Solid tissue simulating phantoms having absorption at 970nm for diffuse optics.

Gordon T Kennedy,Griffin R Lentsch,Anthony J Durkin,Brandon Trieu,Adrien Ponticorvo,Rolf B Saager

doi:10.1117/1.jbo.22.7.076013

Abstract

.Tissue simulating phantoms can provide a valuable platform for quantitative evaluation of the performance of diffuse optical devices. While solid phantoms have been developed for applications related to characterizing exogenous fluorescence and intrinsic chromophores such as hemoglobin and melanin, we report the development of a poly(dimethylsiloxane) (PDMS) tissue phantom that mimics the spectral characteristics of tissue water. We have developed these phantoms to mimic different water fractions in tissue, with the purpose of testing new devices within the context of clinical applications such as burn wound triage. Compared to liquid phantoms, cured PDMS phantoms are easier to transport and use and have a longer usable life than gelatin-based phantoms. As silicone is hydrophobic, 9606 dye was used to mimic the optical absorption feature of water in the vicinity of 970 nm. Scattering properties are determined by adding titanium dioxide, which yields a wavelength-dependent scattering coefficient similar to that observed in tissue in the near-infrared. Phantom properties were characterized and validated using the techniques of inverse adding-doubling and spatial frequency domain imaging. Results presented here demonstrate that we can fabricate solid phantoms that can be used to simulate different water fractions.

Highlights

Biomedical diffuse optical imaging systems require tissue phantoms that mimic the optical properties of tissue for their development, characterization, and calibration
We describe solid silicone tissue phantoms that incorporate a near-infrared pthalocyanine dye to simulate a variation in tissue water absorption
The 3-cm thick phantoms were measured using the technique of spatial frequency domain imaging (SFDI) that we have described in detail in the literature.[3,32]

Summary

Introduction

Biomedical diffuse optical imaging systems require tissue phantoms that mimic the optical properties of tissue for their development, characterization, and calibration. Many different phantom systems have been investigated using a variety of host matrices, scattering particles, and absorbers. When used for calibration or the validation of models, it is desirable that the optical properties of the phantom are similar to those of the target tissue to reduce the likelihood of measurement error related to interpolation and extrapolation of optical properties. For wide-field imaging, homogeneity over a large area may be required. It is sufficient to reproduce the reduced scattering and absorption properties at discrete wavelengths; for spectroscopic measurements, it may be necessary to approximate the spectra of the optical properties of tissue parameters over the range that they are measured

Methods

Results

Conclusion