Quality assurance of EBCT images is especially important in clinic. Factors influencing the quality of images are so variable and complex that comprehensive consideration should be paid to them. The analyses and researches for such factors as surrounding background, machine's inherent property and scanning parameters are made separately.

Objective To verify the usefulness of the corresponding compensation techniques for MRI artifacts after analyzing their generation mechanism. Methods Different compensation techniques were used to eliminate relative artifacts from the angle of improving background,calibrating software and hardware,editing parameters or instructing patients in scanning the patient or phantom with 1.0TMR and 1.5TMR. Results Artifacts were controlled to different extents and the quality of most MR images were improved. Conclusion Most artifacts can be eliminated completely by the use of corresponding compensation techniques while some others only be reduced a little or shifted.

Objective To verify whether it is useful to apply the corresponding preventive measures for the radio frequency(RF) field artifacts in MR images by the research of their influencing factors.Methods Preventive measures were taken according to the factors producing RF field artifacts in MR images.Results Various RF field artifacts in MR images were reduced,shifted or even eliminated completely.Conclusion Most RF field artifacts in MR images can be controlled by the application of the relative preventive measures.

Objective To evaluate the application effect of workload statistic software.Methods According to the actual workflow of the hospital and concrete management index sign,the workload of statistics procedure was designed using Dephi7.0.Results "Comprehensive Management System in Medical Imaging Department" run stable and accurate.What's more,its functions greatly facilitated workload statistics.Conclusion The system plays an important role in excellent workflow,exaltation of work efficiency,reasonable allotment of manpower and material resources,etc.

Objective To evaluate the clinical value of fMRI software.Methods Patients were scanned with the corresponding fMRI software to observe the change of imaging signals in tissue's functional zone.Results The signals in the relative functional zone of tissues varied with their functions.Consulation fMRI software has great value in such clinical applications as tissue physiology,biochemistry and metabolism functions.

Objective To investigate the effectiveness of gamma-knife radiotherapy combined with stent placement for the treatment of cancerous thrombus in inferior vena cava (IVC) in patients with hepatic carcinoma. Methods Stent placement was performed in 26 patients of hepatic carcinoma associated with cancerous thrombus in IVC,which was followed by gamma-knife radiotherapy for the treatment of thrombus. IVC angiography was reexamined at regular intervals to find out the patent situation and to measure the internal diameter of IVC. Results The internal diameter of IVC was increased in different degree after the treatment. After stent placement the internal diameter of IVC was increased by (0.842 ? 0.283) cm,while the internal diameter of IVC was increased by (1.523 ? 0.195) cm after gamma-knife radiotherapy. The internal diameter of IVC after gamma-knife radiotherapy was significantly greater than that before stent placement (P

Objective To master the various characteristics of EBCT and it's applications in clinic in depth. Methods Different scan modes were compared with each other. Results EBCT had the advantage of high speed in scanning and high resolving power of time without mechanical abrasion due to the using of electron beam. Conclusion EBCT is suitable for the examinations of cardiovascular system, and moving organs and uncooperative patients, and also for the application to CT fluoroscopy.

Cerebral ischemia accounts for 70%~80%. Magnetic resonance imaging (MRI) shows infarct focus efficiently, which plays an important role in the diagnosis of ultra-early stage of ischemia and the prediction of infarcts' change. This paper reviewed the recent advance in the effect of MRI on the diagnosis and prediction of cerebral ischemia.

OBJECTIVE:To provide references and suggestions for building and improving the R&D incentive policies for or-phan drugs in China. METHODS:The R&D incentive policies for orphan drugs in USA and the EU were compared in aspects of its legislative history,incentive measures and effects. And suggestions for improving related policies in China were put forward. RE-SULTS & CONCLUSIONS:The R&D incentive policies for orphan drugs in USA and the EU respectively started from Orphan Drug Act in USA(1983)and Orphan Drug Management Specification in the EU(1999),then formed relatively complete system by continuous improvement. The USA and the EU showed differences in its certification standard,procedure and specific incentives [R&D funding,tax deduction,fee reduction,additional incentives for micro and small and medium enterprises (SMEs),market exclusivity and special approval procedure],etc. In terms of fee reduction,for example,prescription application fee,production cost and drug confirmation fee were exempted in USA,while arrangement assist fee,initial and follow-up fee,checking fee before approval,initial listing type were reduced to a certain percentage in the EU. After developing incentive policies for orphan drugs, there is great increase in numbers of recognized qualifications and listing,SMEs have become new force in orphan drug R&D, R&D investment covers all types of diseases,orphan drug R&D are becoming the main direction of drug innovation and biotechnol-ogy development. China should determine the relevant legislation of R&D incentives for orphan drugs as soon as possible,set certi-fication and improve specific measures of R&D incentives for orphan drugs from multiple aspects,while strengthen the cooperation with other countries in qualification and R&D incentives.

Objective To comprehensively analyze the academic impacts of papers published by the Chinese Journal of Rheumatology based on the Chinese biological medical journal citations database(CMCI) 1997-2011 data developed by PLA medical library.Methods Based on the Chinese biological medical journal citations database (CMCI),method of bibliometrics for 1997-2011 was adopted for the analysis.The citation rate,the authors distribution,and the research direction of the citated papers were all included for the evaluation.Results During 1997 to 2010,1700 papers were included into the CMCI by the law of the journal of rbeumatology,8323 times were cited by domestic science and technology journal with the average citation of 4.90 times.The authors of 675 cited papers distributed in 28 provinces and autonomous regions and municipalities.During 1997-2011,the law of the journal of rheumatology cited 170l papers,the rank of the first three topics was the systemic lupus erythematosus (sle),in which 453 articles were cited,rheumatoid arthritis in which 404 article were cited,and relevant ankylosing spondylitis in which 106 articles were cited,Articles with these three topics accounted for 56.61％ of overall citations.Conclusion The papers published by the journal have shown certain depth theoretically and some breakthr-oughs.The articles and papers published have focused on the hot topics and critical research area and topics of rheumatology,therefore,have guided the development of Chinese rheumatology.The journal has important influences on clinical practice and research of Chinese rheumatology.The papers published could be used as valuable resources.The influence and the academic status of this journal is gradually expanding and the quality of the publications is persistently improving.It is one of the major scientific journals in medical research in China.