Abstract (Invited) |
High Intensity Piezoelectric Sources
for Medical Applications: Technical Aspects
D.Cathignol (INSERM Unite 556, Lyon,
France)
e-mail:
cathignol@lyon151.inserm.fr
Therapeutic
ultrasound has received increasing interest during the past few years. However,
the development of this technique depends on the availability of high
performance transducers adapted to power generation constraints allowing to
focus and or steer the ultrasonic energy within the volume to be treated.
Roughly, one may consider two different fields where the constraints are
totally different. In the case of generating CW or long burst wave, problems to
be solved are mainly thermal ones while generating very high pulsed pressure
wave demands to solve electrical breakdown and mechanical problems. We will
give some examples of transducers or generator allowing to generate intensity
of about thirty to forty watts per cm2 during several ten of seconds. In the
field of high pulsed pressure generation some new concepts either in the
material or the electrical driving circuit allow to obtain pressures up to 8
MPa at the surface of the transducer. Finally, it is pointed out that
piezo-composite material plays a more and more important role due to its
exceptional properties as for example; high efficiency, large bandwidth,
predictable beam pattern and high flexibility in term of shaping and definition
of sampling in annular arrays, linear arrays or matrix arrays.
Section
: 5