The First Commercial 730 nm Picosecond-Domain Laser is Safe and Effective for Treating Multicolor Tattoos.

BACKGROUND AND OBJECTIVES: Laser-pumped lasers enable driving a secondary wavelength through pumping with a primary device. Here we investigate the first 730 nm laser-pumped laser for efficacy in tattoo removal. STUDY DESIGN/MATERIALS AND METHODS: Fifteen subjects with 20 tattoos were enrolled to investigate the effect of a new 730 nm, titanium-sapphire laser-pumped laser at removing decorative tattoos. A total of four treatments were administered and photographic improvement of pre- and post-treatment cross-polarized digital images was evaluated by four blinded physician observers using an 11-point scale. RESULTS: Blinded assessment of pre- and post-treatment images found 70%, 77%, 83%, 83%, 26%, and 8% clearance from baseline images for black, green, blue, purple, red and yellow pigments, respectively. Side effects were limited to pinpoint bleeding and erythema immediately after treatment and some crusting and scale up to 1-2 weeks following treatment, and a localized allergic reaction in a single subject. There was no scarring or pigmentary alteration visible in any follow-up images. CONCLUSION: The new 730 nm, picosecond-domain, titanium-sapphire, laser-pumped laser is safe and effective for removing multicolored tattoos. Green, blue, and purple pigments cleared the most as expected, but black ink cleared more completely than was predicted. Lasers Surg. Med. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC.

Treatment of poikiloderma of Civatte using a redesigned pulsed dye laser with a 15 mm diameter treatment spot.

OBJECTIVES: The pulsed-dye laser has long been a gold standard in the treatment of poikiloderma of Civatte. Recent advances in pulsed dye laser technology enable output energies 50% higher, enabling beam diameters of up to 15 mm with clinically relevant fluences. In this study, we investigate this new laser for treatment of this condition. MATERIALS AND METHODS: Twenty subjects were enrolled in the study. A total of four treatments were administered at monthly intervals. Blinded assessment of digital, cross-polarized photographs taken at baseline and two months following the last treatment was performed by blinded physician raters using an 11-point clearance scale. Subject reported pain scores immediately following treatment and side effects at all visits were recorded by the investigator. RESULTS: Seventeen subjects completed the study. Blinded reviewers correctly identified the baseline photo in 48 of 51 cases (94%). All three reviewers mis-identified the same subjects. The blinded reviewers scored 14 out of the 17 subjects with an improvement greater than 40% and 10 out of the 17 subjects greater than 50%. Average improvement was 49% for all 17 subjects. Side effects were limited to mild edema, and mild to moderate erythema and purpura. Pain scores averaged 3.5 on using an 11-point scale. CONCLUSION: This study demonstrates the safety and effectiveness of a new pulsed-dye laser with a 15 mm spot and 50% higher fluences for the treatment of poikiloderma of Civatte. Lasers Surg. Med. 51:54-58, 2019. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Pulsed dye laser treatment of rosacea using a novel 15 mm diameter treatment beam.

BACKGROUND: The pulsed-dye laser has been used to treat facial redness and rosacea for decades. Recent advances in dye laser technology enable 50% higher output energies supporting 50% larger treatment areas, and beam-diameters up to 15 mm with clinically-relevant fluences. In this study, we investigate this novel pulsed-dye laser using a 15 mm diameter beam for treatment of rosacea. METHODS: Twenty subjects with erythemato-telangiectatic rosacea were enrolled in the study. A total of 4 monthly treatments were administered, first treating linear vessels with a 3 × 10 mm elliptical beam, then diffuse redness with a 15-mm diameter circular beam. Blinded assessment of digital, cross-polarized photographs taken 2 months following the last treatment was performed using an 11-point clearance scale. RESULTS: Nineteen subjects completed the study. Blinded reviewers correctly identified baseline photos in 55 out of the total of 57 images (96.5%). The blinded reviewers scored 17 of the 19 subjects with an improvement greater than 40%, and 11 of the 19 subjects greater than 50%. The average improvement was 53.9%. Side effects were limited to mild edema, mild to moderate erythema, and mild to moderate bruising. CONCLUSION: This study demonstrates that a newly designed pulsed-dye laser having a novel 15-mm diameter treatment beam improves the appearance of rosacea with a favorable safety profile. Lasers Surg. Med. 50:808-812, 2018. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Treatment of Photoaging With a Dual-Wavelength, 532 nm and 1,064 nm Picosecond-Domain Laser Producing a Fractionated Treatment Beam Using a Holographic Optic.

