首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
A group of 85 patients with roentgenological evidence of asbestosis were examined on two occasions within a three- to four-year interval, first in 1976-1977 and again in 1979-1981. During this follow-up period, the asbestosis (interstitial pulmonary fibrosis) of 26 (31%) showed progression. The cases with either moderate or advanced fibrosis showed progression more often than those who initially had manifested only slight fibrosis. Included in the group whose interstitial fibrosis showed radiographic progression were asbestos sprayers and cigarette smokers.  相似文献   

16.
BACKGROUND: Occupational exposure to asbestos may cause pleural and lung disorders and, less frequently, diseases of the peritoneum and pericardium. An exceedingly small number of cases of benign pericardial effusion have been described so far in the medical literature. OBJECTIVES: To report a rare case of haemorrhagic pericardial effusion caused by occupational asbestos exposure in a patient with pre-existent aortic regurgitation, bilateral pleural plaques and no signs of interstitial lung involvement due to asbestosis. METHODS: A thorough clinical and instrumental evaluation (laboratory tests, tuberculin skin test, chest X-rays, transthoracic and transesophageal echocardiography, contrast coronary and aortic angiography, a histological examination of pericardial and pleural surgical specimens) was performed to examine all the known causes of pericardial effusion. RESULTS: The tests performed did not demonstrate any specific cause of pericardial effusion. Surgical assessment three months later, during an aortic valve replacement, showed no signs of aortic dissection or intraparietal hematoma. A nine-year follow up did not reveal any reoccurrence of pericardial effusion. CONCLUSIONS: Asbestos related pericardial effusion is rarely described in the medical literature but must be considered in patients with previous occupational asbestos exposure. There are no specific clinical or pathological aspects indicative of this etiology and the diagnosis remains one of exclusion. A thorough occupational history should be obtained in patients with pericardial effusion of unknown etiology.  相似文献   

17.
《Health devices》2000,29(4):97-139
In this study, we evaluate eight radiographic quality control (QC) devices, which noninvasively measure the output from a variety of diagnostic x-ray production systems. When used as part of a quality assurance (QA) program, radiographic QC devices help ensure that x-ray equipment is working within acceptable limits. This in turn helps ensure that high-quality images are achieved with appropriate radiation doses and that resources are used efficiently (for example, by minimizing the number of repeat exposures required). Our testing focused on the physical performance, ease of use, and service and maintenance characteristics that affect the use of these devices for periodic, routine measurements of x-ray system parameters. We found that all the evaluated models satisfactorily measure all the parameters normally needed for a QA program. However, we did identify a number of differences among the models--particularly in the range of exposure levels that can be effectively measured and the ease of use. Three models perform well for a variety of applications and are very easy to use; we rate them Preferred. Three additional models have minor limitations but otherwise perform well; we rate them Acceptable. We recommend against purchasing two models because, although each performs acceptably for most applications, neither model can measure low levels of radiation. This Evaluation covers devices designed to measure the output of x-ray tubes noninvasively. These devices, called radiographic quality control (QC) devices, or QC meters, are typically used by medical physicists, x-ray engineers, biomedical engineers, and suitably trained radiographic technologists to make QC measurements. We focus on the use of these devices as part of an overall quality assurance (QA) program. We have not evaluated their use for other applications, such as acceptance testing. To be included in this study, a device must be able to measure the exposure- and kVp-related characteristics of most x-ray systems. At minimum, it must be able to make routine QC measurements of general radiographic, fluoroscopic, and most mammographic equipment. We prefer that it also be usable with dental x-ray systems, more advanced mammography systems (see the supplementary article on page 103), and computed tomography (CT) systems. The device may be a single unit, or it may be a kit consisting of multiple components that, when combined, can perform all the relevant measurements. The evaluated devices are designed to assess only x-ray production systems, not x-ray detection systems such as image intensifiers and film. Those types of systems are typically assessed using test phantoms and other tools that produce test images, which can be quantitatively measured and compared against standards.  相似文献   

18.
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号