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The ablative fractional coagulation zone influences skin fluorescence intensities of topically applied test molecules-An in vitro study with fluorescence microscopy and fluorescence confocal microscopy
摘要： Background: Ablative fractional laser (AFL) increases uptake of topically applied skin agents. The coagulation zone (CZ) surrounding vertically ablated channels may influence uptake of drugs. Objectives: To investigate impact of CZ thickness on skin fluorescence intensities (FI) of a hydrophilic molecule by means of fluorescence microscopy (FM) and fluorescence confocal microscopy (FCM). Second, to compare FI of hydrophilic and lipophilic test molecules by FCM. Study Design/Methods and Materials: Microchannels with CZ thicknesses of 0, 20, and 80 μm were generated by microneedles or AFL (10,600 nm). Channels were 700 μm deep and number of channels kept constant per skin area. After 4 hours of incubation, FI induced by sodium fluorescein (NAF, hydrophilic, logarithmic partition-coefficient (logP) = -1.52, MW = 376.26) were quantified in both CZ and surrounding skin by FM (0–1,500 μm) and FCM (0–90 μm). FI of NAF and carboxyfluorescein (CAF, lipophilic, logP = 2.9, MW = 376.32) were compared by FCM. Results: By FM, NAF-induced FI were higher in CZ than in surrounding skin (P ≤ 0.001). Highest NAF-FI were induced in skin pretreated with a thin CZ (CZ–20 μm), assessed by both FM and FCM and in particular, FI were higher than in skin pretreated with no CZ (CZ–0 μm) (FM P ≤ 0.041, FCM P < 0.012). Skin FI remained constant to a depth of 500 μm, which corresponded to approximate depth of microchannels (CZ–0 μm, CZ–20 μm, CZ–80 μm: 0–500 μm P ≥ 0.107). In accordance with FM data, FCM showed higher FI within CZ than in surrounding skin, but gradually decreased to zero at a depth of 90 μm. NAF-FI were higher than CAF-FI (P ≤ 0.036), and highest CAF-FI were induced by CZ–0 μm and CZ–20 μm compared to CZ–80 μm (P ≤ 0.009). Conclusions: The influence of the CZ thickness on skin FI differs between small hydrophilic and lipophilic test molecules. Results may have clinical relevance for laser-assisted drug delivery.
关键词： sodium fluorescein,reflectance,carboxyfluorescein,dermatology,drug delivery,skin imaging
更新于2025-09-23 15:23:52
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An Update on Topical Photodynamic Therapy for Clinical Dermatologists
摘要： Photodynamic therapy (PDT) involves the application of a topical photosensitizer, irradiation with light, and oxygen to produce cytotoxic reactive oxygen species that selectively destroy damaged cells while leaving normal skin intact. Topical PDT is a commonly used treatment for non-melanoma skin cancers (NMSCs) due to its excellent clearance rate and cosmetic outcomes. However, PDT is emerging as an off-label treatment modality for many dermatological conditions. A literature review using MEDLINE was performed to identify randomized controlled trials conducted for currently approved and off-label clinical indications and photosensitizers for PDT between 2012 and 2018. The photosensitizer indole-3 acetic acid reduces the incubation time (<30 minutes), avoids the need for photoprotection after irradiation, and inflicts minimal pain. Cyclic PDT in individuals with evidence of field cancerization delays the mean time of actinic keratosis appearance and reduces the total number of new actinic keratoses. Substantial evidence exists outlining the utility of PDT in photorejuvenation due to its ability to improve skin texture, wrinkles, and firmness. The addition of microdermabrasion, microneedling, curettage, or various lasers improves clinical efficacy and cosmetic outcomes. PDT applications are expanding rapidly. Clinicians must stay up to date regarding the efficacy and safety of PDT applications.
关键词： non-melanoma skin cancer,daylight PDT,dermatology,PDT,actinic keratosis,photodynamic therapy
更新于2025-09-23 15:22:29
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Regression Analysis of Protoporphyrin IX Measurements Obtained During Dermatological Photodynamic Therapy
摘要： Photodynamic therapy (PDT) is a light activated drug therapy that can be used to treat a number of dermatological cancers and precancers. Improvement of efficacy is required to widen its application. Clinical protoporphyrin IX (PpIX) fluorescence data were obtained using a pre-validated, non-invasive imaging system during routine methyl aminolevulinate (MAL)-PDT treatment of 172 patients with licensed dermatological indications (37.2% actinic keratosis, 27.3% superficial basal cell carcinoma and 35.5% Bowen’s disease). Linear and logistic regressions were employed to model any relationships between variables that may have affected PpIX accumulation and/or PpIX photobleaching during irradiation and thus clinical outcome at three months. Patient age was found to be associated with lower PpIX accumulation/photobleaching, however only a reduction in PpIX photobleaching appeared to consistently adversely affect treatment efficacy. Clinical clearance was reduced in lesions located on the limbs, hands and feet with lower PpIX accumulation and subsequent photobleaching adversely affecting the outcome achieved. If air cooling pain relief was employed during light irradiation, PpIX photobleaching was lower and this resulted in an approximate three-fold reduction in the likelihood of achieving clinical clearance. PpIX photobleaching during the first treatment was concluded to be an excellent predictor of clinical outcome across all lesion types.
