In vivo breast tissue backscatter measurements with 7.5-and 10-MHz transducers

Measurements of the ultrasound (US) backscatter coefficient (BSC) of fibrog landular and fatty breast tissues in vivo from 5.25 through 13 MHz, using t he reference phantom method, are presented. Radiofrequency echo data were c ollected at a series of locations in the left breasts of 16 adults, age 46 to 84, and in a custom-built phantom calibrated for backscatter and attenua tion. Matched regions of interest (ROIs) were then selected in these images , from which the backscatter coefficient and the backscatter frequency depe ndence were ratiometrically estimated, after compensation for attenuation. The mean results in fibroglandular tissues were 78.9 x 10(-3)/cm, sr at 7.2 MHz (n(ROI) = 43, n = 13) and 146 x 10(-3)/cm, sr at 10.3 MHz (n(ROI) = 19 , n = 10) with frequency dependencies of f(2.28) and f(3.25). The correspon ding results in subcutaneous fat were 2.59 x 10(-3)/cm, sr at 7.2 MHz (n(RO I) = 56, n = 16) and 7.08 x 10(-3)/cm, sr at 10.3 MHz (n(ROI) = 57, n = 16) with frequency dependencies of f(3.49) and f(3.43). These findings are dis cussed and compared to similar measurements in the literature. (E-mail: mar tin.anderson@seas.rochester.edu) (C) 2001 World Federation for Ultrasound i n Medicine & Biology.