Background: The management of metastatic brain tumors is an important issue in patients with malignant tumors or cancer. The authors summarize the results of patients with brain metastases treated at the Xi-Jing Hospital during a 10-year period, in order to assess the best modality of treatment for patients with brain metastases. Methods: Between 1990 and 2000, 463 patients with brain-metastatic tumors were treated at the Xi-Jing Hospital of the Fourth Military Medical University, Xian, China. In most patients, the pathologic diagnosis of primary cancer was obtained before they were referred for their brain metastasis. There were 34 (8.42%) cases with an unknown primary cancer site at the time of initial presentation. Patients were grouped according to treatment methods, which included neurosurgical craniotomy (NS; 130 patients), whole-brain radiotherapy (WBRT; 120 patients). Linac XKnife radiosurgery (RS; 130 patients) and Linac XKnife radiosurgery plus WBRT (RT; 83 cases). Survival was measured from the time of treatment and was analyzed by the Kaplan-Meier product-limit method and then plotted. Differences between curves were evaluated using the log-rank test. Multivariate factors associated with survival were analyzed using the Cox proportional hazards model. Results: The survival time was 68.4 ± 7.20 weeks after NS, 51.3 ± 5.04 weeks after WBRT, 67.9 ± 3.68 weeks after RS and 89.7 ± 4.50 weeks after RT. The presence of active systemic cancer in a larger number of metastatic tumors was associated with a poor survival (p = 0.0003 and 0.0000). The female patients showed better survival rates over the male ones (p = 0.0000). Patients treated with RT had a better survival than those treated with NS, WBRT and RS (p = 0.0048, 0.0000 and 0.1222, respectively), although the latter did not show statistical significance. Conclusions: RS was an effective modality for patients with brain metastases, and if combined with WBRT, survival was better. Progression of systemic cancer and the number of metastatic tumors were the most significant factors for a poor survival after treatment of the brain metastases.

No abstract

No abstract

No abstract

Rare earth silicates (RE2SiO5 or RE2Si2O7; RE=Er, Lu, Y, Yb etc.) possess a low silica activity and good thermal stability, making them good candidates for EBC top coating materials. We have performed first-principles total energy calculations for the Er2O3-SiO2 pseudo binary system. The crystal lattice parameters and internal atomic coordinates of Er2SiO5 and Er2Si2O7 are optimized, and the electronic structure and formation enthalpies are calculated. The present study provides a theoretical basis for exploring practical applications of the materials.