S2k guideline: Laser therapy of the skin.

This guideline aims to improve the efficiency and safety of lasers and optical radiation sources with similar effects (especially IPL). Laser therapy of skin lesions with an increased amount of melanocytes should be performed with caution. Laser treatment of pigmented melanocytic nevi is not recommended. The guideline contains recommendations regarding the treatment of lentigines and café-au-lait spots, non-pigmented dermal nevi, Becker nevus, nevus of Ota/Hori/Ito and melasma. Further recommendations focus on the treatment of skin lesions without an increased amount of melanocytes (ephelides, postinflammatory hyperpigmentation including berloque dermatitis, seborrheic keratoses, traumatic/decorative tattoos and metallic deposits), hypopigmentation (vitiligo), benign non-pigmented neoplasms (fibrous papule of the nose, nevus sebaceus, epidermal nevus, neurofibroma, sebaceous gland hyperplasia, syringoma, xanthelasma palpebrarum), inflammatory dermatoses (acne papulopustulosa/conglobata, acne inversa, granuloma faciale, lichen sclerosus, lupus erythematosus, psoriasis vulgaris, rosacea, rhinophyma), wrinkles/dermatochalasis/striae, hypertrichosis, scars (atrophic, hypertrophic; keloids, burn/scald scars), laser-assisted skin healing, onychomycosis, precancerous lesions and malignant tumors (actinic keratoses/field cancerization, cheilitis actinica, basal cell carcinoma), vascular skin lesions (angiokeratoma, angioma, hemangioma, malformation, spider veins, granuloma telangiectaticum (pyogenic granuloma), rubeosis (erythrosis interfollicularis colli, ulerythema ophryogenes), nevus flammeus, telangiectasias and Osler's disease (hereditary hemorrhagic telangiectasia) and viral skin lesions (condylomata acuminata, mollusca contagiosa, verrucae planae juveniles/vulgares/ verrucae palmares et plantares).

MR guidance and thermometry of percutaneous laser disc decompression in open MRI: an ex vivo study.

PURPOSE: To assess the feasibility of guidance and thermometry by open 1.0 T magnetic resonance (MR) imaging during percutaneous laser disc decompression (PLDD). METHODS: A fluoroscopic proton-density-weighted turbo spin echo sequence was used for positioning a laser fiber and a reference thermosensor within the targeted spinal disc. In 30 lumbar discs from human donors, nonspoiled gradient-echo (GRE) sequences with different echo times (TE) were compared to monitor thermal laser effects (Nd:YAG laser, 1,064 nm). Temperature distribution was visualized in real time on the basis of T1-weighted images and the proton resonance frequency (PRF) technique. Image quality, temperature accuracy, and correlation with macroscopic lesion sizes were analyzed. Image quality was confirmed in healthy volunteers. RESULTS: MR-guided placement of the laser fiber in the center of the targeted disk was precise. Best overall PLDD results-considering image quality (contrast-to-noise ratio), temperature accuracy (R (2) = 0.96), and correlation between the macroscopic and MR lesions (R (2) = 0.63)-were achieved with TE at 7 ms. The same TE value also gave the best image quality with healthy volunteers. CONCLUSION: Instrument guidance and PRF-based thermometry of PLDD in the lumbar spine are feasible and accurate. Open 1.0 T MR imaging with fast spin-echo and GRE sequence designs may render laser discectomies more effective and controllable.

Laser-induced thermotherapy (LITT)--evaluation of a miniaturised applicator and implementation in a 1.0-T high-field open MRI applying a porcine liver model.

OBJECTIVE: To evaluate the feasibility and safety of a novel LITT applicator for thermal ablation of liver malignancies in 1.0-T high-field open MRI. METHODS: A miniaturised 6-F double-tubed protective catheter with a closed cooling circuit was used with a flexible laser fibre, connected to a 1,064-nm Nd:YAG laser and evaluated in non-perfused porcine livers (18-30 W for 10-20 min, 2-W and 2-min increments; n = 210/applicator) in reference to an established 9-F system. As a proof of concept, MR-guided LITT was performed in two healthy domestic pigs in high-field open MRI. RESULTS: Ex-vivo, the coagulation volumes induced by the 6-F system with maximum applicable power of 24 W for 20 min (33.0 ± 4.4 cm(3)) did not differ significantly from those set with the 9-F system at 30 W for 20 min (35.8 ± 4.9 cm(3)) (p = 0.73). A flow-rate of 15 ml/min of the cooling saline solution was sufficient. MR navigation and thermometry were feasible. CONCLUSION: The miniaturised 6-F applicator can create comparable coagulation sizes to those of the 9-F system. Applicator guidance and online-thermometry in high-field open MRI are feasible.

Evaluation of laparoscopic liver resection with two different Nd:YAG lasers for future use in a high-field open MRI.

OBJECTIVE: Laparoscopic liver surgery is a safe and feasible technique for the treatment of benign and malignant liver tumors and has been well established at many specialized centers. Many different techniques of tissue dissection have been developed. As an alternative various lasers have been applied to conventional liver resections. Laser surgery is potentially beneficial for laparoscopic liver resection, allowing parenchymal dissection and vessel coagulation. A second advantage is the non-ferromagnetic character of this instrument, which facilitates magnetic resonance (MR)-guided interventions. In this study two different Nd:YAG lasers were evaluated for laparoscopic liver resection in a porcine model. In other studies this technique will be transferred into an interventional open MRI for image-guided liver resection. MATERIALS AND METHODS: We used 1064-nm and 1318-nm Nd:YAG lasers for laparoscopic wedge, segmental, and left lateral liver lobe resection. During the intervention blood loss, resection time, and cardiopulmonary parameters were quantified. The resected specimen underwent histomorphometric analysis for thermal tissue effects, including parenchymal carbonization, necrosis, and vessel coagulation. RESULTS: The resected volume showed a positive correlation with intraoperative blood loss, which increased from wedge resection (245 mL, SD +/- 71 mL) and segment resection (325 mL), to left lateral resection (455 mL). Total parenchymal dissection was slightly faster with the 1064-nm Nd:YAG laser (9 min, SD +/- 5 min) compared with the 1318-nm Nd:YAG laser (11 min, SD +/- 4 min). Thermally-induced vessel sealing was shown for liver veins and arteries to a maximum diameter of 2 mm. CONCLUSION: Laparoscopic liver resection with both Nd:YAG lasers is a safe and feasible technique, allowing parenchymal dissection and coagulation. The 1064-nm Nd:YAG laser showed increased tissue damage with more effective coagulation capability than the 1318-nm Nd:YAG laser. Because of its non-ferromagnetic characteristics, laser-based laparoscopic liver resection is potentially useful for image-guided surgery in an open MRI.