Use of the CT Scan has increased dramatically since it was introduced 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.

VOA: standard.2010.01.30

So, it was effective, it was rapidly then introduced into general use.

因此,疫苗是有效的,它迅速得到了广泛应用

耶鲁公开课 - 生物医学工程探索课程节选