Friday, November 03, 2006

Hi Res Scans

I couldn't find the original post for this so I'm starting a new one. In response to a comment I made, Samantha said

"Matt - You are right about there being little difference between 40 sec and 20 sec with 0.3 voxel. We've actually eliminated the 40 sec 0.3 voxel scan from new machines."

So now I'm curious... using this same logic, shouldn't there be very little difference between .25 and .3 voxel? Or is there something magical in the math when we go under .3mm?


Blogger Samantha Irving said...

The difference in those two scans was time, 20 vs 40 seconds, both at 0.3 voxel. The extra 20sec of exposure doesn't seem to buy you any/much extra clarity and you get double x-ray dose. That's why we took it out.

I'm stealing from an email from Arun:
"The “raw frames” are fundamentally different between 0.2/0.25 voxel and 0.3/0.4 voxel scans, in terms of “binning” of pixels. The former incorporates 2x2 binning, producing 254 micron pixels, while the latter employs 4x4 binning at acquisition time, making the pixels 508 microns in size."

8:01 PM  
Blogger Matt Kroona said...

That makes sense (I guess). It seems like the more I learn, the more I need to learn. Thanks for the clarification.

Arun mentioned that there is a .1mm voxel scan protocol available. Can you post it (or email it to me)? It might come in handy one day.

10:02 AM  
Blogger Samantha Irving said...

Actually there is a 0.12 voxel scan. It's a more narrow FOV for the scan. Someone from ISI needs to add it to your xml file. If you want, I can set you up. Just need to set up gotomypc and I'll get on and give it to you. You can email me and we can set something up:

10:39 AM  
Blogger Don Croall said...

I have heard that the .12 voxel scan has been tested with XP but not with 2000.
If that is correct, those of us using Windows 2000 on our acquisition computer need to be aware.

1:17 PM  
Blogger Eric Iwamoto said...

BACKGROUND: Don Croall has the very first i-CAT installed in a commercial dental application and we have the second. At that time, the i-CAT was configured for Windows 2000.

CURRENT: The i-CAT now utilizes Windows XP Professional. There is no reason for Windows 2000 users to switch to XP.

FUTURE: As of January 2007, Windows Vista will be broadly available. ISI wisely plans to wait until Vista had been in mass release for a while so Microsoft can fix all the initial bugs BEFORE using that platform in i-CAT scanners.

A couple of days ago, we obtained the .12mm scan protocols from ISI technical support and have successfully performed a scan. We will perform a few more scans (at .12mm)to verify that there are no issues with the initial i-CATs running Windows 2000.

3:00 PM  

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