| 1. |
- Berg, Mats, et al.
(author)
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Flashlamp pulsed dye laser (FPDL) did not cure papulopustular rosacea
- 2004
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In: Lasers in Surgery and Medicine. - : John Wiley & Sons. - 0196-8092 .- 1096-9101. ; 34:3, s. 266-268
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Journal article (peer-reviewed)abstract
- BACKGROUND AND OBJECTIVES: Pharmacological treatment has a fairly good effect on the papulopustular lesions in rosacea, but not as good an effect on the erythema and telangiectases. The aim was to treat rosacea patients with both erythematotelangiectatic and papulopustular lesions with flashlamp pulsed dye laser (FPDL) until telangiectases/erythema disappeared, and to evaluate whether the treatment might also be effective on papulopustular lesions.STUDY DESIGN/MATERIALS AND METHODS: Ten patients were treated on one side of the face with FPDL. The final examination was blinded and performed on the average 10 months after the last treatment.RESULTS: Two of the patients had more lesions after treatment, three were unchanged, three had only slightly less, and two had markedly less papulopustular lesions.CONCLUSION: Our conclusion from this small sample of patients is that FPDL probably has limited value on papulopustular lesions in rosacea. This indicates that the origin of rosacea may not be only vascular.
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| 2. |
- Bjerring, P, et al.
(author)
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Facial photo rejuvenation using two different intense pulsed light (IPL) wavelength bands
- 2004
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In: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 34:2, s. 120-126
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Journal article (peer-reviewed)abstract
- Background and Objectives: Intense pulsed light (IPL) systems are increasingly used for treatment of photo damaged skin. In the present study, we investigated the clinical efficacy and safety of two different wavelength bands generated by the same IPL device. Study Design/Materials and Methods: An IPL device was equipped with either a 555-950 nm filter (VL), or a 530-750 nm filter (PR). Results: Fair, good or excellent clearance of visible telangiectasias was obtained in 81.8% of the patients (PR) and in 58.8% (VL). In the treatment of diffuse erythema, fair, good or excellent clearance was obtained in 72.7% (PR) and in 35.0% (VL). The PR filter was more efficient (P = 0.025) in reduction of diffuse erythema. The average number of treatments was 1.75 (PR) and 1.82 (VL). For the treatment of irregular pigmentation, fair, good or excellent clearance was obtained in 54.5% (PR) and in 61.9% (VL). Multiple treatments of irregular pigmentation were also evaluated. Using the VL filter more than two treatments did not induce further clinical improvement. The patients also scored their over-all satisfaction. Either fair, good or excellent results were reported by 66.7% (PR) and by 76.2% (VL). No skin atrophy, scarring or pigment disturbances were noted after the treatments. Swelling and erythema were registered by 2/3 (PR) and 1/3 (VL) of the patients. Conclusions: The two IPL wavelength bands were both found to be effective in the treatment of photo damaged facial skin. The clinical efficacy and safety of the two different treatment procedures were comparable to those reported in earlier studies, and finally treatment with these filter combinations required less than half the fluence, no active cooling and fewer treatments. Lasers Surg. (C) 2004 Wiley-Liss, Inc.
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| 3. |
- Christiansen, Kaare, et al.
