Wagnières G, Cheng S, Zellweger M, Utke N, Braichotte D, Ballini J P, van den Bergh H
Institute of Environmental Engineering, LPAS-EPFL, Lausanne, Switzerland.
Phys Med Biol. 1997 Jul;42(7):1415-26. doi: 10.1088/0031-9155/42/7/014.
The design and characterization of optical phantoms which have the same absorption and scattering characteristics as biological tissues in a broad spectral window (between 400 and 650 nm) are presented. These low-cost phantoms use agarose dissolved in water as the transparent matrix. The latter is loaded with various amounts of silicon dioxide, Intralipid, ink, blood, azide, penicillin, bovine serum, and fluorochromes. The silicon dioxide and Intralipid particles are responsible for the light scattering whereas the ink and blood are the absorbers. The penicillin and the azide are used to ensure the conservation of such phantoms when stored at 4 degrees C. The serum and fluorochromes, such as Coumarin 30, produce an autofluorescence similar to human tissues. Various fluorochromes or photosensitizers can be added to these phantoms to simulate a cancer photodetection procedure. The absorption and fluorescence spectroscopy of the porphyrin-type fluorescent markers used clinically for such photodetection procedures is similar in these phantoms and in live tissues. The mechanical properties of these gelatinous phantoms are also of interest as they can easily be moulded and reshaped with a conventional cutter, so that complex structures and shapes, with different optical properties, can be designed. The optical properties of these phantoms were determined between 400 and 650 nm by measuring their effective attenuation coefficient (mu eff) and total reflectance (Rd). The microscopic absorption and reduced scattering coefficients (mu a, mu s') were deduced from mu eff and Rd using a Monte Carlo simulation.
本文介绍了一种光学体模的设计与特性，该体模在宽光谱窗口（400至650纳米之间）具有与生物组织相同的吸收和散射特性。这些低成本体模使用溶解在水中的琼脂糖作为透明基质。琼脂糖中添加了不同量的二氧化硅、脂质体、墨水、血液、叠氮化物、青霉素、牛血清和荧光染料。二氧化硅和脂质体颗粒负责光散射，而墨水和血液是吸收体。青霉素和叠氮化物用于确保此类体模在4摄氏度储存时的保存。血清和荧光染料，如香豆素30，产生与人组织相似的自发荧光。可以向这些体模中添加各种荧光染料或光敏剂，以模拟癌症光检测程序。临床上用于此类光检测程序的卟啉型荧光标记物在这些体模和活体组织中的吸收和荧光光谱相似。这些凝胶状体模的机械性能也很重要，因为它们可以很容易地用传统刀具进行模塑和重塑，从而可以设计出具有不同光学特性的复杂结构和形状。通过测量其有效衰减系数（μeff）和总反射率（Rd），在400至650纳米之间确定了这些体模的光学特性。使用蒙特卡罗模拟从μeff和Rd推导出微观吸收系数和约化散射系数（μa，μs'）。
