VOA标准英语2010年-Body Scanners, Touted as Effective Too

Public opinion polls suggest most Americans favor full body scanners as a way to protect against terror attacks on commercial airliners¹. The benefits of scanners are being debated in a number of countries. Some groups have raised privacy issues.  But many people believe the machines could also contain health risks. As Vidushi Sinha reports, the scanners release small amounts of radiation, which over time, some scientists say, could increase the risk of cancer.

If the alleged² bomber³ on a Christmas Day flight to the United States had gone through a full body scanner, his explosives might have been detected and an attempted bombing foiled much earlier.

The United States in addition to Britain, the Netherlands, France and Italy have announced plans to install body scanners at airports.

Using x-rays bounced off the body, the machines generate anatomically correct images and can detect items hidden in clothing.

Aside from concerns over privacy, there's a growing discussion about a possible risk of cancer from radiation emitted by the scanners. 

But according to experts, the risk is small.  The radiation from so called backscatter  technology is 2,000 times less than a chest x-ray and 200,000 times less than a CAT scan. 

"Total exposure time is about 8 to 15 seconds, and the radiation dose levels are quite small because the x-rays used here do not penetrate⁴ the body," Mahadevappa Mahesh explained. "It is very low dose therefore it's just reflecting back, and the scattered⁵ radiation coming from the body is actually captured by a detector⁶ and you get the image."

The alleged Christmas day bomber, Umar Farouk Abdulmutallab, flew through Amsterdam and Lagos, Nigeria's commercial capital.

Media reports say Nigeria had already received body scanners from the United States, but did not use one on the alleged bomber. 

Some experts say these expensive machines will be difficult for many African and poor countries to purchase and install.

Even if developed countries donate the scanners, there still could be health issues. 

The risk of radiation exposure could be greater in developing countries where maintenance might be spottier, some say. 

"As we do in any of these scanners in hospitals, where we do periodic checks to make sure that radiation levels are as specified⁷ and within the acceptable limits, that is important there is always a possiblity that something can go wrong in the scanners and that can emit more radiation and to avoid this it has to be checked periodically," Mahesh said.

Though many experts believe that radiation exposure from full-body scans will not pose a risk of cancer, some urge caution.

"Children in general are more sensitive than adults to radiation.  And the developing embryo⁸ and fetus⁹ in pregnancy¹⁰ are the most sensitive of all," said Dr. David Brenner of Columbia University Medical Center in New York.

Experts say more study is needed.

1 airliners   

n.客机，班机( airliner的名词复数 )

参考例句：

• The fog grounded the airliners. 大雾迫使班机停飞。 来自《简明英汉词典》
• They placed very stable and accurate atomic clocks on regularly scheduled jet airliners. 他们将非常稳定、准确的原子钟装在定期飞行的喷气式班机上。 来自辞典例句

2 alleged   

a.被指控的，嫌疑的

参考例句：

• It was alleged that he had taken bribes while in office. 他被指称在任时收受贿赂。
• alleged irregularities in the election campaign 被指称竞选运动中的不正当行为

3 bomber   

n.轰炸机，投弹手，投掷炸弹者

参考例句：

• He flew a bomber during the war.他在战时驾驶轰炸机。
• Detectives hunting the London bombers will be keen to interview him.追查伦敦爆炸案凶犯的侦探们急于对他进行讯问。

4 penetrate   

v.透(渗)入；刺入，刺穿；洞察，了解

参考例句：

• Western ideas penetrate slowly through the East.西方观念逐渐传入东方。
• The sunshine could not penetrate where the trees were thickest.阳光不能透入树木最浓密的地方。

5 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

6 detector   

n.发觉者，探测器

参考例句：

• The detector is housed in a streamlined cylindrical container.探测器安装在流线型圆柱形容器内。
• Please walk through the metal detector.请走过金属检测器。

7 specified   

adj.特定的

参考例句：

• The architect specified oak for the wood trim. 那位建筑师指定用橡木做木饰条。
• It is generated by some specified means. 这是由某些未加说明的方法产生的。

8 embryo   

n.胚胎，萌芽的事物

参考例句：

• They are engaging in an embryo research.他们正在进行一项胚胎研究。
• The project was barely in embryo.该计划只是个雏形。

9 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。

10 pregnancy   

n.怀孕，怀孕期

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
• Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。