We report a label-free imaging method for microendoscopy that uses a needle-type imaging probe. We inserted a thin GRIN lens that had been attached to a fiber bundle into a medical-grade needle that was used as an imaging probe. The introduction of the needle probe into biological tissue allows for direct access to deep regions that we otherwise could not achieve because of the multiple light scattering. To minimize invasiveness, we introduced the illuminating probe on the tissue surface, using an oblique back-illumination configuration. We achieved three-dimensional depth imaging by changing the depth of penetration. Since only the imaging probe goes deep into the tissue while leaving the illumination channels outside, the achievable signal depends on the location of the illumination channels. We explored this point and investigated the optimal condition for the illumination distance in a systematic way. We also applied this method to ex vivo, as well as in vivo, imaging of a mouse brain, and confirmed that we had visualized the microvasculature embedded deep within the brain.

中文翻译：

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使用微针成像探头进行体内深部组织成像的无标记显微内窥镜检查

我们报告使用针型成像探针的微内窥镜检查的无标签成像方法。我们将一个已经固定在纤维束上的GRIN薄透镜插入了用作成像探头的医用级针中。将针探针引入生物组织可以直接进入较深的区域，否则由于多重光散射而无法实现。为了最大程度地降低侵入性，我们使用倾斜的背向照明配置在组织表面上引入了照明探针。通过更改穿透深度，我们实现了三维深度成像。由于只有成像探针会深入组织，同时将照明通道留在外面，因此可达到的信号取决于照明通道的位置。我们探索了这一点，并系统地研究了照明距离的最佳条件。我们也将此方法应用于小鼠大脑的离体以及体内成像，并证实我们已经可视化了嵌入大脑深处的微脉管系统。