Lecture 1 Flashcards
Invented the whistle that generated high frequency sounds above the range of human hearing.
Galton
Observed that bats navigate in the dark using high frequency echo location.
Spallanzani
Invented the hydrophone, the basis for naval pulse-echo sonar.
Langevin
Was the first to detect gallstones with ultrasound.
Ludwig
Determined that frequency changes with motion.
Doppler
Detected brain tumors with ultrasound.
Dussik
Discovered that when certain crystals are deformed they produce electricity, and when electricity is applied to the crystal the crystal deforms (vibrates). (reception)
Currie brothers
The effect discovered by the Currie brothers.
Piezoelectric Effect
Used cattle tanks to produce ultrasonic images (water path scanner).
Holmes and Howry
With B Mode (greyscale) imaging the depth of the reflector is determined by the _______ it takes for the echo to return.
time
Mathematical formula the machine uses to determine the depth of a reflector.
Depth = Rate x Time /2
With B mode (greyscale) imaging the brightness of a dot placed on the screen is determined by the _______ of the reflection.
Intensity (strength)
Distance equation.
Distance = Rate x Time
The format in which each pulse travels in the same direction from different starting points.
Linear
How long does it take for sound to travel 2 cm and back through soft tissue?
13 us to travel 2 cm
26us
The format in which each pulse originates from the same starting point but goes out in different directions.
Sector
T/F: In color doppler, the color assigned to the top half of the color bar indicates that blood is flowing toward the transducer.
True.
Red - Toward
In color doppler, the darker shades of color indicate:
slower areas of flow.
A doppler shift can be represented by:
Sound, a waveform, or color.
Centi is the metric prefix for:
Hundreths
Milli is the metric prefix for:
Thousandths
+6dB increases intensity:
4x
-20dB decreases the intensity:
1/100 times the original.
