Screen Test
1. Every year millions of women are screened with X-rays to pick up signs of breast cancer. If this happens early enough, the disease can often be treated successfully. According to a survey (調(diào)查)published last year, 21 countries have screening programmes. Nine of them, including Australia, Canada, the US and Spain, screen women under 50.
2. But the medical benefits of screening these younger women are controversial(有爭議的), partly because the radiation(輻射) brings a small risk of inducing cancer. Also, younger women must be given higher doses of X-rays because their breast tissue(組織) is denser.
3. Researchers at the Polytechnic University1 of Valencia analysed the effect of screening more than 160,000 women at 11 local clinics. After estimating the women’s cumulative dose of radiation, they used two models to calculate the number of extra cancers this would cause.
4. The mathematical model recommended by Britain’s National Radiological Protection Board (NRPB) predicted that the screening programme would cause 36 cancers per 100,000 women, 18 of them fatal. The model preferred by the UN Scientific Committee on the Effects of Atomic Radiation led to a lower figure of 20 cancers.
5. The researchers argue that the level of radiation-induced cancers is “not very significant” compared to the far larger number of cancers that are discovered and treated. The Valencia programme, they say, detects between 300 and 450 cases of breast cancer in every 100,000 women screened.
6. But they point out that the risk of women contracting cancer from radiation could be reduced by between 40 and 80 percent if screening began at 50 instead of 45, because they would be exposed to less radiation. The results of their study, they suggest, could help “optimize the technique” for breast cancer screening.
7. “There is a trade-off(平衡) between the diagnostic(診斷的，判斷的) benefits of breast screening and its risks,” admits Michael Clark of the NRPB. But he warns that the study should be interpreted with caution. “On the basis of the current (目前的)data, for every 10 cancers successfully detected and prevented there is a risk of causing one later in life. That’s why radiation exposure should be minimized in any screening programme.”
練習：
1. Paragraph2 ________
2. Paragraph3 ________
3. Paragraph4 _ ____
4. Paragraph5 _____
A. Harm Screening May Do to a Younger Woman
B. Investigating (調(diào)查)the Effect of Screening
C. Effects Predicted by Two Different Models
D. Small Risk of Inducing Cancers from Radiation
E. Treatment of Cancers
F. Factors That Trigger Cancers
5.Early discovery of breast cancer may________.
6.Advantages of screening women under 50 are _______.
7.Delaying the age at which screening starts may ________.
8.Radiation exposure should be ________.
A. be costly
B. harmful
C. save a life
D. still open to debate(爭論)
E. reduce the risk of radiation triggering a cancer
F. reduced to the minimum
答案與題解：
1.A A說^是：用X射線檢查可能對年輕女人不好。下面是第二段講的意思：但是，用X射 線檢查年輕女性，就醫(yī)學上的好處而論，是有爭議的，部分原因是輻射有誘發(fā)癌癥的小小的 危險。另外，年輕女人****組織緊密，給予的X射線的劑量要多一些。
2.B B說的是：調(diào)查用X射線檢查的結果。第三段的第一句話是這么說的:Valencia理工大 學的研究人員分析了 11個社區(qū)診所用X射線檢査16萬以上女性的結果�？梢夿為正確的 選項。
3.C C說的是：兩種不同的模型預測的結果。第四段講的是，兩種不同的數(shù)學模型在預測用 X射線檢查女性誘發(fā)癌癥的結果是不一樣的。C概述了這段話。
4.D D說的是：輻射誘發(fā)癌癥的危險是很小的。第五段的第一句話是這么說的：The researchers argue that the level of radiation-induced cancers is “ not very significant" compared to the far larger number of cancers that are discovered and treated.研究人員爭辯說，與發(fā)現(xiàn)后 接受治療的癌癥數(shù)字相比，由輻射誘發(fā)癌癥的數(shù)字是很小的。
5.C C與題干生成:Early discovery of breast cancer may save a life.乳腺癌發(fā)現(xiàn)得早也許能挽 救生命。答案可以從第一段中找到。
6.D D 與題干生成:Advantages of screening women under 50 are still open to debate. X才 50 歲 以下的女人用X射線撿查的好處仍然是有爭議的。第二段的第一個甸子是這么說的:But the medical benefits of screening these younger women are controversial...但是，用 X 射線檢查 年輕女性，就醫(yī)學上的好處而論，是有爭議的……這兩個句子用詞有些差別，但基本意思是相同的。
7.E E 與題干生成：Delaying the age at which screening starts may reduce Ihe risk of radiation triggerhig^a cancer.延纖用X射線檢查的年齡也許能減少輻射誘發(fā)的危險。答案在第
8.F F與題干生成扭tion exposu諏命cmld be reduced to the minimum.應把接受輻射降低到最小的程度。答案在文章的最后一句。
