Question no 3

(d) Suppose the B-mode image extends to a distance of 20 cm from the probe in order to image the heart, and suppose that there are 200 A-lines in the image. In tachycardia the heart rate can be 150 beats per minute. (i) Explain whether this rapid beating motion of the heart can be imaged in B-mode using this array. (ii) What ultrasound imaging modes have been designed to assist with detecting fast- moving tissue?I (e) Assume that the elements in the probe are manufactured from PZT (sound speed (:0 = 4-600 m-s", density pa = 7500 kg-m'3) and have an acoustic impedance-matched backing. (i) Compute how thick each element is, and therefore calculate the total volume of PET in the probe. (ii) If the elements were air-backed instead, would that make the probe better for imaging or worse? Explain your