A study found that the radiation from CT scans—the tests regularly used to【C1】______internal injuries or signs of cancer—is likely【C2】______for 2 percent of cancer cases in the United States. 【C3】______lots of Americans undergo CT scans, that research is unlikely to【C4】______in doctors" offices: Two-thirds of patients in a new JAMA study reported 【C5】______nothing of the risks of the diagnostic procedure. 【C6】______, 17 percent felt like they played an active role in a discussion【C7】______whether this diagnostic test was the best path forward. "Our study indicates that most decisions to undergo outpatient CT are【C8】______by physicians and risk communication is【C9】______," a team of researchers led by University of Colorado"s Tanner Caverly writes. "The risk communication that took place had limited【C10】______: respondents who recalled discussing the benefits and risks of imaging did not have better 【C11】______." Would a conversation about the【C12】______risks have made a difference? Caverly"s team asked a few other questions that suggest it would: Patients undergoing the scan have little idea about the radiation【C13】______One-quarter self-identified radiation as a risk of a CT scan; 37 percent were able to identify CT scans as having a higher level of radiation【C14】______a chest x-ray. There"s a growing movement in medicine right now to【C15】______on unnecessary treatment or【C16】______of care. Much of this has been led by a group called Choosing Wisely, which has【C17】______ with dozens of medical societies to come up with lists of 【C18】______that doctors themselves don"t think they ought to be using. One of their key messages is that more care isn"t【C19】______better, all medicine comes with some level of risk. That message does not,【C20】______, seem to be delivered in the doctor"s offices studied here.
【答案解析】解析：由下一段的the risks of the diagnostic procedure(诊断过程存在的风险)，推测此处表示“美国2%的癌症病例可能与CT扫描中的辐射有关”，即CT扫描有可能是导致患癌的原因之一。be responsible for表示“对……负有责任，是形成……的原因”，符合此处语境．故本题选D项responsible。