Investigation of a whole-body receiver coil operating at liquid nitrogen temperatures

This communication describes the design and application of a receiver coil operating at liquid nitrogen temperature and intended as a surface coil in a whole-body imager. Its particular application is seen as the external receiver for parasitic internal or implanted detectors.     

观片灯亮度对数字影像照片诊断效能影响的实验研究

目的 了解不同亮度观片灯对数字影像照片诊断准确性的影响.方法 测量临床实际工作环境中用到的所有观片灯,然后选出3个作为研究观片灯,分别代表高、中、低亮度,计算平均亮度值.应用Kodak DR 3000,曝光参数为75 kV、3.2 mAs,焦片距100 cm,对统计学摄影体模(TRG)进行摄影,获得体模影像照片.将该照片分别置于上述3种不同亮度的观片灯上,由3名医学影像科医师进行视读,用5值判断法获得信号和噪声的记分,计算出TRG模体中骨替代物和肌肉替代物的真阳性概率[P(S/s)]和假阳性概率[P(S/n)]值,绘制BOC曲线,并计算其准确性的判断概率值(Pdet).采用配对t检验比较对不同亮度的观片灯的Pdet值.结果3种观片灯的平均亮度值分别为(3489±256)、(2231±220)、(816±168)cd/m2.当骨替代物直径分别为0.6、0.7、0.8 mm,在高亮度观片灯上得到的Pdet值分别为0.558±0.009、0.788±0.008及0.813±0.006;中等亮度的观片灯的Pdet值分别为0.525±0.013、0.713±0.013及0.775±0.016;在低亮度观片灯上得到的Pdet值分别为0.475±0.022、0.550±0.018及0.688±0.020.肌肉替代物直径分别为0.9、1.0、1.2 mm时,在高亮度观片灯上,Pdet值分别为0.663±0.010、0.750±0.008及0.933±0.005;中等亮度观片灯上,得到的Pdet值分别为0.613±0.019、0.650±0.013及0.850±0.019;低亮度观片灯上,得到的Pdet分别为0.550±0.025、0.575±0.021及0.725±0.016,高亮度组与中亮度组、中亮度组与低亮度组之间分别进行配对t检验,差异均有统计学意义(t值分别为5.057和4.681,P<0.05).结论观片灯的亮度可影响诊断的准确性,观片灯的亮度越高,观察到的影像信息越丰富,诊断的准确性越高.     

Reducing Dislocations on the Field

When an athlete dislocates a joint on the field, the team physician must decide whether to reduce the dislocation immediately or after x-rays. Several factors, including the physician's level of experience, point physicians to the appropriate choice.     

Virtual bronchoscopy versus thin section computed tomography in evaluation of moderate and low grade stenoses: receiver operating characteristic curve analysis

Purpose: To evaluate the impact of virtual bronchoscopy, under proper threshold settings, on observer level of confidence in the assessment of bronchial abnormalities producing stenoses ≤75% compared to interpretation of thin section computed tomography (CT) images.

Material and Methods: Sixty-five patients with fiberoptic bronchoscopy positive for tracheobronchial abnormalities were evaluated in a blinded observer study using a commercially available virtual endoscopy software package. The findings of virtual endoscopy were compared with those of fiberoptic bronchoscopy using receiver operating characteristic curves (ROCs) and other statistical tools.

Results: A total of 102 lesions were identified by fiberoptic bronchoscopy, with 44 of these producing bronchial stenoses ≤75%. Concerning the latter lesions, for virtual bronchoscopy the areas under the ROCs were 0.93 and 0.96 for the two observers, respectively, while for thin section CT the corresponding values were 0.86 and 0.88; the differences observed were statistically significant. Contrary to thin section CT, virtual bronchoscopy did not show statistically significant differences from fiberoptic bronchoscopy regarding estimation of degree of stenosis.

Conclusion: Virtual bronchoscopy under proper threshold settings has a statistically significant impact on observer performance where moderate and low-grade bronchial stenoses are concerned and gives an estimate of the degree of stenosis more precisely than thin section CT.     

