Here's a picture from one of those new fancy scanners they have at airports. They work like those James Bond glasses that can see through clothes. They use X-rays. Dr Grumble heard on the radio that the radiation did not penetrate the skin which surprised him.
Have a look at the scan above? Can you see the lungs? Can you see the tibiae? That's odd if the radiation doesn't penetrate the skin.
Do we need to worry? It depends on the dose of radiation we can expect to receive from these scans. We are all exposed to radiation - especially Dr Grumble's Cornish readers - and flying itself exposes you to cosmic rays. Nobody seems to worry about getting irradiated on a transatlantic flight. A few people worry about chest radiographs. Yet a transatlantic flight is roughly three times the radiation dose from a standard chest X-ray. Have you ever worried about eating Brazil nuts?