BACKGROUND: A dual-wavelength, picosecond-domain, fractionated laser delivering 1,064nm and 532nm laser energy through a holographic optic was investigated for safety and effectiveness at improving the appearance of chronic photoaging. MATERIALS AND METHODS: A total of 27 subjects were enrolled with 24 completing the study, and 14 subjects were treated with 1,064 nm and 10 with 532 nm. The 1,064 nm-treated subjects received 5 monthly treatments while the 532 nm-treated subjects received 4 monthly treatments. Improvement was measured by blinded evaluation of pre- and post-treatment images 12 weeks following the final treatment. Subjects also evaluated treatment effect and side-effects. RESULTS: Blinded reviewers correctly identified the baseline image in 52 of 72 paired images, or 72% of the time, with a mean improvement score of 1.4 using an 11-point rating scale (P less than 0.0001). Post-treatment erythema, mild edema, and petechiae were the only side effects noted. CONCLUSION: The fractionated, picosecond-domain, 532 nm and 1,064 nm laser is safe and effective for improvement of facial photodamage. The laser was well tolerated with mild erythema, edema, and petechiae as the most common side-effects.

J Drugs Dermatol. 2017;16(11):1077-1082.

Optical coherence contrast imaging using gold nanorods in living mice eyes.

BACKGROUND: Optical coherence tomography (OCT) is a powerful imaging modality to visualize tissue structures, with axial image pixel resolution as high as 1.6 µm in tissue. However, OCT is intrinsically limited to providing structural information as the OCT contrast is produced by optically scattering tissues. METHODS: Gold nanorods (GNRs) were injected into the anterior chamber (AC) and cornea of mice eyes which could create a significant OCT signal and hence could be used as a contrast agent for in vivo OCT imaging. RESULTS: A dose of 30 nM of GNRs (13 nm in diameter and 45 nm in length) were injected to the AC of mice eyes and produced an OCT contrast nearly 50-fold higher than control mice injected with saline. Furthermore, the lowest detectable concentration of GNRs in living mice AC was experimentally estimated to be as low as 120 pM. CONCLUSIONS: The high sensitivity and low toxicity of GNRs brings great promise for OCT to uniquely become a high-resolution molecular imaging modality.

Single step nanoplasmonic immunoassay for the measurement of protein biomarkers.

A nanoplasmonic biosensor for highly-sensitive, single-step detection of protein biomarkers is presented. The principle is based on the utilization of the optical scattering properties of gold nanorods (GNRs) conjugated to bio-recognition molecules. The nanoplasmonic properties of the GNRs were utilized to detect proteins using near-infrared light interferometry. We show that the antibody-conjugated GNRs can specifically bind to our model analyte, Glucose Transporter-1 (Glut-1). The signal intensity of back-scattered light from the GNRs bound after incubation, correlated well to the Glut-1 concentration as per the calibration curve. The detection range using this nanoplasmonic immunoassay ranges from 10 ng/mL to 1 ug/mL for Glut-1. The minimal detectable concentration based on the lowest discernable concentration from zero is 10 ng/mL. This nanoplasmonic immunoassay can act as a simple, selective, sensitive strategy for effective disease diagnosis. It offers advantages such as wide detection range, increased speed of analysis (due to fewer incubation/washing steps), and no label development as compared to traditional immunoassay techniques. Our future goal is to incorporate this detection strategy onto a microfluidic platform to be used as a point-of-care diagnostic tool.

Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms.

Melanoma accounts for 75% of all skin cancer deaths. Pulsed photothermal radiometry (PPTR), optical coherence tomography (OCT) and ultrasound (US) are non-invasive imaging techniques that may be used to measure melanoma thickness, thus, determining surgical margins. We constructed a series of PDMS tissue phantoms simulating melanomas of different thicknesses. PPTR, OCT and US measurements were recorded from PDMS tissue phantoms and results were compared in terms of axial imaging range, axial resolution and imaging time. A Monte Carlo simulation and three-dimensional heat transfer model was constructed to simulate PPTR measurement. Experimental results show that PPTR and US can provide a wide axial imaging range (75 µm-1.7 mm and 120-910 µm respectively) but poor axial resolution (75 and 120 µm respectively) in PDMS tissue phantoms, while OCT has the most superficial axial imaging range (14-450 µm) but highest axial resolution (14 µm). The Monte Carlo simulation and three-dimensional heat transfer model give good agreement with PPTR measurement. PPTR and US are suited to measure thicker melanoma lesions (>400 µm), while OCT is better to measure thin melanoma lesions (<400 µm).

