From: rxh6@po.CWRU.Edu (Randall Holt)
Newsgroups: alt.folklore.urban
Subject: Re: Courgettes (was Re: doggy style)
Date: 5 Nov 1992 20:06:13 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: thor.ins.cwru.edu


bpb9204@tamsun.tamu.edu (Brent) asks;
> rxh6@po.CWRU.Edu (Randall Holt) writes:
> |
> |Please add to the list, from MRI cases I have seen ;
> |   
> |9/16" Crescent Wrench
> |Plastic Film Cannister
> |1 peeled potato (already sprouting)
>
> From what I've read, doesn't the MRI technology rely on very high
> magnetic fields?  Aren't the high magnetic fields the basis for
> resonating the molecules (water?) in the tissue being imaged?
>
> 
> Conclusion:  I smell a fib or an honest mistake.
>
> Feel free to correct me anywhere I'm wrong, but be sure that the
> MRI image of a wrench was indeed an MRI, and not an X-Ray.
 
My apologies. I mispoke. The wrench was from  Xray. The last two were
magnetic scans. And a further clarification is in order, the potato
was not found in a rectum, but in an uterus. It seems that a middle-aged
Eastern European immigrant regularly used a potato as a device for menstrual
blockage (don't try this at home, toxic shockers), and at some point, one got
lost. Several months later, in severe distress, she went to doctor, who 
suspected some sort of growth. Seeing as how the spud had sprouted, I guess
it really was a growth.
 
 
> Have you ever seen an aluminum or otherwise non-magnetic wrench?
> Fact:  all wrenches are mostly steel for strength reasons.
 
Actually, we use bronze tools to work on the magnet. They don't get
ripped out of your hands by the field, but they are monstrously
expensive.
 
> ObUrbanLegend:  My friend (the new father) was told by a nurse at the
> hospital that, "Some construction workers get small metal flakes behind
> their eyes.  [The flakes just get in their eyes, then work themselves
> to the back.]  The flakes do not cause problems unless they try 
> MRI, then the flakes are pulled forward, causing severe damage to the eye,
> and severe pain to the worker."  T or F?
 
I'm not aware of any cases where field-induced object motion in the eyes 
caused a problem. Mind you, it can be a problem in some cases of 
older-style steel surgical clips, but only a few of the many types 
manufactured have been found to cause problems. Same with bullets. For the
most part only steel-jacketed Chinese AK47 rounds show torsion in the 
very high magnetic field. When anything steel is near a vessel, they
usually opt not to take the risk. But if it is a surgically implanted metal,
most manufacturers have gone to great lengths to make their products MRI-safe.
But, if a metal other than steel, nickle or vanadium is used it will
distort the field for several centimeters around the object, making the
MRI image too warped to make a diagnosis. This is the major reason that 
MRI is rarely done at the site of surgical implant. 
 
The real danger of metallic objects in MRI is energy deposition. The
tissue metal interface gets pretty warm (increases of up 3 to 4 degrees C), 
but not enough to avoid taking scans, since the heat can be distributed.
This isn't the case for the eye, which has no vascularization to carry 
away unwanted heat. In the eye, even mild temperature changes can be 
damaging. A former professor told me that he had heard of cases where
line-repair workers for utility companies would be temporarily blinded 
by high-field discharge, not from light-flashes, but from heat buildup 
in the eye.
 
I have heard that eyeball overheating is very painful. I have also heard
a legend about a non-metal working woman who, during a scan, started screaming
about the pain in her eyes. In turns out she used an iron-based eye-shadow,
which overheated, etc. (In most tellings of this story, Tamy-Faye Bakker's
name comes up).
 
ObMRIUL - I have heard a story of a technician at a US-based MRI construction
	facility who had the misfortune of standing next to a magnet when 
	a construction worker, unknowingly walked by with a Galv. Steel pipe.
	The pipe got snatched by the magnet, and took a core sample of the
	brain of the technician, who lived, is somewhat impaired, but settled
	nicely out of court.
 
 
Randy 'Geez, I'm a professional, shouldn't I be 
			charging for these stories?' Holt
 
By the way, I only saw the xray film, I don't know how it got there.

-- 
Randall W. Holt      rxh6@cwru.po.edu
Newsgroups: alt.folklore.urban