Final answer:
The statement that 'the footprint tends to be small' is NOT true for a linear phased array transducer, as it usually has a larger footprint due to the side-by-side arrangement of multiple elements which assists in creating a detailed rectangular image.
Step-by-step explanation:
The question pertains to the characteristics of a linear phased array transducer. Among the statements provided, the one that is NOT true of a linear phased array transducer is that 'the footprint tends to be small'. Typically, a linear transducer is designed with a relatively large footprint to accommodate numerous elements side by side for better resolution and the creation of a rectangular image. A linear transducer can indeed alter the number of focal zones and the depth, which allows for greater control in image acquisition. It utilizes electronic steering to create images that reflect the shape and density of internal structures. This is achieved by the probe's multiple ultrasound sources being phased to interfere constructively in a given, adjustable direction.
Moreover, the echoes that come back are measured in terms of both position and depth, which allows for a detailed two-dimensional image to be constructed by a computer. This use of a phased array enables the electronic steering of the beam without moving the transducer, providing flexibility in image formation.