Conflict of Interest Disclosure: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and have disclosed the following: M. Milanic was recipient of a USAF student travel grant to present at ASLMS 2012. The laser equipment was provided by Fotona d.d. for study purposes. Fotona d.d. provided no financial support for these studies, nor did they participate in the design, data collection or analysis of result.
Energy deposition profile in human skin upon irradiation with a 1,342 nm Nd:YAP laser†
Article first published online: 6 DEC 2012
Copyright © 2012 Wiley Periodicals, Inc.
Lasers in Surgery and Medicine
Volume 45, Issue 1, pages 8–14, January 2013
How to Cite
Milanič, M. and Majaron, B. (2013), Energy deposition profile in human skin upon irradiation with a 1,342 nm Nd:YAP laser. Lasers Surg. Med., 45: 8–14. doi: 10.1002/lsm.22104
- Issue published online: 24 JAN 2013
- Article first published online: 6 DEC 2012
- Manuscript Accepted: 15 NOV 2012
- Slovenian Research Agency Research. Grant Number: P1-0192
- Nd:YAP laser;
- pulsed photothermal radiometry;
- nonablative photorejuvenation;
- laser dermatologic surgery
Background and Objectives
Nd:YAP laser emitting at 1,342 nm appears promising for nonablative skin rejuvenation treatment, based on favorable absorption properties of water and melanin in this part of the spectrum. A quantitative determination of energy deposition characteristics of Nd:YAP in normal human skin should enable design of a safe and effective treatment protocol for future human studies.
Energy deposition profile of a prototype Nd:YAP laser was determined using pulsed photothermal radiometry. This technique involves time-resolved measurement of mid-infrared emission from a sample after pulsed laser irradiation. The laser-induced temperature depth profile is reconstructed from the radiometric transients using a custom optimization algorithm, developed and tested earlier in our group. Measurements were performed on the extremities of four healthy volunteers at low radiant exposure (2.8 J/cm2). For the purpose of comparison, energy deposition characteristics of commercial Nd:YAG and KTP lasers (at 1,064 and 532 nm, respectively), were also determined at the same test sites.
On average, the Nd:YAP laser deposits 50% of the absorbed energy within the top 0.36 mm of skin and 90% within 0.86 mm, which is significantly shallower than the Nd:YAG laser. The ratio between the dermal versus epidermal heating is more favorable and shows a smaller inter- and intra-patient variance as compared to both Nd:YAG and KTP laser.
Energy deposition characteristics of the 1,342 nm Nd:YAP laser are very suitable for controlled heating of the upper dermis, as required for nonablative skin rejuvenation. The risks of overheating the epidermis or subcutis should be significantly reduced in comparison with the 1,064 nm Nd:YAG laser. Lasers Surg. Med. 45: 8–14, 2013. © 2012 Wiley Periodicals, Inc.