X-Message-Number: 5145
Date: Thu, 9 Nov 1995 09:40:03 -0800
From: John K Clark <>
Subject: SCI.CRYONICS Beyond 2000 and Mind Uploading

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Excellent post by   (Brian Wowk), I'd like to take this 
opportunity to pick his brain with two questions, if  you will excuse the  
expression.


                >What really kills you, though, is the infamous 6th power
                
                >relation between scan time and resolution (at constant SNR)
                
                >that exists in MRI. If you could scan an entire brain with
                
                >1mm resolution in 1 second, it would take you 10^28 years to
                                >scan that brain with 1 nanometer resolution.            
                 

First question. In your opinion what is the practical limit of linear 
resolution for a non destructive conventional MRI scan that doesn't use 
nanotechnology? My suspicion ( and I admit it's only a suspicion) is that 
a 1 nanometer resolution would be far more than what you would need for 
uploading, a resolution of a hundred, perhaps a thousand times less might be 
sufficient. If true the scan would take much less time,... just a billion 
years or so. Oh well, back to the drawing board.

Second question. Please correct me if I'm wrong but my understanding is that  
the MRI signal comes almost entirely from the hydrogen nucleus. Is there any 
possibility of using a "MRI contrast agent",presumably some non toxic element 
with an odd number of protons or neutrons to strengthen the MRI signal?


                                            John K Clark      


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