Three­dimensional technology - known as three­D - gives depth to objects that would otherwise appear two­di­mensional, or flat.Three­D makes movies and video games look more realistic.And now it could help save lives.

　　For years，mammograms (乳房X光照片) have played an important role in finding breast cancer. But these X­ray pictures of the human breast often miss dangerous cancer lumps or tumors. And they also produce false positives. A false positive wrongly appears to show suspicious tissue. And that causes painful，unnecessary biopsies (切片) to examine that tissue.

　　A new study shows that three­D technology could change the way doctors look for breast cancer.

　　When Zulima Palacio discovered she had breast cancer，it already had reached stage three.That means that the cancer was very dangerous.

　　"Even a month before it was detected, I went for a sonogram (超声波) and they told me，'You're fine，go home.'"

　　Ms. Palacio is now cancer free.But the standard two­dimensional mammogram missed all three of her tumors.

　　Jennifer Hoeft is grateful that she had three­D mam­mography.Three­D technology found her tumor.

　　"It was a very small tumor.It was only an 8 millimeter tumor that couldn't be felt. I truly, truly believe that the 3­D mammography is what caught my cancer early and is allowing me to pretty much live my life the way I want to."

　　Sarah Friedewald is a doctor at Lutheran General Hospital in the U．S. state of Illinois.She led a study to compare the results of three­D and two­D mammography from nearly a half million patients.

　　Dr. Friedewald says tumors that are difficult to see on a standard mammogram are easy to find in 3 dimensions.

　　"We found invasive cancers or the cancers that we worry about，the ones that could potentially kill people more frequently in women who had the 3­D mammogram versus the women who just had the 2­D mammogram.At the same time, fewer people had to come back for unneces­sary testing which creates unnecessary anxiety."

　　Dr. Friedewald expects three­D to replace the usual two­D mammograms in time. Her study was published in the Journal of the American Medical Association.

　　语篇解读：本文是一篇说明文。3D技术使得电影和视频游戏显得更加真实，而且现在它还有助于拯救生命。本文讲述的是3D科技在发现癌症方面的作用。

　　1．Why did the doctors tell Ms.Palacio to go home after a sonogram?

　　A．Because they thought she did not suffer breast cancer.

B．Because she was diagnosed with breast cancer.