Interesting cancer scan study

This story is about a scan that is like a mammogram, only it is for lung cancer. The study recently conducted had good results, but unfortunately the study itself is flawed statistically because there was no control group. (Incidentally, do you know where I first remember learning what a control group is? It wasn't science class in school, or a textbook, it was reading The Rats of Nimh. How funny is that?) Anyway, even if the study is flawed, it's something to keep an eye on--no doubt someone will try to construct a study that is similiar but addresses the problems.