That is your choice, but by the time they find the evidence of substantial hazard, it will be too late. Remember that there is no foolproof way to find out whether the scanners are safe until they have been used on a large number of people for several years. Even pharmaceutical companies, which are required to do extensive clinical trials for years on hundreds of patients before marketing a new drug, occasionally discover that a compound is unsafe and have to recall it and face lawsuits.