History Of Ultrasound Flashcards
Frequency of Infrasound
Below 20 hertz
Below audible sound range
Frequency of Audible sound
20-20 000 hertz
We can hear
Frequency of Ultrasound
Above 20 000 hertz
Frequency of Diagnostic Medical uses
1-30 Megahertz
1 Mega = 1 Million
Frequency of Therapeutic uses
1-3 Megahertz
1 Mega = 1Million
Which is more Intense:
Diagnostic Medical uses (1-30 Megahertz)
Therapeutic uses (1-3 Megahertz)
Therapeutic is more intense
What year did an Italian priest/scientist find that a blinded bag could function, but a deaf one could not?
1793
What and When did the Currie Brothers discover?
In 1880 they discovered the piezoelectric effect
What is the piezoelectric effect
Apply pressure waves to quartz crystal caused electrical pulses (voltage)
What is the reverse piezoelectric effect?
Apply voltage (electrical pulses) to a quartz crystal and it produces pressure waves.
What are a couple ways in which ultrasound can be used besides medical uses?
The military
- 1906 used sonar to detect icebergs
- 1916 used to detect submarines
Metal flaw detectors
-1928 these were used to check integrity of metal for ships/aircrafts
Who was Karl Dussik?
- A neurologist/psychiatrist who used ultrasound for medical purposes (1942) in Vienna
- A-mode scanning to see brain tumor
Who was George Ludwig
Used A-mode scanning to diagnose gallstones.
Who was Hertz and Edler
- 1954 they used A-mode to show heart motion
- lead to development of M-mode ultrasound
Who was Ian Donald?
- “Father of Obstetrical ultrasound”
- used ultrasound to identify gestational sac
- developed biparietal diameter measurement (BPD)
What and When did Ian Donald and Tom Brown develop?
In 1957 they developed the first compound scanner (gave an image)
What is Real Time scanning (dynamic scanning) and when was it introduced?
- 1973
- when a single frame or image is created several times per second to give the appearance of movement (B-mode)
- probe is constantly firing/listening
A-mode
-Amplitude
-most basic form
-amplitude over time graph
(Distance between transducer and structure determines where an echo is seen on time axis; spike is produced based on amplitude of echo)
-each spike is a reflector
B-mode
- brightness (white is stronger : black is not there)
- display intensity (amplitude) of echo by varying brightness of dots
- each dot is separate echo intensity and location
- compounding dogs make a 2D image
Bi-stable
- is a B-mode image
- ONLY black and white
- NO soft tissue differentiation
- use cathode ray tube for display
Gray Scale
- is B-mode
- has many shades of grey
- uses scan converter NOT cathode ray tube
M-mode
- motion modulation
- series of B-mode dots displayed on motion over time graph, the structures motion can be seen
Doppler
Means of displaying the motion of red blood cells by detecting a perceived change in the frequency of the emitted sound
(Goes out/comes in at different frequencies)
When did “static scanning” come to term?
Only after real time scanning was introduced
What means the same as static scan?
Static Scan
B-scan
Articulated arm scan
What is contacts scanning?
Is when the transducer actually touches the patient. Describes transition from having patients placed in water bath
What is Compound (static) mode?
Use B-mode to place numerous “lines” of dots together to form an image
What does therapeutic ultrasound do to the body?
It heats up muscle tissue, increases blood flow, overall speeding up the healing process
A compound scanner is the same as what?
Static scan
Articulated arm scan
Simply describe A-mode
Amplitude mode
Strength of returning echos are shown as vertical spikes along time axis
Simply describe B-mode (real time, compound)
Brightness mode
Strength of returning echos are shown as shades of grey (black is NO amplitude)
Simply describe M-mode
Motion mode
Where movement of structures is represented over time
Compare bi-stable and gray scale imaging
Bi-stable : displays back and white, lots of contrast, little tissue differentiation
Gray scale : up to 256 shades and uses scan converter
What is difference between static scanning and real time scanning
Static : articulated arm, only capable of one picture at a time
Real-Time : free hand, appears as live motion
