VOA慢速英语2018--医生有了诊断乳腺癌的新工具

Doctors Have a New Tool to Identify Breast Cancer

Breast cancer is the most common cancer in women worldwide.

Early discovery and treatment can save lives.

Scientists are working new ways to recognize breast cancer while at the same time studying existing methods of identification to find out what is best.

Take mammograms, for example. During the test, a technician takes an X-ray picture of a woman’s breast as it is pressed between two glass plates. A radiologist then examines the image for signs of cancer.

Mammograms are the best tools available for recognizing the disease. The number of breast cancer deaths has fallen by 30 percent in the United States since doctors began offering mammography in the 1970s. The reason: the chances of beating cancer are higher when the disease is found early.

Yet mammograms are not perfect. A mammogram can look normal even when cancer is present. It can also look abnormal, or unusual, when cancer is not present.

Traditional mammograms are two dimensional (2-D). They show length and width. But for the 40 to 50 percent of women with dense¹ breasts, it is difficult for radiologists to see cancer on 2-D images.

Three-dimensional mammograms provide a more detailed² look. So women with dense breasts may get better results from a 3-D mammogram, said Otis Brawley of the American Cancer Society.

“It might find disease that we need to find that two-dimensional does not,” Brawley said. He added that 3-D testing costs more and involves higher levels of radiation. It also is not 100 % perfect, he said.

Cost aside, one study involving 13 U.S. hospitals showed that 3-D mammograms recognized an additional 40 percent of invasive cancers.

For better results, a woman could have a whole-breast ultrasound. This test requires the patient to lie on her back as the ultrasound device slowly moves back and forth³. The exam captures between 3,000 and 5,000 images of the breast.

Megha Garg is the director of the breast-imaging program at the University of Missouri cancer center. She says the whole-breast ultrasound “helps detect additional breast cancers in females who have dense breasts.”

The ultrasound doesn’t use radiation, so it is less risky⁴ than a mammogram. But Garg says the traditional mammogram remains⁵ a helpful tool because it is very effective.

Researchers are studying which method is best at detecting cancer.

North America, Western Europe and Australia have the highest rates of breast cancer. Yet the World Health Organization reports that almost 50 percent of the cases and nearly 60 percent of the deaths happen in less-developed countries.

With improvements, nearly 400,000 women’s lives could be saved every year.

I'm Susan Shand.

Words in This Story

mammogram – n. a photograph of a woman's breasts made by X-rays

radiologist – n. a doctor who is trained in the branch of medicine that uses some forms of radiation (such as X-rays) to diagnose and treat diseases

dimensional – adj. the length, width, height, or depth of something

dense – adj. having parts that are close together

ultrasound – n. a method of producing images of the inside of the body by using a machine that produces sound waves which are too high to be heard

1 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

2 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

3 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。

4 risky   

adj.有风险的，冒险的

参考例句：

• It may be risky but we will chance it anyhow.这可能有危险，但我们无论如何要冒一冒险。
• He is well aware how risky this investment is.他心里对这项投资的风险十分清楚。

5 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。