Optical phantoms with variable properties and geometries for diffuse and fluorescence optical spectroscopy

Abstract

Growing interest in optical instruments for biomedical applications has increased the use of optically calibrated phantoms. Often associated with tissue modeling, phantoms allow the characterization of optical devices for clinical purposes. Fluorescent gel phantoms have been developed, mimicking optical properties of healthy and tumorous brain tissues. Specific geometries of dedicated molds offer multiple-layer phantoms with variable thicknesses and monolayer phantoms with cylindrical inclusions at various depths and diameters. Organic chromophores are added to allow fluorescence spectroscopy. These phantoms are designed to be used with 405 nm as the excitation wavelength. This wavelength is then adapted to excite large endogenous molecules. The benefits of these phantoms in understanding fluorescence tissue analysis are then demonstrated. In particular, detectability aspects as a function of geometrical and optical parameters are presented and discussed.

Comprehensive phantom for interventional fluorescence molecular imaging

“…1(c)] was suggested for characterizing tissue autofluorescence and validating fluorescence tissue analysis. 34 The phantoms were made of porcine skin gelatin and employed rhodamine B (RhB) or FITC to impart fluorescence. The optical properties were selected to correspond to normal and diseased brain tissues.…”

Benchmarking of fluorescence cameras through the use of a composite phantom

“…Histological analysis of biopsies and surgical specimen is nevertheless time consuming, labor intensive, and subject to sampling errors as it involves specialized personnel and subjective interpretation of readouts. [13][14][15][16] Polyurethane-based phantoms were considered recently for assessing the sensitivity of fluorescence cameras or for quantifying the excitation light leakage into the acquired fluorescence images. Thus, new technologies for real-time guidance are needed to address limitations that may lead to incomplete surgical treatment of disease.…”

“…Thus, new technologies for real-time guidance are needed to address limitations that may lead to incomplete surgical treatment of disease. 15,17,18 Nevertheless, most of these phantoms resolve one or a few parameters and do not allow for comprehensive characterization of all variables associated with fluorescence imaging performance. 4 Fluorescence imaging has the potential to improve surgical and endoscopic guidance and positively impact the clinical management and prognosis of numerous diseases.…”

Development of thin skin mimicking bilayer solid tissue phantoms for optical spectroscopic studies

“…But solid phantoms have the ability to hold the desired geometrical shape, thickness and inhomogeneity as that of multi-layered tissues and can be fabricated with controlled optical properties [14,15]. The concept of a thin, solid optical tissue phantom is a challenging task and has gained attention only in the recent past [16][17][18][19]. Fabrication of solid gelatin based mono and bilayer phantoms were attempted previously with individual layer thickness several orders higher than the original tissue to use with optical spectral studies [17].…”

“…The concept of a thin, solid optical tissue phantom is a challenging task and has gained attention only in the recent past [16][17][18][19]. Fabrication of solid gelatin based mono and bilayer phantoms were attempted previously with individual layer thickness several orders higher than the original tissue to use with optical spectral studies [17]. Development of a hard, solid, polyurethane fluorescence phantom was reported to assess the sensitivity of fluorescence cameras and to validate the efficacy of interventional fluorescence molecular level imaging with greater depth dimensions compared to in-vivo conditions [18].…”