Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

Vogt, William C.; Jia, Chunrong; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

doi:10.1117/1.jbo.21.10.101405

Cited by 100 publications

(125 citation statements)

References 50 publications

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“…A wide variety of tissue-mimicking materials (TMMs) have been studied for use as PAT phantoms, including traditional gelatin hydrogel, 17,18 poly(vinyl alcohol) cryogel, 19,20 and poly(vinyl chloride) plastisol (PVCP). [21][22][23][24] Most PAT phantoms presented in the literature use a homogeneous background medium to simulate healthy tissue. However, breast tissue is a highly heterogeneous mixture of fat and fibroglandular tissue.…”

Section: Photoacoustic Tomography and Photoacoustic Tomography Phantomsmentioning

confidence: 99%

“…We have previously developed custom PVCP formulations for use in making PAT phantoms with tunable, biologically relevant optical and acoustic properties. 24 PVCP is a suspension of PVC resin in liquid plasticizers, which fuses into a gel after heating to high temperatures (∼180°C). In this study, we utilize the same base materials, including a dispersion-grade PVC resin (Geon 121A, Mexichem Specialty Resins, Inc., Avon Lake, Ohio), benzyl butyl phthalate (BBP) (Sigma-Aldrich, St Louis, Missouri), and di(2-ethylhexyl) adipate (DEHA) (Sigma-Aldrich).…”

Section: Phantom Fabricationmentioning

confidence: 99%

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Two-layer heterogeneous breast phantom for photoacoustic imaging

et al. 2017

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Photoacoustic tomography (PAT) is emerging as a potentially important aid for breast cancer detection. Well-validated tissue-simulating phantoms are needed for objective, quantitative, and physically realistic testing for system development. Prior reported PAT phantoms with homogenous structures do not incorporate the irregular layered structure of breast tissue. To assess the impact of this simplification, we design and construct two-layer breast phantoms incorporating vessel-simulating inclusions and realistic undulations at the fat/fibroglandular tissue interface. The phantoms are composed of custom poly(vinyl chloride) plastisol formulations mimicking the acoustic properties of two breast tissue types and tissue-relevant similar optical properties. Resulting PAT images demonstrate that in tissue with acoustic heterogeneity, lateral size of imaging targets is sensitive to the choice of sound speed in image reconstruction. The undulating boundary can further degrade a target's lateral size due to sound speed variation in tissue and refraction of sound waves at the interface. The extent of this degradation is also influenced by the geometric relationship between an absorber and the boundary. Results indicate that homogeneous phantom matrixes may underestimate the degradation of PAT image quality in breast tissue, whereas heterogeneous phantoms can provide more realistic testing through improved reproduction of spatial variations in physical properties.

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Section: Photoacoustic Tomography and Photoacoustic Tomography Phantomsmentioning

confidence: 99%

Section: Phantom Fabricationmentioning

confidence: 99%

Two-layer heterogeneous breast phantom for photoacoustic imaging

et al. 2017

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“…Part of the challenge is the access to suitable chromophores and phantoms for proof-of-concept, testing, validation, and optimization. Despite recent advances on the study of phantom matrix materials for general photoacoustic (PA) system characterization and quality control, [8][9][10][11][12] for multiwavelength and quantitative PAI purposes further efforts are needed, with one of the crucial issues being finding suitable chromophores. 13,14 It is essential for these to be well-characterized, well-behaved, and stable.…”

Section: Introductionmentioning

confidence: 99%

Sulfates as chromophores for multiwavelength photoacoustic imaging phantoms

2017

J. Biomed. Opt.

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Abstract. As multiwavelength photoacoustic imaging becomes increasingly widely used to obtain quantitative estimates, the need for validation studies conducted on well-characterized experimental phantoms becomes ever more pressing. One challenge that such studies face is the design of stable, well-characterized phantoms and absorbers with properties in a physiologically realistic range. This paper performs a full experimental characterization of aqueous solutions of copper and nickel sulfate, whose properties make them close to ideal as chromophores in multiwavelength photoacoustic imaging phantoms. Their absorption varies linearly with concentration, and they mix linearly. The concentrations needed to yield absorption values within the physiological range are below the saturation limit. The shape of their absorption spectra makes them useful analogs for oxyand deoxyhemoglobin. They display long-term photostability (no indication of bleaching) as well as resistance to transient effects (no saturable absorption phenomena), and are therefore suitable for exposure to typical pulsed photoacoustic light sources, even when exposed to the high number of pulses required in scanning photoacoustic imaging systems. In addition, solutions with tissue-realistic, predictable, and stable scattering can be prepared by mixing sulfates and Intralipid, as long as an appropriate emulsifier is used. Finally, the Grüneisen parameter of the sulfates was found to be larger than that of water and increased linearly with concentration. © The Authors.Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…[20, 26, 27] Other materials such as polyvinyl chloride plastisol (PVCP) have been used for phantoms. [28]…”

Section: Introductionmentioning

confidence: 99%

Algorithm for rapid determination of optical scattering parameters

et al. 2017

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Preliminary experiments at the NIST Spectral Tri-function Automated Reference Reflectometer (STARR) facility have been conducted with the goal of providing the diffuse optical properties of a solid reference standard with optical properties similar to human skin. Here, we describe an algorithm for determining the best-fit parameters and the statistical uncertainty associated with the measurement. The objective function is determined from the profile log likelihood, including both experimental and Monte Carlo uncertainties. Initially, the log likelihood is determined over a large parameter search box using a relatively small number of Monte Carlo samples such as 2·104. The search area is iteratively reduced to include the 99.9999% confidence region, while doubling the number of samples at each iteration until the experimental uncertainty dominates over the Monte Carlo uncertainty. Typically this occurs by 1.28·106 samples. The log likelihood is then fit to determine a 95% confidence ellipse. The inverse problem requires the values of the log likelihood on many points. Our implementation uses importance sampling to calculate these points on a grid in an efficient manner. Ultimately, the time-to-solution is approximately six times the cost of a Monte Carlo simulation of the radiation transport problem for a single set of parameters with the largest number of photons required. The results are found to be 64 times faster than our implementation of Particle Swarm Optimization.

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Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

Cited by 100 publications

References 50 publications

Two-layer heterogeneous breast phantom for photoacoustic imaging

Two-layer heterogeneous breast phantom for photoacoustic imaging

Sulfates as chromophores for multiwavelength photoacoustic imaging phantoms

Algorithm for rapid determination of optical scattering parameters

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