This was from their public affairs office.

I also asked them if I refuse Cast Scope, can they require me to complete the scanning, in much the way they can require you to complete scanning if you decide you don't want them to touch your "junk" midway through the procedure. They did not seem to know but confirmed that Cast Scope is NOT optional.

Cast Scope according to TSA's website requires 4 images to be taken, Popular Mechanics reports it's 10 on average if you *don't* have a mechanical knee --more if you do (yikes).

I asked TSA's public affairs if I felt the number of xrays they were taking was excessive (say more than 10 when I their website says four) could I stop the screening and exit the airport. They did not know the answer to that.

They are using these machines on 6 year old kids (or at least their website says they are "safe" on anyone over age 5.