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 -----BEGIN PGP SIGNED MESSAGE----- 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 -----BEGIN PGP SIGNATURE----- Version: 2.6.i iQCzAgUBMKI7Z303wfSpid95AQHuqQTvZaFqUjNYLu10BmvehpBaMl1ZH8KBj1FN 9+fP5MTqoD6mefN/CLzDbiCWZsRps8gxZJayZlAUlxSdFwGE519XxUA0h3bEHt9S w6603CgUjxMd3525fd82IY05oKDt4Aj7hOAcvFD0BU+qNmAO25hulSY36Y3b4GmT XBwQy8X3v1LVraHDNFx5ghOgJn81bWVm47vbMt71YiklLCEhcE4= =Se5X -----END PGP SIGNATURE----- Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=5145