(author)
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5-ALA for photodynamic photorejuvenation - Optimization of treatment regime based on normal-skin fluorescence measurements
- 2007
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In: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 39:4, s. 302-310
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Journal article (peer-reviewed)abstract
- Background and Objectives: Photodynamic therapy using 20% 5 aminolevulinic acid (5-ALA) has recently been introduced as a new tool in optical skin rejuvenation. The primary objective of this study was to optimize incubation time, the topical delivery mechanism (vehicle) and the concentration of 5-ALA by detecting the dynamic changes of normal skin after 5-ALA application. The secondary objective was to develop a treatment regime which minimizes post-treatment photosensitivity. Study Design/Materials and Methods: Skin fluorescence distribution patterns after topical application of low concentrations of 5-ALA (0.5% and 1% preparations encapsulated in liposomes), were investigated. Twenty percent 5-ALA in moisturizing cream was used as a control. Ten healthy volunteers participated, and skin fluorescence was documented by fluorescent photography. The fluorescent intensity was measured in % of maximum obtained fluorescence after 3 hours 5-ALA application. Results: Skin fluorescence intensity after topical application of 0.5% and 1% non-occluded liposome-encapsulated 5-ALA application was heterogeneous distributed and reached saturation level after approximate 2 hours. The maximal fluorescence for 0.5% and 1% 5-ALA treated areas was 4.2% (SD: 3.5%) and 2.4% (SD: 2%), respectively, and this difference was statistically significant (P = 0.036). The fluorescence decayed linearly shortly (within 15 minutes) after end of application and was back to baseline within 8 hours. In contrast, the fluorescence of areas treated more than 1 hour with 20% 5-ALA was very uniform and a linear relationship (r 2 = 0.998) to the incubation time (0-3 hours) was registered. Furthermore, fluorescence intensity (15.2-57.9%) continued to increase after the end of 5-ALA application. The maximum fluorescence reach a level of 1.6-9 times the fluorescence measured by end of the 5-ALA application and occurred 8:13 hours (SD: 0:49 hours) after the end of 20% 5-ALA application. The average skin surface fluorescence induced by the liposome-encapsulated 0.5% 5-ALA applied for longer than 2 hours, was found to be statistically equal (P = 0.47) to the average measured skin surface fluorescence (4.2%) obtained after 30 minutes exposure to 20% 5-ALA cream (4.3%). Conclusion: Changing the 5-ALA vehicle from a moisturizing cream to liposome encapsulation, the 5-ALA concentration can be lowered by a factor of 40, and still induce the same skin fluorescence and at the same time eliminates the need for occlusion. The low post-treatment fluorescence also suggests a significantly reduced risk of post-treatment phototoxicity. Lasers Surg. Med. 39:302-310, 2007.
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| 4. |
- Dahlstrand, Ulf, et al.
(author)
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Spectral Signatures in the Different Layers of the Human Eyelid by Photoacoustic Imaging
- 2019
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In: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101.
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Journal article (peer-reviewed)abstract
- BACKGROUND AND OBJECTIVES: The eyelids are susceptible to a number of skin cancers, which are challenging to excise radically without sacrificing excessive healthy tissue. Photoacoustic (PA) imaging is an emerging non-invasive biomedical imaging modality that could potentially be used for intraoperative micrographic control of the surgical margins of eyelid tumors. In this study, non-cancerous human eyelid tissue was characterized using PA as a first step in the development of this technique.STUDY DESIGN/MATERIALS AND METHODS: Twelve full-thickness samples from nine patients were analyzed ex vivo using PA imaging. Two-dimensional PA images were acquired using 59 wavelengths in the range of 680-970 nm to obtain the spectral signatures of the skin, orbicularis oculi muscle, and the tarsal plate. Three-dimensional images were obtained by scanning the tissues using a linear stepping motor. Spectral unmixing was performed to visualize the chromophore distribution.RESULTS: The resulting PA spectra could be used to differentiate between the orbicularis oculi muscle and the other two structures (P < 0.05). The signals from the skin and the tarsal plate were more similar in appearance, probably due to similarities in their molecular composition. Spectral unmixing provided a clear visualization of the overall architecture of the eyelids.CONCLUSIONS: PA imaging can be used to differentiate between the orbicularis oculi muscle and the eyelid skin and tarsal plate. The main structures of human eyelids could be visualized in three dimensions using PA imaging. This technique could potentially be used to examine eyelid tumors intraoperatively in the future. However, further studies on tumors in vivo are needed before considering such clinical use. Lasers Surg Med. © 2019 Wiley Periodicals, Inc.
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| 5. |
- Eker, Charlotta, et al.