Depth resolved photothermal OCT detection of macrophages in tissue using nanorose.

Application of photothermal Optical Coherence Tomography (OCT) to detect macrophages in ex vivo rabbit arteries which have engulfed nanoclusters of gold coated iron oxide (nanorose) is reported. Nanorose engulfed by macrophages associated with atherosclerotic lesions in rabbit arteries absorb incident laser (800nm) energy and cause optical pathlength (OP) variation which is measured using photothermal OCT. OP variation in polydimethyl siloxane tissue phantoms containing varying concentrations of nanorose match values predicted from nanoparticle and material properties. Measurement of OP variation in rabbit arteries in response to laser excitation provides an estimate of nanorose concentration in atherosclerotic lesions of 2.5x10(9) particles/ml. OP variation in atherosclerotic lesions containing macrophages taking up nanorose has a different magnitude and profile from that observed in control thoracic aorta without macrophages and is consistent with macrophage presence as identified with RAM-11 histology staining. Our results suggest that tissue regions with macrophages taking up nanorose can be detected using photothermal OCT.

Small multifunctional nanoclusters (nanoroses) for targeted cellular imaging and therapy.

The ability of 20-50 nm nanoparticles to target and modulate the biology of specific types of cells will enable major advancements in cellular imaging and therapy in cancer and atherosclerosis. A key challenge is to load an extremely high degree of targeting, imaging, and therapeutic functionality into small, yet stable particles. Herein we report approximately 30 nm stable uniformly sized near-infrared (NIR) active, superparamagnetic nanoclusters formed by kinetically controlled self-assembly of gold-coated iron oxide nanoparticles. The controlled assembly of nanocomposite particles into clusters with small primary particle spacings produces collective responses of the electrons that shift the absorbance into the NIR region. The nanoclusters of approximately 70 iron oxide primary particles with thin gold coatings display intense NIR (700-850 nm) absorbance with a cross section of approximately 10(-14) m(2). Because of the thin gold shells with an average thickness of only 2 nm, the r(2) spin-spin magnetic relaxivity is 219 mM(-1) s(-1), an order of magnitude larger than observed for typical iron oxide particles with thicker gold shells. Despite only 12% by weight polymeric stabilizer, the particle size and NIR absorbance change very little in deionized water over 8 months. High uptake of the nanoclusters by macrophages is facilitated by the dextran coating, producing intense NIR contrast in dark field and hyperspectral microscopy, both in cell culture and an in vivo rabbit model of atherosclerosis. Small nanoclusters with optical, magnetic, and therapeutic functionality, designed by assembly of nanoparticle building blocks, offer broad opportunities for targeted cellular imaging, therapy, and combined imaging and therapy.

Quality assessment for spectral domain optical coherence tomography (OCT) images.

Retinal nerve fiber layer (RNFL) thickness, a measure of glaucoma progression, can be measured in images acquired by spectral domain optical coherence tomography (OCT). The accuracy of RNFL thickness estimation, however, is affected by the quality of the OCT images. In this paper, a new parameter, signal deviation (SD), which is based on the standard deviation of the intensities in OCT images, is introduced for objective assessment of OCT image quality. Two other objective assessment parameters, signal to noise ratio (SNR) and signal strength (SS), are also calculated for each OCT image. The results of the objective assessment are compared with subjective assessment. In the subjective assessment, one OCT expert graded the image quality according to a three-level scale (good, fair, and poor). The OCT B-scan images of the retina from six subjects are evaluated by both objective and subjective assessment. From the comparison, we demonstrate that the objective assessment successfully differentiates between the acceptable quality images (good and fair images) and poor quality OCT images as graded by OCT experts. We evaluate the performance of the objective assessment under different quality assessment parameters and demonstrate that SD is the best at distinguishing between fair and good quality images. The accuracy of RNFL thickness estimation is improved significantly after poor quality OCT images are rejected by automated objective assessment using the SD, SNR, and SS.