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- Ericson, Marica B, 1974, et al.
(författare)
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Bispectral fluorescence imaging combined with texture analysis and linear discrimination for correlation with histopathologic extent of basal cell carcinoma
- 2005
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668 .- 1560-2281. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescence imaging has been shown to be a potential complement to visual inspection for demarcation of basal cell carcinoma (BCC), which is the most common type of skin cancer. Earlier studies have shown promising results when combining autofluorescence with protoporphyrin IX (Pp IX) fluorescence, induced by application of delta-5-aminolaevulinic acid (ALA). In this work, we have tried to further improve the ability of this technique to discriminate between areas of tumor and normal skin by implementing texture analysis and Fisher linear discrimination (FLD) on bispectral fluorescence data of BCCs located on the face. Classification maps of the lesions have been obtained from histopathologic mapping of the excised tumors. The contrast feature obtained from co-occurrence matrices was found to provide useful information, particularly for the ALA-induced Pp IX fluorescence data. Moreover, the neighborhood average features of both autofluorescence and Pp IX fluorescence were preferentially included in the analysis. The algorithm was trained by using a training set of images with good agreement with histopathology, which improved the discriminability of the validation set. In addition, cross validation of the training set showed good discriminability. Our results imply that FLD and texture analysis are preferential for correlation between bispectral fluorescence images and the histopathologic extension of the tumors.
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- Ericson, Marica, 1974, et al.
(författare)
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Photodynamic therapy of actinic keratosis at varying fluence rates : Assessment of photobleaching, pain and primary clinical outcome
- 2004
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 151, s. 1204-1212
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although photodynamic therapy (PDT) is becoming an important treatment method for skin lesions such as actinic keratosis (AK) and superficial basal cell carcinoma, there are still discussions about which fluence rate and light dose are preferable. Recent studies in rodents have shown that a low fluence rate is preferable due to depletion of oxygen at high fluence rates. However, these results have not yet been verified in humans. Objectives: The objective was to investigate the impact of fluence rate and spectral range on primary treatment outcome and bleaching rate in AK using aminolaevulinic acid PDT. In addition, the pain experienced by the patients has been monitored during treatment. Patients/methods Thirty-seven patients (mean age 71 years) with AK located on the head, neck and upper chest were treated with PDT, randomly allocated to four groups: two groups with narrow filter (580-650 nm) and fluence rates of 30 or 45 mW cm-2, and two groups with broad filter (580-690 nm) and fluence rates of 50 or 75 mW cm-2. The total cumulative light dose was 100 J cm-2 in all treatments. Photobleaching was monitored by fluorescence imaging, and pain experienced by the patients was registered by using a visual analogue scale graded from 0 (no pain) to 10 (unbearable pain). The primary treatment outcome was evaluated at a follow-up visit after 7 weeks. Results: Our data showed a significant correlation between fluence rate and initial treatment outcome, where lower fluence rate resulted in favourable treatment response. Moreover, the photo-bleaching dose (1/e) was found to be related to fluence rate, ranging from 4.5 ± 1.0 J cm -2 at 30 mW cm-2, to 7.3 ± 0.7 J cm-2 at 75 mW cm-2, indicating higher oxygen levels in tissue at lower fluence rates. After a cumulative light dose of 40 J cm-2 no further photobleaching took place, implying that higher doses are excessive. No significant difference in pain experienced by the patients during PDT was observed in varying the fluence rate from 30 to 75 mW cm-2. However, the pain was found to be most intense up to a cumulative light dose of 20 J cm-2. Conclusions: Our results imply that the photobleaching rate and primary treatment outcome are dependent on fluence rate, and that a low fluence rate (30 mW cm-2) seems preferable when performing PDT of AK using noncoherent light sources.
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- Hörfelt, Camilla, 1970, et al.
(författare)
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Single Low-dose Red Light is as Efficacious as Methyl-aminolevulinate-Photodynamic Therapy for Treatment of Acne: Clinical Assessment and Fluorescence Monitoring
- 2009
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555. ; 89:4, s. 372-378
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Tidskriftsartikel (refereegranskat)abstract
- This controlled study investigated single low-dose red light photodynamic therapy and methyl-aminolevulinate (MAL) for treatment of moderate to severe facial acne in 19 patients. The right cheek was treated with MAL (160 mg/g) for 3 h prior to illumination. The left cheek received red light only. Both cheeks were illuminated with narrow-band red light (635 nm) at a light dose of 15 J/cm(2). The global severity of acne was assessed at baseline and at follow-up, 10 and 20 weeks after treatment. Fluorescence images, clinical photographs and skin surface biopsies were obtained. Both MAL-photodynamic therapy and control areas showed a significant decrease in acne score at follow-up; no significant difference was found compared with control. MAL-photodynamic therapy was associated with adverse effects such as erythema and stinging. Fluorescence images revealed poor selectivity of MAL-induced fluorescence to the acne lesions, suggesting a general photoablating mechanism rather than selective destruction of sebaceous glands. No significant reduction in Propionibacterium acnes or sebum excretion was found.
