The generalized finite amplitude insert-substitution method for B/A measurement of tissues and liquids

B/A holds promise as a biomarker for tissue characterization. Moreover, measuring B/A enables identifying isomer types in biological liquids, potentially aiding diagnosis of some diseases. The standard finite amplitude insert-substitution method of measuring B/A has several limitations. It assumes a linear dependency of the attenuation coefficient on frequency, limiting it to tissue applications, and necessitates sample positioning close to the receiver. Here we propose the generalized finite amplitude insert-substitution method, which allows for B/A measurement of tissues and liquids, and gives freedom in sample positioning. In this work, we present the derived formula and validate the experimental procedure. For this purpose, B/A measurements of corn oil, porcine fat and porcine liver were conducted. For each substance, several conditions were tested, including various distances between the source and the receiver, various sample positions and amplitudes of the transmitted pulses. A better agreement with literature data was found for lower source pressure amplitudes and distances within the near field of the source transducer. In these conditions, the measurement error was confined to 8% and 25% of the literature values of corn oil and the considered tissues, respectively. No clear indication of the influence of sample position on the measurement accuracy was found.