A Two Dimensional PVDF Transducer Matrix as a Receiver in an Ultrasonic Transmission Camera

Ultrasonic Projection

“…Generating narrow ultrasonic wave beams in biological media by multi-element probes, built as matrices of elementary piezoceramic transducers in a rectangular configuration, can be realised using transducers having a spherical surface, ultrasonic lenses, mechanical elements (e.g. complex system of properly rotated prisms), focusing devices or electronic devices, which control the system of activating and powering individual matrix elements in a proper manner (Drinkwater & Wilcox, 2006;Ermert et al, 2000;Granz & Oppelt, 1987;Green et al, 1974;Nowicki, 1995;Opielinski et al, 2009;Opielinski & Gudra, 2010a, 2010cOpielinski et al 2010aOpielinski et al , 2010bRamm & Smith, 1983;Thomenius, 1996). Exciting individual transducers of the multi-element probe using pulses with various delay is a universal method of focusing and deflecting a beam (Johnson et al, 2005;Thomenius, 1996).…”

“…Adequate delays between activations of each successive elementary transducer allow shaping of the wave front and the direction of its propagation. In case of multi-element ultrasonic matrices (Opielinski et al, 2009(Opielinski et al, , 2010a(Opielinski et al, , 2010b used for projection imaging of internal structure of biological media (Ermert et al, 2000;Granz & Oppelt, 1987;Green et al, 1974;Opielinski & Gudra, 2005), introduction of delays of propagation of pulse ultrasonic wave for individual transducers can result in www.intechopen.com imaging errors associated with side lobes. However there are a number of mechanisms that suppress grating side lobes (a few wavelengths short excitation pulses, apodization weighting functions, a different transmit and receive geometries, random element spacing) and hence allow this criterion to be somewhat relaxed in practice (Drinkwater & Wilcox, 2006;Karaman et al, 2009;Kim & Song, 2006;Lockwood & Foster, 1996;Thomenius, 1996;Yen & Smith, 2004).…”

“…with a slight constant delay, resulting from the need of data buffering and processing), thus, a device using this method can be called an ultrasonic transmission camera (UTC) (Ermert et al, 2000). There are several know works regarding such cameras, conducted at some centres in the world, as described in Introduction (Brettel et al, 1981;Ermert et al, 2000;Granz & Oppelt, 1987;Green et al, 1974;Lehmann et al, 1999).…”

“…The device presented in work (Granz & Oppelt, 1987) functions in pseudo-real time and its construction is similar to the camera described in (Brettel et al, 1981). An incoherent ultrasonic wave passes through an object in a wide beam in order to reduce the effect of spots.…”

“…Due to the possibility of obtaining images in pseudoreal time, the device using this method was named the ultrasonic transmission camera (UTC) (Ermert et al, 2000). Only some centres in the world work on this issue and there are a low number of laboratory research setups, which enable pseudo-real time visualisation of biological structures using UTC: Stanford Research Institute in USA (Green et al, 1974;Green et al, 1976), Gesellschaft für Strahlen-und Umweltforschung at Neuherberg in Germany (Brettel et al, 1981;Brettel et al, 1987), Siemens Corporate Technology in Germany (Ermert et al, 2000;Granz & Oppelt, 1987;Keitmann et al, 2002), Wroclaw University of Technology in Poland (Opielinski & Gudra, 2000;Opielinski & Gudra, 2005, Opielinski et al, 2010a, 2010b, University of California in San Diego and University of Washington Medical Center in Seattle (Lehmann et al, 1999). In most of studies, the projection parameter is the signal amplitude, not its transition time, which seems to more attractive due to the simplicity and precision of measurements.…”