You use milk as a optical phantom? Is this sufficiently stable and reproducible?

What analytical technique (kind of radiation) you are interested in? I simply googled

optical phantom analysis (no quotes) and immediately got a quite instructive article descibing methods how to quantify the match.

If you are interested to get hints to more specific questions as are so easily obtainable from the web, you probably have to be more specific with your question.

Hi Justice,

In general, liquid lipid-based optical phantoms exhibit scattering properties (mus and mus') that are quite high and close to those of biological tissues. However, the spectral dependence of these quantities usually differs from the dependencies that are exhibited by biological tissues. Absorption parameters on the other hand are lower than typical absorption of biological tissues. To increase absorption, various absorbers can be added like ICG, Hb, HbO2 etc. Again, one has to be clear about their spectral dependence because absolute values usually don't follow the absorption of typical biological tissues in the entire spectral range.

Usually, people try to match properties of the certain tissue of interest (skin, muscle, prostate etc.) at the selected wavelength combining a lipid phantom with an added absorber and playing with corresponding concentrations. One of the benefits of working with liquid phantoms is an ease of preparations and adjusting the concentrations to meet specs of the certain tissue (again, usually at a fixed wavelength). Such phantoms produce reproducible results and don't have a degree of heterogeneity typical for actual biological tissues.

Bottom line, it depends on what tissue you're trying to mimic and in what spectral range. In principle you can have pretty good match of mus and mua, but it all depends on what is coming next - a final goal of the study. Hope it helps!

Check this work

https://www.researchgate.net/publication/322722312_Gel_wax-based_tissue-mimicking_phantoms_for_multispectral_photoacoustic_imaging