I’m not sure why you haven’t seen the scanners at Dulles. Norfolk does not have them yet but Dulles has them. Most airports have them.
Here is a list of US Airports with the scanners. Some have just been installed and may not yet be in use.
ABQ
ATL
BDL
BIS
BNA
BOI
BOS
BRO
BUF
BWI
CLE
CLT
CMH
CRP
CVG
DCA
DEN
DFW
DTW
ELP
EWR
FAR
FAT
FLL
FWA
GEG
GFK
GPT
GRR
HNL
HRL
IAD
IAH
JAX
JFK
LAS
LAX
LGA
LIH
LRD
MIA
MCI
MCO
MDT
MFE
MEM
MIA
MKE
MSP
MSY
OAK
OMA
ORD
PIT
PBI
PHL
PHX
PVD
RDU
ROC
RIC
SAN
SAT
SEA
SFO
SMF
SJC
SJU
SLC
STL]
TPA
TUL
It’s because I fly out of Norfolk to connecting flights, and I don’t go through security again. The only domestic airports that I return to Norfolk from are Seattle, San Diego and Newark, and I have never been patted-down or scanned at those airports.