Local ablative techniques-percutaneous ethanol injection, microwave coagulation therapy and radiofrequency ablation (RFA)-have been developed to treat unresectable hepatocellular carcinoma (HCC). The success rate of p...Local ablative techniques-percutaneous ethanol injection, microwave coagulation therapy and radiofrequency ablation (RFA)-have been developed to treat unresectable hepatocellular carcinoma (HCC). The success rate of percutaneous ablation therapy for HCC depends on correct targeting of the tumor via an imaging technique. However, probe insertion often is not completely accurate for small HCC nodules, which are poorly def ined on conventional B-mode ultrasound (US) alone. Thus, multiple sessions of ablation therapy are frequently required in diffi cult cases. By means of two breakthroughs in US technology, harmonic imaging and the development of second-generation contrast agents, dynamic contrast-enhanced harmonic US imaging with an intravenous contrast agent can depict tumor vascularity sensitively and accurately, and is able to evaluate small hypervascular HCCs even when B-mode US cannot adequately characterize the tumors. Therefore, dynamic contrast-enhanced US can facilitate RFA electrode placement in hypervascular HCC, which is poorly depicted by B-mode US. The use of dynamic contrast-enhanced US guidance in ablation therapy for liver cancer is an effi cient approach. Here, we present an overview of the current status of dynamic contrast-enhanced US-guided ablation therapy, and summarize the current indications and outcomes of reported clinical use in comparison with that of other modalities.展开更多
Neutron imaging techniques were investigated at Peking University based on a 4.5 MV Van de Graaff accelerator.The thermal neutron radiography,fast neutron radiography and fast neutron resonance radiography were tested...Neutron imaging techniques were investigated at Peking University based on a 4.5 MV Van de Graaff accelerator.The thermal neutron radiography,fast neutron radiography and fast neutron resonance radiography were tested.The low neutron flux limits the image quality.A new radio frequency quadrupole (RFQ) accelerator based on neutron source with a yield of 1 012 n/s is being set up.展开更多
A new technique for estimating quiet day curve(QDC)was suggested.To validate the new approach,QDCs were derived from data acquired by the imaging riometer installed at the Chinese Zhongshan Station in Antarctic.The ev...A new technique for estimating quiet day curve(QDC)was suggested.To validate the new approach,QDCs were derived from data acquired by the imaging riometer installed at the Chinese Zhongshan Station in Antarctic.The evaluation was performed by comparing the difference between QDC derived by the new technique and those derived by Tanaka’s technique.The results were discussed in terms of the diurnal variation and discrepancy.Also,cosmic noise absorption(CNA)images were built using both techniques in order to evaluate the implications of the changes when obtaining them using different methods of the QDC determination.The influence of the multiplicative factor value on the QDC determination in Tanaka’s technique was evaluated.展开更多
文摘Local ablative techniques-percutaneous ethanol injection, microwave coagulation therapy and radiofrequency ablation (RFA)-have been developed to treat unresectable hepatocellular carcinoma (HCC). The success rate of percutaneous ablation therapy for HCC depends on correct targeting of the tumor via an imaging technique. However, probe insertion often is not completely accurate for small HCC nodules, which are poorly def ined on conventional B-mode ultrasound (US) alone. Thus, multiple sessions of ablation therapy are frequently required in diffi cult cases. By means of two breakthroughs in US technology, harmonic imaging and the development of second-generation contrast agents, dynamic contrast-enhanced harmonic US imaging with an intravenous contrast agent can depict tumor vascularity sensitively and accurately, and is able to evaluate small hypervascular HCCs even when B-mode US cannot adequately characterize the tumors. Therefore, dynamic contrast-enhanced US can facilitate RFA electrode placement in hypervascular HCC, which is poorly depicted by B-mode US. The use of dynamic contrast-enhanced US guidance in ablation therapy for liver cancer is an effi cient approach. Here, we present an overview of the current status of dynamic contrast-enhanced US-guided ablation therapy, and summarize the current indications and outcomes of reported clinical use in comparison with that of other modalities.
基金supported by National Natural Science Foundation of China(No.10735020No.10575006)
文摘Neutron imaging techniques were investigated at Peking University based on a 4.5 MV Van de Graaff accelerator.The thermal neutron radiography,fast neutron radiography and fast neutron resonance radiography were tested.The low neutron flux limits the image quality.A new radio frequency quadrupole (RFQ) accelerator based on neutron source with a yield of 1 012 n/s is being set up.
基金supported by the National Natural Science Foundation of China(Grant Nos.41104105,41374159,41274164)the Chinese Polar Environment Comprehensive Investigation&Assessment Program(Grant Nos.CHINARE-2014-04-01,CHINARE-2014-02-03)
文摘A new technique for estimating quiet day curve(QDC)was suggested.To validate the new approach,QDCs were derived from data acquired by the imaging riometer installed at the Chinese Zhongshan Station in Antarctic.The evaluation was performed by comparing the difference between QDC derived by the new technique and those derived by Tanaka’s technique.The results were discussed in terms of the diurnal variation and discrepancy.Also,cosmic noise absorption(CNA)images were built using both techniques in order to evaluate the implications of the changes when obtaining them using different methods of the QDC determination.The influence of the multiplicative factor value on the QDC determination in Tanaka’s technique was evaluated.
