Cabrelli Luciana C, Pelissari Pedro I B G B, Deana Alessandro M, Carneiro Antonio A O, Pavan Theo Z
Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil.
Phys Med Biol. 2017 Jan 21;62(2):432-447. doi: 10.1088/1361-6560/62/2/432. Epub 2016 Dec 20.
Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.
模拟生物组织特定特性的体模对于全面表征医疗设备至关重要。水基材料通常用于制造用于超声和光学成像技术的体模。然而，这些材料存在缺点，例如易于降解和时间稳定性低。在本研究中，我们提出了一种用于超声和光学成像的新型油基组织模拟材料，其优点是具有低时间降解性。在矿物油样品中制备了苯乙烯 - 乙烯/丁烯 - 苯乙烯（SEBS）共聚物，将SEBS浓度在5% - 15%之间变化，低密度聚乙烯（LDPE）浓度在0% - 9%之间变化。使用1 - 10 MHz的频率获得了诸如声速和衰减系数等声学特性，并且这些特性与软组织的特性一致。通过改变SEBS和LDPE的浓度来控制这些特性。为了表征样品的光学特性，测量了漫反射率和透射率。计算了每种化合物在400 nm - 1200 nm范围内的散射系数和吸收系数。SEBS凝胶是一种半透明材料，在光谱的可见光区域呈现低光学吸收和散射系数，但LDPE的存在增加了浊度。添加LDPE增加了体模材料的吸收和散射。获得了由含有球形内含物的LDPE/SEBS制成的异质体模的超声和光声图像。将胭脂树橙染料添加到内含物中以增强光吸收。结果表明，共聚物凝胶在超声和光学成像方面具有前景，这也使其在光声成像中可能具有潜在用途。
