Optical properties of intralipid: A phantom medium for light propagation studies

Abstract

Intralipidm is an intravenous nutrient consisting of an emulsion of phospholipid micelles and water. Because Intralipid is turbid and has no strong absorption bands in the visible region of the electromagnetic spectrum, and is readily available and relatively inexpensive, it is often used as a tissue simulating phantom medium in light dosimetry experiments. In order to assist investigators requiring a controllable medium that over a finite range of wavelengths is optically equivalent to tissue, we have compiled previously published values of the optical interaction coefficients of Intralipid, most of which were measured at a wavelength of 633 nm. We have extended the measurements of the absorption and reduced scattering coefficients from 460 to 690 nm and the total attenuation coefficient from 500 to 890 nm. These measurements show that, for stock 10% Intralipid, the absorption coefficient varies from 0.015 to 0.001 cm-' between 460 and 690 nm, the reduced scattering coefficient varies from 92 to 50 cm-' between 460 and 690 nm, the total attenuation coefficient varies from 575 to 150 cm-l between 500 and 890 nm, and the average cosine of scatter varies from 0.87 to 0.82 between 460 and 690 nm. With these data, we discuss the design of an optically tissue-equivalent phantom consisting of Intralipid and black India ink. 0 1992 Wiley-Liss, Inc.

Doppler OCT imaging of cytoplasm shuttle flow in Physarum polycephalum

“…The 2% Intralipid solution with known scattering coefficient was used as the reference to validate the procedure of parameter determination. Intralipid [22,23] is a polydisperse suspension of almost spherical particles of about 0.3 mm mean radius suspended in glycerine and water solution. The particles are soyabean oil droplets covered with a 2.5-5.0 nm-thick lipid membrane.…”

A wireless handheld probe with spectrally constrained evolution strategies for diffuse optical imaging of tissue

“…We chose Intralipid R for its well-documented optical properties and prior use in phantom studies to mimic tissue optical properties. 37,38 Likewise, black ink is commonly used in optical phantoms and is a water-soluble absorber that has a flat absorption spectrum in our wavelength range. Epolight TM 2375 is a water-soluble near-infrared dye that has peak absorption at 970 nm, and therefore displays a different spectral response from India ink in the near-infrared range.…”

“…39 The scattering in the medium is due to the Intralipid R scatterers and decreases at higher wavelengths (expected μ s : 6.74, 6.48, 6.12, 5.70 cm −1 @ 780, 808, 850, 904 nm). 37,38 We increased the reduced scattering coefficient by increasing the concentration of Intralipid R from 3.4% (34 ml/l) to 5.2% (52 ml/l) in increments of 0.2% (2 ml/l) resulting in a μ s ranging from ∼6 to 10 cm −1 . Note that an increase in the Intralipid R concentration does not change the absorption of the solution.…”

Characterizing Phantom Arteries with Multi-channel Laser Ultrasonics and Photo-acoustics

“…The phantom is composed of 1% Intralipid R (Sigma Aldrich, St. Louis, MO, USA), 1% highly purified agar (A0930-05, USBiological, Swampscott, MA, USA), and deionized water. Intralipid R is a phospholipid emulsion that is widely used for optical and photoacoustic phantom studies, because it is a homogeneous and turbid medium without distinct absorption bands [11,13,17,30,59]. Agar was used to solidify the phantom, without notably increasing turbidity or absorption [11].…”