[ RadSafe ] Mistake on the UMRC web site

[Stewart Farber]

Hi all,
As an aside to Roger Helbig's raising the issue of accurately calculating the dose delivered from some assumed particle of uranium, I must point out what is clearly an even more fundamental misstatement in the UMRC comment about their calculation of the dose delivered and its significance vs. regulatory limits.

A quote as reproduced by Roger Helbig from the UMRC is copied below. Even if the dose they calculate to some minute volume of tissue is 170 rem/year, it is totally meaningless to compare this to CFR limits specified for whole body exposure. As they write:

"In the US, the Code of Federal Regulations regarding energy specifies an  annual limit of 0.17 rem/year and a specific limit of 0.5 rem/year for an individual in the general  population."

My point is that exposure from any source would properly be converted to the Whole Body Dose Equivalent [WBDE] for which any dose to a minute volume of tissue would yield a minute WBDE nowhere near limits of concern for indiviudals or the general public.

Stewart Farber, MS Public Health



 to individuals or the general public which they state as being
----- Original Message ----- 
From: "Roger Helbig" <rhelbig at california.com>
To: "radsafelist" <radsafe at radlab.nl>

>> Date: Sat, 11 Mar 2006 06:05:55 -0000
>> Subject: [du-list] A mistake on the UMRC web site
>> 
>> Just for the fun of it, I was looking at the UMRC http://www.umrc.net/default.aspx web site tonight and  found a very signicant mistake. They have a page > titled "Radiation and  the human body" http://www.umrc.net/radiation_and_the_human_body.aspx which contains the following text quoted below. ....................................
>> The 37.6 alpha particles will deliver a radiation
>> dose of 17  rads/year. With an RBE (Relative Biological
>> Effectiveness) factor of 10, the dose rate is 170 rem/year for the
>> surrounding body tissue. In the US, the Code of Federal Regulations regarding
>> energy specifies an  annual limit of 0.17 rem/year and a specific limit
>> of 0.5 rem/year for an individual in the general  population.
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