High frequency ultrasonic characterization of human skin In vivo

High frequency (>20 MHz) ultrasound has numerous potential applications in dermatology because of its ability to penetrate several millimeters into the skin and provide information at a spatial resolution of tens of microns. However, conventional B-scan images of skin tissues often lack the capability to characterize and differentiate various skin tissues. In this work, quantitative ultrasonic methods using the attenuation coefficient, backscatter coefficient, and echo envelope statistics were studied for their potential to characterize human skin tissues in vivo. A high frequency ultrasound system was developed using polymer transducers, a pulser/receiver, high-speed digitizer, 3-axis scanning system, and a PC. Data collected using three different transducers with center frequencies of 28, 30 and 44 MHz were processed to determine the characteristics of normal human dermis and subcutaneous fat. Attenuation coefficients were obtained by computing spectral slopes vs. depth, with the transducers axially translated to minimize diffraction effects. Backscatter coefficients were obtained by compensating recorded backscatter spectra for system-dependent effects, and additionally for one transducer, using the reference phantom technique. Good agreement was seen between the results from the different transducers/methods. The attenuation coefficients were well described by a linear frequency dependence whose slope showed significant differences between the forearm and fingertip dermis, but not between the forearm dermis and fat. The backscatter coefficient of the dermis showed an increasing trend with frequency and was significantly higher than that of fat.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Raju, Balasundara I. (Balasundara Iyyavu), 1972-

Advisor dc:contributor.advisor

• Mandayam A. Srinivasan and Dennis M. Freeman.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29232

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29232