chapter one intro

what two factors determine the speed of sound through structures

density and stiffness

and soft tissue the assumed average propagation velocity is ____ m/sec

1540

acoustic _____ is the measure of a materials resistance to the propagation of sound

impedence

Who discovered pizoelectricity

curre brothers

One advantage of diagnostic ultrasound is that it does not involve radiation

ultrasound is audible by the human ear

____ distinguishes the adjacent structures in an object

resolution

The velocity of propagation is constant for a given tissue and not affected by the frequency or wavelength of a pulse

sound as a result of mechanical energy that produces alternating

compressions and rarefactions factions

how are power and intensity related?

directly

___ is the rate at which energy is transmitted

power

change and direction of sound when sound meets an interface between two tissues that transmit sounds at different speeds

refraction

propagation of energy that moves back-and-forth or vibrates at a study rate

wave

what describes instrumentation used in ultrasound

sonogram, ultrasonography, diagnostic medical sonography

The loss of sound energy secondary to its conversion to thermal energy

absorption

The reduction in intensity and amplitude of a sound wave as it travels through a medium. The sum of acoustic energy loss.

attenuation

speed of sound in the various materials in increasing order

gas, liquid, soft tissue, solids

unit used to measure intensity, amplitude, and power of an ultrasound wave

decibel

refers to the redirection of sound and multiple directions

scattering

Number of cycles per given time. for ultrasound refers to the oscillations per second

frequency

ultrasound is specifically sound having a frequency greater than ____ khz

20

The creation of electrical potential as the result of physical pressure applied to a crystal is

piezoelectricity

in addition to technical skills, a sonographer must also have ____ skills

written and verbal

A sonographer should ask the patients history before performing an ultrasound exam

patients are not permitted to get their medical records

violators of a patient’s privacy rights, under hippa our subject to civil and criminal penalties

when an ultrasound is ordered, who’s responsibility is it to explain the image

sonographerz

ALARA is abbreviation for what principle

as low as reasonably achievable

explaining nature of procedure/intervention associated risks, benefits, alternatives and assessment of understanding

informed consent

what are the three types of standards created by HIPAA?

privacy, security and administrative implication

only the department managers are responsible for maintaining department guidelines and manuals