Lead Aprons

[Ccja@aol.com]

Does anyone know the history of the racheting-up of the de facto standard in
equivalency, to the point where most everyone (I think) uses 0.5mm? Does this
seem like overkill to anyone? The amounts of leakage from fluoroscopic source
assemblies nowadays is extremely small, so almost all of the radiation to
which people are exposed (excepting the case in which a physician has his/her
hands in the beam) is Compton garbage scattered by the patient (and other
"objects").

E.g., the half-value layer (Pb) for 30 keV is 0.02mm, if I'm reading the Rad
Health Handbook correctly. That's 12.5 half-values given by a 0.25mm
Pb-equivalent apron, or a 99.98% reduction of the entrance exposure. Does
that seem insufficient?

chris alston
ccja@aol.com