问题 单项选择题

有关X线信息影像的形成与传递过程的叙述,错误的是()

A.X线透过被照体后形成X线信息影像

B.X线照射到屏/片系统,经显影形成光学密度影像

C.被照体是信息源.X线是信息载体

D.照片密度影像通过大脑判断,形成诊断

E.X线管发射的X线强度分布是不均匀的

答案

参考答案:E

解析:如果把被照体作为信息源,X线作为信息栽体,那么X线诊断的过程就是一个信息传递与转换的过程。此过程分为五个阶段。第一阶段:X线对三维空间的被照体进行照射,取得栽有被照体信息成分的强度不均匀分布。第二阶段:将不均匀的X线强度分布,通过接受介质(屏/片系统Ⅱ、CR、DR系统等)转换为二维的光强度分布。此阶段是把不可见的X线信息影像转换成可见密度影像的中心环节。第三阶段:借助看片灯(或显示器),将密度分布转换成可见光的空间分布,然后投影到人的视网膜。第四阶段:通过视网膜上明暗相间的图案,形成视觉的影像。第五阶段:最后通过识别、判断做出评价或诊断。此阶段信息传递取决于医师的学历、知识、经验、记忆和鉴别能力。

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 阅读理解     

     A lot of adults worry that spending too much  time playing video games 

isn't good for a kid's health. But some doctors have noticed that kids who

bring their handheld game players to the hospital seem less worried about

being there. They also seem to have less pain when they are playing games.  

        Some patients must be hooked up to dialysis machines ( 透析器) at

least three hours each time. Doctors allow kids to play online sports,racing,

and other games with each other. "We want to use the power of the Internet

to bring kids together and let them know they are not alone," said the doctor.

He loves video games himself  and got the idea to connect kids all over the

country. 

        Many researchers are testing video programs that might help young

patients. For example,a nine-year-old boy who was struggling with cancer

helped to design avideo game to let players get rid of cancer cells. 

     Doctors already know that reducing pain and worry helps patients heal

 faster.

1. Most adults think that playing video games too much is                

A. good for kid's health      

B. bad for kid's health      

C. good for kid's study      

D. bad for kid's eyes  

2. Some doctors think playing games can help the kids get         hen they are ill in hospital.    

A. more worried and pain    

B.less worried and pain    

C. more care from their parents    

D.less care from the nurse  

3. The Chinese meaning of the underlined phrase " get rid of" is               

A.得到  

B.除掉  

C.关心  

D.放心  

4. The doctors allow these kids to         with each other.      

A. play online games    

B. play cards      

C. sing popular songs  

D. study English  

5. The writer wants to tell us         in this passage.      

A. how to play video games      

B. playing video games can be good to the kids who are ill         

C. adults think it is good for kids to play video games      

D. kids should often play video games

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