Raman spectroscopy of bladder tissue in the presence of 5-aminolevulinic acid

Dept. of Medical Technology and Clinical Physics, University Medical Centre, Utrecht, The Netherlands.
Journal of photochemistry and photobiology. B, Biology (Impact Factor: 2.96). 04/2009; 95(3):170-6. DOI: 10.1016/j.jphotobiol.2009.03.002
Source: PubMed


Raman spectroscopy has the ability to provide differential diagnosis of different cancers with high sensitivity and specificity. A major limitation in its clinical application is the weak nature of Raman signal, which inhibits scanning large surface areas of tissues. In bladder cancer diagnosis, fluorescence-guided endoscopy with 5-aminolevulinic acid (5-ALA) has gained interest as a technique that can provide such spatial differentiation, thus improving early detection and more complete removal of superficial tumors. However, several studies have demonstrated the poor specificity of this modality. Combining fluorescence with Raman spectroscopy could improve its diagnostic capability. However, little is known about the effect of agents such as 5-ALA on Raman spectra of tissue. In this paper, we present measuring Raman spectroscopy from benign and malignant bladder tissues in the presence of 5-ALA and attempt to evaluate the potential to discriminate between different pathologies.

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    • "Presently, white light cystoscopy, which is most often used to diagnose bladder cancer, has sensitivities and specificities between 62 – 84% and 43 – 98%, respectively [7] , whereas Raman-based cystoscopy has shown a sensitivity of 85% and specificity of 79% within the first in vivo study [8] , and sensitivity and specificity of 85.7% and 100% using a confocal fiber-optic probe ex vivo [9] . Fluorescence cystoscopy using 5-aminolevulinic acid (5-ALA) or its hexyl ester, hexaminolevulinate (HAL), has previously been shown to achieve sensitivities and specificities of 76 – 97% and 43 – 79% respectively [10] ; when fluorescence and Raman spectroscopy modalities are combined, 100% sensitivity and specificity has been demonstrated [11] . Urine cytology has the advantage of being entirely non-invasive but its low sensitivity, particularly for low-grade tumors, which represent the bulk of cases, has meant that it is generally not used as a primary diagnostic tool. "
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    ABSTRACT: Biomolecular changes associated with cancer progression can be identified using Raman spectroscopy, allowing for this technique to be utilized as a non-invasive tool for the diagnosis of bladder cancer. Applications of Raman spectroscopy for diagnostics in real-time have consistently produced higher sensitivities and specificities than current clinical methods. This technique can be applied in vivo during bladder visualization (cystoscopic) procedures as an “optical biopsy” or in vitro to cells obtained from urine cytology specimens. This review follows the evolution of studies in this field from the first in vitro experiment to the most recent in vivo application, identifies how diagnostic algorithms are developed, and provides molecular information associated with the etiology of the biochemical continuum of disease progression. Future prospects for the application of Raman spectroscopy in bladder cancer diagnostics are also discussed.
    Full-text · Article · May 2014 · Photonics and Lasers in Medicine
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    • "Raman spectroscopy is an optical technique that has been proposed as a discriminating/diagnostic tool in the life sciences [9] [10] [11] [12] [13] [14]. This technique is based upon the inelastic scattering interactions between light and matter. "
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    ABSTRACT: New developments in optical diagnostics have a potential for less invasive and improved detection of bladder cancer. To provide an overview of the technology and diagnostic yield of recently developed optical diagnostics for bladder cancer and to outline their potential future applications. A PubMed literature search was performed, and papers on Raman spectroscopy (RS), optical coherence tomography (OCT), photodynamic diagnosis (PDD) and narrow-band imaging (NBI) regarding bladder cancer were reviewed. Technology, clinical evidence, and future applications of the techniques are discussed. With RS, the molecular components of tissue can be measured objectively in qualitative and quantitative ways. The first studies demonstrating human in vivo applicability are still awaited. OCT produces high-resolution, cross-sectional images of tissue, comparable with histopathology, and provides information about depth of tumour growth. The first in vivo studies of OCT demonstrated promising diagnostic accuracy. RS and OCT are not suitable for scanning the entire bladder. PDD is a technique using fluorescence to indicate pathologic tissue. Several studies have shown that PDD increases the detection rate of bladder tumours and improves resection, resulting in fewer early recurrences. The relatively low specificity of PDD remains a problem. NBI enhances contrast of mucosal surface and microvascular structures. The NBI technique has clear advantages over PDD, and the two studies published to date have shown promising preliminary results. PDD and NBI do not contribute to histopathologic diagnosis. RS and OCT aim at providing a real-time, minimally invasive, objective prediction of histopathologic diagnosis, while PDD and NBI aim at improving visualisation of bladder tumours. For RS, OCT, and NBI, more research has to be conducted before these techniques can be implemented in the management of bladder cancer. All techniques might be of value in specific clinical scenarios.
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