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

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US007322972B2

(12) United States Patent

Viator et al.

(io) Patent No.: (45) Date of Patent:

US 7,322,972 B2 Jan. 29, 2008

(54) IN VIVO PORT WINE STAIN, BURN AND

MELANIN DEPTH DETERMINATION USING
A PHOTOACOUSTIC PROBE

(75) Inventors: John A. Viator, Portland, OR (US);

Steven L. Jacques, Portland, OR (US);
J. Stuart Nelson, Laguna Niguel, CA
(US); Guenther Paltauf, Graz (AT)

(73) Assignee: The Regents of the University of California, Oakland, CA (US)

( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 662 days.

(21) Appl. No.: 10/359,782

(22) Filed: Feb. 7, 2003

(65) Prior Publication Data

US 2004/0039379 Al Feb. 26, 2004

Related U.S. Application Data

(60) Provisional application No. 60/371,900, filed on Apr. 10, 2002.

(51) Int. CI.

A61B 18/18 (2006.01)

(52) U.S. CI 606/9

(58) Field of Classification Search 600/595,

600/474, 300, 437, 463, 476, 473, 587, 407, 600/310,306; 73/633 See application file for complete search history.

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.

8 Claims, 31 Drawing Sheets

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