Characterisation of a fibre optic Raman probe within a hypodermic needle
We demonstrate the first use of a multifibre Raman probe that fits inside the bore of a hypodermic needle. A Raman probe containing multiple collection fibres provides improved signal collection efficiency in biological samples compared with a previous two-fibre design. Furthermore, probe performance (signal-to-noise ratios) compared favourably with the performance achieved in previous Raman microscope experiments able to distinguish between benign lymph nodes, primary malignancies in lymph nodes and secondary malignancies in lymph nodes. The experimental measurements presented here give an indication of the sampling volume of the Raman needle probe in lymphoid tissues. Liquid tissue phantoms were used that contained scattering medium encompassing a range of scattering properties similar to those of a variety of tissue types, including lymph node tissues. To validate the appropriateness of the phantoms, the sampling depth of the probe was also measured in excised lymph node tissue. More than 50 % of Raman photons collected were found to originate from between the tip of the needle and a depth of 500 μm into the tissue. The needle probe presented here achieves spectral quality comparable to that in 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 centimetres below the skin’s surface.
KeywordsNon-invasive Diagnostics Needle Raman spectroscopy Lymph nodes
The authors thank Martha Vardaki for India ink characterisation and Gloucester Hospitals NHS Foundation Trust for providing the excised human lymph node tissue. This work was funded by a UK National Institute for Health Research Invention for Innovation (i4i) grant, number II_LA_1111_20007.
Conflict of interest
The authors declare that they have no conflict of interest.
- 16.Matthäus C, Dochow S, Bergner G, Lattermann A, Romeike BFM, Marple ET, Krafft C, Dietzek B, Brehm BR, Popp J (2012) In vivo characterization of atherosclerotic plaque depositions by Raman-probe spectroscopy and in vitro coherent anti-stokes Raman scattering microscopic imaging on a rabbit model. Anal Chem 84:7845–7851CrossRefGoogle Scholar
- 23.Shim M, Song LMWK, Marcon NE, Wilson BC (2000) In vivo near-infrared Raman spectroscopy: demonstration of feasibility during clinical gastrointestinal endoscopy. Photochem Photobiol 72(1):146–150Google Scholar
- 31.The Engineering ToolBox. Smaller circles in larger circles. http://www.engineeringtoolbox.com/smaller-circles-in-larger-circle-d_1849.html. Accessed 9 Dec 2014
- 33.Iping Petterson IE, Ariese F (2012) Time-resolved Raman spectroscopy for non-invasive detection through non-transparent materials. Spectrosc Eur 24(1):19–21Google Scholar
- 37.Spinelli L, Botwicz M, Zolek N, Kacprzak M, Milej D, Liebert A, Weigel U, Durduran T, Foschum F, Kienle A, Baribeau F, Leclair S, Bouchard J-P, Noiseux I, Gallant P, Mermut O, Pifferi A, Torricelli A, Cubeddu R, Ho H-C, Mazurenka M, Wabnitz H, Klauenberg K, Bodnar O, Elster C, Bénazech-Lavoué M, Bérubé-Lauzière Y, Lesage F, Di Ninni P, Martelli F, Zaccanti G (2012) Inter-laboratory comparison of optical properties performed on intralipid and India ink. In: Biomedical optics and 3-D imaging, OSA technical digest. Optical Society of America, Washington, paper BW1A.6Google Scholar