VOA标准英语2010年-CT Scan Radiation Draws Concern
时间：2018-12-08 作者：英语课 分类：VOA标准英语2010年(一月)
Doctors use X-rays to view internal organs, obtain clear images of possible disease and to treat cancer. For years radiation has been used to save lives, but there is growing concern that some patients are getting more than they ask for when they undergo what's called a CT (Computed Tomography) scan. Research has shown that exposure to radiation can cause cancer and some recent studies raise doubts about the overall safety of CT Scans.
Patricia Quirk 1 of Illinois had radiation to treat her endometrial cancer. The radiation killed the cancer. It also killed her by rupturing 2 her bowel 3. The hospital record shows she was given 50 percent more radiation than she needed.
Her husband, Tom Quirk, says it should never have happened.
"I pray to God that it never happens to anybody again," said Tom Quirk.
More than half of the cancer patients in the U.S. receive radiation as part of their treatment.
The CT (Computed Tomography) Scan is a method often used to diagnose cancer. It exposes a patient to much larger doses of radiation than the usual x-ray.
Use of the CT Scan has increased dramatically since it was introduced 40 years ago. A 2007 report in The New England Journal of Medicine estimated that at least 62 million CT scans were conducted yearly in the United States.
Of those, about four million were done on children. Children are 10 times more sensitive to radiation.
Recent studies reflect growing concern in the medical community about the risks associated with large amounts of radiation given to patients.
Dr. Rebecca Smith-Bindman of the University of California San Francisco led a study of more than one thousand patients in four of the city's biggest hospitals. She found that some patients received 20 times more radiation than others during CT scans for the same condition.
"We don't have standards that say this is allowable. This is not allowable. This is an area that really lacks close oversight," she said.
In two other cities, Los Angeles, California and Huntsville, Alabama, a study also showed significant differences in radiation. In some cases, patients received eight times more radiation for the same scan.
In any CT scan, the radiologist determines the required level of radiation. A medical physicist 4 calibrates 5 the scanner. But nowhere on the screen is an indication of how much radiation the patient is really getting.
The American College of Radiology says its members are concerned about the amount of radiation patients receive. A spokesman for the group says CT scans are frequently used in hospital emergency rooms because the results can be read quicker than with other tests, like ultrasound or MRIs, that do not use radiation.
Radiologists say patients should ask their doctors whether tests using radiation are needed, and, if so, ask for the lowest dose possible.
The doctor should also check to make sure the amount of radiation given is the correct amount.
- He had a strange quirk of addressing his wife as Mrs Smith.他很怪，把自己的妻子称作史密斯夫人。
- The most annoying quirk of his is wearing a cap all the time.他最令人感到厌恶的怪癖就是无论何时都戴著帽子。
- The second major method of chemically rupturing cells is solubilization by detergents. 第二种是利用表面活性剂的增溶法。 来自互联网
- Bile salts are unusually effective at rupturing cell walls. 胆汁酸盐对于破坏细胞壁通常很有效。 来自互联网
- Irritable bowel syndrome seems to affect more women than men.女性比男性更易患肠易激综合征。
- Have you had a bowel movement today?你今天有排便吗？
- He is a physicist of the first rank.他是一流的物理学家。
- The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。
- The system precisely calibrates all of your CRT, LCD, and laptop displays. 该系统精确地测定你的CRT、LCD和笔记本电脑显示器。 来自互联网
- Locates the set in advance, calibrates the world, the drift angle. 预先定位套准，校准天地，斜我的偏差使整套图案位置准备，一线不差。 来自互联网