Sanchit,

If you only require a passive electrical phantom, you may wish to consider phantoms made with saline, gelatin, Intralipid (soy emulsion), and whatever ink suits your needs.

regards,

David

Thank you so much David, but if we would like to implement both passive as well as little bit of active electrical properties of the human cortex considering the durability of our structure too.

If we go by the conventional agar gel based phantoms will it be a good choice in that case ?

Thanks in advance :)

For mechanical and optical properties close to the brain, you can try agarose gel with skim milk see link. It'll be interesting to find out something that has similar electrical properties to the brain as well. But I suspect that might be more involved.

http://www.sciencedirect.com/science/article/pii/S0925400505009822

For optical tests we use a beaker-in-beaker setup with intralipid and a fraction of blood for optical, but not for electrical measurements.

Check out for a starter this little paper below - another one was just presented at the SPIE in SanFrancisco, but looks ugly in the preprint, though.

ITIS foundation, Zurich, Switzerland: Virtual Family

Thank you so much for your answers and suggestions everyone.

Few more points to consider for your optical measurements. If you want to perform interstitial measurements, then a liquid phantom (based on Intralipid) would be a better choice because of the ease of fiber placements and translations. However, it doesn't matter much for reflectance measurements so you can use both liquid and solidified phantoms. Since Intralipid has mus and mus' close to typical biological tissues, you may need to add an absorber as was correctly pointed above. It might be difficult to match both mua and mus in a wide spectral range to corresponding values of your tissue of interest. So, you may consider getting them matched at a particular wavelength and perform your studies at the fixed wavelength.

There are some reviews summarizing optical properties of various human tissues in a wide spectral range:

1) Cheong W F, Prahl S A and Welch A J 1990 A review of the optical properties of biological tissues Quantum Electronics, IEEE Journal of 26 2166-85

2) Sandell J L and Zhu T C 2011 A review of in-vivo optical properties of human tissues and its impact on PDT Journal of Biophotonics 4 773-87

3) Bashkatov A N, Genina E A and Tuchin V V 2011 Optical properties of skin, subcutaneous, and muscle tissues: a review J. Innov. Opt. Health Sci. 4 9-38

4) Jacques S L 2013 Optical properties of biological tissues: a review Phys. Med. Biol. 58 R37-R61

Regarding Intralipid optical properties, we did extensive measurements of mueff, mua, mus, mus' of Intralipid-1% in a wide spectral range (~450-900 nm) so you may have some ideas about optical properties of the background material (see two links). Hope it helps!

https://www.researchgate.net/publication/232321554_Separation_of_absorption_and_scattering_properties_of_turbid_media_using_relative_spectrally_resolved_cw_radiance_measurements?ev=prf_pub

Article Separation of absorption and scattering properties of turbid...

Article Experimental spectro-angular mapping of light distribution i...

For optical phantoms you could contact:

[email protected]

http://www.lmtb.de/gb_bmo/tissue_optics_phantoms_en.php

They are quite experienced in this field.

Martin

We have had some difficulty with glass layers (as in the beaker in a beaker described above). These non-diffuse layers break the diffusion approximation and can have signifiant effects on the detected signal and quantification of optical properties.

David is correct. To treat non-scattering regions one would need to add a radiosity model to the overall picture. The following references address this problem:

https://www.researchgate.net/publication/12347590_Boundary_conditions_for_light_propagation_in_diffusive_media_with_nonscattering_regions?ev=pub_cit

https://www.researchgate.net/publication/12347589_Optical_tomography_in_the_presence_of_void_regions?ev=pub_cit

https://www.researchgate.net/publication/24394791_3D_optical_tomography_in_the_presence_of_void_regions?ev=pub_cit

https://www.researchgate.net/publication/51361893_Photon_migration_in_non-scattering_tissue_and_the_effects_on_image_reconstruction?ev=pub_cit

https://www.researchgate.net/publication/14471172_An_investigation_of_light_transport_through_scattering_bodies_with_non-scattering_regions?ev=pub_cit

https://www.researchgate.net/publication/227260142_Topographic_Distribution_of_Photon_Measurement_Density_Functions_on_the_Brain_Surface_by_Hybrid_Radiosity-Diffusion_Method?ev=pub_cit

https://www.researchgate.net/publication/220222267_Locating_Transparent_Regions_in_Optical_Absorption_and_Scattering_Tomography?ev=pub_cit

Article Boundary conditions for light propagation in diffusive media...

Article Optical tomography in the presence of void regions

Article 3D optical tomography in the presence of void regions

Article Photon migration in non-scattering tissue and the effects on...

Article An investigation of light transport through scattering bodie...

Article Topographic Distribution of Photon Measurement Density Funct...

Article Locating Transparent Regions in Optical Absorption and Scatt...

Thank you so much everyone for sharing such detailed information and suggestions. It is really a great help to me to narrow down my options.

Regards

Sanchit

@Dr Serge: as suggested by you, to perform interstitial measurements, a liquid phantom (based on Intralipid) is a better choice. Since my work is with optrodes and would not involve fiber motion, what difference in the optical behavior I can expect if i go with a solid model ?

As long as you match optical properties of your intended target with either liquid or solid phantoms - not much. Liquid phantom is only a better choice when you want to translate fibers or place them anywhere else in the phantom and continue using the same phantom without worries of having voids (!) after removing the fibers.

Check our recent work on the genetration of patient specific phantoms

https://www.researchgate.net/publication/321378314_Anatomically_realistic_ultrasound_phantoms_using_gel_wax_with_3D_printed_moulds