Medical assistance systems are an integral part of the health security system and they represent the integrity and adequacy of health risk protection. The overwhelming majority of developed countries have already es-tablished medical assistance systems to improve the accessibility of healthcare services and provide catastrophic pro-tection for families, especially for the poor. The paper conducts a comparative study of typical foreign medical assis-tance systems, where in the general method by which developed countries embed catastrophe protection mechanisms into public healthcare security systems and provide tilt protection to the needy is described. Medical assistance is pro-vided on a means-test basis and the development of private health insurance is encouraged to alleviate pressure on the public side. Corresponding implications for China are also warranted, including the provision of tilt protection to the needy, to re-define objects and standards of medical assistance, and enhance the coordination of different medical se-curity systems.

Digital angiography system is mainly composed of Digital Subtraction Angiography(DSA)equipment and mostly used in angiography and interventional radiology.With the improvement of image quality,modern DSA equipment has a higher radiation output capacity,which increases the potential radiation damage to the operators and patients.Dose optimization studies the relationship between image quality and radiation dose for reasonable reduction of radiation dose and good image quality.

ObjectiveTo reduce the effective dose and maintain the image quality by adjusting the image processing parameters in the lumbar spine examinations.Methods This study investigated the influence of image processing parameters on image quality of Philips DR system by evaluating image quality of CDRAD 2.0 phantom.The parameters include detail contrast enhancement,noise compensation,unsharp masking and unsharp masking kernel.The entrance surface dose of phantom was measured by solidose meter.A synthetical parameters optimization project was proposed by analyzing the results of the investigation.This project was also testified by phantoms.ResultsImportant effects were the main effects of DCE,unsharp masking and kernel at the clinically used tube potential of 70 kVp( F =91.45,373.79,429.88,P ＜ 0.05).These effects indicated an increase of the 1QF about 20 units with increasing unsharp masking,while an increase of DCE and kernel led to decrease of IQF about 10 and 21 units.When the tube potential was increased to 85 kV,keeping the settings of the process parameters unchanged,the IQF increased.The results showed statically significant difference ( t =5.31,P ＜ 0.05 ).ConclusionIt is possible to lower the effective dose to the patient by the use of a higher tube potential and maintain a good image quality,and it will have little influence on clinic diagnosis through the most optimal setting of the process parameters.

AIM:To introduce the concept of bridging study and its strategies in clinical trials for new drug application.METHODS:The concept of bridging study proposed in the ICH E5 guideline was introduced,with a case using bridging strategies in the new drug applications(NDAs)approved by the regulatory authority in Japan.The concrete mode and the development of bridging studies in Asia were summarized.RESULTS:With the application of the ICH E5,some countries and regions have successfully used the bridging strategy in the new drug applications.The bridging strategy is becoming a common and practical basis for the decision making of marketing approvals of new drugs in the Asia-pacific country.CONCLUSION:The currently bridging studies in Asia will play an important role in the extrapolation of foreign clinical data in new drug application.Using bridging study is very helpful in judging ethnic differences of drugs,reducing duplication of clinical trails,as well as shortening clinical development periods.

In allusion to the constant development of degree students majoring in medicine recent years,the essay discusses the future development trend of medicine degree student on analysis of education demand of the neighboring countries and the contrast of different cultivate model and the quality standardization.

