In vivo port wine stain, burn and melanin depth determination using a photoacoustic probe

US7322972B2 · kind B2 · utility

Assignee

• The Regents of the University of California · US

Inventors

• John Andrew Viator · Pittsburgh, US
• Steven L. Jacques · Portland, US
• J. Stuart Nelson · Laguna Niguel, US
• Guenther Paltauf · Graz, AT

Key dates

• Filing date: Feb 7, 2003
• Grant date: Jan 29, 2008
• Expiry date: Nov 30, 2024

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61B2018/00458
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A photoacoustic probe for port wine stain (PWS), burn and melanin depth measurements is comprised of optical fibers for laser light delivery and a piezoelectric element for acoustic detection. The probe induced and measured photoacoustic waves in acryl amide tissue phantoms and PWS skin in vivo. Acoustic waves were denoised using spline wavelet transforms, then deconvolved with the impulse response of the probe to yield initial subsurface pressure distributions in phantoms and skin. The waves were then analyzed for epidermal melanin concentration, using a photoacoustic melanin index (PAMI) related to the amount of laser energy absorbed by melanin. Propagation time of the photoacoustic wave was used to determine the depth of blood perfusion underlying necrotic, burned tissue. Thus, the photoacoustic probe can be used for determining PWS, burn and melanin depth for most patients receiving laser therapy.