Spectrograms comparison between normal and abnormal signal of in vivo mammary tissue, obtained by back-scattering infrared light

Abstract

High breast cancer incidence and mortality rates in Colombian women motivated the research group CIMBIOS to develop methodologies for early detection of cancer. To this aim, a method to study alterations in breast tissue has been proposed by CIMBIOS. Colombian invention patent application No NC2017 / 0003413 describes its method. A technological design called FEDSA emerged from this process. With FEDSA, the breast was irradiated in vivo (near infrared), and the back-scattering light by tissue was measured. Twenty-four women with seventeen normal and seven abnormal diagnoses were studied with this device, and intensity as a function of time was obtained for them. Data pre-processing to eliminate white noise was implemented, and fast Fourier transforms with two sampling windows, 512 and 1024, was applied. With the squared magnitude of the FFT, 1104 spectrograms were constructed, or 48 spectrograms per patient. Abnormal and normal spectrogram were labeled according to their clinical history, and these data were ordered by sampling window and frequency. Differences between normal and abnormal tissue in the breast quadrants were found with the statistical method ANOVA. In the breasts, outer upper and lower quadrant, and inner upper right in abnormal and normal women were different with p<0.05. These results agree with the clinical history of patients with abnormal classification.