首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
医学
Since the first brain scanner was constructed several years ago, computed tomography or computed medical imagery, has become fai
Since the first brain scanner was constructed several years ago, computed tomography or computed medical imagery, has become fai
admin
2013-12-14
25
问题
Since the first brain scanner was constructed several years ago, computed tomography or computed medical imagery, has become fairly widely used. Its rapid acceptance is due to the fact that it has overcome several of the drawbacks of conventional X-ray technology.
To begin with, conventional two-dimensional X-ray pictures cannot show all of the information contained in a three-dimensional object. Things at different depths are super imposed, causing confusion to the viewer. Computed tomography can give three-dimensional information. The computer is able to reconstruct pictures of the body’s interior by measuring the varying intensities of X-ray beams passing through sections of the body from hundreds of different angles. Such pictures are based on series of thin "slices".
In addition, conventional X-ray generally differentiates only between bone and air, as in the chest and lungs. They cannot distinguish soft tissues or variations in tissues. The liver and pancreas are not discernible at all, and certain other organs max only be rendered visible through the use of radio paque dye. Since computed tomography is much more sensitive, the soft tissues of the kidneys or the liver can be seen and clearly differentiated. This technique can also accurately measure different degrees of X-ray absorption, facilitating the study of the nature of tissue.
A third problem with conventional X-ray methods is their inability to measure quantitatively the separate densities of the individual substances through which the X-ray has passed. Only the mean absorption of all the tissues is recorded. This is not a problem with computed tomography. It can accurately locate a tumor and subsequently monitor the progress of radiation treatment, so that in addition to its diagnostic capabilities, it can play a significant role in therapy.
Conventional X-rays mainly show the difference between______.
选项
A、bone and air
B、liver and pancreas
C、muscle and other body tissues
D、heart and lungs
答案
A
解析
细节题。答案源自于文章第三段第一句话“conventional X-ray generally differentiates onlybetween bone and air”即传统的X光线通常只能显示出骨骼与气体之间的不同。故答案为A。
转载请注明原文地址:https://kaotiyun.com/show/5OU3777K
本试题收录于:
医学博士外语题库考研分类
0
医学博士外语
考研
相关试题推荐
Cultureshockmightbecalledanoccupationaldiseaseofpeoplewhohavebeensuddenlytransplantedabroad.Likemostailments,
Youfeelgenerallydepressedandunabletoconcentrate.Your【C1】______ofdailyactivitymaychange;youfindyourself【C2】______a
Confrontedwithpatientfacingdeath,physiciansmayfeelasenseofmedicalimpotenceandfailure.Yearsoftrainingandzealt
TherewereredfacesatoneofBritain’sbiggestbanksrecently.Theyhadacceptedatelephoneordertobuy$100,000worthof
Thetutortellstheundergraduatesthatonecanacquire______inaforeignlanguagethroughmorepractice.
I’m______passinganewlawthathelpspoorchildrengetbettermedicine.
IdenticaltwinsistershaveledBritishscientiststoabreakthroughinleukemiaresearchthatpromisesmoreeffectivetherapies
Socialscientistsbelievethatsocietieswitha______ofyoungmenwithouthopeofmarriagesufferfrominstability,violenceand
Thephysicaldistributionofproductshastwoprimaryaspects:transportationandstorage.Bothaspectsarehighlydevelopedand
随机试题
根据《水利水电工程设计工程量计算规定》,关于金属结构工程量的说法中,错误的是()。
阅读《陌上桑》中的一段诗句,回答下列问题:使君从南来,五马立踟蹰。使君遣吏往,问是谁家妹?“秦氏有好女,自名为罗敷。”“罗敷年几何?”“二十尚不足,十五颇有余。”“使君谢罗敷,宁可共栽不?”罗敷前置辞:“使君一何愚!使君自有妇,罗敷自有夫。”
关于腮腺炎患者腮腺肿大的特点,不正确的是
在以下财产中,属于典权客体的是()。
《中华人民共和国建筑法》规定,国务院建设行政主管部门确定的()可以不用申请领取施工许可证。
董事会应当制订压力测试政策;明确各部门职责分工;审议压力情景设定,定期组织开展压力测试,评估压力测试结果对银行的影响,制订和落实风险改进措施,将压力测试结果运用到银行的各项经营管理决策中。()
学生的学习特点受()因素和内外部因素的影响。
对鉴定结论,办案单位或办案人认为不确切或者有错误,以及犯罪嫌疑人、被害人提出合理申请的,应当(),但不得强迫或者暗示鉴定人或鉴定单位作出某种结论。
某班有37名小学生,他们都订阅了《小朋友》、《儿童时代》、《少年报》中的一种或几种,那么其中至少有多少名学生订的报刊种类完全相同?
公民未能依法履行义务,根据情节轻重,应当承担相应的法律责任。具体的法律责任主要包括()
最新回复
(
0
)