(author)
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Multivariate analysis of laryngeal fluorescence spectra recorded in vivo
- 2001
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In: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 28:3, s. 259-266
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Journal article (peer-reviewed)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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| 6. |
- Haj-Hosseini, Neda, et al.
(author)
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Optical Touch Pointer for Fluorescence Guided Glioblastoma Resection Using 5-Aminolevulinic Acid
- 2010
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In: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 42:1, s. 9-14
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Journal article (peer-reviewed)abstract
- Background and Objective: Total tumor resection in patients with glioblastoma multiforme (GBM) is difficult to achieve due to the tumor's infiltrative way of growing and morphological similarity to the surrounding functioning brain tissue. The diagnosis is usually subjectively performed using a surgical microscope. The objective of this study was to develop and evaluate a hand-held optical touch pointer using a fluorescence spectroscopy system to quantitatively distinguish healthy from malignant brain tissue intraoperatively. Study Design/Materials and Methods: A fluorescence spectroscopy system with pulsed modulation was designed considering optimum energy delivery to the tissue, minimal photobleaching of PpIX and omission of the ambient light background in the operating room (OR). 5-Aminolevulinic acid (5-ALA) of 5 mg/kg body weight was given to the patients with a presumed GBM prior to surgery. During the surgery a laser pulse at 405 nm was delivered to the tissue. PpIX in glioblastoma tumor cells assigned with peaks at 635 and 704 nm was detected using a fiber optical probe. Results/Conclusion: By using the pulsed fluorescence spectroscopy, PpIX fluorescence is quantitatively detected in the GBM. An effective suppression of low power lamp background from the recorded spectra in addition to a significant reduction of high power surgical lights is achieved. Lasers Surg. Med. 42:9-14, 2010. (C) 2010 Wiley-Liss, Inc.
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| 7. |
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| 8. |
- Liljemalm, Rickard, et al.
(author)
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Heating during infrared neural stimulation
- 2013
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In: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 45:7, s. 469-481
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Journal article (peer-reviewed)abstract
- Background and Objective Infrared neural stimulation (INS) has recently evoked interest as an alternative to electrical stimulation. The mechanism of activation is the heating of water, which induces changes in cell membrane potential but may also trigger heat sensitive receptors. To further elucidate the mechanism, which may be dependent on cell type, a detailed description of the temperature distribution is necessary. A good control of the resulting temperature during INS is also necessary to avoid excessive heating that may damage the cells. Here we present a detailed model for the heating during INS and apply it for INS of in vitro neural networks of rat cerebral cortex neurons. Study Design/Materials and Methods A model of the heating during INS of a cell culture in a non-turbid media was prepared using multiphysics software. Experimental parameters such as initial temperature, beam distribution, pulse length, pulse duration, frequency and laser-cell distance were used. To verify the model, local temperature measurements using open pipette resistance were conducted. Furthermore, cortical neurons in culture were stimulated by a 500 mW pulsed diode laser (wavelength 1,550 nm) launched into a 200 μm multimodal optical fiber positioned 300 μm from the glass surface. The radiant exposure was 5.2 J/cm2. Results The model gave detailed information about the spatial and temporal temperature distribution in the heated volume during INS. Temperature measurements using open pipette resistance verified the model. The peak temperature experienced by the cells was 48°C. Cortical neurons were successfully stimulated using the 1,550 nm laser and single cell activation as well as neural network inhibition were observed. Conclusion The model shows the spatial and temporal temperature distribution in the heated volume and could serve as a useful tool for future studies of the heating during INS.
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| 9. |
- Ponticorvo, Adrien, et al.
