Tissue-mimicking phantoms

Increasing interest in optical techniques for noninvasive biomedical diagnostics and therapy leads to development of new methods and devices. For verification of newly developed tools a special kind of object with well-controlled optical properties is required. Also there is a need for a stable and reproducible instrument for testing and calibration of existing techniques. All these facts show necessity for durable and reproducible test objects mimicking optical properties of real tissue. Use of phantoms will also decrease the need for animal experiments as well. Skin studies require a specific type of phantoms: solid-state, stable, with specified optical properties. It is known that a 2% Intralipid aqueous solution with some absorbing additives appropriately mimics skin as a whole in the wavelength range of 1000-2200 nm. However, for the visualization purposes the main feature of skin, multi-layerness, should be preserved.

Many types of phantoms were developed to mimic tissue with relevant optical properties for biomedical optics applications. Materials currently used include Intralipid, polyacrylamide gels, albumin, fibrin, agar, epoxy resin and silicon filled up by micro- and nanoparticles. Usually, substances used nowadays absorb or evaporate water causing alterations in the phantom optical properties over time. Agar and albumin phantoms rapidly degrade due to fungal growth. To this end, phantoms insoluble in water with a long life span (months) are of high necessity.

We focus on manufacturing of fully functional capillary network embedded into the multilayer phantom. Additionally, a possibility to model a vascular pathology such as stenosis or aneurysm is taken into account.

Manufactured capillary system in a transparent phantom layer.


A hypothetical aneurysm model in transparent phantom. Vessels are fillled with 4% Intralipid solutions.



Manufactured phantoms with scattering (left piece) and transparent (right piece).

OCT images of the capillaries in transparent phantom layer filled with Intralipid 4% (upper row) and capillaries filled with whole blood embedded into the scattering phantom layer (bottom row). Concentration of the scattering particles is of 1.5 mg/ml

References

A.V. Bykov, A.P. Popov, A.V. Priezzhev, R. Myllylä, “Multilayer tissue phantoms with functioning capillary system for OCT and DOCT imaging”, Proc. SPIE 8091, 80911R (2011). [PDF]

A.V. Bykov, A.P. Popov, M. Kinnunen, T. Prykäri, A.V. Priezzhev, R. Myllylä, “Skin phantoms with realistic vessel structure for OCT measurements”, Proc. SPIE 7376, 73760F (2010). [PDF]

Last updated: 9.9.2016