Effects of laser excitation wavelength and optical mode on Raman spectra of human fresh colon, pancreas, and prostate tissues
Effects of laser excitation wavelength and optical mode on Raman spectra of human fresh colon, pancreas, and prostate tissues
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DOI：
10.1002/jrs.4540
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发表时间：
2014-09-01
影响因子：
2.5
通讯作者：
Allen, Heather C.
中科院分区：
文献类型：
--
作者：
Li, Ran;Verreault, Dominique;Allen, Heather C.
早期癌症检测是允许成功治疗和由此产生的积极的长期患者结果的中心和最重要的因素。最近，光学技术已被应用于这一目的，虽然每一个有固有的局限性。特别是，拉曼光谱法应用于癌组织的病理诊断受到越来越多的关注，其优点是对组织成分中的生化变化高度敏感并且可在体内应用。然而，高背景强度掩盖了生物分子的拉曼信号，阻碍了其应用。本文研究了激光激发波长（785nm和830nm）和光学模式（单模和多模）对新鲜人体组织背景强度的影响。结果表明，在相同的光模条件下，830 nm激发的拉曼光谱比785 nm激发的拉曼光谱具有更好的背景抑制效果，但拉曼信号强度反而降低，信噪比（SNR）没有提高。通过对单模和多模785nm激光的比较，发现具有较小束腰和光束传输因子的单模激光具有更好的背景抑制能力和信噪比的改善。据推测，这种背景强度的降低来自于光学模式对来自生物组织的米氏散射的影响。基于仔细选择激光激发波长和光学模式的高质量光谱将有利于拉曼测量在进一步的研究，重点是光谱解释和组织病理学相关性，最终旨在术中应用。版权所有（c）2014约翰威利父子有限公司
Early cancer detection is the central and most important factor for allowing successful treatment and resultant positive long-term patient outcomes. Recently, optical techniques have been applied to this purpose, although each has inherent limitations. In particular, Raman spectroscopy applied in the pathological diagnosis of cancerous tissues has received increasing attention, with the merit of being highly sensitive to the biochemical alterations in tissue compositions and applicable in vivo. Nevertheless, its application has been impeded by the high background intensity, which masks the Raman signal of biological molecules. In this work, the influence of laser excitation wavelength (785 vs. 830nm) and optical mode (single mode vs. multimode) on the background intensity of fresh human tissues was studied. Based on the results, laser with 830nm excitation demonstrated better background reduction than that with 785nm excitation for the same optical mode, but the Raman signal intensity was conversely reduced, and the signal-to-noise ratio (SNR) not improved. In contrast, by comparing single-mode and multimode 785nm excitations, it was shown that the single-mode laser with its smaller beam waist and beam propagation factor had better background reduction ability and an improvement of the SNRs. It is speculated that this decrease in background intensity comes from the effect of the optical mode on the Mie scattering from the biological tissue. High-quality spectra based on a careful selection of both laser excitation wavelength and optical mode will benefit Raman measurements in further research focusing on spectral interpretation and histopathological correlation ultimately aimed toward intraoperative applications. Copyright (c) 2014 John Wiley & Sons, Ltd.