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171.
A Trakic F Liu H Sanchez Lopez H Wang S Crozier 《Magnetic resonance in medicine》2007,57(6):1119-1130
The switching of magnetic field gradient coils in magnetic resonance imaging (MRI) inevitably induces transient eddy currents in conducting system components, such as the cryostat vessel. These secondary currents degrade the spatial and temporal performance of the gradient coils, and compensation methods are commonly employed to correct for these distortions. This theoretical study shows that by incorporating the eddy currents into the coil optimization process, it is possible to modify a gradient coil design so that the fields created by the coil and the eddy currents combine together to generate a spatially homogeneous gradient that follows the input pulse. Shielded and unshielded longitudinal gradient coils are used to exemplify this novel approach. To assist in the evaluation of transient eddy currents induced within a realistic cryostat vessel, a low-frequency finite-difference time-domain (FDTD) method using the total-field scattered-field (TFSF) scheme was performed. The simulations demonstrate the effectiveness of the proposed method for optimizing longitudinal gradient fields while taking into account the spatial and temporal behavior of the eddy currents. 相似文献
172.
173.
在给病人使用化疗药物的过程中,护士不可避免地接触抗肿瘤药物,因而对自身健康产生危害。为了维护护士的健康,提高护理人员的防护意识,我们对肿瘤专科护士做一个防护调查,现将情况介绍如下。1临床资料与方法1.1临床资料选取山西省肿瘤医院临床一线,参加工作2年以上并经常接触化 相似文献
174.
Pulmonary Lophomonas blattarum infection in patients with kidney allograft transplantation 总被引:3,自引:0,他引:3
Yong Wang Zheng Tang Shuming Ji Zhen Zhang Jinsong Chen Zhen Cheng Dongrui Cheng Zhihong Liu Leishi Li 《Transplant international》2006,19(12):1006-1013
The aim of the study was to analyse the clinical manifestation and management of pulmonary Lophomonas blattarum infection in four allograft transplantation recipients retrospectively. Four patients with pulmonary L. blattarum infection were diagnosed by using Fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) examination. Their clinical manifestation and management are summarized. Four cases of pulmonary L. blattarum were found during the period from the second month to the third month after transplantation. Concurring infection by other pathogens was found in three of them. Common initial symptoms included fever (>38 degrees C) without cough and breathlessness. Lower lobe shadowing could be found on chest X-ray. Body temperature decreased to the normal range in three patients and to 37.5 degrees C in the other one, after intravenous injection of metronidazole and tapering immunosuppressant. Radiological examination confirmed improved health condition of the patients afterwards. Two patients received repeated FOB and only dead L. blattarum was found. Pulmonary L. blattarum infection in allograft transplant recipients carry relatively obscure initial symptoms. Possible L. blattarum infection needs to be screened in post-transplantation pulmonary infection patients with similar symptoms, especially in those who respond poorly to anti-infection treatment. Microscopic examination of BAL fluid can help to identify pulmonary L. blattarum infection and metronidazole is an ideal treatment choice. 相似文献
175.
A new strategy to yield information from the maximum number of voxels, each at the optimum signal-to-noise ratio (SNR) per unit time, in MR spectroscopic imaging (MRSI) is introduced. In the past, maximum acquisition duty-cycle was obtained by multiplexing in time several single slices each repetition time (TR), while optimal SNR was achieved by encoding the entire volume of interest (VOI) each TR. We show that optimal SNR and acquisition efficiency can both be achieved simultaneously by multiplexing in space and time several slabs of several slices, each. Since coverage of common VOIs in 3D proton MRSI in the human brain typically requires eight or more slices, at 3 T or higher magnetic fields, two or more slabs can fit into the optimum TR (approximately 1.6 s). Since typically four or less slices would then fit into each slab, Hadamard encoding is favored in that direction for slice profile reasons. It is demonstrated that per fixed examination length, the new method gives, at 3 T, twice as many voxels, each of the same SNR and size, compared with current 3D chemical shift imaging techniques. It is shown that this gain will increase for more extensive spatial coverage or higher fields. 相似文献
176.
医药企业对电子商务营销模式的科学选择 总被引:1,自引:0,他引:1
根据电子商务在我国快速发展的形势,分析我国医药企业可选择的电子商务应用模式,研究企业进行模式选择时所需要考虑的因素,提醒医药企业选择电子商务模式时应依据自身特点积极稳妥地决策,切忌盲目一哄而上。 相似文献
177.
目的通过2004年和2005年本校女教职工妇科查体结果的分析,发现女教职工中未被识别的疾病与致病因子,从而达到防病、治病的目的。通过两年查体结果的分析比较,进一步说明高校女教职工定期进行妇科查体的必要性。方法收集、整理2004年和2005年两年的妇科查体结果,并对不同年龄组的患病率进行分析、比较,查找原因。结果两年的查体结果表明,2005年各年龄段妇科疾病的发病率明显较2004年低,经卡方比较,差异有显著性。结论对女教职工实施定期的妇科查体,对及旱发现妇科疾病、及时进行适当的治疗、保障女教职工的身体健康起了重要作用。 相似文献
178.
Xiangdong Xie Guoshan Yang Hongmei Zhou Decheng Qu 《Journal of radiological protection》2006,26(3):301-308
An OUR-QGD gamma ray stereotactic body radiotherapy system (body knife), made in China, is described. According to its structure and the principle of gamma radiation revolved on a focus, the energy distribution of scattered radiation in its treatment room is calculated. The structural shielding of the wall, roof, and door for a certain treatment room is calculated according to the local radiation protection law. 相似文献
179.
随着全球资讯的飞速发展,在市场竞争日益激烈的今天,医疗卫生事业需要且必须进行重大的改革。过去的医疗运行模式将阻碍医院进一步发展。如何在新形势下满足人们的多种需求,对医院来说是一个新的挑战。这样,医院不仅要进一步加强业务规范管理与技术创新,而且要进一步提高医疗服 相似文献
180.
妊娠期糖尿病62例临床分析 总被引:1,自引:0,他引:1
目的 探讨妊娠期糖尿病的合理处理及预后.方法 选择62例妊娠期糖尿病患者进行回顾性分析.结果 妊娠期糖尿病62例,其中单纯饮食控制17例,饮食控制 胰岛素治疗43例,2例未治疗.剖宫产42例,阴道产20例.合并妊高症3例,羊水过多2例,羊水过少4例,羊水栓塞1例,早产5例,高胆红素血症3例,真性红细胞增多症2例,死胎2例,新生儿窒息4例,新生儿畸形1例.结论 对妊娠合并糖尿病的孕妇进行早期的诊断及治疗,选择合适的时间及方式终止妊娠可以减少母儿并发症的发生率. 相似文献