Sonography Canada CORE (Physics) | 2023/24 questions and answers

Sonography Canada CORE (Physics) | 2023/24 questions and answers what is a transducer? - anything that converts one form of energy to another form of energy what does an ultrasound transducer do? - converts electropotential energy into mechanical and mechanical energy into electropotential energy what is the curie point? - if a crystal is heated beyond the curie point (360 degrees for PZT) the crystal can lose piezoelectric effects what material is traditionally used for ultrasound trasnducers? - Lead ziconate titanate (PZT) what are modern transducers made out of? - composite materials to achieve greater conversion efficiency with less of an acoustic impedance mismatch Near zone (fresnel) - the area between the face of the transducer and the beam focus Far zone (Fraunhofer) - Region past the focus Focus - Where the beam reaches its minimum diameter Focal region - Region over whch the beam is most tightly focused Detail resolution - Ability to distinguish between two objects in any of the three dimensions (Axial,lateral, elevational) Operating frequency - Center frequency of the transmit bandwidth what are four methods of focusing the ultrasound beam - 1)Lenses 2)curved elements 3)electronic focusing 4)mirrors define lateral