Selective detection of fluorophore layers in turbid media: the role of fiber-optic probe design

Pfefer, T. Joshua; Matchette, L. Stephanie; Ross, Amanda M.; Ediger, M. N.

doi:10.1364/ol.28.000120

Cited by 65 publications

(47 citation statements)

References 9 publications

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“…The non-overlapping probe is maximally sensitive to the fluorescence originating from sub-surface tissue layers (exact depth within the tissue depends on multiple factors, including tissue optical properties and the illumination-collection fiber separation), while the overlapping probe is maximally sensitive to the fluorescence originating from the tissue surface directly beneath the illumination-collection area. These results were experimentally validated using synthetic twolayer tissue phantoms (1). Although there are distinct differences in the depth-dependence of the fluorescence detected with the overlapping and non-overlapping probe geometries, no studies have been carried out to evaluate their effect on the fluorescence-based diagnosis of epithelial pre-cancers in vivo.…”

Section: Introductionmentioning

confidence: 95%

“…In invasive cancer, these cells ultimately break through the basement membrane and invade into the stroma. Approximately one million cases of non-melanoma cancers of the stratified squamous epithelia are identified each year (1). Early detection and treatment of these cancers is important to minimize morbidity and mortality.…”

Section: Introductionmentioning

confidence: 99%

“…The geometry of the illumination and collection system is an important component of tissue fluorescence spectroscopy and fiber-optic probes are most commonly used for this purpose (1,(9)(10)(11)(12)(13)(14)(15). The geometry of the illumination and collection fibers on the tissue surface, the optical properties (absorption and scattering) and the fluorescence efficiency of the tissue through which the light propagates, define the optical sensing depth (1,13,14,16). In most currently used probe geometries, the illumination and collection fiber geometries are configured such that the illumination and collection areas on the tissue surface are either overlapping or non-overlapping (with a fixed distance between them).…”

Section: Introductionmentioning

confidence: 99%

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Investigation of fiber‐optic probe designs for optical spectroscopic diagnosis of epithelial pre‐cancers

et al. 2004

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Background and Objective-The first objective of this study was to evaluate the performance of fluorescence spectroscopy for diagnosing pre-cancers in stratified squamous epithelial tissues in vivo using two different probe geometries with (1) overlapping vs. (2) non-overlapping illumination and collection areas on the tissue surface. Probe (1) and probe (2) are preferentially sensitive to the fluorescence originating from the tissue surface and sub-surface tissue depths, respectively. The second objective was to design a novel, angled illumination fiber-optic probe to maximally exploit the depth-dependent fluorescence properties of epithelial tissues.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of fiber‐optic probe designs for optical spectroscopic diagnosis of epithelial pre‐cancers

et al. 2004

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“…Oblique-incidence illumination and/or collection geometries using angled fibers have been used to target superficial tissue regions [25][26][27]. Variations in fiber size, illumination-collection fiber separation, and probe-sample spacing have been shown to influence sensitivity to different fluorophore layers in turbid media [28]. Differential pathlength spectroscopy has been demonstrated as a technique for preferential detection of photons scattered from shallow depths [29].…”

Section: Introductionmentioning

confidence: 99%

Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe

et al. 2008

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Optical spectroscopy can provide useful diagnostic information about the morphological and biochemical changes related to the progression of precancer in epithelial tissue. As precancerous lesions develop, the optical properties of both the superficial epithelium and underlying stroma are altered; measuring spectral data as a function of depth has the potential to improve diagnostic performance. We describe a clinical spectroscopy system with a depth-sensitive, ball lens coupled fiber-optic probe for noninvasive in vivo measurement of oral autofluorescence and diffuse reflectance spectra. We report results of spectroscopic measurements from oral sites in normal volunteers and in patients with neoplastic lesions of the oral mucosa; results indicate that the addition of depth selectivity can enhance the detection of optical changes associated with precancer.

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“…3,4 Single-fiber probe configurations, in which the same fiber is used for illumination and collection, are sensitive to light scattering from superficial tissue regions. 5,6 However, the use of single-fiber probes for optical measurements is limited by lower signalto-noise ratios that are due to autofluorescence generated by impurities in the fiber core and by specular reflection from fiber surfaces.…”

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confidence: 99%

Ball lens coupled fiber-optic probe for depth-resolved spectroscopy of epithelial tissue

et al. 2005

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A ball lens coupled fiber-optic probe design is described for depth-resolved measurements of the fluorescence and reflectance properties of epithelial tissue. A reflectance target, fluorescence targets, and a two-layer tissue phantom consisting of fluorescent microspheres suspended in collagen are used to characterize the performance of the probe. Localization of the signal to within 300 µm of the probe tip is observed by use of reflectance and fluorescence targets in air. Differential enhancement of the fluorescence signal from the top layer of the two-layer tissue phantom is observed. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptOptical spectroscopy is emerging as an effective diagnostic technique for noninvasive detection of cancers and precancers that originate in the epithelial lining of organs such as the uterine cervix, the oral cavity, the urinary bladder, and the esophagus. 1 The progression of precancer in these tissues produces morphologic and biochemical changes in the epithelium and supporting stroma. These changes include alterations in epithelial cell morphology and metabolic activity, changes in stromal protein morphology and cross-linking, and increasing stromal angiogenesis. As a result, the concentration and distribution of endogenous fluorophores such as reduced nicotinamide adenine dinucleotide, flavin adenine dinucleotide, keratin, tryptophan, and collagen cross-links, and absorbers such as hemoglobin, are altered with the progression of precancer. 2 Thus knowledge of the depth-dependent distribution of chromophores may have important diagnostic significance.Endogenous chromophores can be detected noninvasively in vivo by use of fiber-optic fluorescence and reflectance spectroscopy. Many fiber-optic probe designs collect the integrated signal from both the epithelium (which is typically of the order of 300 µm thick) and the underlying stroma. In these systems, sophisticated analysis strategies are required for deconvolution of spectroscopic data to yield quantitative concentrations of chromophores, and little information about depth-related changes is obtained. Fiber probes that can localize spectroscopic information by depth to distinguish epithelial and stromal optical signatures should improve the ability of spectroscopy to evaluate noninvasively the progression of precancerous changes.A variety of probe designs for obtaining localized or depth-resolved spectroscopic data have been reported. 3,4 Single-fiber probe configurations, in which the same fiber is used for illumination and collection, are sensitive to light scattering from superficial tissue regions. 5,6 However, the use of single-fiber probes for optical measurements is limited by lower signalto-noise ratios that are due to autofluorescence generated by impurities in the fiber core and by specular reflection from fiber surfaces. With multiple-fiber probes, many configurations are possible. Straight-fiber geometries with different source-detector separations permit some depth discrimination; ...

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Selective detection of fluorophore layers in turbid media: the role of fiber-optic probe design

Cited by 65 publications

References 9 publications

Investigation of fiber‐optic probe designs for optical spectroscopic diagnosis of epithelial pre‐cancers

Investigation of fiber‐optic probe designs for optical spectroscopic diagnosis of epithelial pre‐cancers

Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe

Ball lens coupled fiber-optic probe for depth-resolved spectroscopy of epithelial tissue

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