Module 1 : History of Ultrasound Flashcards
infrasound range
below 20 Hz
audible sound range
20 - 20000Hz (20kHz)
ultrasound range
above 20000 Hz
diagnostic medical sonography range
1-30 MHz
therapeutic ultrasound range
1 - 3 MHz
what year did the currie brothers discover the piezoelectric effect
1880
piezoelectric effect
applying pressure waves to a quartz crystal caused electrical pulses (voltage)
A Mode ultrasound was first used for what
used as a metal flaw detector then to see a brain tumor
what does the A in A mode stand for
A = amplitude
A Mode led to the development of what other mode of ultrasound
M Mode
who is Ian Donald and what measurement did he develop
- Father of Obstetrical ultrasound
- biparietal diameter measurement BPD
real time scanning is also called
dynamic scanning
how real time scanning is accomplished
a single frame is created several times per second to give the appearance of movement
ultrasound modes
- A Mode
- B Mode
- Real time Mode
- M Mode
- Doppler ( spectral and color )
- 3D 4D
characteristics of A Mode scanning
- most basic form
- distance between transducer and a structure determines where an echo is seen along the time axis
- a spike is produced according to an amplitude (strength) of echo
characteristics of B Mode scanning
- B = brightness
- method of displaying intensity of an echo by varying the brightness of a dot to correspond to strength
- each bright dot represents an echo intensity and location
- compounding the dots results in a 2D image
Bi-stable imaging
- a B-mode image represented by either a black dot or a white dot
- crappy for tissue differentiation but good contrast
gray scale imaging
- B Mode image that has many shades of gray
- uses a scan converter
characteristics of real time scanning
- B Mode pictures captured at a rate fast enough to mimc physiological imaging
- probe is firing and listening constantly
characteristics of M Mode scanning
- M = motion
- series of B Mode dots displayed on a moving time base the motion of a mobile structure can be seen
characteristics of doppler imaging
using the doppler equation the velocity of blood flow or frequency of blood is determined
static scanning
- term used after real time invented
- static scan = b scan = articulated arm scan
contact scanning
describes transition from having patients in water bath to having transducer touch the patient
