Abstract
We report on application of pulsed photothermal radiometry (PPTR) to determine the depth of port wine stain (PWS) blood vessels in human skin. When blood vessels are deep in the PWS skin (>100 microm), conventional PPTR depth profiling can be used to determine PWS depth with sufficient accuracy. When blood vessels are close or partially overlap the epidermal melanin layer, a modified PPTR technique using two-wavelength (585 and 600 nm) excitation is a superior method to determine PWS depth. A direct difference approach in which PWS depth is determined from a weighted difference of temperature profiles reconstructed independently from two-wavelength excitation is demonstrated to be appropriate for a wider range of PWS patients with various blood volume fractions, blood vessel sizes, and depth distribution. The most superficial PWS depths determined in vivo by PPTR are in good agreement with those measured using optical Doppler tomography (ODT).
Highlights
Successful laser treatment of port wine stainPWSbirthmarks in human skin is based on selective thermal damage to the targeted blood vessels
Outline of this article is: ͑1͒ depth determination of deep PWS layers, where we compare the pulsed photothermal radiometry (PPTR) results with those obtained with optical Doppler tomographyODT;14–17 ͑2͒ depth determination of shallow PWS layers where we analyze the validity of the first order approximation previously described; and3͒ when this approximation is not valid, we present a direct difference analysis method to extract PWS depth and compare the results with those obtained using ODT
To verify the PWS depth determined by PPTR, we measured the same area with ODT
Summary
Successful laser treatment of port wine stainPWSbirthmarks in human skin is based on selective thermal damage to the targeted blood vessels. The ideal laser treatment should cause irreversible thermal injury to the PWS vessels without injuring the overlying epidermis. Heat produced in the epidermis, if not controlled, may cause serious injury, resulting in permanent complications such as hypertrophic scarring, dyspigmentation, atrophy, or induration. Cryogen spray coolingCSCwas introduced to cool selectively and protect the epidermis from thermal damage.[1,2,3,4] When a cryogen spurt is applied to the skin sur-. Pulsed photothermal radiometryPPTRis a noncontact method for depth profiling of layered materials.[6,7] PPTR has been used to determine the depth of subsurface chromophores in tissue phantoms and PWS blood vessels in human skin.[8,9,10] While conventional PPTR using one-wavelength excitation works well for depth determination of deep PWS (Ͼ100 m), the technique fails to resolve blood vessels ly-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
