Back in March, the Transportation Security Administration’s Blogger Bob trumpeted a study that supported the TSA’s claims about the relative safety of its Advanced Imaging Technology body scanners. Case closed, right? Maybe. The study made several qualifications, and at least one of its co-authors thinks the scanners should be subject to outside testing. Now ProPublica reports she is not alone, citing other scientists who remain concerned, particularly due to the lack of independent testing of in-operation scanners. The TSA may well be correct about the relative risk posed by the scanners, particularly when they are operating as intended, but questions remain.