Intralipid-Based Phantoms for the Development of New Optical Diagnostic Techniques

Abstract

Intralipid is a material widely employed for the preparation of phantoms for optical imaging and biophotonics applications in medical field. The development of new optical diagnostic equipment in these fields requires the use of well-designed phantoms with optical properties (including scattering and absorption) mimicking those of biological tissues in all the pre-clinical stages of investigations. For this reason, great research effort has been devoted to optically characterize Intralipid and at preparing optimal phantoms. In this short review, we summarize the principal physico-chemical characteristics of Intralipid and the main contributions in the assessment of its scattering and absorption properties. In addition, the most largely used Intralipid-based homogeneous and non-homogeneous phantoms are discussed. Even though other materials are available for the preparation of phantoms, the use of Intralipid still offers an inexpensive and easy-to-use method for preparing phantoms with finely tuned optical properties.

Criteria for the design of tissue-mimicking phantoms for the standardization of biophotonic instrumentation

“…Lipid-based emulsions such as milk or intralipid are popular in water-based phantoms due to their simple application and biological similarity to fat-based structures found in tissue, allowing incorporation of aqueous absorbers or fluorophores. Here, Intralipid 28,29 (or similar compounds 30 such as Nutrilipid, Lyposyn, Vasolipid, Lipofundin etc), a suspension of soybean oil, egg phospholipids, and glycerol in water, is most commonly employed due to its high stability, low absorption coefficient, regulatory controlled low batch-to-batch variability 30,31 and extensive validation in the literature 18,[28][29][30][31][32][33] . Microspheres are a favourable option for precision phantoms due to their well-controlled size, refractive index and predictable scattering properties in Mie theory 34 , but they are typically high cost, limiting their use to small volumes.…”

“…The speed of sound can be increased by the addition of ethanol (e.g., 7.4% by mass for 1540 m•s -1 ) 64 . For tuning optical scattering properties, fat emulsions 28,29,58,[30][31][32][33][54][55][56][57] or microspheres 59,60 are preferred, while optical absorption can be tuned by adding whole blood or extracted erythrocytes 56,59,65 , inks 43,66,67 , molecular dyes 61,62 . Blood-based phantoms 59,65,[68][69][70][71] can also mimic changes in oxygen saturation (SO2), by addition of oxygenating (e.g., oxygen) or deoxygenating compounds (e.g., yeast 65,68,71 ).…”

Croconaine-based nanoparticles enable efficient optoacoustic imaging of murine brain tumors

“…Tissue-mimicking cylindrical phantoms with different radii were made by using the mixture of intralipid (2 mL), agar (2 g), India ink solution (98 mL, absorbance 0.15 at 780 nm) [ 46 , 47 ]. Then tubing containing different concentration of CR780RGD-NPs was inserted into the tissue-mimicking phantoms for optoacoustic detection from different depths using an MSOT inVision 256-TF.…”

A multiparameter tissue-mimicking phantom for multispectral endoscopic imaging

“…The primary feature of phantom development for optical imaging techniques is the control of optical properties (reduced scattering and absorption coefficients) to mimic human tissue 10 , which has previously been characterized and can provide a guideline 11 . Early phantoms are static homogeneous liquid with intralipid [12][13][14] , which can reproduce optical properties well. The use of Intralipid still offers an inexpensive and easy-to-use method for preparing phantoms with finely tuned optical properties, But, the static homogeneous material is unable to characterize an intricate spatial distribution.…”