So privacy issues aside (but not forgotten), how often are these machines calibrated and inspected? The article says the image quality suffers due to a misalignment in the machine. How long did that persist? Were people exposed to higher doses of radiation as a result? Why should we trust security guards to run what basically amounts to adapted medical equipment? If we are going to have these machines, shouldn't they be operated by trained radiologists who have some hope of recognizing when the machine is not working in spec and understand the potential consequences?