the only way to detect hidden objects inside prosthetic devices and other hiding criteria of the same type. Treatment of transgender people Current machines installed by the TSA require agents in the US to designate each passenger as either male or female, after which the software compares the passenger's body against a normative body of that sex. Transgender passengers have reported that full body scanners at several U.S. airports have falsely raised alarms based on their anatomy. Health concerns Health concerns relating to the use of full-body scanning technology are present, especially pertaining to the use of X-ray scanners. The issue is mainly regulated by ANSI 43.17.2009, which limits the dose on a per-person basis. However this 2010-era document is intended to apply primarily in the context of standard civilian-airport security. It is generally not considered applicable to unusual terrorism-threat detection concerns in high-security environments (prisons, special-purpose airports) or military institutions. Nor is ANSI 43.17.2009 considered to be the appropriate standard for highly concealed threats such liquid bombs inside body cavities or swallowed drugs. Due to fundamental physical limitations of how each type of detection technology functions, these highly covert types of threats are impossible to detect by any means other than transmission X-rays. From the perspective of annual dosage, the ANSI 43.17.2009 standard stipulates that a transmission X-ray dosage of 0.25 μSv per scan, in conjunction with an annual total limit at 250 µSv, equates to a per-person maximum of such 1000 scans per year for a civilian-aviation passenger. However, counting all medical X-ray procedures (as a typical person might undergo in an average year), and if the total annual dose of 250 µSv is taken to include all medical-related doses, then the number of flights/scans permitted for that person could be greatly reduced, assuming that transmission-type X-ray technology is used at each security screening that the civil-aviation passenger undergoes. But because the medical X-ray dosages vary tremendously (over several orders of magnitude) depending on the diagnostic procedures that the patient is subjected to, the proportional contribution of airport-security X-raying to the person's total annual dosage cannot be calculated unless an accounting of the medical X-ray dosages is also present. Millimeter wave scanners Currently adopted millimeter wave scanners operate in the millimeter or sub-terahertz band, using non-ionizing radiation, and have no proven adverse health effects, though no long-term studies have been done. Thomas S. Tenforde, president of the National