DOI 10.1515/plm-2013-0047 Photon Med 2013; 2(4): 265–267

Editorial Progress in

Fortschritte in der Dermatologie

This issue of Photonics & Lasers in addresses the protoporphyrin IX, in the neoplastic cells. The major role of photonics and lasers in the skin, which we often advantage of PDT over surgical methods of skin refer to as the largest human organ. Due to the skin’s easy treatment is a better cosmetic outcome (little to no scar- accessibility it was the target for the earliest attempts of ring) [20–23]. The challenge here is how to improve on photon-based in humans. Examples include the a suboptimal response rate that has been attributed to application of ultraviolet phototherapy for the treatment variations in porphyrin formation rates between differ- of cutaneous tuberculosis by Niels Finsen [1–3], as well as ent tumors and between different patients. One proposed the first trial using photodynamic (PDT) of basal remedy for this problem is to quantify porphyrin accumu- cell cancer of the skin by Hermann Tappeiner [4, 5]; both lation via fluorescence measurements, preferably in real of these pivotal innovations happened over a century ago. time, so that the dose could be adjustmented to make PDT Skin is our border and defense barrier to the outside more effective and reliable as a good alternative to world and it is continuously exposed to a range of outside [24]. stimuli [6, 7]. The sun plays a central role, and is both good The article by Yu and Baron [25], on evaluation of and bad as ultraviolet exposure is necessary for vitamin D photoaging, offers a review of current optical rating synthesis in the skin but can also cause sunburn and skin systems that attempt to quantify wrinkling and photo­ cancer [8]. damage in the skin. Despite an intense interest by pharma- Several articles in this issue concentrate on diagnos- ceutical companies and physicians in performing reliable tic tools. The article by Meschieri et al. [9] reviews the cosmetic assessments, the article clearly highlights an value of in-vivo reflectance confocal as a tool urgent need for quantitative, objective alternatives to in cutaneous oncology. One of his co-authors, Millind current photonumeric scales (which are, for the most part, Rajadhyaksha has been crucial in developing this tech- entirely descriptive). Perhaps one or more imaging tech- nology and bringing it to practical application [10–14]. niques described elsewhere in this issue may eventually As the major technical limitation of this method is the brought to bear to help solve this problem. image depth of up to 300 μm, its main role may be in early All the imaging methods that are featured in above detection of skin malignancies, specifically in directing articles may have significant impact on the practice of necessary biopsies and avoiding unnecessary ones. In medicine. One of the inherent challenges is that the their latest work, the research group combines reflectance optimal use of the described techniques requires not only and optical coherence tomography new devices but also operators that are familiar with the (OCT) imaging for skin burn assessment [15]. The differ- novel images that these deliver. Added physician time ence between OCT and reflectance confocal microscopy is and device cost will only be acceptable if the respective the ability of OCT to image to a depth of 1 mm; however, method promises improved patient care, and thus poten- this increased penetration depth comes at the cost of tially reduced long-term cost. reduced resolution. Ultimately, of course, this method Li et al. [26] discuss in their review the current state of also aims at reducing the need for invasive biopsies by enhanced transdermal drug delivery using ablation. providing reliable images that allow for diagnostic deci- The top part of the epidermis, the stratum corneum, is an sions and for treatment response monitoring [16–18]. amazingly specialized layer that is nearly impervious and Rollakanti et al. [19] review the use of fluorescence provides a barrier to unwanted chemicals and pathogens. measurements as a tool to optimize aminolevulinic acid While such protection is desirable, the stratum corneum (ALA)-based PDT of non-melanoma skin cancer. The also inhibits transcutaneous delivery of drugs and vac- exogenous exposure of skin cancer precursors and skin cines that we consider desirable [27]. Laser technology to a physiological heme precursor (ALA) results and nanoparticles can provide an approach to fine-tune in selective accumulation of porphyrins, predominantly disruption of that barrier and allow penetration of larger 266 B. Ortel and E.V. Maytin: Progress in dermatology molecules [28]. The stratum corneum is also the topic of a on epiphyseal cartilage in the femur and tibia of rabbits. report by Andree et al. [29] who used diffuse light reflec- They found that HeNe laser irradiation (632.8 nm, 6 J/cm2) tance to assess carotenoid accumulation in palmar skin as stimulates the cartilage ossification to bone, causing some a function of time and cumulative ingestion of carrot juice. delay in growth and development of the epiphyseal plate. The lipophilicity of carotenoids causes their accumula- Their results highlight the importance of studying carti- tion not only in the fatty tissue but also in the stratum lage morphology and its interaction with LLLT in order corneum, which is readily accessible for spectral analysis. to prevent disturbances in epiphyseal plate in growing Incidentally, the dermatological term for the visible dis- individuals. coloration of palmar skin due to carotenoids is aurantia- In addition to the scientific contributions you will find sis, meaning the “orange color” of the palms. the abstracts from the 20th Annual Meeting “Unmet Needs The issue is completed by two free contributions. in Biophotonics and Laser Medicine” of the Deutsche Zabarylo et al. [30] report about image processing methods Gesellschaft für Lasermedizin (DGLM) e.V., which was held for the registration of scattered light pictures and X-ray on May 14, 2013 as part of the LASER World of PHOTON- radiographs. This image fusion is superior compared ICS Congress and Exhibition, supplemented by the proto- to a separate interpretation of radiographs and optical col of the general meeting of the DGLM. Our international images. Three laser diodes emitting in the visible and near readers will hopefully excuse the fact that the protocol is infrared range are used to optimize distinction between written in German language as it specifically addresses normal and diseased tissue. Early detection of disease the members of the DGLM. activity by novel methods such as the one described here Finally we would like to stress, that it has been a privi- can inform timely intervention in inflammatory joint lege to be guest editors for Photonics & Lasers in Medicine, disease. Increased sensitivity in the detection of localized and we want to thank Prof. Lilge for his invitation. We also disease activity may help reducing morbidity and long- want to thank the authors for their contribution to the der- term sequelae of joint inflammation in conditions such as matology theme of this issue. Human skin is a fascinating rheumatoid arthritis. organ with a diversity of crucial functions. Light-based Ribeiro et al. [31] conducted a study with the aim to methods will continue to enable research and ultimately evaluate the influence of low-level laser therapy (LLLT) help physicians to improve skin health.

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