| 1. |
- Andersson-Engels, Stefan, et al.
(författare)
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Preliminary evaluation of two fluorescence imaging methods for the detection and the delineation of basal cell carcinomas of the skin
- 2000
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Ingår i: Lasers in Surgery and Medicine. - 0196-8092. ; 26:1, s. 76-82
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background and ObjectiveFluorescence techniques can provide powerful noninvasive means for medical diagnosis, based on the detection of either endogenous or exogenous fluorophores. The fluorescence of δ-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) has already shown promise for the diagnosis of tumors. The aim of the study was to investigate the localization of skin tumors after the topical application of ALA, by detecting the PpIX fluorescence either in the spectral or in the time domain.Study Design/Materials and MethodsTwo fluorescence imaging systems were used to identify basal cell carcinomas of the skin in humans, after topical application of 20% ALA ointment. Both systems rely on the comparison between the exogenous and the endogenous fluorescence, performed either in the spectral domain or in the time domain. The first system works by using three images acquired through different spectral filters, whereas the second one measures the spatial map of the average fluorescence lifetime of the sample.ResultsA clear demarcation of skin malignancies was successfully performed in vivo noninvasively with both fluorescence imaging systems.ConclusionThe two complementary approaches considered in the present study show promise for skin tumor detection and delineation based on specific fluorescence features. Lasers Surg. Med. 26:76–82, 2000. © 2000 Wiley-Liss, Inc.
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| 2. |
- Eker, Charlotta, et al.
(författare)
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Multivariate analysis of laryngeal fluorescence spectra recorded in vivo
- 2001
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Ingår i: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 28:3, s. 259-266
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objective: The potential of using various multivariate analysis methods for classification of fluorescence spectra acquired in vivo from laryngeal tissues in Patients was investigated. Study Design/Materials and Methods: Autofluorescence spectra were measured on 29 normal tissue sites and 25 laryngeal lesions using 337-nm excitation. Four different multivariate analysis schemes were applied. Laryngeal fluorescence spectra from patients who had been administered F-aminolevulinic acid (ALA) were obtained using 405-nm excitation and were classified using partial least squares discriminant analysis (PLS-DA). Results: For autofluorescence spectra, logistic regression based on principal component analysis (PCA) or PLS, or PLS-DA all resulted in sensitivities and specificities around 90% for lesion vs. normal. Using ALA and 405-nm excitation gave a sensitivity of 100% and a specificity of 69%. Conclusion: Multivariate analysis of fluorescence spectra could allow classification of laryngeal lesions in vivo with high sensitivity and specificity. PLS performs at least as well as PCA, and PLS-DA performs as well as logistic regression techniques on these data.
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| 3. |
- Rydell, Roland, et al.
(författare)
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Fluorescence investigations to classify malignant laryngeal lesions in vivo.
- 2008
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Ingår i: Head and Neck. - : Wiley. - 1043-3074 .- 1097-0347. ; 30:4, s. 419-426
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:: The extent of surgical resection for malignant laryngeal lesions influences voice quality. An instrument to estimate histopathologic grading of dysplasia in vivo may spare normal tissue without increasing the risk of local failure. METHODS: Laryngeal lesions (N = 39; 21 after administration of delta-aminolevulinic acid (ALA)) were investigated with laser-induced fluorescence, and the results correlated to histopathologic grading in 4 groups: non/mild dysplasia (I), moderate dysplasia (II), severe dysplasia/cancer in situ (III), and carcinoma. RESULTS: At 337-nm excitation, there were differences in the fluorescence ratio I(431)/I(390) between groups I/III and carcinoma. Following 405-nm excitation, I(500 nm) group I differed significantly from group III and cancer. The sensitivity for the fluorescence method was 89%, and the specificity was 100%. CONCLUSIONS: There are differences in the in vivo tissue fluorescence between tissue with different gradings of dysplasia and carcinoma. (c) 2007 Wiley Periodicals, Inc. Head Neck, 2008.
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