Accelerated tattoo removal with acoustic shock wave therapy in conjunction with a picosecond laser

The effect of the perfluorodecalin patch on particle emission and skin temperature during laser-induced tattoo removal

Laser-based procedures for tattoo removals are popular due to high efficacy and a relatively moderate insult. However, it often requires multiple sessions to achieve a satisfactory effect. The perfluorodecalin (PFD) patch utilizes an optical clearing agent to speed up the removal process and may decrease skin insult and harmful particles emission during treatment. This study assessed in pigs the effect of the PFD patch in connection with laser treatment of skin with and without tattoos to determine whether the PFD patch provides benefit in lowering thermal skin insult and particle emission during treatment. Skin temperature measured by infrared thermometer during laser treatment or shortly thereafter showed a significant (approximately 40%) decrease with the PFD patch in sites with tattoos. For laser-treated sites without tattoos, there was a significant decrease of particles observed with the PFD patch. In laser-treated sites with tattoos, a strong trend was seen (approximately a twofold decrease) but did not reach statistical significance due to high variability. The present data show that the PFD patch limits the increase in skin temperature produced with laser during treatment. Moreover, it decreases the emission of particles in sites without tattoos and is suggestive of a similar effect in sites with tattoos.

Quantitative Monitoring of Tattoo Contrast Variations after 755-nm Laser Treatments in In Vivo Tattoo Models

Laser lights have been used by dermatologists for tattoo removal through photothermal interactions. However, most clinical studies used a visual scoring method to evaluate the tattoo removal process less objectively, leading to unnecessary treatments. This study aimed to develop a simple and quantitative imaging method to monitor the degree of tattoo removal in in vivo skin models. Sprague Dawley rat models were tattooed with four different concentrations of black inks. Laser treatment was performed weekly on the tattoos using a wavelength of 755 nm over six weeks. Images of non-treated and treated samples were captured using the same method after each treatment. The intensities of the tattoos were measured to estimate the contrast for quantitative comparison. The results demonstrated that the proposed monitoring method quantified the variations in tattoo contrast after the laser treatment. Histological analysis validated the significant removal of tattoo inks, no thermal injury to adjacent tissue, and uniform remodeling of epidermal and dermal layers after multiple treatments. This study demonstrated the potential of the quantitative monitoring technique in assessing the degree of clearance level objectively during laser treatments in clinics.

Increased Tattoo Fading in a Single Laser Tattoo Removal Session Enabled by a Rapid Acoustic Pulse Device: A Prospective Clinical Trial

Background and Objectives

The ability to provide improved tattoo fading using multiple laser passes in a single office laser tattoo removal session is limited. In part, this is due to the loss of laser effectiveness caused by epidermal and dermal vacuole “whitening” generated during the initial laser pass at the tattoo site. The Rapid Acoustic Pulse (RAP) device generates acoustic shock wave pulses that clear epidermal and dermal vacuoles to enable multiple laser passes in a single office laser tattoo removal session. The objectives of this study were to determine if the RAP device, when used as an accessory to the 1064 nm Nd:YAG Q‐switched (QS) laser can enable delivery of multiple laser passes in a single office laser tattoo removal session, and therefore result in increased tattoo fading compared to the clinical standard single‐pass QS laser tattoo removal session.

Study Design/Materials and Methods

The RAP device was evaluated in a single‐center (SkinCare Physicians), prospective, IRB approved study. A total of 32 black ink tattoos, from 21 participants, were divided into three zones and treated with either multiple QS laser passes, each followed by 1 minute of RAP device application (Laser + RAP) in zone one and single‐pass QS laser treatment (Laser‐Only) in zone two, separated by an untreated control zone. The treatment sites were assessed for the number of laser passes and adverse events immediately, 6 weeks, and 12 weeks following the treatment session. Photographs of the treatment sites were assessed for percent fading at 12 weeks post‐treatment by three blinded reviewers.

Results

When the RAP device was applied as an accessory to the QS laser in a multi‐pass laser tattoo removal treatment, an average of 4.2 laser passes were delivered in a single session, with no unexpected or serious RAP device‐related adverse events. At the 12‐week follow‐up, tattoos treated with Laser + RAP showed a statistically significant increase in average fading (44.2%) compared with tattoos treated with Laser‐Only (24.8%) (P < 0.01). Additionally, a significantly higher overall proportion of tattoos treated with Laser + RAP (37.5%) had a response of >50% fading compared with tattoos treated with QS Laser‐Only (9.4%) (P < 0.01) as well as a response of >75% fading from Laser + RAP treatment (21.9%) compared with Laser‐Only treatment (3.1%) (P < 0.05).

Conclusions

The RAP device, applied as an accessory to the 1064 nm Nd:YAG QS laser, safely enables multiple QS laser treatments in a single office laser tattoo removal session by clearing the whitening caused by the previous QS laser pass. Enabling multiple QS laser passes results in a statistically significant increase in tattoo fading in a single office laser tattoo removal session compared to the clinical standard single‐pass QS laser tattoo removal session. © 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Enhanced laser surface ablation with an integrated photoacoustic imaging and high intensity focused ultrasound system

BACKGROUND AND OBJECTIVE

Combined laser and ultrasound treatments have been found to have synergistic effects, which may be of particular note in dermatology. We aim to investigate the potential of this technology for dermatology through in vitro and ex vivo experiments.

METHODS

In vitro tissue phantoms made of agar and tattoo ink and tattooed ex vivo chicken breast tissue were used. An integrated photoacoustic imaging and high intensity focused ultrasound (HIFU) system, using a 5-ns tunable OPO laser system and a 5 MHz HIFU transducer, was used to perform photoacoustic analysis to identify the optical contrast, and perform combined laser and ultrasound ablation. On the tissue phantoms, lines of ablation were created under various operating conditions. The samples were then quantified to determine the level of ablation. Same procedures were performed on the tattooed chicken breast tissue and the tattoo was removed by using combined laser and ultrasound.

RESULTS

Ablation in the in vitro tissue phantoms was observed with properly synchronized laser and ultrasound while no ablation was found with either laser or ultrasound alone. Increases to the intensity or pulse duration of ultrasound caused an increase in ablation to the samples. The tattoo was removed from the ex vivo chicken breast using combined laser and ultrasound with a radiant exposure of 1.2 J/cm² while laser and ultrasound alone were unable to remove the tattoo.

CONCLUSIONS

We determined that by supplementing nanosecond laser pulses with ultrasound, ablation, and tattoo removal can be achieved at laser radiant exposures levels would otherwise be ineffective. The area of ablation can be adjusted through changes in the intensity and duration of the ultrasound burst with a constant laser intensity. Additionally, the system can be used to perform photoacoustic analysis of the tissue to estimate the relative optical absorbance at various available wavelengths, allowing for pretreatment analysis. Lasers Surg. Med. 9999:1-9, 2019. © 2019 Wiley Periodicals, Inc.