We have designed a photoacoustic probe for port-wine stain (PWS) depth measurements consisting of optical fibers for laser light delivery and a piezoelectric element for acoustic detection. We characterized the capabilities and limitations of the probe for profiling PWS skin. The probe induced and measured photoacoustic waves in acrylamide tissue phantoms and PWS skin <i>in vivo</i>. The optical properties of the phantoms were chosen to mimic those of PWS skin. We denoised acoustic waves using spline wavelet transforms, then deconvolved with the impulse response of the probe to yield initial subsurface pressure distributions in phantoms and PWS skin. Using the phantoms, we determined that the limit in resolving epidermal and PWS layers was less than 70 μm. In addition, we used the phantoms to determine that the maximum epidermal melanin concentration that allowed detection of PWS was between 13 and 20%. <i>In vivo</i> measurements of PWS skin with different epidermal melanin concentrations correlated with the phantoms. Thus the photoacoustic probe can be used to determine PWS depth for most patients receiving laser therapy.
© 2003 Optical Society of America
(170.1870) Medical optics and biotechnology : Dermatology
(170.4580) Medical optics and biotechnology : Optical diagnostics for medicine
(170.5120) Medical optics and biotechnology : Photoacoustic imaging
John A. Viator, Bernard Choi, Martin Ambrose, Jerome Spanier, and J. Stuart Nelson, "In vivo Port-Wine Stain Depth Determination with a Photoacoustic Probe," Appl. Opt. 42, 3215-3224 (2003)