時差N小時:掃描有風險?

Dear Yael and Don: I know that imaging tests like CTscans and MRI and nuclear imaging are great toolsbecause they allow doctors to see inside the body.But don't they also expose people to radiation?And if so, isn't this a bad thing?

親愛的雅艾爾和唐：我知道像CT掃描和核磁共振成像等影像學檢查是很好的醫(yī)療設備，因為它們能協(xié)助醫(yī)生看見身體內部。但它們不會讓人受到輻射嗎?如果是，這難道不是件壞事?

Yael: Yes. And no. Some imaging tests do exposepeople to radiation. But just to be clear, MRI, whichstands for magnetic resonance imaging, does not use radiation. So if you have an MRI,there's no risk of exposure.

雅艾爾：是，也不是。有些影像學檢查確實對人體有輻射作用。但你要清楚，MRI掃描，也就是核磁共振成像卻并不涉及到輻射。因此如果你做MRI掃描，并不會有接觸輻射的風險。

Don: But other types of imaging tests do use risk of exposure. Like nuclear imaging, which isused to look for heart disease. And CT, or CAT scans, which use x-rays to take 3D picturesinside the body. And, unfortunately, over time these tests do sometimes expose people todangerously high levels of radiation. High enough to cause cancer, in some cases.

唐：但其它類型的影像學檢查確實有輻射，比如用來檢查心臟病的核成像，CT或CAT掃描，利用X光線拍攝人體內部的3D影像。但不幸的是，時間長了這些掃描確實會讓人們暴露在高水平的、危險的輻射中去。在某些情況下，輻射的水平高到足以致癌。

Yael: But why would doctors order tests that put people at risk for getting cancer?

雅艾爾：但為什么醫(yī)生還要求病人冒著患上癌癥的風險做檢查呢?

Don: Well, mainly because the tests are often very useful. For example, mammography is thebest way to look for early signs of breast cancer. But it's not as clear that other tests, such asnuclear imaging, are as useful for detecting heart disease. It may be, but there's not enoughhard evidence to be certain.

唐：好吧，主要原因是這些檢查非常有用。例如，乳房X光檢查是尋找乳腺癌早期癥狀的最佳方法。但其他的一些檢查卻不明確，比如核成像是否對檢測心臟病有用?；蛟S有用，但沒有足夠的證據來證明。

Yael: So, the risks of radiation exposure from a CT scan or a nuclear imaging may outwaythe benefits.

雅艾爾：那么，進行CT掃描或者核成像的益處可能要超過它所帶來的輻射風險。

Don: Right. It's not that people should always avoid these imaging tests. But they should beaware of the risks.

唐：對。人們不應該總是去回避影像學檢查，不過也應該意識到它的風險。