinical symptoms and provides decreased or disappeared lesions. The response rates increase with time, maximum at nine months after treatment and depend on the numbers and the size of brain metastases. There is no fatal complication relative to the course of treatment.