Optical and acoustic properties at 1064 nm of polyvinyl chloride-plastisol for use as a tissue phantom in biomedical optoacoustics

Abstract

A novel optoacoustic phantom made of polyvinyl chloride-plastisol (PVCP) for optoacoustic studies is described. The optical and acoustic properties of PVCP were measured. Titanium dioxide (TiO2) powder and black plastic colour (BPC) were used to introduce scattering and absorption, respectively, in the phantoms. The optical absorption coefficient (mua) at 1064 nm was determined using an optoacoustic method, while diffuse reflectance measurements were used to obtain the optical reduced scattering coefficient (mu's). These optical properties were calculated to be mua = (12.818 +/- 0.001)ABPC cm(-1) and mu's = (2.6 +/- 0.2)S(TiO2) + (1.4 +/- 0.1) cm(-1), where ABPC is the BPC per cent volume concentration, and S(TiO2) is the TiO2 volume concentration (mg mL(-1)). The speed of sound in PVCP was measured to be (1.40 +/- 0.02) x 10(3) m s(-1) using the pulse echo transmit receive method, with an acoustic attenuation of (0.56 +/- 1.01) f(1.51+/-0.06)MHz (dB cm(-1)) in the frequency range of 0.61-1.25 MHz, and a density, calculated by measuring the displacement of water, of 1.00 +/- 0.04 g cm(-3). The speed of sound and density of PVCP are similar to tissue, and together with the user-adjustable optical properties, make this material well suited for developing tissue-equivalent phantoms for biomedical optoacoustics.

Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

“…After fusion, PVCP is poured into mold cavities to cool and solidify into arbitrary shapes. PVCP has been investigated as a material for photoacoustic phantoms, [37][38][39][40][41][42] and solid PVCP inclusions within background PVCP matrix have been reported stable for at least six months, 38 suggesting that this material is suitable for fabricating highly robust phantoms with stable properties. The PVCP formulation reported in the literature is a commercial product for making soft fishing lures (M-F Manufacturing Co., Inc., Fort Worth, Texas).…”

Sulfates as chromophores for multiwavelength photoacoustic imaging phantoms

“…A variety of matrix materials can be used, but materials such as agar or gelatin will require that the hollow spaces to be filled with aqueous solutions are encapsulated in tubes (walled channels). 16 Hydrophobic and more long-lasting materials such as PVCP 8 or PDMS 48 can instead be used to circumvent the need for tubes, forming wall-less channels that can be refilled and used multiple times. An example of such PVCP constructs and obtained images (though with chloride solutions) can be found in Ref.…”

“…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.…”

Imaging technique for real-time temperature monitoring during cryotherapy of lesions

“…The PVCP phantom matrix was prepared according to Ref. 41 with embedded PTFE tubes, which were later filled with blood samples. Gelatin from porcine skin (Sigma-Aldrich, St. Louis, Missouri) was used in preparation of gelatin 15-wt.…”