关键词： photobleaching,aminolevulinic acid (ALA; Ameluz),dermatology,protoporphyrin IX (PpIX),imaging,methyl aminolevulinate (MAL; Metvix),photodynamic therapy (PDT),fluorescence,non-melanoma skin cancer (NMSC)
更新于2025-09-23 15:22:29
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Improving clinical diagnosis of early-stage cutaneous melanoma based on Raman spectroscopy
摘要： BACKGROUND: Clinical diagnosis of early melanoma (Breslow thickness less than 0.8 mm) is crucial to disease-free survival. However, it is subjective and can be exceedingly difficult, leading to missed melanomas, or unnecessary excision of benign pigmented skin lesions. An objective technique is needed to improve the diagnosis of early melanoma. METHODS: We have developed a method to improve diagnosis of (thin) melanoma, based on Raman spectroscopy. In an ex vivo study in a tertiary referral (pigmented lesions) centre, high-wavenumber Raman spectra were collected from 174 freshly excised melanocytic lesions suspicious for melanoma. Measurements were performed on multiple locations within the lesions. A diagnostic model was developed and validated on an independent data set of 96 lesions. RESULTS: Approximately 60% of the melanomas included in this study were melanomas in situ. The invasive melanomas had an average Breslow thickness of 0.89 mm. The diagnostic model correctly classified all melanomas (including in situ) with a specificity of 43.8%, and showed a potential improvement of the number needed to treat from 6.0 to 2.7, at a sensitivity of 100%. CONCLUSION: This work signifies an important step towards accurate and objective clinical diagnosis of melanoma and in particular melanoma with Breslow thickness <0.8 mm.
关键词： dermatology,Raman spectroscopy,early diagnosis,Breslow thickness,melanoma
更新于2025-09-23 15:21:21
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Accurate depth estimation of skin surface using a light-field camera toward dynamic haptic palpation
摘要： Background: Haptic skin palpation with three-dimensional skin surface reconstruction from in vivo skin images in order to acquire both tactile and visual information has been receiving much attention. However, the depth estimation of skin surface, using a light field camera that creates multiple images with a micro-lens array, is a difficult problem due to low-resolution images resulting in erroneous disparity matching. Methods: Multiple low-resolution images decoded from a light field camera have limitations to accurate 3D surface reconstruction needed for haptic palpation. To overcome this, a deep learning method, Generative Adversarial Networks, was employed to generate super-resolved skin images that preserve surface detail without blurring, and then, accurate skin depth was estimated by taking multiple subsequent steps including lens distortion correction, sub-pixel shifted image generation using phase shift theorem, cost-volume building, multi-label optimization, and hole filling and refinement, which is a new approach for 3D skin surface reconstruction. Results: Experimental results of the deep-learning-based super-resolution method demonstrated that the textural detail (wrinkles) of super-resolved skin images is well preserved, unlike other super-resolution methods. In addition, the depth maps computed with our proposed algorithm verify that our method can produce more accurate and robust results compared to other state-of-the-art depth map computation methods. Conclusion: Herein, we first proposed depth map estimation of skin surfaces using a light field camera and subsequently tested it with several skin images. The experimental results established the superiority of the proposed scheme.
关键词： depth estimation,skin imaging,disparity estimation,dermatology,light field camera,haptic palpation
更新于2025-09-19 17:15:36
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Optical coherence tomography angiography and photoacoustic imaging in dermatology
摘要： Optical coherence tomography angiography (OCTA) is a relatively novel functional extension of the widely accepted ophthalmic imaging tool named optical coherence tomography (OCT). Since OCTA’s debut in ophthalmology, researchers have also been trying to expand its translational application into dermatology. The ability of OCTA in resolving microvasculature has shown promising results in imaging skin diseases. Meanwhile, photoacoustic imaging (PAI), which uses laser pulse induced ultrasound waves as the signal, has been studied to differentiate human skin layers and to help skin disease diagnosis. This perspective article gives a short review of OCTA and PAI in the field of photodermatology. After an introduction of the principles of OCTA and PAI, we describe the most updated results of skin disease imaging using these two optical imaging modalities. We also put an emphasis on dual modality imaging combining OCTA and photoacoustic tomography (PAT) for dermatological applications. In the end, the challenges and opportunities of these two imaging modalities in dermatology are discussed.
