Deformation measurement of liquid-filled elastic tube embedded in soft material using optimal pulse width method under photoacoustic excitation

Abstract

To pursue higher precision and wider range of noninvasive vascular deformation measurement for medical diagnosis, this paper presents a photoacoustic measurement method based on the acoustic resonance perspective other than usual imaging-based method. In-vitro experiments were conducted for red-ink-filled soft tubes having diameter of less than 1 mm embedded in a tissue-mimicking phantom. A 3-W laser diode and a 2-MHz ultrasound transducer together with an external compressing device were used. Percentage error of 4% was marked in estimating the inner diameter of tube samples. The results demonstrated that the proposed method was feasible to detect a sub-millimeter deformation for thin tubes with ultrasound transducer of relatively low center frequency and electronic circuit of limited temporal resolution.