How important is your mobile phone, better known to Americans as a cell phone?
你的移动电话（美国人常称为手机）的重要性如何？

I use my phone all the time. I'm always on my phone.
“我时时刻刻都要用手机。我总在打电话。”

It's kind of pretty much important to me because it's like my life saver.
“手机对我而言相当重要，它就像我生命的拯救者。”

I need my cell phone.
“我需要手机。”

So far, no studies have proven beyond question that the radio signals from cell phones cause brain cancer or other health problems. 
迄今为止，尚无任何研究能确切证实手机发出的无线电信号会导致脑癌等健问题。

But a new study by government scientists in the United States has some people wondering what to think.
但美国政府科学家所做的一项新研究使人们对要考虑什么问题产生疑惑。

The scientists found that holding a cell phone to your ear for at least 50 minutes increases brain cell activity. 
科学家发现将手机持在耳边达50分钟会增加脑细胞的活动。

Even the scientists themselves are not sure about the meaning of their findings.
甚至科学家他们自己也不确定这样的发现意味着什么。

Dr. Nora Volkow led the study. 
诺拉·沃尔考领导了这项研究。

She heads the National Institute on Drug Abuse, part of the National Institutes of Health. 
沃尔考是美国国立卫生研究院所属的国家药物滥用研究所的负责人。

Dr. Volkow says she would not be concerned that 50 minutes of cell phone exposure would harm anyone. 
沃尔考称，她不担心暴露在手机辐射下50分钟会对人造成伤害。

But she says the research does show the need to study whether or there are long-lasting effects of repeated exposure over several years.
但她表示，研究的确显示，需要针对持续数年反复暴露在手机辐射下是否存在长期影响进行研究。

Her team studied 47 healthy volunteers between January and December of 2009. 
她领导的研究小组在2009年1-12月间对47位健康的志愿者进行了研究。

The volunteers had cell phones placed against both ears while the scientists made images of their brain activity.
志愿者在两边耳朵旁都放了手机，与此同时，科学家绘出他们的大脑活动影像。

As part of the test, one phone was activated but muted for 50 minutes. 
测试的部分内容为，一只手机开机50分钟，同时设成静音模式。

The other phone was off. 
另一只手机则处于关机状态。

After that, the people were tested with both phones turned off. 
之后，再把两部手机都关掉测一次。

Dr. Volkow says the brain scans showed increased activity in brain cells closest to the activated phone.
沃尔考称，脑部扫描显示，离开机状态手机最近的脑部细胞活动增加。

This right area of the brain that was very close to the antenna shows the largest increase in metabolism as compared when the telephones were off. 
跟手机关机时相比，特别接近天线的大脑右部区域的新陈代谢在开机时增加得最多。

Even though the radio frequencies that are emitted from current cell phone technologies are very weak, they are able to activate the human brain to have an effect.
尽管目前手机技术发出的无线电频率很弱，但仍能激活人的大脑，产生某种影响。

The scans showed how the brain cells used sugar to produce energy, a normal activity. 
扫描显示了脑细胞如何利用糖份来产生能量（这是一种正常的脑部活动）。

The activity was 7% higher in areas of the brain closest to the cell phone antenna.
最接近手机天线的大脑区域的活跃度高了7个百分点。

The study appeared in the Journal of the American Medical Association.
这项研究报告刊登在《美国医学协会杂志》上。

Experts say people who are concerned about mobile phones can take steps like using a hands-free device.
专家称，如果人们对使用手机感到担心，可以采取一些措施，如使用免提装置。

Dr. Giuseppe Esposito is a nuclear medicine expert at Georgetown University Medical Center in Washington. 
朱塞佩·埃斯波西托博士是华盛顿乔治敦大学医学中心的核医学专家。

He says after many years of studies, better kinds of research are still needed to settle questions about cell phone safety. 
他表示，尽管人们已进行了多年的研究，仍需要更高质量的研究来解决手机的安全性问题。

These studies would take years.
这些研究要花上很多年。

We need what are called epidemiological studies where you will follow a population using cell phones -- high users or light users -- and then see what happens over the years.
我们需要进行流行病学研究，即跟踪一群手机使用者，包括高频率使用者和低频率使用者，跟踪他们多年，然后看看其间发生了什么。