Objective To expore the effect of nerve repair for patients with traumatic suprascapular nerve combined with axillary nerve injuries.Methods Data of 13 cases with traumatic suprascapular nerve combined axillary nerve injuries treated by surgery from June 2003 to September 2011 were retrospectively analyzed.All the cases were males,and the average age was 28 years old.There were 2 cases of neck of scapula fracture combined with clavicle fracture,3 of floating shoulder injury,1 of humerus neck fracture combined with glenoid cavity fracture,3 of clavicle fracture,1 of acromion fracture,2 of shoulder blade fracture and 1 of atlanto-axial vertebral fractures.All the 13 cases performed isolated lost of the function of shoulder abduction and external rotation completely,and the muscle strength of deltoid,the supraspinatus and infraspinatus was M0.The electrophysiological examination showed complete denervation of axillary nerve and suprascapular nerve.The suprascapular nerve was broken in 10 cases in which 6 cases were repaired by 1 band sural nerve graft and 1 case was repaired by 1 band superficial cervical plexus,and 3 cases were irreparable because of the distal avulsion injury from the target muscle,and 3 cases were performed with neurolysis.The axillary nerve ruptured in 12 cases,in which 10 cases was repaired by 2-3 bands sural nerve graft,and fascicles selected from the median nerve were used to neurotize axillary nerve in 2 cases.The neurolysis of axillary nerve was performed at the quadrilateral space in 1 case.10 of the 13 cases had both the suprascapular nerve and axillary nerve ruptured.Results 13 cases were followed up,the follow up period was 36 to 134 months.In 7 cases,the functional recovery of shoulder abduction were 180° and the average external rotation was 56° and the muscle strength of deltoid attained M4.In 5 cases,the average shoulder abduction was 38°;the range of external rotation was-40°-30°,and the muscle strength of deltoid achieved M4 in 1 case,M3 in 2,M2 in 2.There was no improvement in 1 case.Conclusion The suprascapular nerve associated axillary nerve injury should be suspected in the patients with isolated lost the function of shoulder abduction and extemal rotation completely.Repair of axillary nerve and suprascapular nerve by nerve graft simultaneously could achieve good outcome,and early surgery should be conducted.

Objective To investigate balanced steady-state free precession with flow-sensitive dephasing magnetization preparation (FSD-bSSFP) in the assessment of arteries of foot in diabetic patients.Methods The lower-extremity peripheral arteries of 43 diabetic patients were evaluated by FSD-bSSFP no contrast MRA and contrast-enhanced MRA (CE-MRA)in. Two experienced observers assessed the image quality, degree of venous contaminated and visibility of pedal artery branches by FSD-bSSFP and CE-MRA respectively in consensus. The signal intensity( SI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the source images of both groups were measured and Wilcoxon and t tests were performed. Results The image score of FSD-bSSFP group was 2.7 ± 1.1 and CE-MRA was 2.6 ± 0.8, there was no statistical difference ( Z = 0. 134, P ＞ 0. 05 ). The image score of demonstration of the pedal artery branches and degree of venous contamination on FSD-bSSFP were 3.2 ± 0. 9 and 1.8 ± 0. 4 respectively which were superior to that of CE-MRA (2.5 ± 0.9 and 2.1 ± 0.8 respectively). Significant statistical difference existed between the two groups in demonstration of pedal artery branches ( Z = 5.246, P ＜ 0.05 ) and degree of venous contamination (Z =2.541 ,P ＜0.05). SNR of FSD-bSSFP was 148.6 ±26.7, CNR was 88.3 ± 19.0. SNR of CE-MRA was 148.5 ± 45.6, CNR was 121.0 ± 41.0. No statistical difference existed between SNR between two methods (t = 0.013, P ＞ 0.05 ). But CNR of CE-MRA was superior to that of FSD-bSSFP and significant statistical difference existed between these two methods ( t = 5.113, P ＜ 0.01 ). Conclusion FSD-bSSFP without contrast could be used in the evaluation of foot arteries in patients of renal dysfunction and diabetes.

Objective To introduce a new spinal surgery navigation system based on structured light scanning(structured light navigation system,SLNS),and to compare accuracy of pedicle screw placement using SLNS,CT based navigation system and free hand technique.Methods Thirty-two calf vertebral pedicles,40 and 32 were placed with pedicle screws using SLNS,CT navigation system,and free hand technique,respectively.The pedicle breakage ratio,transverse section angle (TSA),sagittal section angle (SSA),screw offset deviation of each screw were detected according to CT images.Results The pedicle breakage ratio of pedicle screws in SLNS group,CT navigation group and free hand group were 6%(2./32),5%(2/40),25%(8/32),respectively.The difference between each of the two navigation groups and free hand group were statistically significant regarding frequency of screw misplacement.The difference between the two navigation systems was not obvious.The average SSA error and TSA error in SLNS group were 2.58°±2.74° and 4.26°±5.20°.For CT navigation group,they were 2.95°±2.61° and 3.13°±-2.75°.There was no statistical difference between the two navigation methods for the SSA or TSA error.There was no statistical difference in offset deviation among SLNS group,CT navigation group and free hand group.Conclusion The SLNS is a new and practical navigation system,which has similar accuracy with CT navigation system.

