Raman ChemLighter: Fiber optic Raman probe imaging in combination with augmented chemical reality

Abstract

Raman spectroscopy using fiber optic probe combines non‐contacted and label‐free molecular fingerprinting with high mechanical flexibility for biomedical, clinical and industrial applications. Inherently, fiber optic Raman probes provide information from a single point only, and the acquisition of images is not straightforward. For many applications, it is highly crucial to determine the molecular distribution and provide imaging information of the sample. Here, we propose an approach for Raman imaging using a handheld fiber optic probe, which is built around computer vision–based assessment of positional information and simultaneous acquisition of spectroscopic information. By combining this implementation with real‐time data processing and analysis, it is possible to create not only fiber‐based Raman imaging but also an augmented chemical reality image of the molecular distribution of the sample surface in real‐time. We experimentally demonstrated that using our approach, it is possible to determine and to distinguish borders of different bimolecular compounds in a short time. Because the method can be transferred to other optical probes and other spectroscopic techniques, it is expected that the implementation will have a large impact for clinical, biomedical and industrial applications.

Real-time molecular imaging of near-surface tissue using Raman spectroscopy

“…Block 1 : As described in ref. 18 , a handheld fiber-optic Raman probe is used to acquire Raman spectra. First, a database of reference spectra from the relevant components of the sample is built.…”

“…This could also be favorably combined with augmented reality (AR) and mixed reality (MR) to enhance the perception of molecular information. These virtual reality (VR) approaches offer an interesting potential to improve the precision of real-time diagnosis or surgery 22 and have readily been combined with various imaging modalities, such as computed tomography 23 , optical coherence tomography 24 , magnetic resonance tomography 25 , 26 , fluorescence lifetime imaging 17 , 19 , and others 18 , 19 , 27 , 28 .…”

Translational biophotonics with Raman imaging: clinical applications and beyond

“…This approach was used to generate an overlay of spectral mapping that was projected onto a simultaneously captured brightfield image. 30 In this demonstration, the authors pre-defined the specific tissue components of interest and used pre-recorded spectra for each to generate an color image (RGB) overlay of specific sample locations that correspond to a particular tissue type. In a similar approach, by adding simple fiducial markers onto a typical handheld Raman probe, Horgan et al were able to demonstrate in ex vivo and in vivo animal studies that digital probe tracking could be used to define a tumor tissue margin through the combined use of Raman spectral measurements and exogenous fluorescence detection.…”

Looking for a perfect match: multimodal combinations of Raman spectroscopy for biomedical applications

“…For biological tissue samples, the situation is more nuanced and typically reported acquisition times range between 0.5 and 10 s. 23 As such, imaging-based RS in patients has particular challenges, primarily due to the low quantum yield of the inelastic Raman scatters of tissue components. It is not entirely impossible to rapidly acquire Raman images of biological tissue as was recently demonstrated by Yang et al., 32 where a new development of a fiber-based Raman imaging approach was introduced, allowing rapid Raman-based tissue characterization. The presented ChemLighter approach enables a fiber-probe–based molecular imaging of the tissue with real-time data analysis, enabling the visualization of molecular information and detection of molecular tissue boundaries ad hoc as augmented chemical reality ( Fig.…”

“… Previous implementations of fiber-based RS have been used for a point-based measurement of tissue, without any imaging information of the tissue of interest. Yang et al 32 have nicely demonstrated that a hand-held, fiber-based Raman probe can actually be used for imaging applications of biological tissue, which has significant potential for the detection of tumor margins. (a) Bright-field image with Raman spectra of indicated molecular signatures for lipid, bone and protein.…”