A fully clothed man imaged by a QinetiQ millimetric wave camera. Note the concealed gun. T-ray cameras are said to be similar but more powerful.
Here’s a little explanation on what a T-Ray exactly is. T-Ray or Terahertz radiation are electromagnetic waves sent at terahertz frequencies which travel in line of sight. These waves can pass through clothes, paper, wood, plastic, and fog. However they cannot penetrate metal or water. Here are some ways it could be used.
Medical – Since Terahertz radiation is non-ionizing it is not expected to damage DNA unlike X-rays. It can also detect differences in water content and density of a tissue.
Security – Nothing to tell that you haven’t figured out for yourself 😛