Interferometric optical testing to discriminate benign and malignant brain tumors

When normal cells suffer from the malignant disease, changes occur in cellular size and structure, and their constituents. These changes can affect the biological response of cells and tissues. Conventional hematoxylin and eosin staining, which is the gold standard of tumor diagnosis provide a very detailed view of the tissue by staining cell structures to diagnose a disease based on the deformation of the cells. However, this study shows changes in cells and tissues structure due to malignant diseases can also affect the optical properties. The purpose of this research was to assess and compare these effects to identify benign and malignant brain tissues from each other. Various samples of adult human brain tissues were studied using Mach-Zehnder interferometer as an optical method and using the Fourier transform method as an analytical process. The formed interference patterns of benign and malignant brain tumors were investigated to obtain the phase distribution of tumors. The obtained information demonstrated that the phase distribution of malignant brain tissues was different from benign brain tissues. The phase distribution approximately ranged from 10 to 120 rad for benign samples and from 10 to 160 rad for malignant samples. Moreover, the average of unwrapped phase distribution was 63.79 and 85.69 rad in benign and malignant samples, respectively. This results indicated that the proposed laser-based technique, Mach-Zehnder interferometer method, can be used as an auxiliary procedure along with histological techniques to identify benign and malignant brain tumors from each other. It is suggested that the unwrapped phase distribution of tissues be considered as an optical property for differentiating various brain tumors.