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  3. 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

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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.
What is the author’s attitude toward this new technique?
选项 A、Cautious.
B、Tolerant.
C、Enthusiastic.
D、Critical.
答案C
解析 态度题。文中作者一直在描述新技术相比于旧技术而言的优越性。可见作者对这种新技术的态度既非小心谨慎的，也非容忍的、批判的，而是充满热情的，故答案为C。
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