I've attended a council meeting in Harrisburg PA, and was told that the X-ray device is not commercially available. A leading Harrisburg medical authority stated that zinc-protoporiphrin is the only safe way to test for lead. A military pilot, the focus of a documentary on a major national T.V. network, along with his wife, who had spent time in Europe, lost flying capacity due to lead containing table-ware. His wife was diagnosed by a hospital, as having a neurological disorder, which the pilot proved erroneous by doing research, and proving she had lead poison. Response You are correct that X-rays are being used to study lead in bones as a means of determining an adult's historic exposure to lead.
Primary use is as a research tool.
As to zinc-protoporiphrin. It is no longer used. Only the blood-lead test is used now to determine lead levels. Hair analysis is not considered appropriate as a test for lead. Our daughter was found to have a blood lead level of 18.2 micrograms per decilitre.