Institute for Biological and Medical Imaging, Helmholtz Center Munich, Neuherberg, Germany.
Faculty of Medicine, Technical University of Munich, Munich, Germany.
J Biophotonics. 2019 Jun;12(6):e201800387. doi: 10.1002/jbio.201800387. Epub 2019 Feb 20.
Accurate image reconstruction in volumetric optoacoustic tomography implies the efficient generation and collection of ultrasound signals around the imaged object. Non-uniform delivery of the excitation light is a common problem in optoacoustic imaging often leading to a diminished field of view, limited dynamic range and penetration, as well as impaired quantification abilities. Presented here is an optimized illumination concept for volumetric tomography that utilizes additive manufacturing via 3D printing in combination with custom-made optical fiber illumination. The custom-designed sample chamber ensures convenient access to the imaged object along with accurate positioning of the sample and a matrix array ultrasound transducer used for collection of the volumetric image data. Ray tracing is employed to optimize the positioning of the individual fibers in the chamber. Homogeneity of the generated light excitation field was confirmed in tissue-mimicking agar spheres. Applicability of the system to image entire mouse organs ex vivo has been showcased. The new approach showed a clear advantage over conventional, single-sided illumination strategies by eliminating the need to correct for illumination variances and resulting in enhancement of the effective field of view, greater penetration depth and significant improvements in the overall image quality.
在体光学声断层成像中的精确图像重建需要有效地产生和收集被成像物体周围的超声信号。激发光的非均匀传输是光声成像中的一个常见问题，通常会导致视场减小、动态范围和穿透深度受限以及定量能力受损。本文提出了一种优化的体层析成像照明概念，该概念利用 3D 打印的增材制造技术与定制光纤照明相结合。定制设计的样品腔确保了对被成像物体的便捷访问，以及对样品的精确定位和用于采集体积图像数据的矩阵阵列超声换能器。光线追踪用于优化腔室内各个光纤的位置。在组织模拟琼脂球中证实了生成的光激发场的均匀性。该系统已经展示了对整个小鼠器官进行离体成像的适用性。与传统的单侧照明策略相比，这种新方法具有明显的优势，因为它不需要对照明变化进行校正，从而增强了有效视场，增加了穿透深度，并显著提高了整体图像质量。
