Physikalisch-Technische Bundesanstalt, Germany.
HAWK Hochschule für Angewandte Wissenschaft und Kunst, Germany.
J Biomed Opt. 2022 Jun;27(7). doi: 10.1117/1.JBO.27.7.074702.
Fluorescence imaging of rheumatoid diseases with indocyanine green (ICG) is an emerging technique with unique potential for diagnosis and therapy. Device characterization, monitoring of the performance, and further developments of the technique require tissue-equivalent fluorescent phantoms of high stability with appropriate anatomical shapes.
Our investigations aim at the development of a three-dimensional (3D) printing technique to fabricate hand and finger models with appropriate optical properties in the near-infrared spectral range. These phantoms should have fluorescence properties similar to ICG, and excellent photostability and durability over years.
We modified a 3D printing methacrylate photopolymer by adding the fluorescent dye Lumogen IR 765 to the raw material. Reduced scattering and absorption coefficients were adjusted to values representative of the human hand by incorporating titanium dioxide powder and black ink. The properties of printed phantoms of various compositions were characterized using UV/Vis and fluorescence spectroscopy, and time-resolved measurements. Photostability and bleaching were investigated with a hand imager. For comparison, several phantoms with ICG as fluorescent dye were printed and characterized as well.
The spectral properties of Lumogen IR 765 are very similar to those of ICG. By optimizing the concentrations of Lumogen, titanium dioxide, and ink, anatomically shaped hand and vessel models with properties equivalent to in vivo investigations with a fluorescence hand imager could be printed. Phantoms with Lumogen IR 765 had an excellent photostability over up to 4 years. In contrast, phantoms printed with ICG showed significant bleaching and degradation of fluorescence over time.
3D printing of phantoms with Lumogen IR 765 is a promising method for fabricating anatomically shaped fluorescent tissue models of excellent stability with spectral properties similar to ICG. The phantoms are well-suited to monitor the performance of hand imagers. Concepts can easily be transferred to other fluorescence imaging applications of ICG.
用吲哚菁绿（ICG）对类风湿疾病进行荧光成像，是一种具有独特诊断和治疗潜力的新兴技术。设备特性分析、性能监测以及该技术的进一步发展，需要具有高稳定性和适当解剖形状的、类似于组织的荧光体模型。
我们的研究旨在开发一种三维（3D）打印技术，用于制造具有适当近红外光谱范围内光学特性的手和手指模型。这些模型应具有类似于 ICG 的荧光特性，并且在数年内具有优异的光稳定性和耐用性。
我们通过在手性光聚合原料中添加荧光染料 Lumogen IR 765，对 3D 打印甲基丙烯酸盐光聚合技术进行了改良。通过掺入二氧化钛粉末和黑色墨水，将散射和吸收系数调整到代表人手的数值。使用紫外/可见分光光度法和荧光光谱法以及时间分辨测量法，对不同组成的打印模型的性能进行了表征。用光像仪研究了光稳定性和漂白性。为了进行比较，还打印并表征了一些含有 ICG 作为荧光染料的模型。
Lumogen IR 765 的光谱特性与 ICG 非常相似。通过优化 Lumogen、二氧化钛和墨水的浓度，可以打印出与荧光手像仪体内研究等效的、具有解剖形状的手和血管模型。具有 Lumogen IR 765 的模型具有长达 4 年的出色光稳定性。相比之下，随着时间的推移，打印有 ICG 的模型的荧光会显著漂白和降解。
使用 Lumogen IR 765 进行 3D 打印是一种很有前途的方法，可以制造具有出色稳定性的解剖形状荧光组织模型，其光谱特性类似于 ICG。这些模型非常适合监测手像仪的性能。该概念可以很容易地应用于其他 ICG 荧光成像应用。
