Physical ultrasound

1. Al-Quds university
Graduate School
Radwan Al-qasrawi
Arwa Badarin
Ultrasound

2. Contact
1. Introduction
2. Ultrasound tissue interaction
3. Compound of ultrasounds
4. Image formation
5. Image display
6. Application of ultrasound

3. Sound
•Sound is a mechanical, longitudinal wave that trave a straight line
• Sound waves are transmitted as a series of alternating pressure waves with
high pressure and low pressure pulses.
•The high pressure areas (compression) are where the particles have been
squeezed together; the low pressure areas (rarefaction) are where the
particles have been spread apart.
• Sound waves cannot travel in vaccum

5. CHARACTERISTICS OF SOUND
• A sound beam is similar to x-ray beam in that both
are waves transmitting energy but important
difference is that x-rays pass through a vacuum
where as sound require a material medium ( solid,
liquid , gas ) for transmission, they will not pass
through the vacuum.
• Sound must be generated mechanically by
vibrating body matter

6. History
• Piezoelectricity discovered by Pierre and Jacques Curie in 1880 using
natural quartz
• SONAR was first used in 1940s war time
• Diagnostic medical applications in use since late 1950's

7. "Ultra".......sound?
Ultrasound imaging is a medical imaging technique
It uses high-frequency sound waves to create images of internal body structures
It is safe, painless, and non-invasive
Audible range is 20 to 20,000 cycles per second
• Ultrasound has frequency greater than 20,000 cycles per second

9. Ultrasound tissue interaction :
1. Reflection
2. Refraction
3. Absorption
4. Attenuation
5. Scattering

10. Compound of ultrasounds :
1-transducer :that produces
and receives sound waves,
2-CPU:a processing unit that
generates images
3-display:a display to view the
images
4.control panel to adjust
settings
5- power supply
6- printer: prints the image
from the displayed data

11. How is ultrasound imaging done?
"From sound to image"

12. The Transducer
Converts electrical energy into sound
• Components:
Piezoelectric crystal
• Dampening material
• Matching layer covers crystals
Electrodes

14. ACOUSTIC IMPEDANCE
• The ratio of the pressure over an imaginary surface in a sound
wave to the rate of particle flow across the surface.
• It's the fundamental properties of matter.
Z= p V
Z = acoustic impedance
p = density
V = velocity of sound

15. How is an image formed on the monitor?
• The amplitude of each reflected wave is represented by a dot
• The position of the dot represents the depth from which the echo is received
• The brightness of the dot represents the strength of the returning echo
• These dots are combined to form a complete image

16. Position of Reflected Echoes
Position of Reflected Echoes
• How does the system know the depth of the reflection?
• TIMING
- The system calculates how long it takes for the echo to return to the transducer
- The velocity in tissue is assumed constant at 1540m/sec
Velocity = Distance x Time/2
Reflected Echoes
• Strong Reflections = White dots
- Pericardium, calcified structures, diaphragm
• Weaker Reflections = Grey dots
- Myocardium, valve tissue, vessel walls, liver
• No Reflections = Black dots

17. A-mode displays the depth of structures based
on amplitude.
B-mode displays a 2D cross-sectional imag.
M-mode displays motion over time.
2D mode provides real-time 2D imaging.
The reflected signal can be displayed in four modes

18. Application of ultrasound
1-Obstetrics and Gynecology: used during pregnancy to monitor fetal
development and check for any abnormalities
2-Cardiology: which can be used to diagnose conditions such as heart valve
disease, heart failure
3-Radiology: used to create images of various organs and tissues in the body,
including the liver, kidneys
4-Vascular medicine: used to diagnose and monitor conditions affecting the
blood vessels, such as deep vein thrombosis

19. Thank you