ULTRASOUND 1 & 2

Doppler ultrasound

Measures tissue motion and blood flow using the doppler effect

Sonography

Medical imaging using 2D, 3D, and 4D ultrasound for anatomy and bloodflow

Pulse echo technique

Sonography is accomplished with a _____

Sound

It is a form of energy which causes a mechanical disturbance in the form of vibration of molecules within medium

Longitudinal wave

Sound is a mechanical wave that travels in a medium in a _______

Longitudinal waves, transverse waves

Type of sound waves (2)

Ultrasound, audible sound, infrasound

3 categories of sound

Period

The time taken for one complete cycle to occur

Inverse

Relationship between period and frequency

Wavelength

Length of a wave or cycle

Amplitude

The maximum displacement that occurs in an acoustic variable

Amplitude

It is defined by the difference between the peak (maximum) or trough (minimum) of the wave and the average value

Pascals or MPa

Unit of amplitude expressed in pressure parameters

Frequency

It is the number of cycles that occurs in one second

Frequency

It affects penetration of sound and image quality

Pulse repetition period (PRP)

Time from the beginning of one pulse to the beginning of the next

Inverse

Relationship between PRP and PRF

Pulse duration

Time it takes for one pulse to occur

Inverse

Relationship between PULSE DURATION and FREQUENCY

Velocity

It is dependent on the compressibility and density of the medium

Power (Watts)

It is the rate of energy transferred through the soundwave

Intensity

It is the concentration of energy in a sound wave

Intensity

It is dependent on the Power and the cross sectional area of a sound beam

Lazzaro Spallanzani 1794

First to study ultrasound physicsby deducing bats

Jean Daniel Colladon 1826

He uses church bell to calculate speed of sound through water

Christian Andreas Doppler 1842

Suggests that the frequency of a sound wave depends on the speed of the source

Pierre and Jacques Curie 1880

Discovered the Piezo-Electric effect

Paul Langevin 1915

After titanic sink, he invented hydrophone to detect icebergs submarines during WW1

Kark Dussik 1942

The first physician to use ultrasound for medical diagnosis (brain tumors)

George Ludwig 1948

He first described the use ultrasound to diagnose gallstones

Inge Edler and Hellmuth Hertz 1953

They performed the first successful echocardiogram

Ian Donald 1958

Pioneer of OB-GYN ultrasound

Douglass Howry and Joseph Holmes 1950s

They pioneered the 2D B-mode ultrasound

Late 1950s

The first contact compound B-scanner (using olive oil as lubricant) was developed

Kazunori Baba 1980s

3D ultrasound technology and captured 3D images of a fetus in 1986

1990s

4D real time capabilities and ultrasound guided biopsies

1-10 MHz

Range of diagnostic ultrasound

0.7-1.0 MHz

Range of therapeutic ultrasound

1-5 MHz

Range of surgery ultrasound

25-400 kHz

Range of industrial ultrasound

20-50 kHz

Range of military ultrasound

331

Speed in m/sec of Air (at 32° F)

1531

Speed in m/sec of Water/Sea (at 77° F)

5200

Speed in m/sec of Solid (Steel)

16

Infrasound’s frequency is below ___ Hz

94

1 Pa = ___ db SPL

0.00002244

1 db SPL = ___ Pa

Pulse repetition frequency (PRF)

Number of pulses occuring in 1 s

Pulse repetition period (PRF)

Time from the beginning of one pulse to the beginning of the next

Thermal index

It is a predictor of max. temperature increases under clinicallt relevant conditions

Mechanical index

Gives an estimation of cavitation effect of uktrasound