Objective Retrospectively evaluate the effect of Z-axis tube-current modulation technique with desired noise level to improve image quality (image noise level) and decrease radiation doses of MSCT (16-slice CT) in chest scanning. Methods Consecutive two hundred patients whose CT scan projection radiographs showed no significant abnormal were randomly divided into two groups by the examination order: Z-axis tube-current modulation (ZTCM) group (odd number, test group) and constant tube-current (CTC) group (even number, contrast group). The desired noise level of ZTCM group was 10HU and the machine automatically set the dynamic tube-current in scanning according to attenuated information of chest acquired in scan projection radiographs, the tubo-current of CTC group was set at 200mA, while the other scan parameters remained totally the same. The maximum tube-current value,CTDIvol, DLP and the tube-current of the slice at the maximum breast level of female patients were recorded respectively. The noise of image at upper lung, aorta arch, left atrium and bottom lung level were measured and compared. The qualities of Images were classified in three levels (excellent, good, poor) with double blind method. Results The mean value of maximum mA, CTDIvol, DLP and mA of the slice at the maximum breast level of ZTCM group were (178.5±125.6) mA, (10.5±3.8) mGy, (231.6±24.3)mGy/cm and (116.0±22.5) mA, those of CTC were 200.0 mA, 12.8 mGy, (274.7±18.4)mGy/cm and 200.0 mA, ZTCM group decreased by 10.8%, 19.9%, 15.7% and 42.0%,respectively, as compared with CTC group. The image quality at upper lung and bottom lung level in ZTCM group was improved significantly (P < 0.05) and the cases of excellent images in ZTCM group was significantly higher than that of CTC group (P < 0.05). Conclusion ZTCM technique not only contributes to more rational distribution of radiation doses but also realizes individuation, decreases the total radiation doses and improves image quality in chest CT scanning. It is valuable and promising in chest CT scan.

Objective To explore a new scanning technique to reduce and avoid image artifacts of thoracoabdominal CT and improve image quality for patients who cannot raise their arms. Methods Sixty-one patients with arm-raising disability between March 2004 and May 2009 were enrolled in the study. Thirty-one cases before June 2007 were scanned with their arms beside their body (control group), 30 cases after June 2007 were scanned with their arms shifting to different imaging planes of the spine(study group), and another 30 patients who can raising their arms were taken as routine group. The images artifacts were blindly evaluated by 5-points scale (severe, less severe, moderate, minimum and no artifact) by 2 experienced CT technologists and one radiologist and compared between the three groups (χ~2 test). CT values and its noise of the liver with or without artifact of the three groups were measured and analyzed by one-way ANOVA test. Results In the control group, 11 cases had severe, 15 cases had less severe, 5 cases had moderate. In the study group, 6 cases had moderate, 15 cases had minimum, 9 cases had no artifact. In the routine group, 8 cases minimum and 22 cases had no artifact. Image quality was significantly improved in the study group compared to the conventional group where χ~2 = 95.32 and P <0.01. CT value and the noise of the liver without artifact were (54.5±3.0) HU and 10. 7±2.4 in the control group, (52.0±3.5) HU and 10.7±0.5 in the study group, (53.7±3.1) HU and 9.9±0.5 in the routine group, respectively. CT value and noise of the liver with artifact were (41.7±8.4) HU and 17.9±2.6 in control group, (53.1±6.9) HU and 11.0±0.7 in the study group, (54.1±2.4) HU and 9.9±0.5 in the routine group, respectively. The CT value and its noise variation with artifact were significantly higher in the control group than the study group and the control group, where F = 36.352,235. 848, respectively and P <0.01. Conclusion The image quality can be improved and the artifact can be minimized for the patients with arm-raising disability by shifting their arm position to the different imaging planes of the spine.