5 - ultrasound - 45 mim

Ultrasound

Beginnings in the 1880s when Pierre Curie Beginnings in the 1880s when Pierre Curie introduced simple echo sounding introduced simple echo sounding methods. methods.

1913 discovery of SONAR 1913 discovery of SONAR --(Sound (Sound Navigating and Ranging)Navigating and Ranging)

First introduced to medical world in 1950sFirst introduced to medical world in 1950s

History

Dog whistleDog whistle Bets and dolphins communication and Bets and dolphins communication and

orientationorientation SonarSonar SubmarineSubmarine--boat communication boat communication

Applications

UltrasoundUltrasound--welding (for plastic)welding (for plastic) Materials testingMaterials testing Multiphase flow measurementMultiphase flow measurement

Applications

Disinfection of instruments Disinfection of instruments

ImagingImaging Detection of tumors (Oncology)Detection of tumors (Oncology) AssesmentAssesment of the development of fetus of the development of fetus

(OB/GYN)(OB/GYN) Evaluation of blood flow (Cardiology)Evaluation of blood flow (Cardiology) InsertionsInsertions

TherapyTherapy

Medical Applications

Frequency Range

Low bass notes Animals

Medical and destructive

Diagnostic

Physics

REFLECTED WAVEINCIDENT WAVE

MEDIA 1 - water

MEDIA 2 - air

TRANSMITTED WAVE

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=16

Same frequency in both materialshttp://interactagram.com/physics/optics/refraction/

Indices of Refraction

Animation:http://health.howstuffworks.com/adam-200128.htm

Principle

Transducer

Transducer

Distance equal to less than a wavelength for the minimum interference and reduced grating lobes

Transducer

Transducer

CRC Press - Biomedical Technology and Devices Handbook


Transducer

Transducer

9.19

Images

A-Mode

V

t

Images

B-Mode

DLigne US Ligne US

(analogique) (Vidéo)

Images

B-Mode: Normal Imaging


Images

Images

M-Mode (Motion-mode imaging)Image line is a function of time

Examples:• Heart valves• Cross-section of a carotid artery

Images

M-Mode (Motion-mode imaging)

Images

Doppler Mode

Images

Doppler Mode

http://www.kettering.edu/~drussell/Demos/doppler/doppler.html

Images

Doppler Mode

Images

Doppler Mode - Flow track

Images

3D Imaging (4D + time)

ImagesFrame Rate

The size of an area in a scene that is The size of an area in a scene that is represented by one pixel in the imagerepresented by one pixel in the image

Lower resolution leads to data reduction!Lower resolution leads to data reduction!

Resolution

Tradeoff between resolution and attenuation Tradeoff between resolution and attenuation ↑↑higher frequency higher frequency ↓↓shorter wavelength shorter wavelength ↑↑ higher attenuationhigher attenuation

Power loss:Power loss:

Typical Ultrasound Frequencies: Typical Ultrasound Frequencies: Deep Body Deep Body 1.5 to 3.0 MHz1.5 to 3.0 MHzSuperficial Structures Superficial Structures 5.0 to 10.0 MHz5.0 to 10.0 MHz

Resolution

MHz cmdB 1

Amplification

Gain compensation as fuction of the deep

Amplification lineAmplification line

Echo 1 Echo 2

1dB / 1MHz / 1cm

Reflection coefficient

Rmuscle/blood=1,63 - 1,561,63 + 1,56

Muscle 1,63Blood 1,56FatFat 1,421,42

2)

0,00079 0,079%

(

Air 0,0004

Total reflection

1,63 - 0,00041,63 + 0,0004

Rair/muscle = )( 2

0,99887 99,88%

Gel

No gel with gel

Ultrasound at high energy can be used to Ultrasound at high energy can be used to ablate (kill) tissue.ablate (kill) tissue.

Cavitation (bubble formation)Cavitation (bubble formation)

Temperature increase is limited to 1Temperature increase is limited to 1ºº C for C for safety.safety.

Safety

Block Diagram

Block Diagram

RF AMPLIFIER FM DEMODULATOR AMPLIFIER SIGNAL PROCESSING

RECEPTOR

TRANSMITTER OSCILLATOR

BODY

SPEAKER DISPLAY

Block Diagram

Cell Phone Ecography

Gathering data with the phones and sending it where specialists can analyze the image

Cost: $2,000 (goal of $500)

Therapy

Phacoemulsification

Phacoemulsification - Videos

Kidney Stones

A biplane xA biplane x--ray apparatus is used to make sure the stone is at the focal poiray apparatus is used to make sure the stone is at the focal point of sparknt of spark--generated shock generated shock waves from the ellipsoidal reflector.waves from the ellipsoidal reflector.

Kidney Stones - Shock Wave Lithotripsy

http://www.umm.edu/patiented/articles/kidney_stones_animation_000475.htmhttp://hcd2.bupa.co.uk/fact_sheets/html/Kidney_stones.html

Kidney Stones

UreteroscopyPercutaneous Nephrolithotomy

Disinfection of Instruments

Experience

5 - ultrasound - 45 mim

Documents