Effect of Abdominal Wall Inhomogeneities on the Focusing of an Ultrasonic Beam at Different Positions of the Transducer

A study is performed of the effect acoustic inhomogeneities of the abdominal wall have on the focusing of a powerful ultrasonic beam at different positions of a transducer. A focused beam generated by a 1 MHz transducer is modeled numerically using an acoustic model of the human body created via computer-aided tomography. It is found that the focal maximum of the field of intensity shifts in space, and the maximum achievable intensity in the beam when focusing through the acoustically inhomogeneous abdominal wall is reduced. The best location of the transducer is selected to minimize distortions.