(author)
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Quantitative long-term measurements of burns in a rat model using Spatial Frequency Domain Imaging (SFDI) and Laser Speckle Imaging (LSI)
- 2017
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In: Lasers in Surgery and Medicine. - : John Wiley & Sons. - 0196-8092 .- 1096-9101. ; 49:3, s. 293-304
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Journal article (peer-reviewed)abstract
- Background and OjectivesThe current standard for diagnosis of burn severity and subsequent wound healing is through clinical examination, which is highly subjective. Several new technologies are shifting focus to burn care in an attempt to help quantify not only burn depth but also the progress of healing. While accurate early assessment of partial thickness burns is critical for dictating the course of treatment, the ability to quantitatively monitor wound status over time is critical for understanding treatment efficacy. SFDI and LSI are both non‐invasive imaging modalities that have been shown to have great diagnostic value for burn severity, but have yet to be tested over the course of wound healing.MethodsIn this study, a hairless rat model (n = 6, 300–450 g) was used with a four pronged comb to create four identical partial thickness burns (superficial n = 3 and deep n = 3) that were used to monitor wound healing over a 28 days period. Weekly biopsies were taken for histological analysis to verify wound progression. Both SFDI and LSI were performed weekly to track the evolution of hemodynamic (blood flow and oxygen saturation) and structural (reduced scattering coefficient) properties for the burns.ResultsLSI showed significant changes in blood flow from baseline to 220% in superficial and 165% in deep burns by day 7. In superficial burns, blood flow returned to baseline levels by day 28, but not for deep burns where blood flow remained elevated. Smaller increases in blood flow were also observed in the surrounding tissue over the same time period. Oxygen saturation values measured with SFDI showed a progressive increase from baseline values of 66–74% in superficial burns and 72% in deep burns by day 28. Additionally, SFDI showed significant decreases in the reduced scattering coefficient shortly after the burns were created. The scattering coefficient progressively decreased in the wound area, but returned towards baseline conditions at the end of the 28 days period. Scattering changes in the surrounding tissue remained constant despite the presence of hemodynamic changes.Conclusions Here, we show that LSI and SFDI are capable of monitoring changes in hemodynamic and scattering properties in burn wounds over a 28 days period. These results highlight the potential insights that can be gained by using non‐invasive imaging technologies to study wound healing. Further development of these technologies could be revolutionary for wound monitoring and studying the efficacy of different treatments.
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| 10. |
- Richter, Johan C.O., et al.
(author)
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Fluorescence Spectroscopy Measurements in Ultrasonic Navigated Resection of Malignant Brain Tumors
- 2011
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In: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 43:1, s. 8-14
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Journal article (peer-reviewed)abstract
- Background and Objective: Glioblastoma multiforme is a highly malignant primary brain tumor. It has no border but at best a marginal zone, however, invisible to the surgeon. An optical touch pointer (OTP) enabling differentiation of healthy and tumor tissue by means of fiber-optic fluorescence spectroscopy has been developed. In combination with an ultrasonic navigation system, the OTP may be used for demarcation of resectable tumor tissue. The aim of the study was to evaluate the clinical performance of OTP during surgery of malignant brain tumors. Study Design/Materials and Methods: Nine patients were operated on with the standard surgical procedure, including white light microscopy and navigation. A total of 5 mg/kg bodyweight of 5-amino-levulin acid was orally administrated before surgery. The OTP was calibrated into the ultrasound-based navigation system and measurements were performed in tumor core and along the tumor border. The ratio between the protoporphyrin IX fluorescence at 635 nm and the autofluorescence was used for quantifications of data. Biopsies (n = 20), ultrasound images (n = 30), and visual inspection (n = 180) were compared to the fluorescence ratio. Results/Conclusion : Healthy and tumor tissue could be identified and differentiated with the OTP(P < 0.001). The fluorescence ratio in average was 0 outside the tumor and low in the gliotic edema zone around the tumor. It increased in the marginal zone and was highest in the solid tumor tissue. In the necrotic tissue, in the center of the tumor, the ratio in average was 0. The OTP can be used in combination with ultrasound-based navigation and may help to determine whether to resect otherwise not identifiable tissue. Lasers Surg. Med. 43:8-14, 2011. (C) 2011 Wiley-Liss, Inc.
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