SONOGRAPHY CANADA CORE (PHYSICS) EXAM
QUESTIONS AND ANSWERS GRADED A+
what is a transducer? ANS >>> anything that converts one form of energy
to another form of energy
what does an ultrasound transducer do? ANS >>> converts electro
potential energy into mechanical and mechanical energy into electro
potential energy
what is the curie point? ANS >>> 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 transducers? ANS >>>
Lead zirconate titanate (PZT)
what are modern transducers made out of? ANS >>> composite materials
to achieve greater conversion efficiency with less of an acoustic
impedance mismatch
, Near zone (Fresnel) ANS >>> the area between the face of the transducer
and the beam focus
Far zone (Fraunhofer) ANS >>> Region past the focus
Focus ANS >>> Where the beam reaches its minimum diameter
Focal region ANS >>> Region over which the beam is most tightly focused
Detail resolution ANS >>> Ability to distinguish between two objects in
any of the three dimensions (Axial, lateral, elevational)
Operating frequency ANS >>> Centre frequency of the transmit
bandwidth
what are four methods of focusing the ultrasound beam ANS >>> 1)
Lenses
2)curved elements
3)electronic focusing
4)mirrors
define lateral resolution. What are other names for lateral resolution?
ANS >>> The ability to resolve two structures as well as the limit to
measurement accuracy in the lateral dimension of an image
QUESTIONS AND ANSWERS GRADED A+
what is a transducer? ANS >>> anything that converts one form of energy
to another form of energy
what does an ultrasound transducer do? ANS >>> converts electro
potential energy into mechanical and mechanical energy into electro
potential energy
what is the curie point? ANS >>> 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 transducers? ANS >>>
Lead zirconate titanate (PZT)
what are modern transducers made out of? ANS >>> composite materials
to achieve greater conversion efficiency with less of an acoustic
impedance mismatch
, Near zone (Fresnel) ANS >>> the area between the face of the transducer
and the beam focus
Far zone (Fraunhofer) ANS >>> Region past the focus
Focus ANS >>> Where the beam reaches its minimum diameter
Focal region ANS >>> Region over which the beam is most tightly focused
Detail resolution ANS >>> Ability to distinguish between two objects in
any of the three dimensions (Axial, lateral, elevational)
Operating frequency ANS >>> Centre frequency of the transmit
bandwidth
what are four methods of focusing the ultrasound beam ANS >>> 1)
Lenses
2)curved elements
3)electronic focusing
4)mirrors
define lateral resolution. What are other names for lateral resolution?
ANS >>> The ability to resolve two structures as well as the limit to
measurement accuracy in the lateral dimension of an image
