Quantitative phase imaging (QPI) has emerged as a valuable method for investigating cells and tissues. QPI operates on unlabelled specimens and, as such, is complementary to established fluorescence microscopy, exhibiting lower phototoxicity and no photobleaching. As the images represent quantitative maps of optical path length delays introduced by the specimen, QPI provides an objective measure of morphology and dynamics, free of variability due to contrast agents. Owing to the tremendous progress witnessed especially in the past 10–15 years, a number of technologies have become sufficiently reliable and translated to biomedical laboratories. Commercialization efforts are under way and, as a result, the QPI field is now transitioning from a technology-development-driven to an application-focused field. In this Review, we aim to provide a critical and objective overview of this dynamic research field by presenting the scientific context, main principles of operation and current biomedical applications.

定量相成像（QPI）已经成为一种研究细胞和组织的有价值的方法。QPI对未标记的标本进行操作，因此，它是已建立的荧光显微镜的补充，具有较低的光毒性且无光漂白。由于图像代表了标本引入的光程长度延迟的定量图，因此QPI提供了客观的形态学和动力学度量，没有由于造影剂引起的变化。由于尤其是在过去的10至15年间见证了巨大的进步，许多技术已经变得足够可靠，并已转化为生物医学实验室。商业化努力正在进行中，结果，QPI领域现在正从以技术开发为驱动力的领域过渡到以应用程序为中心的领域。在这篇评论中，