Chapter 3 penny Flashcards
the rules that states that it takes 13 microseconds for sound to travel 1 centimeter in soft tissue
13 us rule
the interference pattern caused by scatterers that produces the granular appearance of tissue on a sonographic image
acoustic speckle
the height of the spike on the image is related to the strength (amplitude) of the echo generated by the reflector
A mode
as low as reasonably achievable; the principle that states one should always use the lowest power and shortest scanning time to reduce potential exposure to the patient
ALARA
the part of the receiver that increases or decreases the received echoes equally, regardless of depth
amplification
the maximum or minimum deviation of an acoustic variable from the average of that variable; the strength of the receiver
amplitude
the part of the digital scan converter that converts the analog signals from the receiver to binary for processing by the computer
analog-to-digital converter
without echoes, or black
anechoic
the technique that varies the voltage to the individual elements to reduce grating lobes
apodization
echoes on the screen that are not representative of actual anatomy, or reflectors in the body that are not displayed on the screen
artifacts
a non-Doppler technology that offers real time imaging of blood flow while scanning in grayscale
B-flow imaging
the brightness of the dots is proportional to the strength of the echo generated by the reflector
B mode
the part of the machine that shapes and steers the beam on the transmit end
beam former
the digital language of zeroes and ones
binary system
black and white image
bistable
the smallest unit of memory in a digital device
bit
eight bits of memory
byte
display that uses an electron gun to produce a stream of electrons toward a phosphor-coated screen
Cathode ray tube
a way of processing the pulse to improve contrast resolution and reduce speckle
coded excitation
a type of reverberation artifact caused by small reflectors
comet tail
the function of the receiver that changes the brightness of the echo amplitudes to compensate for attenuation with depth
compensation
the function of the receiver that decreases the range of signal amplitudes present within the machine’s receiver; opposite of dynamic range
compression
the ability to differentiate one shade of gray from another
contrast resolution
the function of the receiver that makes the signal easier to process by performing rectification and smoothing
demodulation