Quiz 4 Review

27 cards·by Rachel Valley

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A transducer coverts one form of ________ to another

Energy

Does the matching layer reduce or increase the amount of reflection?

Reduce

Without the matching layer, how much energy would be reflected back to the transdcuer?

80%

True or False? You should always autoclave your ultrasound transducer in order to properly clean it

False - Only use cold sterilization or disinfectant. Autoclave will heat up the element and ruin your transducer

True or False? A transducer can be any device that is capable of changing one form of energy to another

True

The ultrasound transducer converts electrical energy into what?

Ultrasound energy

__________________ is the conversion of acoustic pressure enrgy into electrical energy or vice versa

Piezoelectric effect

The matching layer should have an ______________ impedance between the skin and element.

Intermediate

When electricity is applied to the transducer to create sound, this is called _______________.

Indirect Piezoelectric effect

When sound is applied to the transducer and creates electrical energy, this is called the _____________

Direct piezoelectric effect

List the natural piezoelectric elements

Amber, Toumaline, Quartz, Rochelle Salt

Does the matching layer increase reflection or transmission of the transducer element

Increase transmission

What is placed behind the element in order to reduce the pulse duration?

Damping Layer

A thinner element will produce ___________ frequencies

Higher

________________ is the range of frequencies that are present in a pulse

Bandwidth

The ideal thickness of the matching layer is ___________ the wavelength

1/4

Does the damping material increase or decrease the frequencies present in the pulse?

Increase

The number that indicates to what extent the transducer can operate at the main frequency is called __________.

Quality Factor

How do you calculate the quality factor?

Operating frequency divided by Bandwidth

What are the other names for operating frequency?

Resonance, Preferred, Natural

What two factors determine the operating frequency of the transducer?

Propagation speed and thickness of the element

What is the quality factor for a transducer that has a bandwidth of 2 MHz and an operating frequency of 4 MHz?

2.0

Which frequency would have the thinnest element, 2 MHz or 8 MHz?

8 MHz

True or False? The acoustic impedance of the matching layer is approximately the same as the acoustic impedance of the skin

False

True or False? Imaging transducers are usually of high rather than low bandwidth

True

Do Diagnostic Imaging transducers have a high Q factor or Low Q factor?

Low Q factor

True or False? The damping material in a transducer increases the sensitivity

False