I actually have always wondered why Lois or Clark for that matter would not keep a sheet of lead foil on their persons for cases just like this.
Just my two cents: one could think that a thin layer of lead wouldn't be enough to stop the radiations emitted by kryptonite... I'm glad it worked in this case, though!
Might be but it seems often a coat of lead paint, which would probably be less than the density of lead foil, can stop Clark's x-ray vision so I don't know how much it would take. We also do not know the level of radiation that Kryptonite puts out it might be a very small level that is just deadly to Kryptonians. Since all of this is made up arguing physics while discussing issues regarding a man who can fly might be considered a bit absurd...
Mike