【英语时差8,16】通过超声波透析胎中婴儿

 

The first picture an expecting mother is likely to see of her developing fetus¹ is not, technically², a picture at all.   

Most likely, it's an ultrasound image, produced by technology that has more to do with hearing than with seeing. On today's program we'll learn how ultrasound works.

 

You might think ultrasound is similar to X-rays. After all, they're both used by doctors to glimpse the inside of your body. Actually, X-ray machines use high frequency radiation--an energetic, souped-up form of regular, visible light. Such X-ray radiation would be harmful to a developing fetus, so that's why ultrasound is used on pregnant women instead.

 

Ultrasound doesn't use any type of light or radiation at all. It uses high frequency sound waves instead. The physician holds a probe to the woman's skin, and the probe sends these sound waves into her body. Like an echo off a canyon³ wall, some of these waves bounce off the developing fetus and return to the probe. These return echoes are carefully measured for timing⁴ and direction, and this information is used to construct a moving image of what's going on inside the woman's body.

 

In addition to viewing fetuses⁵, medical ultrasound can also be used for imaging a patient's bones and organs, and for measuring blood flow through arteries⁶. Ultrasound can even be used as treatment for some types of cancer. By turning up the volume of those high frequency sound waves, and focussing them carefully, they can sometimes break up a tumor⁷ inside the body, without surgery. That's quite a lot for this versatile, sound-based technology

1 fetus   

n.胎，胎儿

参考例句：

• In the fetus,blood cells are formed in different sites at different ages.胎儿的血细胞在不同时期生成在不同的部位。
• No one knows why a fetus is not automatically rejected by the mother's immune system. 没有人知道为什么母亲的免疫系统不会自动排斥胎儿。

2 technically   

adv.专门地，技术上地

参考例句：

• Technically it is the most advanced equipment ever.从技术上说，这是最先进的设备。
• The tomato is technically a fruit,although it is eaten as a vegetable.严格地说，西红柿是一种水果，尽管它是当作蔬菜吃的。

3 canyon   

n.峡谷，溪谷

参考例句：

• The Grand Canyon in the USA is 1900 metres deep.美国的大峡谷1900米深。
• The canyon is famous for producing echoes.这个峡谷以回声而闻名。

4 timing   

n.时间安排，时间选择

参考例句：

• The timing of the meeting is not convenient.会议的时间安排不合适。
• The timing of our statement is very opportune.我们发表声明选择的时机很恰当。

5 fetuses   

n.胎，胎儿( fetus的名词复数 )

参考例句：

• DNA was extracted from fetuses at mid-gestation, about 10 days past conception. DNA从受孕大约10天后的中期妊娠胚胎中提取。 来自互联网
• Brucellosis is a disease that causes fetuses to abort in cattle. 普鲁士菌病是一种可以导致牲畜胎儿夭折的疾病。 来自互联网

6 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

7 tumor   

n.（肿）瘤，肿块(英)tumour

参考例句：

• He was died of a malignant tumor.他死于恶性肿瘤。
• The surgeons irradiated the tumor.外科医生用X射线照射那个肿瘤。