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The number of biomedical applications of Raman spectroscopy for tissue characterization is growing rapidly [e.g. 1, 2]. Many of these studies, however, focus on an in vitro application because remote fiber based in vivo acquisition of tissue spectra has been hampered by large fiber material Raman signals interfering with the small tissue Raman signals. Recently we showed that tissue characterization of atherosclerotic artery samples with dedicated optical fiber probes provided good quality Raman spectra [3]. Here we present in vivo results obtained with a Raman system fitted with these optical fiber probes during laparoscopy.

For effective treatment of infection, it is critical to know the identity and antibiotic susceptibility profile of the causative micro-organism(s). Without rapid laboratory results that provide this information, the clinician is faced with the difficult task of prescribing appropriate antibiotics which target the micro-organisms and importantly, to which the micro-organisms are not already resistant. Ineffective antibiotics not only result in further deterioration of the patient’s condition, but can also contribute to the emerging problem of drug resistant micro-organisms. The current microbiological diagnostic methods involve initial culturing of the micro-organism for approximately 16 hours to obtain a mass of 106 to 108 cells. The biomass is then used for biochemical assays and antibiotic susceptibility testing. These routine methods require 2–3 days before a result is known. In life threatening situations, this time delay cannot be afforded. Recent methods such as DNA amplification routines are attractive since little sample material is required and test results can be obtained in 1 day. Despite their high sensitivity, these techniques still experience technical hurdles such as the problem of cross-contamination [1]. Moreover, they are costly and involve highly trained personnel. Thus there is a need for novel methods which can rapidly (within hours to 1 day of receipt of samples) provide the clinician with the identity and antibiotic susceptibility profile of micro-organisms responsible for infection.

Raman spectroscopy provides detailed information about the molecular composition and structure of a sample. It is a non-destructive technique, which makes it highly suitable for in vivo studies of skin. A field that has received considerable attention, from both medical and cosmetic point of view, is skin hydration in relation to skin moisturizers [1–3]. The skin itself produces a mixture of moisturizing substances in the stratum corneum (SC). This mixture is denoted as natural moisturizing factor or NMF. We have demonstrated earlier that variations of the NMF concentration in skin can be detected in vivo by confocal Raman spectroscopy [4]. A popular humectant in skin care products is lactate. Skin lactate is secreted by sweat glands and it may play an important physiological role in the desquamation process of SC [5]. However, data on the penetration of lactate into and through the SC is absent. Here we present spatially resolved in vivo Raman spectra of the fingertip that demonstrate large differences in the lactate concentrations, between the skin surface and ca. 30 μm below the surface.

NIR-multichannel Raman microspectroscopy was used to obtain spectra of rat and human liver. Raman spectra of rat liver in situ were obtained by means of a simple Raman fiber optic probe.

The structure and chemical composition of atherosclerotic plaques appear to determine whether a plaque will rupture, resulting in an acceleration of clinical symptoms. Previous studies showed that Raman spectroscopy techniques can determine the chemical composition of coronary artery wall.1 The calculated relative weights of the major lipid classes and calcium deposits in homogenised human coronary artery wall agreed with those determined by standard lipid assays (± 3%) and calcium salts assays (±5%).1 In addition, we have shown that Raman spectroscopy techniques can be applied on intact atherosclerotic plaques. Information about the depth of structures inside the vascular wall, such as calcifications and cholesterol deposits, is needed to integrate this quantitative compositional information with information about the localisation of these structures.

Raman spectroscopy is a new and powerful tool for biomedical research [1]. With the recent development of CCD cameras that are sufficiently sensitive in the NIR region, rapid acquisition of Raman spectra with low interference from tissue fluorescence has become possible. Raman spectroscopy, which provides histochemical information, offers the potential of an early and objective in vivo diagnosis of a large class of diseases, because structural and clinical disease symptoms are preceded by changes in tissue molecular composition.

Due to chronic duodeno-gastro-esophageal reflux, the epithelial lining of the esophagus can undergo a change to a more intestinal like type of epithelium. This condition, referred to as Barrett’s esophagus, markedly increases the risk of developing esophageal adenocarcinoma [1]. This type of cancer is rapidly increasing in western society and shows a very high mortality, primarily due to late detection. Early detection of malignancy can significantly increase survival rates. Most detection methods depend on histological examination from endoscopically collected biopsies. However, there are no endoscopically clearly observable differences between healthy tissue, metaplasia and severe displasia. Therefore it is necessary to randomly collect biopsies, with a significant risk of missing malignant degenerations.