Application of Raman Spectroscopy Using a Handheld Probe to Characterize Human White Adipose Tissue

Raman spectroscopy analysis has been used successfully to distinguish normal from neoplastic tissue during surgical resection of tumors. However, microscopic Raman spectroscopy is typically time-consuming and restricted to examining only a small, specific region of the tissue. Recently developed handheld Raman probes have shown promise to overcome these limitations and thus be developed as an intraoperative tool to categorize and identify various types of tissues. In this paper, we evaluated the use of Raman spectroscopy by a handheld probe in feasibility studies of fresh samples of normal human white adipose tissue (WAT) taken from adjacent to four sarcomas to determine the accuracy and consistency of measurements under varying ex vivo conditions. We also studied if the results are affected by freezing the samples, a common practice in ex vivo protocols, or by covering the probe with polyethylene, which could be used under sterile conditions during surgery. Our findings showed that the handheld probe provided consistent Raman measurements in white adipose samples and that exposing fat tissue to different freezing protocols does not significantly affect the integrity and representation of prominent peaks for the tissue, resulting in consistent identification of tissue spectra. We also found that covering the probe with polyethylene had minimal effects on measurement of the WAT spectra, which suggests that sterile polyethylene could be used to cover the probe in the operating room to maintain sterility. Our findings suggest that Raman spectroscopy with a handheld probe has potential to be developed for use in the OR to identify normal adipose tissue in a surgical bed.