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


Current medical imaging techniques mostly provide information based on morphological or anatomic differences of the tissue, disregarding the underlying molecular composition.

Molecular-sensitive methods, such as Raman spectroscopy, have shown significant potential for clinical in vivo diagnostics by providing the intrinsic molecular fingerprint of a sample label-free, without contact, and non-destructive.

The advantage is that the information can be used to detect and potentially delineate cancer from healthy tissues. However, current implementations of fiber optic probe-based Raman systems remain far behind the technological possibilities the method can offer.

In a new paper published in Light: Science & Applications, a team of scientists, led by Professor Dr. Iwan Schie from the Leibniz Institute of Photonic Technology (Leibniz IPHT) and the Department of Medical Engineering and Biotechnology from the University of Applied Sciences, Jena, as well as Professor Dr. Gunther Hofmann from the Jena University hospital, Germany, have developed a fiber optic probe-based Raman imaging system for the real-time molecular virtual reality data visualization of chemical boundaries on a computer screen and the physical world.

The reported imaging platform combines molecular measurements, simultaneous computer vision-based positional tracking with real-time data processing and real-time formation of molecular virtual reality (MVR) images.

The proposed approach achieves a spatial resolution of 0.5 mm in the transverse plane and a topology resolution of 0.6 mm, with a spectral sampling frequency of 10 Hz and can be used to image large tissue areas in a few minutes, making it highly suitable for clinical tissue-boundary demarcation.

The MVR images can be perceived as augmented chemical reality (AR) on the computer screen or, through the additional implementation of a laser projector system, directly mapped on the tissue, creating mixed reality (MR) information that can be perceived in real-time by naked eye. Because most samples have a topological surface profile, the researchers have additionally implemented a photometric stereo measuring system, which allows mapping the molecular information on a 3D sample surface.

The presented work outlines the potential for future clinical translation of real-time molecular imaging, by allowing easy access to patients and by providing biochemical distributions from the region of interest for disease tissue differentiation during surgical resection.

"With the proposed system, we intend to extract the whole potential of fiber optic probe-based Raman spectroscopy. Our approach enables handheld imaging acquisition using a fiber optic probe as well as real-time processing and reconstruction of molecular information. It also allows a smart and intuitive visualization of the data using AR and MR, as well as to add sample topologies to the acquired data.

Our solution offers new opportunities and can be a potential tool for real-time molecularly specific clinical diagnostics and molecular boundary demarcation. Because the proposed approach is universal, it can also be applied to non-medical applications, e. g. in manufacturing, quality control or in conjunction with and additional optical and non-optical modalities," says Professor Dr. Iwan Schie.

» Original publication

Source: Leibniz Institute of Photonic Technology (IPHT)