| 1. |
- Andersson-Engels, Stefan, et al.
(författare)
-
Preliminary evaluation of two fluorescence imaging methods for the detection and the delineation of basal cell carcinomas of the skin
- 2000
-
Ingår i: Lasers in Surgery and Medicine. - 0196-8092. ; 26:1, s. 76-82
-
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.
|
|
| 2. |
- Berg, Mats, et al.
(författare)
-
Flashlamp pulsed dye laser (FPDL) did not cure papulopustular rosacea
- 2004
-
Ingår i: Lasers in Surgery and Medicine. - : John Wiley & Sons. - 0196-8092 .- 1096-9101. ; 34:3, s. 266-268
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 3. |
- Bjerring, P, et al.
(författare)
-
Facial photo rejuvenation using two different intense pulsed light (IPL) wavelength bands
- 2004
-
Ingår i: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 34:2, s. 120-126
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 4. |
- Christiansen, Kaare, et al.
(författare)
-
5-ALA for photodynamic photorejuvenation - Optimization of treatment regime based on normal-skin fluorescence measurements
- 2007
-
Ingår i: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 39:4, s. 302-310
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 5. |
- Dahlstrand, Ulf, et al.
(författare)
-
Spectral Signatures in the Different Layers of the Human Eyelid by Photoacoustic Imaging
- 2019
-
Ingår i: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101.
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 6. |
- Eker, Charlotta, et al.
(författare)
-
Multivariate analysis of laryngeal fluorescence spectra recorded in vivo
- 2001
-
Ingår i: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 28:3, s. 259-266
-
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.
|
|
| 7. |
- Grönqvist, Anders, et al.
(författare)
-
Bactericidal effect of pulsed 1,064 nm Nd: YAG laser light on Staphylococcus epidermidis is of photothermal origin : an In Vitro Study
- 2000
-
Ingår i: Lasers in Surgery and Medicine. - : John Wiley & Sons. - 0196-8092. ; 27:4, s. 336-340
-
Tidskriftsartikel (refereegranskat)abstract
- Background and Objective: The aim was to investigate the bactericidal effect of the 1,064 nm Nd:YAG laser on Staphylococcus epidermidis.Material and Methods: S. epidermidis was inoculated on agar plates and then exposed to pulsed laser light in three different modes: with an uninterrupted train of pulses, or with two different repeated cycles of fractionated trains of pulses. The agar temperature was measured directly after uninterrupted radiation.Results: A bacterial growth inhibition area of 0.3 cm2 and maximum temperature of approximately 80 degrees C was observed after uninterrupted radiation at 2,000 J cm-2. The corresponding figures after an exposure of 5,000 J cm-2 were 0.9 cm2 and 100 degrees C, respectively. No bacterial inhibition was observed after exposure to repeated cycles of 20 seconds of radiation followed by 60 seconds of rest.Conclusion: The antimicrobial effect of the 1,064 nm Nd:YAG laser light is caused by a photothermal rather than a photochemical effect.
|
|
| 8. |
- Haj-Hosseini, Neda, et al.
(författare)
-
Optical Touch Pointer for Fluorescence Guided Glioblastoma Resection Using 5-Aminolevulinic Acid
- 2010
-
Ingår i: Lasers in Surgery and Medicine. - : Wiley. - 0196-8092 .- 1096-9101. ; 42:1, s. 9-14
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 9. |
- Ivarsson, K, et al.
(författare)
-
Feedback interstitial diode laser (805 nm) thermotherapy system: Ex vivo evaluation and mathematical modeling with one and four-fibers
- 1998
-
Ingår i: Lasers in Surgery and Medicine. - 0196-8092. ; 22:2, s. 86-96
-
Tidskriftsartikel (refereegranskat)abstract
- Background and Objective: In this study a newly developed microprocessor controlled power regulation and thermometry system integrated with a diode laser (805 nm wavelength) was evaluated with respect to temperature distribution, effectiveness of regulation, and ability to predict temperature distributions by computer simulation. Study Design/Materials and Methods: Experiments were performed in ground bovine muscle using either a single laser fiber or four-fibers. The target temperature at one (feedback) thermistor, placed 5 mm from one of the laser fibers, was set to 50 degrees C and was maintained by means of stepwise power regulation. The temperature distribution was monitored using multiple thermistor probes. A numerical model based on the bioheat equation was used to calculate the temperature distributions. Results: Temperature regulation was excellent with a tendency towards better regulation in the four-fiber than in the single-fiber experiments. Agreement between calculated and measured temperatures was good. The coagulated (>55 degrees C) and hyperthermic (>45 degrees C) volumes were 6 and 10-11 times larger, respectively, with four-fibers than with a single fiber. Conclusion: It is concluded that the stepwise power regulation system was efficient in maintaining a stable target temperature. The results indicate that the system can produce lesion volumes adequate for treating a relatively large tumor in a single session and that computer simulation may be useful for predicting temperature distribution. (C) 1998 Wiley-Liss, Inc.
|
|
| 10. |
|
|
