Expert: Frederick R. Liewehr DDS, MS, FICD - 11/7/2007

Question
What year or when did it first become safe for a patient to not wear a lead apron. In other words when did the first xray machines become available that met the ada standards that did not require the patient to wear the lead apron to protect the thyroid gland and reprductive organs?

Answer
Nothing has changed for many years. Long cone machines with collimation and so forth have been used since at least the 70's, when I went to dental school. This, by the way, has nothing to do with digital/film, as the only difference is shorter exposure time with digital, and more accurate timers on the machines. When I was remodeling clinics in the 90's, we were told by the radiation hygiene folks that they no longer required all the shielding as there was adequate protection afforded by being 6 feet away, and by the plasterboard and so forth in the walls. We still use an apron, why not? It can't hurt anything. Similarly, film badges (to detect exposure to staff) are no longer used. This is because they literally never come back positive. After years of experience, it seemed a waste of money. So, we are finally getting less paranoid about the radiation hazard, which is a good thing.