20 February 2010

What can you see?




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?


5 comments:

Dr Grumble said...

As regular readers will know, Mrs Grumble does not read the blog. But Dr Grumble did show her the scan and ask what she could see. She too was surprised - perhaps shocked. "What about people with Li-Fraumeni syndrome?" she said.

Dr Grumble nodded and tut-tutted. And then he googled it.

Aaron said...

from what little I have learnt about radiation during my physics degree and a small amount of research online I came to the conclusion that the dose is negligible. The dose form the extra cosmic rays up there is much greater.

And the reason they xrays don't penetrate (too far) is that they are tuned to energies which bounce off electrons that they meet, and it is the xrays which bounce back that are detected. they do penetrate a little though to get though clothes.

However not all scanners use xrays some use mm radiowaves

Julie said...

Thanks for putting me off my cornflakes with that picture, Dr Grumble. From now on I'm getting the train..

Dr Grumble said...

I think you have it right, Aaron, but the authorities, in trying to reassure the public, have told a few white lies about the penetration. Those are the lungs and the bones we can see.

This is all about risk versus benefit. It is a very attractive idea to introduce a magic scanner and deal with the terrorist problem but it is very naive to think this will solve our problems.

I cannot see why a scan would be better than a thorough body search - apart from being quicker and, perhaps, preferred by some passengers.

I am not going to point out the weaknesses of the scanners here but we do know that terrorists in the past have looked at the security measures in force and found new ways around them. It is even possible that a clever scanner with weaknesses could provide a false sense of security.

I have to go to Brussels and I do find all this stuff at the airport of bit of a nuisance. Unless it looks like snow, like Julie, I will take the train.

Anonymous said...

Forget about the radiation, Would women be scanning other women and men for men? At least to provide some dignity?!