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- Nandi, Saikat, et al.
(författare)
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Generation of entanglement using a short-wavelength seeded free-electron laser
- 2024
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Ingår i: SCIENCE ADVANCES. - 2375-2548. ; 10:16
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Tidskriftsartikel (refereegranskat)abstract
- Quantum entanglement between the degrees of freedom encountered in the classical world is challenging to observe due to the surrounding environment. To elucidate this issue, we investigate the entanglement generated over ultrafast timescales in a bipartite quantum system comprising two massive particles: a free-moving photoelectron, which expands to a mesoscopic length scale, and a light-dressed atomic ion, which represents a hybrid state of light and matter. Although the photoelectron spectra are measured classically, the entanglement allows us to reveal information about the dressed-state dynamics of the ion and the femtosecond extreme ultraviolet pulses delivered by a seeded free-electron laser. The observed generation of entanglement is interpreted using the time-dependent von Neumann entropy. Our results unveil the potential for using short-wavelength coherent light pulses from free-electron lasers to generate entangled photoelectron and ion systems for studying spooky action at a distance.
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- Sandberg, Carin, 1969, et al.
(författare)
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Important factors for pain during photodynamic therapy for actinic keratosis
- 2006
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Ingår i: Acta dermato-venereologica. - : Medical Journals Sweden AB. - 1651-2057 .- 0001-5555. ; 86:5, s. 404-8
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Tidskriftsartikel (refereegranskat)abstract
- Photodynamic therapy (PDT) is an efficient treatment for actinic keratosis. A common problem, however, is pain. The aim of this study was to investigate pain during PDT for actinic keratosis. The possibility of using capsaicin cream for pain relief was also assessed. Pain was investigated during aminolaevulinic acid PDT in 91 patients. Size, redness, scaling and induration of the lesions were recorded. Maximum pain during treatment was registered, using a visual analogue scale (0-10). The pain-reducing efficacy of capsaicin was tested in a pilot study in six patients (10 lesions). These patients were pre-treated with capsaicin cream for one week before commencing PDT. Pain was found to be normally distributed around a mean value of visual analogue scale 4.6. Larger lesions gave more pain (p=0.001). The redness of the actinic lesions was found to be related to PDT-induced pain (p=0.01), the reduction of actinic area (p=0.007), and the cure rate (p=0.01). The redder the actinic area, the better the treatment outcome and the more pain experienced. Patients with the largest reduction in the actinic area experienced more pain (p=0.053). The most important factors for presence of pain seem to be the size and the redness of the lesion. No significant pain relief was experienced after pre-treatment with capsaicin.
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- Stenquist, Bo, 1937, et al.
(författare)
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Bispectral fluorescence imaging of aggressive basal cell carcinoma combined with histopathological mapping: a preliminary study indicating a possible adjunct to Mohs micrographic surgery
- 2006
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Ingår i: Br J Dermatol. - : Oxford University Press (OUP). - 0007-0963. ; 154:2, s. 305-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Fluorescence imaging is an attractive diagnostic technique for skin tumour demarcation with potential to move to clinical use. Bispectral fluorescence imaging combines skin autofluorescence with delta-aminolaevulinic acid-induced fluorescence. To evaluate the technique, fluorescence data must be compared with the histopathological extent of the tumour, which is the purpose of the current study. OBJECTIVES: To investigate the agreement between bispectral fluorescence images and the histopathological tumour boundary of ill-defined basal cell carcinomas (BCCs). After fluorescence imaging the tumours were removed using Mohs micrographic surgery (MMS) to obtain histopathological maps of the tumour boundaries. METHODS: Twelve patients with aggressive BCC of mean diameter 16 mm (range 5-32) in the face were included in the study. The patients were subjected to bispectral fluorescence imaging within the 2 months prior to MMS. The fluorescence images and histopathological maps were aligned using image warping. RESULTS: Five patients (42%) showed good agreement with the histopathological mapping and the remaining seven patients (58%) showed partial agreement. Bispectral investigation combining autofluorescence with protoporphyrin IX (PpIX) fluorescence generally yielded better agreement with the histopathological boundaries of the tumours compared with using only the PpIX fluorescence. CONCLUSIONS: In this preliminary study the fluorescence has been compared with the histopathological tumour boundaries. The result implies that the technique can be applied as a useful tool for indicating tumour boundary of aggressive BCCs. Further refinement is needed to be able to indicate the exact tumour border.
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