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Re: dental x-rays



PERHAPS SOMEBODY WILL SOON REPLACE THE WORD
"KILOGRAM". WHY? BECAUSE A BASIC UNIT SHOULD
NOT HAVE THE KILO PREFIX. REPLACING "RAD" BY
"GRAY" IS EQUIVALENT. WHO WAS GRAY? WAS IT
THE SAME GRAY WHO DISCOVERED THAT METALS
CONDUCT ELECTRICITY? IF SO THEN WHY WAS
THE DOSE UNIT NAMED AFTER HIM?

1 RAD = 100 ergs/gram 1 GRAY = 1 J/kg = 100 rads
***********************************************

Yes, Brian did write "3.600 mSv annual dose". I assumed it
was a typing error and that he used a period where it should
have been a comma. Why? Because 3600 mSv is 360 mrem;
or only twice as large as what most people quote for the
average natural background in the US. It may be as high
as 360 mrem in some locations, for example, in Denver.

The annual dose of 3.6 mSv (0.36 mrem) would be too low
to be accepted. It would conflict with what is usually quoted.
Somebody is wrong somewhere. It can be my memory. I do
not see anything wrong in my previous message. I wrote:

1Gy (dose of one Gray) is when 1 kg of body tissue absorbs
1 joule of energy. The older unit of dose, 1 rad, is the same as
0.01 Gy or 10 mGy.

For x rays one can assume that 1 rem=1 rad (or 1 Sv = 1 Gy).
Therefore:

Dental bitewing (4 films) 0.038 milisievert (mSv) --> ?
0.038 mSv = 0.038 mGy = 0.0038 rads = 3.8 mrads = 3.8 mrem

or roughly 1 mrem per film. In other words, what we receive from
this 4-films procedure is about 2% of what every part of our body
receives in one year from the environment. I am assuming the yearly
dose is 200 mrem. Brian quoted (see below) the average yearly
dose of 3600 mSv (360 mrad). This probably accounts for medical
treatments. Right? Otherwise 360 is about two times larger than what
is usually printed for the so-called "natural background."

to which brian whatcott responded:

Ludwik wrote:

1Gy (dose of one Gray) is when 1 kg of body tissue absorbs
1 joule of energy. The older unit of dose, 1 rad, is the same as
0.01 Gy or 10 mGy.

For x rays one can assume that 1 rem=1 rad (or 1 Sv = 1 Gy).

Hence 1Gy = 100 rad = 100 rem = 1Sv for Ludwik's assumptions.

THIS IS NOT AN ASSUMPTION, THIS IS TRUE FOR X RAYS.

/snip/

Brian quoted (see below) the average yearly
dose of 3600 mSv (360 mrad).

/snip/
Ludwik Kowalski

I did not! 3600mSv = 360 rem. Cockroaches maybe, humans no.
I expect Ludwik had 3600 uSv in mind.

NO, NO, NO --> 3600 mSv = 360 mrem (not 360 rem).