Considerations of in-vivo breast tissue assessment using raman spectroscopy: a review article

Raman spectroscopy, as an emerging and promising molecular assessment tool, has attracted the attention of researchers, especially for disease diagnosis in human organs such as the breast. Although most of the Raman studies on the breast have dealt with ex-vivo examination of either intact or processed excised tissue specimens, there are some in-vivo studies, including intraoperative tumor margin assessment and a few non-invasive studies. Since the non-invasive or minimally invasive Raman assessment technique is an essential need for translation to clinical approaches, in the present article, the most recent and relevant studies in this regard have been reviewed to find and introduce the most proper Raman spectroscopy system’s specifications for in-vivo assessment of breast tissue. Scholarly documents, including articles, books, and dissertations related to Raman assessment of breast tissue or in-vivo Raman assessment of other human organs, were perused in search of the most relevant technical details of Raman systems employed so far. On the one hand, the present study has covered Raman instrumentation aspects of diverse types of Raman spectroscopy, different types of laser source and their specifications, optical elements used in the delivery and collection of light to and from the tissue such as lenses and fibers, detectors and even calibration settings. On the other hand, the main Raman features corresponding to different breast pathologies have been studied, speculating their variations in a non-invasive setting. Having studied all, we tried to find the best feasible configuration for a Raman system in terms of the ability to meet the needs of a non-invasive, in vivo clinical examination of the breast.  In terms of the Raman spectroscopy modality and laser source, SORS/TRS and 785nm laser diode, were selected for in vivo examination of the breast respectively. The pertinent parameters of the spectrograph, detector, and fiber optic probe were introduced as well. In the present study, detailed specifications of a non-invasive, in vivo Raman apparatus for examination of breast tissue have been studied and specified.