Convert SCSI to USB??
SCSI's a dead technology. Really hasn't been produced for about 10 years. It's also pretty complex and was tough to put in a USB adapter. There were a few USB 2.0 to SCSI adapters made, but they were buggy and expensive. You might be able to find one on ebay, but no guarantees it will work or have drivers for your laptop/OS.
It looks like your scanner had a firewire option. If your laptop has an expresscard or cardbus slot, you can get a IEEE1394 (firewire) port to use the scanner. Those are still being made.
There's also a network adapter (For $350) you can buy for the scanner to use it on the network. That would be easy.
If this scanner is worth it and provides an important service for you, you also might consider setting up a cheap old desktop with an internal PCI SCSI card to scan from
I expect you're right in that a replacement pc would be the most practical route. We've a closet full of OLD Dells that I expect could be used to come up with something.
It's an old scanner but I got it from a company that didn't use it that much and it was completely overhauled (doc feeder, belts, etc) shortly after we got it. Don't need the 17 inch bed that much but when we do, it's great to have.
I went around and around with Epson re. a network connection some years ago. I just remember that there were issues with either the adapter or the drivers. As it doesn't currently have a firewire card, I expect that would be a similar situation.
I just took at look at the spec on that page I linked to and at first glance saw that the minimum requirement was 64 GB of RAM. Wha'... ?!? Oh, hang on, that's 64 *M*B of RAM. Sheesh... things sure have changed ...