Radiation and xrays - Page 1
Forum section: electronics / general

author: J.Xerneas
author_rank: Contributor
timestamp: February 04, 2016, 12:54:51 am
content: I am watching an episode of House and he is treating a kid that had radiation poisoning. The kid had a radioactive device used for testing wells on a key chain not knowing what it was. In the episode he said that he went on a flight and the key chain was on his carry on bag and obviously went through a X-Ray machine.My question is What would a radioactive source look like under an X-Ray machine? Would it see it as a metal housing (in this case lead) or would it look like something different?

author: helius
author_rank: Super Contributor
timestamp: February 04, 2016, 01:11:33 am
content: X-ray screening machines come in different types. The ones used to screen most luggage are transmissive and cast a wide beam of x-rays onto the unknown, with a scintillator detector on the opposite side. Any material that absorbs all of the energy, like lead, will appear completely opaque regardless of what is inside. That is why you can protect sensitive films in lead-lined bags. If a gamma emitter capsule was inside the luggage, it might be pointed down to the scintillator and affect the image, but it would be off-axis and appear in a random position. I don't think luggage screeners are trained to recognize such patterns.A newer type of screening machine uses backscatter x-rays to characterize the materials in the unknown. These machines can famously see through passengers' clothes, but the backscatter technique is also used to measure the atomic contents of materials, as in detecting specific alloys. The sensors are in front of the unknown, on the same side as the x-ray tube, and are designed to detect precise levels of x-ray energy. It is unlikely that they would register off-axis gamma radiation, or if they did they would have no way to detect its direction. This is more likely to confuse the machine or take if off-line.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 04, 2016, 02:03:33 am
content: The X-ray image would appear washed out or 'overexposed' with a blurry halo centered around the object. The picture would appear grainy or 'snowy'.Btw, at airports they can detect doses low enough to know if you've had chemo recently. That kid would have been shot and family sent to Guantanamo if something like that happened IRL.

author: johnh
author_rank: Regular Contributor
timestamp: February 04, 2016, 08:29:56 am
content: QuoteDo you mean radiation therapy? Ther are two type External beam radiation or Internal radiation.The first one External radiation therapy is like getting an x-ray. ( I had this for 5 days a week for 4 weeks total , wasn't a lot of fun )http://www.cancercouncil.com.au/1024/b1000/radiotherapy-38/external-radiotherapy/?pp=74156&cc=3354&&ct=35The second one implant are either left in for a short period time or or left for a longer periodhttp://www.cancercouncil.com.au/1257/b1000/radiotherapy-38/internal-radiotherapy/

author: grumpydoc
author_rank: Super Contributor
timestamp: February 04, 2016, 08:38:27 am
content: Quote from: johnh on February 04, 2016, 08:29:56 amRadioiodine for thyroid is the one which make you radioactive enough to need to take precautions for a few days.I suppose low dose brachytherapy seeds would be detectable but IIRC mainly alpha and beta emitters are used which won't get out of the target organ, much less the body.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 04, 2016, 08:58:32 am
content: Quote from: johnh on February 04, 2016, 08:29:56 amSorry to hear that. I hope you are better now.Not actually sure which one. The second case is obviously detectable, but even the first case may be detectable due to residual beta decay.