Imaging soft biomaterials in vivo is a significant challenge, as most conventional techniques are limited by biomaterial contrast, penetration depth, or spatial resolution. Exogeneous contrast agents used to increase contrast may also alter material properties or exhibit local toxicity. The capability to observe biomaterial constructs in vivo without introducing exogenous contrast would improve preclinical testing and evaluation. Conventional X-ray Computed Tomography allows fast, high-resolution imaging at high penetration depth, but biomaterial contrast is low. Previous studies employing X-ray phase contrast (XPC) and utilizing a synchrotron source provided support for the significant potential of XPC in imaging biomaterials without contrast agents. In this study, XPC tomography was used to image alginate hydrogel microspheres within a small animal omental pouch model using a commercially available X-ray source. Multilayer microbeads could be identified in the XPC images with volumetric and structural information not possible in histological analysis. The number of microbeads present and microbead volume and diameter could be quantified from the images. The results of this study show that XPC tomography can be a useful tool for monitoring of implanted soft biomaterials in small animal models.

中文翻译：

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全动物模型中藻酸盐微珠相衬增强几何中的X射线CT。

由于大多数常规技术都受到生物材料对比度，穿透深度或空间分辨率的限制，因此在体内对软生物材料进行成像是一项重大挑战。用于增加对比度的外源性造影剂也可能会改变材料特性或表现出局部毒性。在不引入外源对比的情况下在体内观察生物材料结构的能力将改善临床前测试和评估。传统的X射线计算机断层扫描可以在高穿透深度下进行快速，高分辨率的成像，但生物材料的对比度却很低。先前使用X射线相衬（XPC）和使用同步加速器源的研究为XPC在不含造影剂的生物材料成像中的巨大潜力提供了支持。在这个研究中，使用市售X射线源，使用XPC断层扫描对小型动物网膜袋模型中的藻酸盐水凝胶微球成像。可以在XPC图像中识别出多层微珠，而其体积和结构信息在组织学分析中是不可能的。存在的微珠的数量以及微珠的体积和直径可以从图像中量化。这项研究的结果表明，XPC断层扫描可以成为监测小型动物模型中植入的软生物材料的有用工具。