Disorder strength calculation for label-free diagnosis of tissue biopsies using quantitative phase imaging

Abstract

The standard method for cancer diagnosis is the microscopic investigation of tissue biopsies. Because the tissues do not significantly absorb and scatter light, traditionally, the observation is performed using bright-field microscopy after staining. Although this approach has been widely adopted all over the world for 100 years, it generally takes a long preparation time and sometimes the early carcinogenesis is missed due to a variation in a quality of a staining. Quantitative phase imaging (QPI) can access objective information on thickness and refractive index changes from an unstained tissue slice, which cannot be observed by conventional microscopes. This can be an attractive advantage in the field of a medical diagnosis, especially since QPI can access the tissue architecture information with nanoscale sensitivity. In this paper, we used quantitative phase imaging to measure the tissue disorder strength, which is known as one of the effective markers of early carcinogenesis. We retrieved the disorder parameter from the local refractive index fluctuation map obtained by spatial light interference microscopy (SLIM). We show that SLIM imaging combined with the disorder analysis is a valuable approach for screening of benign and malignant breast tissue biopsies.