All of the high tech mail scanning gear I have seen is completely impractical for use in mass scanning. Systems that can detect drugs in a package with 100% certainty are not so scary when you learn that it takes them five minutes to scan a single package. I am sure they will continue to make technological improvements in this area, and maybe some day it will be practical for them to automatically scan every piece of mail for contraband, but right now this technology is rarely used outside of prisons and for scanning mail that has already been set aside for more thorough analysis after it was flagged for other reasons. Their nuclear and biohazard scanning equipment seems to be much better from the technical papers I have read on them, versus what I have read about drug scanners. They want to be able to detect radiation and biological attacks with extremely high precision, and apparently are capable of doing so in some cases. On the other hand bombs are still mailed through, and anthrax has been but they totally revamped their biological attack detection systems after that happened. Their counter terrorism equipment seems to be much better, but still apparently has limitations.