Optical diffraction tomography meets metrology — Measurement accuracy on cellular and subcellular level

Three-dimensional quantitative phase imaging (3D QPI) delivers volumetric information about the refractive index distribution within microobjects. Such imaging and measurement capabilities are of great interest for technical and biomedical applications, yet there are no standardized methods for testing and reporting metrological performance. Proper metrology is crucial for further developments in QPI and for cross-referencing a range of physical properties with other laboratories and techniques. In this paper we present methodology for metrological evaluation of the 3D QPI instruments for single-cell and subcellular structures. The methodology entails suitable phantom, its digital twin, quality assessment metric and easily reproducible protocol that is attainable for both numerical and experimental analysis. We demonstrate its applicability by comparing simulated reconstructions with measurement results from 3 optical diffraction tomography systems. The results will serve as a reference point for past and future research, encourage to benchmark the new systems in a similar manner and further the efforts towards the standardization in 3D QPI metrology.