Cyberknife treatment for advanced or terminal stage hepatocellular carcinoma

AIM: To investigate the safety and efficacy of the Cyberknife treatment for patients with advanced or terminal stage hepatocellular carcinoma(HCC).METHODS: Patients with HCC with extrahepatic metastasis or vascular or bile duct invasion were enrolled between May 2011 and June 2015. The Cyberknife was used to treat each lesion. Treatment response scores were based on Response Evaluation Criteria in Solid Tumors v1.1. The trends of tumor markers,including alpha fetoprotein(AFP) and proteins induced by vitamin K absence Ⅱ(PIVKA Ⅱ) were assessed. Prognostic factors for tumor response and tumor markers were evaluated with Fisher's exact test and a logistic regression model. Survival was evaluated with the Kaplan-Meier method and multivariate analysis was performed using the Cox proportional hazards model.RESULTS: Sixty-five patients with 95 lesions were enrolled. Based on the Barcelona Clinic Liver Cancer classification,all patients were either in the advanced or terminal stage of the disease. The target lesions were as follows: 52 were bone metastasis; 9,lung metastasis; 7,brain metastasis; 9,portal vein invasion;4,hepatic vein invasion; 4,bile duct invasion; and 10 other lesion types. The response rate and disease control rate were 34% and 53%,respectively. None of the clinical factors correlated significantly with tumor response. Fiducial marker implantation was associated with better control of both AFP(HR = 0.152; 95%CI: 0.026-0.887; P = 0.036) and PIVKA Ⅱ(HR = 0.035; 95%CI: 0.003-0.342; P = 0.004). The median survival time was 9 mo(95%CI: 5-15 mo). Terminal stage disease(HR = 9.809; 95%CI: 2.589-37.17,P < 0.001) and an AFP of more than 400 ng/m L(HR = 2.548; 95%CI: 1.070-6.068,P = 0.035) were associated with worse survival. A radiation dose higher than 30 Gy(HR = 0.274; 95%CI: 0.093-0.7541,P = 0.012) was associated with better survival. In the 52 cases of bone metastasis,36 patients(69%) achieved pain relief. One patient had cerebral bleeding and another patient had an esophageal ulcer after treatment.CONCLUSION: The Cyberknife can be safely administered to patients with advanced or terminal stage HCC. High AFP levels were associated with worse survival,but a higher radiation dose improved the survival.

Aerodynamic Behavior of Snowflakes on an Uneven Road Surface during a Snowstorm

The removal of snow from a road or railroad results in an uneven surface and thus the formation of snowdrifts. However, the effect of a surface bump on the scale of a snowdrift is not clear. Snowdrift wind tunnel tests have long been performed to predict the snow cover distribution due to a snowstorm. However, such tests require a large-scale experimental device, have high installation and maintenance costs, and are not easy to perform. The present study thus used a small water tunnel that is easier to implement. The snowdrift pattern for the real phenomenon of a cube model was reproduced using the small water tunnel and the performance of the tunnel thus verified. The snowdrift water tunnel was then used to predict the snowdrift distribution for uneven surfaces. The tunnel well reproduced the snow cover distribution when the sedimentation velocity ratio and Stokes number in the water tunnel test were the same as those for the real phenomenon, again verifying the performance of the water tunnel test.