Reducing the Impact of Same-Day Missed Appointments

Radiologist reimbursement cuts over the last few years have driven outpatient imaging centers to find innovative ways to cut costs and improve efficiency while maintaining high image quality. A California-based outpatient imaging center has been tackling the problem of same-day missed appointments since 2014. The lack of meaningful change with each experiment in the last 4 years has led the organization to change direction and look for ways to actively maintain a desired utilization level. An interim solution to cut examination times in modalities with high cancellation rates allows schedulers to schedule more examinations every day. This article covers the history of continuous improvement around reducing same-day missed appointments and eventually realizing the need to open capacity, and it makes the argument for an integrated system that predicts the probability of patients cancelling their examination to facilitate proactive measures.     

Reducing the variability of oxygen consumption measurements

The oxygen consumption (O₂) of 10 able-bodied adults each walking at a variety of cadences and hence speeds was measured. The effect on variability of subtracting the resting oxygen rate from gross measurements and of normalising walking speed to the subject's height was investigated. Both of these were indeed found to reduce variability. A total reduction of more than 40% in the variability of O₂ cost measurements was observed. Using these techniques it was found that, at walking speeds below the average, nett O₂ cost per height was very nearly independent of walking speed.     

Reducing the risks for contrast-induced nephropathy

Contrast-induced nephropathy (CIN) is one of the most serious adverse events associated with the use of contrast media (CM). Patients who develop this complication can have increased morbidity, higher rates of mortality, lengthy hospital stays, and poor long-term outcomes. Although CIN cannot be eliminated, the chances of developing this condition can be reduced by using appropriate prevention strategies. An important first step to reduce the chance of CIN is to identify risk factors associated with this condition. Patients with a previously elevated serum creatinine level, especially when secondary to diabetic nephropathy, are at great risk for developing CIN. Other patient-related risk factors include concurrent use of nephrotoxic medications, dehydration, congestive heart failure, age greater than 70 years, and probably the presence of diabetes mellitus even if serum creatinine is normal. Adequate hydration is widely accepted as an important prophylactic measure for preventing CIN, but the optimal hydration regimen is still debatable. The risk of CIN increases with greater doses of CM, as well as with the type of CM used. A high-osmolar CM poses a greater risk of CIN than does a low-osmolar CM and, as recent but limited data suggest, the use of an isoosmolar CM is less nephrotoxic than a low-osmolar CM in patients with renal impairment following intra-arterial procedures, although this finding needs to be verified in future clinical studies. Pharmacologic agents such as calcium channel blockers, dopamine, atrial natriuretic peptide, fenoldopam, prostaglandin El, and endothelin receptor antagonist have not been proven effective against CIN development. Controversies still exist on the possible effectiveness of theophylline and N-acetylcysteine. Simple strategies for the prevention of CIN in at-risk patients are reviewed and unproven interventions are discussed.     

杂交手术室的设计探讨

目的 研究满足现代介入手术需求,布局合理,实用性强,有一定前瞻性的杂交手术室设计方案.方法 通过设计规划新建放射外科大楼的过程,总结了新建杂交手术室要综合考虑的各种因素,如:机房面积、功能分区、操作流程、无菌规范等,设计了符合介入手术和开放性手术操作要求,功能全面的杂交手术室.结果 充分论证、科学设计是建设杂交手术室非...     

加强业务训练 克服人才断层

近年来，按照军队专业技术干部管理有关规定，我院一大批高职和中职军龄到“杠”的专业技术干部陆续退休或转业，加之部分干部因种种原因调走或入学学成未归，使我院专业技术干部队伍严重断层和缺编。面对这一实际情况，我们积极探索人才培养新方法，走出了一条具有我院特色的业务训练新路子，较好地解决了人才断层和缺编带来的不利影响，为军队疗养院医疗工作的圆满完成提供了可以借鉴的人才培养之路。