An instrument for monitoring the force applied by breast compression devices on mammography X-ray sets

Faulkner, K.; Chambers, I. R.; Hedley, P; Thompson, Sean

doi:10.1088/0143-0815/10/2/007

Cited by 3 publications

(1 citation statement)

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“…Forces between 1 and 20 N were manually applied to the skin surface of the breast at a strain rate of approximately 0.03 s −1 while RF frames were recorded. For comparison, mammographic techniques commonly employ compressive forces between 100 and 200 N. 25 The ultrasonic frame rate was set externally to 5 fps using a waveform generator and the ECG trigger function of the scanner. The sampling rate of the force sensor was 10 samples/ second.…”

Section: Iiia Linearitymentioning

confidence: 99%

Ultrasonic measurements of breast viscoelasticity

Sridhar

Insana

2007

Medical Physics

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In vivo measurements of the viscoelastic properties of breast tissue are described. Ultrasonic echo frames were recorded from volunteers at 5 fps while applying a uniaxial compressive force (1-20 N) within a 1 s ramp time and holding the force constant for up to 200 s. A time series of strain images was formed from the echo data, spatially averaged viscous creep curves were computed, and viscoelastic strain parameters were estimated by fitting creep curves to a second-order Voigt model. The useful strain bandwidth from this quasi-static ramp stimulus was 10(-2) < or = omega < or = 10(0) rad/s (0.0016-0.16 Hz). The stress-strain curves for normal glandular tissues are linear when the surface force applied is between 2 and 5 N. In this range, the creep response was characteristic of biphasic viscoelastic polymers, settling to a constant strain (arrheodictic) after 100 s. The average model-based retardance time constants for the viscoelastic response were 3.2 +/- 0.8 and 42.0 +/- 28 s. Also, the viscoelastic strain amplitude was approximately equal to that of the elastic strain. Above 5 N of applied force, however, the response of glandular tissue became increasingly nonlinear and rheodictic, i.e., tissue creep never reached a plateau. Contrasting in vivo breast measurements with those in gelatin hydrogels, preliminary ideas regarding the mechanisms for viscoelastic contrast are emerging.

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Section: Iiia Linearitymentioning

confidence: 99%