关键词： microvasculature,dermatology,Optical coherence tomography angiography,photoacoustic imaging,skin imaging
更新于2025-09-19 17:15:36
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Diode lasers for the treatment of genital warts
摘要： Background: Human papillomavirus (HPV) infections are the most common sexually transmitted diseases leading to genital warts. Developing lesions start off as small papules, which then grow larger and protrude, eventually coalescing into plaque-like formations. Objectives: The aim of this study was to evaluate the efficacy of diode laser coagulation as a treatment for genital warts relative to their number, size, localisation, and recurrence rate. Materials and Methods: Altogether, 45 patients were evaluated in this study. Patients were initially assigned to one of two groups, depending on the size and number of their genital warts, and received a maximum of two laser treatments. Patients were assessed up to three months after intervention. A cure was defined as the complete removal of condylomata. Results: In Group I, 84% of the patients (21/25) were free of recurrence after three months (last follow-up visit). In Group II, 60% of the patients were free of recurrence after three months (12/20 patients); 25% after the first and 35% after the second treatment. Overall, a cure rate of 73% was achieved (33/45 patients). Conclusion: By splitting the laser treatment for multiple, extensive, and/or coalescing genital warts into two sessions, thereby being less destructive to the surrounding tissue, it was possible to achieve comparable cure rates between the two groups. This study indicates that laser treatment is an effective therapy option. Further studies including larger patient cohorts are necessary to ultimately confirm the advantages of laser treatment.
关键词： diode laser,genital warts,condylomata,dermatology,urology
更新于2025-09-12 10:27:22
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Nonablative Fractional 1,550-nm Laser for the Treatment of an Unusual Nevus Sebaceus
摘要： Nevus sebaceus is a benign congenital neoplasm that presents as a hairless yellow, waxy thin plaque on the scalp or face. Initially asymptomatic, the nevus sebaceus often becomes verrucous during puberty prompting evaluation by a dermatologist. Historically, the mainstay of treatment was prophylactic surgical excision due to the potential for malignant transformation; however, the literature has now demonstrated that the incidence of developing a malignancy within a nevus sebaceous is actually quite low at approximately 1%. Currently, there is a lack of consensus regarding the optimal management of nevus sebaceus, and less-invasive approaches are being explored. In this article, we report a case of an unusual nevus sebaceus treated successfully with a nonablative fractional 1,550-nm laser.
关键词： nevus sebaceus,dermatology,nonablative fractional laser,treatment
更新于2025-09-12 10:27:22
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Successful treatment of multinucleate cell angiohistiocytoma in an adult male patient with potassium-titanyl-phosphate laser in combination with intralesional corticosteroids
摘要： Multinucleate cell angiohistiocytoma (MCAH) is a rare, benign, idiopathic disease characterized by strong female predominance and predilection for the extremities and face. Most often asymptomatic, MCAH follows an indolent, yet progressive course, with spontaneous remission being uncommon. Many aspects of this vascular and fibrohistiocytic proliferation are controversial, including pathogenesis and treatment recommendations. We present a case of MCAH in a male patient successfully treated with potassium-titanyl-phosphate (KTP) laser.
关键词： vascular,general dermatology,dermatopathology,fibrohistiocytic,potassium-titanyl-phosphate,laser,multinucleate cell angiohistiocytoma
更新于2025-09-12 10:27:22
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Treatment of Necrobiosis Lipoidica With Pulsed Dye Laser
摘要： Necrobiosis lipoidica (NL) represents a rare chronic granulomatous inflammatory skin disease of unknown etiology that is classically associated with diabetes. This cutaneous process is characterized by formation of yellow atrophic plaques with peripheral red-brown borders typically on the lower extremities which can occasionally ulcerate and significantly affect quality of life. NL has historically been and remains a difficult condition to treat, and therefore, a plethora of therapies have been reported in the literature: topical and intralesional glucocorticoids, topical calcineurin inhibitors, platelet aggregation inhibitors, various immunosuppressants, antimalarials, tumor necrosis factor-alpha inhibitors, phototherapy, photodynamic therapy, hyperbaric oxygen, and CO2 or pulsed dye laser (PDL) therapy. Regarding usage of PDL for treatment of NL, literature is limited, and treatment protocols are not well defined. To highlight efficacy of laser-based treatments in NL, we present an individual with a long-standing history of NL treated with PDL (Vbeam, 595-nm wavelength, 7.5-J/cm2 energy fluence, 7-mm spot size, and 6-ms pulse duration; Candela Corporation, Wayland, MA) with excellent cosmetic response.
关键词： treatment,dermatology,Necrobiosis lipoidica,pulsed dye laser
更新于2025-09-12 10:27:22