of radiation on just one spot of the body. The researchers write: Moreover, there are a number of 'red flags' related to the hardware itself. Because this device can scan a human in a few seconds, the X-ray beam is very intense. Any glitch in power at any point in the hardware (or more importantly in software) that stops the device could cause an intense radiation dose to a single spot on the skin. Who will oversee problems with overall dose after repair or software problems? The TSA is already complaining about resolution limitations; who will keep the manufacturers and/or TSA from just raising the dose, an easy way to improve signal-to-noise and get higher resolution? Lastly, given the recent incident (on December 25th), how do we know whether the manufacturer or TSA, seeking higher resolution, will scan the groin area more slowly leading to a much higher total dose? Proponents of backscatter X-ray scanners argue that the ANSI N43.17 standard addresses safety requirements and engineering design of the systems to prevent the occurrence of accidental high radiation due to defects and errors in hardware and software. Safety requirements include "fail-safe" controls, multiple overlapping interlocks and engineering design to ensure that failure of any systems result in safe or non-operation of the system to reduce the chance of accidental exposures. Furthermore, TSA requires that certification to the ANSI N43.17 standard is performed by a third party and not by the manufacturer themselves. But there are cases where types of medical scanning machines, operated by trained medical personnel, have malfunctioned, causing serious injury to patients that were scanned. Critics of full-body scanners cite these incidents as examples of how radiation-based scanning machines can overdose people with radiation despite all safety precautions. In March 2011, it was found that some of the full body scanners in the US were emitting 10 times the normal level of radiation: Contractors charged with routinely examining the scanners submitted reports containing discrepancies, including mathematical miscalculations showing that some of the devices emitted radiation levels 10 times higher than normal:Peter Kant, executive vice president of Rapiscan Systems, said that "In our review of the surveys we found instances where a technician incorrectly did his math and came up with results that showed the radiation readings were off by a factor of 10". The X-rays from backscatter scanners "are a form of ionizing radiation, that is, radiation powerful