Radiation Detection: Hand-Held Device for Human Body

[Nidal]

Is there a hand-held device measures the percentage of radiation in the human body?

 

[daveb]

Do you mean what % of background radiation is coming from a person?

 

[Drakkith]

Your question is too vague. Do you understand what radiation exactly is and how it is created? If not, we can help you with that and then with your question.

 

[Bob S]

Google "whole body counter".

 

[Nidal]

I do not have sufficient knowledge I heard about ( dosimeter ), this device WBC looks large, does not measure all the radiation, I thought that the topic was simpler than that.
Why there is no tables for the minimum and the maximum of what the body can bear and thus the person measuring the body

 

[Drakkith]

I do not have sufficient knowledge I heard about ( dosimeter ), this device WBC looks large, does not measure all the radiation, I thought that the topic was simpler than that.
Why there is no tables for the minimum and the maximum of what the body can bear and thus the person measuring the body

Because radiation is not a simple thing. There are 4 types of radiation, each with their own properties. The energy of each can drastically change depending on the circumstances that they cause their production. The types and energy of each particular type of radiation will decide how it affects the body and other material. To put it simply, it is not a simple subject.

 

[fatra2]

Hi there,

I fully support what Drakkith said. Furhtermore, there are some kind of tables for the maximum radiation the body can bear. Anyway, estimation of what should not be over.

The topic is quite complex since the danger comes from the different types of radiation, whether the radiation is external or internal, and each and every individual. This means that not everyone reacts the same way to radiation.

Look at it the same way as with tobacco. It is impossible to say which cigarette will give you cancer. With some people it might be the first one, while others can smoke all their life without a problem. The same applies to radiation.

 

[Bob S]

Whole Body Counters (WBC) are designed to measure all the ingested, inhaled, or injected radioactivity in the body to very high accuracy, for even very minute quantities. It will not detect alphas, unless accompanied by gammas. The detector is usually a lage (8" by 8" or larger) sodium iodide, and it is in a radiation clean room surrounded by pre-WW-II 6" thick steel walls for shielding. Patients are usually required to remove their clothing and wear special clean suits, and sit near the detector for 10 to 15 minutes.

Hand held counters cannot duplicate the sensitivity of whole body counters. The best hand held units are usually 3" by 3" sodium iodide or equivalent detectors. However, the hand held unit cannot easily discriminate between radioactivity on the clothing, on the body, or in the body.

In both cases, a pulse height analyzer is required to identify radioactive isotopes.

Bob S

 

[BishopUser]

Hmmm.. well anyone who works at a nuclear power plant must enter a whole body counter before he/she leaves work to ensure that he/she is not leaving with any contamination. The counter is designed to measure both internal and external contamination though. I guess if you cleaned up/stripped down and went into one of those you'd get a pretty accurate internal count.


By the way, what is the purpose of the thick steel plating? Can't the detector simply zero itself against the background count?

 

[Bob S]

This pdf describes a typical vault-type whole body counter.

http://www.ornl.gov/info/reports/1988/3445602689160.pdf

The thick steel vault shielding is made from low activation World War II steel armor shielding, and reduces the background counting rate to a very small % of natural (post nuclear weapon testing) background.

Bob S

 

[Drakkith]

By the way, what is the purpose of the thick steel plating? Can't the detector simply zero itself against the background count?

The natural background levels will vary depending on your location.

 

[Bob S]

By the way, what is the purpose of the thick steel plating? Can't the detector simply zero itself against the background count?

Here is a simple example. Suppose the measured background counting rate inside the vault in a certain pulse height range is 1 count per second, or 1000 counts in 16.7 minutes. Suppose the patient is put in the vault, and the total counts is 1050 for the same period, so the difference is 50 counts. But the standard deviation on each of these measurements is ±32 and ±33 counts respectively, for a combined statistical error of ±47 counts. Was there any activation (of the order of 5% of background inside the vault) in the patient?

Read http://www.sprawls.org/ppmi2/STATS/

Bob S

 

[daveb]

By the way, what is the purpose of the thick steel plating? Can't the detector simply zero itself against the background count?

The main reason is to reduce background rates so that you can exceed what is called the Minimum Detectable Activity, which is the minimum activity the counting system can discriminate from background radiation. It is a function of detector efficiency, counting time, and background rate.

This site has a good explanation. http://www.rss.usda.gov/publications/mdatb.htm"