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Re: eBay x-ray tubes & justified fears (fwd)
---------- Forwarded message ----------
Date: Sun, 05 Aug 2007 11:14:07 -0400
From: Dave Pierson <davep@xxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: eBay x-ray tubes & justified fears (fwd)
>> If you think the word idiot is too strong, please consider the fact this
>> moron was attempting to run a 120 kV X-ray tube out in the open air with
>> virtually no shielding of any type.
>Um... In hospitals they aim those at people. They did it to me, yet I'm
You were tended to, and treatment guided by, skilled professionals.
There have been instances, thru technical failure and lack of
knowledge, where people have been seriously killed.
Suggest talking to the radiologist about the precautions they
take. Suggest noting that when, eg, dental xrays are taken
technician staands away, and behind shielded wall.
Those machines have lotsa shielding to control where the beam goes.
Tube in open air means main beam and strays go anywhere.
>High-voltage hobbyists will notice many tempting x-ray tubes being
>constantly listed on eBay. I'd always assumed that they were lethal.
>But I've recently been wondering about the genuine danger of common
>sources of ionizing radiation, versus the hysterical overreaction typical
>of Americans. Ra-dee-ation! "Any risk is too much risk?" Yeah, right.
>But specifically, if the radiation burns weren't an issue, perhaps the
>cancer risk isn't as high as I've always imagined. How much of our
>opinion of x-ray tubes is based on reality?
How much of beliefs in safety is based on the fact that low doses are
cumulative, show up effects later. Yes 'some' risks are overstated.
SOME ARE REAL. Suggest calm discussion with professional radiologist.
>For example, if you stand outside in unshielded sunlight for a couple of
>hours, you receive a serious radiation burn, with skin peeling and falling
>off. Yet the cancer risk is quite small, and people in tropical countries
>even ignore the problem entirely. The effect might be mostly limited to
>the outer 1mm layers.
But make no mistake, it's a genuine radiation burn.
and, repeated over time gives cancer. Operative word is _repeated_:
tropical residents get browned, once and then more or less protected.
temperate residents, who burn REPEATEDLY (if incautious) get cumulative
damage, later elevated cncer levels.
>If you take a geiger counter along on a cross-country airline flight, be
>prepared for a surprise. It starts clicking within seconds of takeoff.
>At cruising altitude it roars: ten or twenty counts per second ( and
>supposedly much higher during solar flares.) But we aren't terrified of
>air travel because of this. Should we be?
Please quantify '20 counts per minute' to rems, then to observable,
effects levels. Hint: 20 counts per minute is Way Below the high
risk levels. Hint II: there are data showing higher cancer levels amongst
really frequent flyers, last i looked. Haven't got a cite.
>If you look up the ratings for modern dental x-ray equipment, and
>calculate the exposure needed for the mildest of x-ray burns, guess what
>the exposure time is. Seven thousand hours. You'll heal too fast. You
>can't get an x-ray burn from a dental unit; increased cancer risk is the
>only danger, and it's the dental techs using the equipment every day who
>should worry. (And how does the risk compare with other real-world
>acceptable risks, such as cancer from peanut butter, or the risk from
>solar UV in outdoor employment?)
>The USA is weird about x-ray tubes, but I'm starting to get skeptical
>about the justification. At the science museum in Paris, "Palais de
>Decouvertes," there's an exhibit case with an unshielded Crookes-era x-ray
>tube, a fluorescent plate, and a sample object. Press the button, and you
>see the green glowing image; bright enough that it's easily seen in a well
>lit museum. The tube is behind the fluorescent plate, so the x-rays are
>aimed at your face! Maybe the cancer risk ridiculously insignificant.
>Or is that museum exhibit a clear danger to the public?
It might be.
>So here's the important questions:
> If intensity is below the threshold for x-ray burns, then what is
> the cancer risk from common x-ray sources? Specifically, how does it
> compare with cancer risk of ionizing radiation which EASILY causes
> radiation burns: the risk of going outside in the sun? Or how dangerous
> is an x-ray tube when compared with the risk of working outdoors, or of
> living in a tropical country and getting huge amounts of hard UV
> exposure every day?
Not clear to me that comparing UV (sunlight) to X Ray is apropos.
Suggest that comparing 'energy' across UV vs XRay exposure is iffy.
(yes: the two specta merge one to the other...)
> Also: intensity being equal, (or if accumulated exposure is equal,) how
> much worse are x-ray frequencies when compared with solar UV? I
> realize that UV produces surface cancers which are easily noticed,
> while x-rays cause hidden damage deep inside. But ignoring that fear,
> how much worse for cancer risk is a dental x-ray tube when compared
> with a very dim UV sunlamp which cannot produce a sunburn? Tens of
> times worse? Thousands? Or much less? In other words, is our fear of
> low-power x-ray tubes justified?
Suggest calm discussion with professional radiologist.
Also what is 'low power' xray? 120KV?
>Just this year a research group discovered that x-ray cancer is not equal
>for all humans. The risk depends on genetics. (This is contrary to what
>everyone has always assumed.) In a study of patients exposed to a dose of
>head x-rays in the 1950s, the incidence of cancer was concentrated in
>certain families. Note that this was a major dose, one intended to kill
>ringworm infections, and which caused hair to fall out. People from
>certain families got brain cancer.
>This resembles the "moon children" problem, xeroderma pigmentosa, where
>certain people who lack a DNA repair molecule will immediately acquire
>skin cancer if they ever go outdoors in the sun.
>Odd thought: perhaps humans are immune to x-rays, but people with a
>certain genetic defect cannot tolerate even a small exposure, and this
>population has biased our stats.
and thus are not human?
>Odder thought: for Hiroshima-scale radiation exposure, I wonder if some
>rare people never aquired radiation sickness. Imagine if some "human
>cockroaches" exist who would easily survive a nuke war.
I trust i may be pardoned for not volunteering myself, my family, nor
my neighbours (accidentally) as someone (HYPOTHETICALLY!) experiments
with such research?
And cockroach genetics are different than human: simpler.
I assist at professional pyrotechnic displays.
'some' folk get hurt at thi, every year, many because they think/say:
'O that rule isn't important'.
I have (small) time in licensed manufacturing operations. One
occaisionally encoutners the attitude:
I don't think 'this mix' is all that sensitive.
Such people lose fingers, hands, lives, etc.