Computed tomography (CT) has been widely used in clinical diagnosis and made a great contribution to diagnosis by providing anatomical information with high-resolution.However,when metal implants exist in patients' body,reconstructed CT images are seriously interfered by metal artifacts.Metal artifacts are usually expressed as many dark and bright radiant streak artifacts which seriously reduce diagnosis reliability and bring errors into the calculation of dose distribution in radiotherapy.Therefore,the study of metal artifact reduction (MAR)is of great importance.This article reviews main methods on MAR developed in recent years,and give deep analysis on some of the methods.

To better understand the current status of medical students in clinical medical ethics,we design the relevant questionnaire,with 468 medical students conducting a questionnaire survey.Findings in general are more satisfactory.but there are great differences on certain issues.Educational Strategies:medical education curriculum should open more humanities courses and post-clinical teachers should pay close attention to ethics education for medical students.

Intensity-modulated radiation therapy is widely used in the treatment of tumor,and the dose distribution highly conforms to tumor target area in three-dimension.However,the factors such as complex beam,data error,algorithm error and machine error may cause large dose deviation in intensity-modulated radiation therapy,which may lead to unnecessary radiation accident.Therefore,standing on the patients' safety point of view,dose verification is usually performed before executing the treatment plan in order to ensure the safe implementation of the treatment plan and to avoid un-planned irradiation dose.Currently,there are many tools and methods of dose verification in clinic,including point dose verification tools like finger-shaped ionization chamber and thermoluminescence dosimeter;two-dimensional dose verification tools like Mapcheck,MatriXX and films;three-dimensional dose verification tools like ArcCHECK,Delta4 and the third-party software.These common clinical dose verification methods are reviewed in this paper.

Objective To explore the curative effects of open reduction and internal fixation with Cable Pin or tension band wire for patellar transverse fractures.Methods Totally 28 cases and another 30 cases were enrolled in the Cable Pin group(8 months for average follow-up time) and the tension band wire group respectively(16 months for average follow-up time).The operative time,the average clinical healing time and the average range of the knee flexion between the 2 groups were compared.Results Obvious superiority was observed in the Cable Pin group over the tension band wire group concerning the average clinical healing time and the average range of the knee flexion 6 months postoperatively (P

More and more patients were treated by surgery with metal implants in clinic.Metal artifacts in CT images caused by metal implants brought challenges for postoperative evaluation and diagnosis of tumor.It also led to the possibility of missed diagnosis and misdiagnosis.In recent decades,the improved methods based on filtered-backprojection and iterative reconstruction algorithms have great progresses in reducing effects of metal artifacts.The actuality of techniques for metal artifact reduction were reviewed in this article.

Objective To explore the correlation between delirium and dementia in elderly patients undergoing hip fracture surgery.Methods A prospective study was conducted on 118 elderly patients with hip fracture who were free from prefracture dementia.Caregivers or the relatives described the patients' prefracture cognition by the Informant Questionnaire on Cognitive Decline in the Elderly-short form (IQCODE SF).Delirium was assessed by the Confusion Assessment Method (CAM).After 6 months,cognition was reassessed by using 5 cognitive tests,taking DSM-Ⅳ as the diagnostic criteria.Results Among 32 cases (27％) suffered from delirium in the acute phase,12 cases (38％) reached to the diagnostic criteria of dementia after 6 months follow up,while there were 6 cases (7％) reached to the diagnostic criteria of dementia after 6 months follow-up in the group without delirium in the acute phase (x2 =16.81,P＜0.001).IQCODE-SF score had no statistically significant difference in the prediction of dementia.Conclusions In elderly patients without the history of dementia,delirium after hip fracture surgery is the major predictor of dementia within half years.

Objective To study the detective sensitivity for position of multi-leave collimators ( MLC) using Delta-4. Methods First,the small positional deviation of MLC was simulated and measured using the linac (Varian,Trubeam) equipped with EPID.Then,two beam fields 2. 0 cm (x)×6. 0 cm (y), 7. 0 cm (x)×6. 0 cm (y) were designed,the x1 and x2 of MLC were expanded 0. 1 mm,0. 2 mm,0. 3 mm... 0. 9 mm and 1. 0 mm,2. 0...5. 0 mm to external simultaneously,different parameters of 3 mm/3%,2. 5 mm/2. 5%,2 mm/2%, 1. 5 mm/1. 5% and 1 mm/1% were used in Gamma analysis to analyze the difference between dose distribution detected by Delta-4 and original dose distribution with unexpanded MLC position derived from TPS. Results For 2. 0 cm ( x) × 6. 0 cm ( y) beam field, the pass rate of original dose distribution was 100%,and that decreased to 95. 5% when x1 ,x2 of MLC were expanded 0. 3 mm to external, and decreased to 89. 4% when expanded 0. 5 mm at 2. 5 mm/2. 5% statistical standards. For 7. 0 cm ( x) × 6. 0 cm ( y) beam field,the pass rate of original dose distribution was 96. 5%,and that decreased to less than 95% when x2,x2 of MLC were expanded 0. 3 mm to external,and passing rate was above 90% when MLC expanded less than 0. 5 mm at 1. 5 mm/1. 5% statistical standards. Conclusions For MLC' s positional deviation in decimillimeter level,raise standards of Gamma analysis properly may improve the capability of Delta-4 for detecting small positional deviation,but it won' t detect all the positional deviation of MLC in decimillimeter level. For different size of beam field,it is proposed to use different analytical standards for Delta-4.

Objective To observe the distribtuion of NOS positive neurons in the projecting pathway to the subnucleus reticularis dorsalis(SRD) in the rat. Methods We used a double staining technique combined retrograde tract tracer and NADPH d histochemistry. Results FG/NOS double labeled neurons were found in the laminae Ⅰ,Ⅹ of spinal cord,dorsal raphe nucleus(DR),linear raphe nucleus(LR),and raphe obscurus nucleus(RO).In the periaqueductal gray(PAG),there were many FG labeled or NOS labeled neurons,but no FG/NOS double labeled neurons were found.Conclusion\ NO might play a role in the pathway of afferent projections of the SRD.\;[

Objective To observe the activation of astrocytes,microglia and expression of proinflammatory cytokines in the periaqueductal gray(PAG) by Complete Freunds Adjuvant(CFA)-induced inflammatory pain. Methods Heat hyperalgesia and mechanical allodynia were observed and the expressions of mRNA,protein of glial markers,and proinflammatory cytokines in the PAG were examined following intraplantar administration CFA in right hindpaw of the rat by behavioral testing,reverse transcription polymerase chain reaction(RT-PCR), Western blotting,and immunohistochemistry. Results CFA injection induced chronic thermal hyperalgesia and mechanical allodynia.After injection,the thermal hyperalgesia was recovered on Day 14,but the mechanical allodynia lasted more than 21 days.Microglial marker(Cluster of differentiation 14,CD14) and proinflammatory cytokines(Interleukinin-1?,tumor necrosis factor-?) showed a significant increase in their expression during all phases(acute,subacute and chronic) of inflammation.GFAP was observed only in PAG at subacute and chronic phases of inflammation.Conclusion The activation of microglia and astrocytes may be involved in the initiation and maintenance of inflammatory pain.Enhanced cytokines expression might play a role in eliciting behavioral hypersensitivity.