I totally agree with DWI on this matter. Its a human performance error which can happen to anyone in their work. For e.g: i counted my $20 bills for total $400 and went to deposit in a bank. Then the banker counted infron of me and got $20 short. i asked her than there should be $400 in total. So she re-counted it and got the right amount. She made an excuse of having a long day and everything went fine. Now its a samll human error right?? i correlated my case with the X-ray thing disregarding the expensive cost of X-ray, and the risk of chest X-ray exposure of the kid. This place is built on improving and correcting as things go which is very important to understand. And it is very true no to expect Perfectness just coz it a developed country. This is my opinion. I might be wrong or conflict with other's view which won't be a shocker to me, but this issue raised is an important one. Thanks.