title: Attenuation coefficient and sound speed in human myometrium and uterine fibroid tumors.
abstract: OBJECTIVE
  To develop a noninvasive method for treatment of uterine fibroid tumors using high-intensity focused ultrasound. Optimal high-intensity focused ultrasound treatment would be dependent on quantitative information about ultrasonic tissue characteristics.
  
  
  METHODS
  Ultrasonic attenuation and the sound speed of fresh human fibroid tumors and myometrium were measured as a function of frequency (1-3 MHz) by using a pulse transmission technique before and after in vitro high-intensity focused ultrasound treatment (3.5 MHz at an intensity of 2,000 W/cm2).
  
  
  RESULTS
  The ranges of the attenuation coefficients, before and after high-intensity focused ultrasound treatment, were 0.9 to 2.2 and 1.8 to 3.9 dB/cm2, respectively, for fibroid tumors and 0.5 to 1.6 and 1.7 to 3.3 dB/cm2, respectively, for myometrium. Although the sound speed appeared to be independent of frequency (1,611 to 1,616 m/s at 1 to 3 MHz) in both types of tissues, a slight increase of approximately 4 to 14 m/s was observed after high-intensity focused ultrasound treatment.
  
  
  CONCLUSIONS
  The results of this study represent our first reported values of the attenuation coefficient and sound speed in fibroid tumors and myometrium before and after high-intensity focused ultrasound treatment.
authors.affiliation: Department of Bioengineering, University of Washington, Seattle 98195, USA.
authors.forename: A
authors.initials: A
authors.lastname: Keshavarzi
authors.forename: S
authors.initials: S
authors.lastname: Vaezy
authors.forename: P J
authors.initials: PJ
authors.lastname: Kaczkowski
authors.forename: G
authors.initials: G
authors.lastname: Keilman
authors.forename: R
authors.initials: R
authors.lastname: Martin
authors.forename: E Y
authors.initials: EY
authors.lastname: Chi
authors.forename: R
authors.initials: R
authors.lastname: Garcia
authors.forename: V Y
authors.initials: VY
authors.lastname: Fujimoto
mesh_terms: D000162:Acoustics; D005260:Female; D006801:Humans; D007889:Leiomyoma / Q000000981:diagnostic imaging* / Q000628:therapy; D009215:Myometrium / Q000000981:diagnostic imaging*; D014464:Ultrasonic Therapy; D014463:Ultrasonography; D014594:Uterine Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy