[Homer-users] A problem about of the fNIRS system

[a]

Professor Huppert,
Thank you for your detail introduction of the way you mkae your phantom and your advice. As you said, it is not very easy to make such phantom by a mechatronics engineer alone. So, if I can't find it on the internet, I will try to find some worshops in our school to help me.








At 2014-01-16 22:26:51,"Huppert, Ted" <huppertt at upmc.edu> wrote:
>We build our own phantoms (particularly for our FM-NIRS system from ISS) and we have done various scatter/absorption phantoms.
>
>We use a silicon product from http://www.smooth-on.com which comes as a two part formula and we mix with dry pigment paints (titanium oxide for scattering and carbon black for absorption).  The trick is uniformly mixing the pigments and then setting up the phantom to cure under a strong vacuum.  You have to make dilution series to figure out the right mixture ratios of the two paints (and then need some way to confirm you made a phantom with the right properties).   We have done phantoms in sizes ranging from small blocks to casts of realist head sizes using negative molds of infant and adult heads.  Its a bit of an involved process to get everything right the first time, so I would recommend that you go talk to your engineering department.  A lot of schools have undergrad engineering classrooms/workshops that have a lot of the equipment for mixing and vacuum that you need.  I was lucky enough to have a great undergrad with a double degree in art and engineering that did all the casts in the art pottery workshops on campus.  Its good to have someone who has done casting before because there are a bunch of trade secrets to getting the phantom out of the cast.
>
>Of course, we use our phantoms for actual calibration and quantitative accuracy with our frequency-domain NIRS system.  If you just needed something that “just works" for QA of your instrument, you probably don’t need to worry so much about air bubbles or getting the MUA/MUS exactly right.  You could also just do a liquid phantom with intra-lipid.  Those are a bit messy, but require less work.
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>----------------
>Theodore Huppert, PhD
>Assistant Professor
>Departments of Radiology and Bioengineering
>University of Pittsburgh
>Email: huppertt at upmc.edu
>Phone: (412) 647-8459
>
>
>
>"Insanity: doing the same thing over and over and expecting different results"-  Einstein
>
>From: a <ypflll at 163.com<mailto:ypflll at 163.com>>
>Reply-To: "homer-users at nmr.mgh.harvard.edu<mailto:homer-users at nmr.mgh.harvard.edu>" <homer-users at nmr.mgh.harvard.edu<mailto:homer-users at nmr.mgh.harvard.edu>>
>Date: Wednesday, January 15, 2014 at 9:47 PM
>To: "homer-users at nmr.mgh.harvard.edu<mailto:homer-users at nmr.mgh.harvard.edu>" <homer-users at nmr.mgh.harvard.edu<mailto:homer-users at nmr.mgh.harvard.edu>>
>Subject: Re: [Homer-users] A problem about of the fNIRS system
>
> I've seen your product. However, what I want to buy is just a phantom that has the similar absorption coefficients and scattering coefficients with the forearm muscle. Thank you all the same.
>
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>At 2014-01-15 22:38:16,"Chester Wildey" <wildey at mrrainc.com<mailto:wildey at mrrainc.com>> wrote:
>We make a simple solid phantom that may work for you.
>
>http://mrrainc.com/products.php?product=Product-5
>
>Feel free to email me for details.
>
>
>Chester Wildey, Ph.D.
>Founder and CEO
>MRRA Inc.
>817-301-3794
>wildey at mrrainc.com<mailto:wildey at mrrainc.com>
>www.mrrainc.com<http://www.mrrainc.com>
>
>On Jan 15, 2014, at 7:57 AM, a <ypflll at 163.com<mailto:ypflll at 163.com>> wrote:
>
> Hello,
>       I am a university student in China, and I have tried to develop a simple fNIRS system.
>       However, I can't find a suitable optical phantom to test the system. Now I have a Static Callibration Phantom bought from Nirx Corp( USA), but the scattering and absorption is too weak.
>       I have seen someone use a solid silicone phantom. Can someone give me more information about how I can get it or where to buy it?
>       Thanks!
>
>
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