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1.
A method is presented for 3D MRI in an extended field of view (FOV) based on continuous motion of the patient table and an efficient acquisition scheme. A gradient-echo MR pulse sequence is applied with lateral (left-right (L/R)) frequency-encoding direction and slab selection along the direction of motion. Compensation for the table motion is achieved by a combination of slab tracking and data alignment in hybrid space. The method allows fast k-space coverage to be achieved, especially when a short sampling FOV is chosen along the direction of table motion, as is desirable for good image quality. The method can be incorporated into different acquisitions schemes, including segmented k-space scanning, which allows for contrast variation with the use of magnetization preparation. Head-to-toe images of volunteers were obtained with good quality using 3D spoiled gradient-echo sequences. As an example of magnetization-prepared imaging, fat/water separated images were acquired using chemical shift selective (CHESS) presaturation pulses. 相似文献
2.
Image processing is a critical part of obtaining high-quality digital radiographs. Fortunately, the user of these systems does not need to understand image processing in detail, because the manufacturers provide good starting values. Because radiologists may have different preferences in image appearance, it is helpful to know that many aspects of image appearance can be changed by image processing, and a new preferred setting can be loaded into the computer and saved so that it can become the new standard processing method.Image processing allows one to change the overall optical density of an image and to change its contrast. Spatial frequency processing allows an image to be sharpened, improving its appearance. It also allows noise to be blurred so that it is less visible. Care is necessary to avoid the introduction of artifacts or the hiding of mediastinal tubes. 相似文献
3.
该文从疾病谱和死因谱的改变、医学模式的转变、卫生经费的降低、自我保健意识的改变四个角度,论述了全面开展 生活方式教育的必要性和重要性;从以社区为依托、以医院为基础、以生活方式为指导三个方面,探讨了生活方式教 育的工作模式. 相似文献
4.
In this work, the dosimetric characteristics of a new commercial carbon fiber treatment table are investigated. The photon beam attenuation properties of the Siemens image-guided radiation therapy (IGRT) tabletop were studied in detail. Two sets of dosimetric measurements were performed. In the first experiment a polystyrene slab phantom was used: the central axis attenuation and the skin-sparing detriment were investigated. In the second experiment, the off-axis treatment table transmission was investigated using a polystyrene cylindrical phantom. Measurements were taken at the isocenter for a 360° rotation of the radiation beam. Our results show that the photon beam attenuation of the Siemens IGRT carbon fiber tabletop varies from a minimum of 2.1% (central axis) to a maximum of 4.6% (120° and 240° beam incidence). The beam entrance dose increases from 82% to 97% of the dose at the depth of maximum for a clinical 6-MV radiation field. The depth of maximum also decreases by 0.4 cm. Despite the wedge cross section of the table the beam attenuation properties of the IGRT tabletop remain constant along the longitudinal direction. American Association of Medical Dosimetrists. 相似文献
5.
目的:观察火把花根片治疗激素依赖性皮炎的疗效和安全性。方法:患者81例,分为治疗组和对照组。对照组:口服氯雷他定片,10mg/次,1次/天,同时外用氧化锌软膏;治疗组:在对照组用药的基础上加服火把花根片,5片/次,3次/天;疗程均为2个月。结果:治疗组总有效率达68.29%,对照组总有效率达24.24%,两组疗效比较有显著性差异(P〈0.01)。结论:火把花根片治疗面部激素依赖性皮炎安全、有效。 相似文献
6.
本文采用转蓝法紫外分光光度法测定了三家药厂七批白霉素片体外溶出度,求得T_(50),Td威布尔函数参数具有显著差异,表明不同厂家所生产的白霉素片的溶出度相差显著,提出了影响药物溶出的某些因素,建议国产白霉素片有必要制定溶出标准。 相似文献
7.
The purpose of this cross-sectional study was to determine whether measures on a selected groups of visual and psychomotor variables distinguished between groups of elite, intermediate and novice table tennis players. The variables included commonly of Melbourne measured clinical functions such as static visual acuity, extent of visual field and oculomotor balance and more experimental visual tasks such as recognition of, peripheral targets, saccadic latency and dynamic visual acuity. Psychomotor performance was assessed by measures of simple reaction time, choice response time and hand movement time. Although elite level competitors had significantly better dynamic visual acuity, a wider visual field and superior recognition of peripheral targets compared to less skilled competitors, the magnitude, or practical significance of these differences was not great and individually accounted for less than 5 per cent of population variance. Elite competitors had significantly faster psychomotor responses than novice players with die skill variables individually accounting for between 21 per cent and 62 per cent of population variance in psychomotor performance. These results indicate that the psychomotor parameters could be a useful part of a test battery for talent identification amongst table tennis players. 相似文献
8.
目的:为了能在自然界大型水体和旷野中对中华按蚊种群进行研究。方法:研制出适合于稻田浅水定量研究的实验简,适合于深水的实验网和接近自然状态的大实验笼。应用这些工具进行了自然界中华按蚊种群生命表的研究。结果:利用系列研究工具定量研究出1988年第8代中华按蚊自然种群生命表。求出各发育历期的死亡数和死亡因素,死亡率,存活率和死亡因素k值,分析出各发育阶段的关键死亡因素,计算下代预计产卵量为8288粒,种群趋势指数I为6.3027。结论:系列研究工具使中华按蚊自然种群的定量研究成为可能。郑州中华按蚊第9代种群数量还趋于增加之中。 相似文献
9.
Mur-Veeman I van Raak A 《The International journal of health planning and management》1994,9(3):245-258
The demand for home care in the Netherlands is growing and changing. A decreasing rate of institutionalization, combined with an increasing number of elderly people with special age-related, often complex health problems, has led to new groups of patients, to be cared for in their home settings. This requires a strong coordination of services between suppliers from the primary and secondary health care sectors. In order to promote coordinated care, Dutch health care providers are building inter-organizational networks. The development of such arrangements was the target of 12 demonstration projects, selected by the Ministry of Health for the National Home Care Programme. This article presents some of the results of an evaluation study of the Programme, with special attention given to the question of the extent to which such inter-organizational networks contribute to the balance between quality and cost. 相似文献
10.
对重庆市交通警察1988~1997 年全死因和去死因截缩寿命进行了分析,结果显示:15 岁组平均期望寿命53.18 岁,较重庆市七区居民(1989 年)低4.1 岁,平均死亡年龄为56.53 岁,寿命损失量随年龄增加而增大。主要死因顺位为恶性肿瘤、心脑血管疾病和意外死亡(以车祸为主)。经研究表明,改善交警工作环境,延长交警寿命的任务还很艰巨 相似文献