Development of a reliable and reproducible phantom manufacturing method using silica microspheres in silicone

Jones, Charlotte Maughan; Munro, Peter

doi:10.1117/1.jbo.22.9.095004

Cited by 4 publications

(4 citation statements)

References 18 publications

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“…The silicone (Elastosil RT 601 A/B – Wacker Chemie AG., Munich, Germany) and TiO 2 phantoms were manufactured using a previously developed method for silicone and silica microspheres [ 7 ] which we describe here briefly. The method begins by adding the required mass of TiO 2 scatterers to the required mass of silicone part A.…”

Section: Resultsmentioning

confidence: 99%

“…Such phantoms are considered stable and reproducible, and have previously been used in, for example, optical coherence tomography [ 3 ] and elastography [ 4 ], as well as to create complex multi-layered tissue mimicking phantoms [ 5 ] and in the creation of general optical phantoms for use in the near infrared [ 6 ]. However such silicone phantoms require long manufacturing processes [ 7 ], as described in Section 3.1. Epoxy resin is another example of a phantom matrix material which also requires a lengthy manufacturing process [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

“…They also result in an anisotropy factor ( g ) of approximately 0.9 which is more tissue realistic than other inorganic scattering materials. Despite their high cost, and well documented predisposition to clumping due to charge interactions [ 7 , 14 ], silica microspheres continue to be a popular choice of optical scatterer as they are able to be modelled accurately using Mie and continuum theory [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

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Stability of gel wax based optical scattering phantoms

Jones

Munro

2018

Biomed. Opt. Express

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Phantoms with tuneable optical scattering properties are essential in the development and refinement of optical based imaging techniques. Mineral oil based ‘gel wax’ phantoms are the subject of increasing interest due to their ease and speed of manufacture, non-toxic nature, ability to cast into anatomically realistic shapes, as well as their cost-effective nature of production. The addition of scatterers such as titanium dioxide powder and monodisperse silica microspheres to the gel wax allows for the creation of phantoms with a controllable optical scattering coefficient. To enable repeated use of such phantoms, the stability of the scattering properties must be determined–a property which has yet to be investigated. We present an analysis of the stability of the reduced scattering coefficient (μs') of such phantoms over time. We conclude that due to the measurable reduction in scattering coefficient over time, gel wax phantoms embedded with silica spheres may not be suitable for repeated use over time, however gel wax-TiO2 phantoms are much more temporally stable.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stability of gel wax based optical scattering phantoms

Jones

Munro

2018

Biomed. Opt. Express

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“…Typically, they are based around a wax or a polymer matrix, such as PDMS, with additional components that assure appropriate scattering and absorption. 11 – 16 An exciting development in solid tissue phantoms is the advent of three-dimensional printing technology, which allows the production of complex geometrical features found in realistic tissue samples. 17 – 19 These phantoms significantly improve the shelf-life and stability of manufactured phantoms, but they often include monodisperse microspheres as a scattering component, thus increasing the price dramatically.…”

Section: Introductionmentioning

confidence: 99%

Effects of phantom microstructure on their optical properties

Stergar,

Hren,

Milanič

2024

J. Biomed. Opt.

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. Significance Developing stable, robust, and affordable tissue-mimicking phantoms is a prerequisite for any new clinical application within biomedical optics. To this end, a thorough understanding of the phantom structure and optical properties is paramount. Aim We characterized the structural and optical properties of PlatSil SiliGlass phantoms using experimental and numerical approaches to examine the effects of phantom microstructure on their overall optical properties. Approach We employed scanning electron microscope (SEM), hyperspectral imaging (HSI), and spectroscopy in combination with Mie theory modeling and inverse Monte Carlo to investigate the relationship between phantom constituent and overall phantom optical properties. Results SEM revealed that microspheres had a broad range of sizes with average and were also aggregated, which may affect overall optical properties and warrants careful preparation to minimize these effects. Spectroscopy was used to measure pigment and SiliGlass absorption coefficient in the VIS-NIR range. Size distribution was used to calculate scattering coefficients and observe the impact of phantom microstructure on scattering properties. The results were surmised in an inverse problem solution that enabled absolute determination of component volume fractions that agree with values obtained during preparation and explained experimentally observed spectral features. HSI microscopy revealed pronounced single-scattering effects that agree with single-scattering events. Conclusions We show that knowledge of phantom microstructure enables absolute measurements of phantom constitution without prior calibration. Further, we show a connection across different length scales where knowledge of precise phantom component constitution can help understand macroscopically observable optical properties.

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Merging Mie solutions and the radiative transport equation to measure optical properties of scattering particles in optical phantoms

et al. 2020

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We present a new method to calculate the complex refractive index of spherical scatterers in a novel optical phantom developed by using homemade monodisperse silica nanospheres embedded into a polyester resin matrix and an ethanol–water mixture for applications in diffuse imaging. The spherical geometry of these nanoparticles makes them suitable for direct comparison between the values of the absorption and reduced scattering coefficients ( μ a and μ s ′ , respectively) obtained by the diffusion approximation solution to the transport equation from scattering measurements and those obtained by the Mie solution to Maxwell’s equations. The values of the optical properties can be obtained by measuring, using an ultrafast detector, the time-resolved intensity distribution profiles of diffuse light transmitted through a thick slab of the silica nanosphere phantom, and by fitting them to the time-dependent diffusion approximation solution to the transport equation. These values can also be obtained by Mie solutions for spherical particles when their physical properties and size are known. By using scanning electron microscopy, we measured the size of these nanospheres, and the numerical results of μ a and μ s ′ can then be inferred by calculating the absorption and scattering efficiencies. Then we propose a numerical interval for the imaginary part of the complex refractive index of S i O 2 nanospheres, n s , which is estimated by fixing the fitted values of μ a and μ s ′ , using the known value of the real part of n s , and finding the corresponding value of I m ( n s ) that matches the optical parameters obtained by both methods finding values close to those reported for silica glass. This opens the possibility of producing optical phantoms with scattering and absorption properties that can be predicted and designed from precise knowledge of the physical characteristics of their constituents from a microscopic point of view.

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Development of a reliable and reproducible phantom manufacturing method using silica microspheres in silicone

Cited by 4 publications

References 18 publications

Stability of gel wax based optical scattering phantoms

Stability of gel wax based optical scattering phantoms

Effects of phantom microstructure on their optical properties

Merging Mie solutions and the radiative transport equation to measure optical properties of scattering particles in optical phantoms

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