Characterisation of a fibre optic Raman probe within a hypodermic needle

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. AbstractHere we demonstrate the first use of a multifibre Raman probe that fits inside the bore of a hypodermic needle. A Raman probe utilising multiple collection fibres provides improved signal collection efficiency in biological samples compared with a previous 2-fibre design. Furthermore, probe performance (signal-to-noise ratios (SNRs)) compared favourably with those achieved in previous Raman microscope experiments able to distinguish benign, primary malignancies and secondary malignancies in lymph nodes.Experimental measurements presented in this paper give an indication of the sampling volume of the Raman needle probe in lymphoid tissues. Liquid tissue phantoms were used, containing scattering media encompassing a range of scattering properties similar to a variety of tissue types, including lymph node tissues. To validate the appropriateness of phantoms, the sampling depth of the probe was also measured in excised lymph node tissue. Greater than 50% of Raman photons collected were found to originate between the tip of the needle and a depth of 500 µm into the tissue.The needle probe presented here achieves comparable spectral quality to numerous studies previously demonstrating Raman disease discrimination. It is expected that this approach could achieve targeted subcutaneous tissue measurements and be viable for use for the in vivo Raman diagnostics of solid organs located within a few cm below the skin's surface.

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“…This probe accurately identifies invasive cancer cells in the brain, based on Raman signal, guiding the surgeon in real time in the operating room. A related development is the incorporation of a fibre-optic Raman probe in a hypodermic needle, in order to achieve subcutaneous tissue measurements for in vivo diagnostics [70]. This non-invasive probe has huge potential for evaluating bone composition through the skin.…”

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