Objective To study the percentage depth dose difference (PDD) between Monte Carlo method and the measurement method.Methods Based on the detail treatment head structure designing by the manufacture,the BEAMnrc Monte Carlo code was used to simulate the 6 MV photon beams of a Siemens Primus linear accelerator.DOSXYZnrc program generated 6 MV X-ray parameters such as PDD,and it was measured by MP3 three-dimensional water of PTW corporation phantom.The deviation of PDD was calculated using formulas ((measured value-simulation algorithm value)/measured value × 100％).Results Distance from the surface of the water was less than 1.2 cm,the deviation of PDD was ＞ 2％.Distance from the surface greater than 1.2 cm,the deviation of PDD was ＜ 2％.Conclusion In the built-up areas,PDD obtained by the Monte Carlo simulation algorithm is more accurate.

Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Middle Aged ; Thrombosis ; etiology

BACKGROUND: At present, the materials that are successful y applied in rib fracture internal fixation mainly include titanium, nitinol rib encircling bone bonding plate, imported poly-L-lactic acid absorbable rib nails and anatomical plate.
OBJECTIVE: To study the biomechanical characteristics of new magnesium al oy absorbable rib intramedul ary nail in the rib fracture fixation, and to compare with imported poly-L-lactic acid absorbable rib intramedul ary nail in order to provide scientific basis for clinical application.
METHODS: Thirty fresh adult fifth rib specimens were col ected, and the specimens were used to make models for the middle rib fractures. The specimens were fixed with AZ31B magnesium al oy absorbable rib intramedul ary nail (magnesium al oy group) and poly-L-lactic acid absorbable rib intramedul ary nail (poly-L-lactic acid group), and the normal rib specimen group was set as control. The biomechanical characteristics of the nails in each group were tested with stress analysis.
RESULTS AND CONCLUSION: Three-point bending strength measurement results showed that the bending strength in the magnesium alloy group was close to the normal value of the specimen (P > 0.05), and there was significant difference in the bending strength between magnesium alloy group and the poly-L-lactic acid group (P < 0.05). Torsional strength measurement showed that there was no significant difference in torsional strength between magnesium alloy group and the normal specimens, and the results showed that the magnesium alloy was better than poly-L-lactic acid in fixation (P < 0.05). Tensile tests showed that the tensile strength and anti-pulling force of the magnesium alloy fixation were better than those of poly-L-lactic acid fixation (P < 0.05). The results indicate that the magnesium alloy absorbable rib intramedullary nail is better than poly-L-lactic acid absorbable rib intramedullary nail in strength and tensile strength, which is the ideal fixation material for rib fixation.

Objective To compare the outcomes of traumatic flail chest with multiple injuries treated by operative fixation versus conservative approach. Methods The clinical data of 60 patients with traumatic flail chest with multiple injuries were retrospectively analysed, and the outcomes between operation group (treated by operative fixation, n=32)and non-operation group (treated by conservative approach, n=28) were compared. Results The mean time of hospital stay, ICU stay and mechanical ventilation was significantly shorter, and the prevalences of chest wall deformity, pulmonary infection, pulmonary atelectasis and respiratory failure were significantly lower in operation group than those in non-operation group (P<0.05). Six months after discharge, the pulmonary function parameters such as inspiratory capacity, forced vital capacity, forced expiratory volume in one second, peak expiratory flow, total lung capacity and maximal midexpiratory flow were significantly higher in operation group than those in non-operation group (P<0.05). Conclusion Traumatic flail chest with multiple injuries treated by operative fixation may lead to less flail chest associated complications. Operative fixation has short- and long-term benefits to flail chest.

ObjectiveTo investigate the hemostatic effect of fibrin sealant (FS) powder on severe wound surface and find out the minimum effective dosage.Methods1 cm2 round wound surface was made on the liver of New Zealand white rabbits. Different dosages of FS powder were administrated on the wound surface. Bleeding time and bleeding volume were examined to find out optimized dosage. Hemostatic effect of FS powder was observed and compared with chitin cotton, gelfoam and normal gauze.ResultsBleeding time (0.57±0.21 min)and bleeding volume (0.35±0.29 ml)of FS 10 mg/cm2 group were obviously different from FS 8 mg/cm2 group (P<0.05), not significantly different from FS 12 mg/cm2 group. FS 10 mg/cm2 group got the shortest bleeding time and the lowest bleeding volume, which was obviously different from chitin cotton, gelfoam and gauze groups (P<0.05～0.01).ConclusionThe hemostatic effect of FS powder is better than gelfoam, chitin cotton and gauze and its optimized dosage is 10 mg/cm2.

The present paper is aimed to study the preparation and application of individual artificial bone of carbon/carbon composites. Using computer tomography images (CT), we acquired a three-dimensional image. Firstly, we described bone contour line outlined with manual and automatic method by the binary volume data. Secondly, we created 3D object surface information by marching cubes. Finally, we converted this information to non-uniform rational B-spine (NURBS) by using geomagic software. Individual artificial bone with carbon/carbon composite was prepared through the CNC Machining Center. We replaced the humeral head of the tested rabbit, and then observed the effects of implantation in neuroimaging and pathological section. Using this method, we found that the bone shape processed and bone shape replaced was consistent. After implantation, the implant and the surrounding bone tissue bound closely, and bone tissue grew well on the surface of the implant. It has laid a sound foundation of the preparation using this method for individual artificial bone of carbon/carbon composite material.
Animals ; Bone Substitutes ; chemistry ; Carbon ; chemistry ; Imaging, Three-Dimensional ; Rabbits ; Software ; Tomography, X-Ray Computed

Actins ; analysis ; Antigens, CD34 ; analysis ; Carcinoma, Papillary ; classification ; metabolism ; pathology ; Female ; Humans ; Immunohistochemistry ; Keratin-19 ; analysis ; Keratin-20 ; analysis ; Muscle, Smooth ; chemistry ; Pancreatic Neoplasms ; classification ; metabolism ; pathology ; Proto-Oncogene Proteins c-kit ; analysis ; Receptors, Estrogen ; analysis ; Receptors, Progesterone ; analysis

Drugs, Chinese Herbal ; toxicity ; Humans ; Liver ; drug effects

Objective Due to the superior performance,Carbon-Carbon composites,although still at their early stage of development,have gained more and more attention and showed great application potential.Methods According to the National Standard,the biological safety evaluation of carbon-carbon composites were done in the following aspects:cytotoxicity test,acute systemic toxicity test,haemolysis test,pyrogen test,intramuscular implantation test.Results test results showed the biological safety evaluation of carbon-carbon composites well meet the requirement of the national standard with fine biological compatibility.Conclusion The experiment results demonstrate that carbon-carbon composites can be put in clinical application

Hepatitis C, Chronic ; complications ; surgery ; virology ; Humans ; Liver Failure ; etiology ; surgery ; Liver Transplantation ; adverse effects ; Secondary Prevention