生物細胞與組織內不均勻的結構反映在折射率的變化，可以提供顯微鏡觀察的對比，不需要外在的螢光或染色標定。無標定的觀察除了避免樣本型態或功能的改變，更使得活細胞可以長時間的觀察。相較於傳統的相位差與微分干涉差顯微術以及新興的二維定量相位顯微術等，三維折射率分布可提供更豐富的結構資訊，因此三維定量折射率顯微術近年來逐漸受到生醫光學領域的重視。本文簡介三維折射率顯微術和重建理論的發展脈絡與原理，並且以作者實驗室所發展的兩個三維折射率顯微鏡，分別為馬赫－詹德干涉和共光路干涉的架構，介紹驗證重建理論與顯微影像之結果以及活細胞影像範例。

Refractive index (RI) fluctuations in biological cells and tissue provide an intrinsic source of imaging contrastwithout external labels. The intrinsic phase contrast not only avoids morphological and functional alterations of biosamplesbut also enables long term observation of living specimens. Compared to more conventional phase contrastand differential interference contrast microscopies and emerging two-dimensional quantitative phase microscopy,imaging of the three-dimensional (3D) RI distribution provides more structural information of heterogeneities inbio-samples. As a result, 3D quantitative RI microscopy has attracted increasing attention in the fi eld of biomedicaloptics recently. In this manuscript, we review the principle and development history of 3D RI microscopy andassociated reconstruction algorithms. Validation of reconstruction algorithms and two optical setups, one based ona Mach-Zehnder interferometer and the other based on a common-path confi guration, developed in our laboratoryis provided. Finally, an example of live-cell imaging is demonstrated and potential biomedical applications arediscussed.