Ultrasound machine

1. Regents Biology 2015/2016
[ ultrasound Machine ]
Mohamed M.Elsaied
2017/2018
Supervised by Dr. Dalia El-Kamshoshy
Allied Medical Science
Medical equipment technology
MEDICAL ELECTRONICS

2.  Introduction
Mohamed M.Elsaied
2017/2018
 Sound waves above 20 KHz.
 Sound waves propagate mechanical energy causing periodic
vibration of particles in a continuous, elastic medium.
 Sound waves cannot propagate in a vacuum
 Sound is propagated through a mechanical movement of a particle
through compression and rarefaction that is propagated through the
neighbor particles depending on the density and elasticity of the
material in the medium.

3. Mohamed M.Elsaied
2017/2018
 The velocity of the sound in
 Air: 331 m/sec
 Water: 1430 m/sec
 Soft tissue: 1540 m/sec
 Fat: 1450 m/sec
 Ultrasound medical imaging: 2MHz to 10 MHz
 2 MHz to 5 MHz frequencies are more common.
 5 MHz ultrasound beam has a wavelength of 0.308 mm in
soft tissue with a velocity of 1540 m/sec.

4.  Physical Properties Of ultrasound
Mohamed M.Elsaied
2017/2018
 When an ultrasound wave meets a boundary between two different
materials some of it is refracted and some is reflected.
The reflected wave is detected by the ultrasound scanner and forms
the image. The proportion of the incident wave that is reflected
depends on the change in the acoustic impedance, Z.
 Acoustic Impedance,
Z = Pc
1. Where P = the density of the material, kgm-3
2. c = speed of sound in that material, ms-1

5. Mohamed M.Elsaied
2017/2018
 Intensity reflection coefficient At a boundary between mediums,
the ratio of the intensity reflected, Ir to the intensity incident, I0 is
known as the intensity reflection coefficient, 

6.  Ultrasound Device
Mohamed M.Elsaied
2017/2018
1. Displaying Monitor
2. Transducer / Probe
3. Keyboard
4. Probe Connector
5. Printer (B/W & Color)
6. Power Supply

7.  Ultrasound System
Mohamed M.Elsaied
2017/2018
 Display - The system will have some way of displaying the data it
acquires.
 User Interface - It must have a user interface, this may be
mechanical or voice activated.
 Transducer – Your ultrasound system will have a transducer to
convert electrical impulses to sound and back.
 Image Processing - The ultrasound machine will have some sort
of image processing. This may be analog or digital.
 Power Supply - Finally it will have a power supply, again analog
or digital.
 Peripherals ( may include cameras, or printers).

8.  Schematic Of Ultrasound
Mohamed M.Elsaied
2017/2018

9.  Probe of Ultrasound
Mohamed M.Elsaied
2017/2018


10.  Impedance Matching
Mohamed M.Elsaied
2017/2018
 When ultrasound passes through two very different materials the
majority of it is reflected. This happens between air and the body,
meaning that most ultrasound waves never enter the body.
 To prevent this large difference
in impedance a coupling medium
(Gel) is used between the air and the skin.

11.  Ultrasonic transducer
Mohamed M.Elsaied
2017/2018
 Piezoelectric materials
 Natural quartz
 Barium titanate
 Rochelle salts
 Lead zirconate titanate
 In the case of ultrasound two transducer function are recognized:
 conversion of ac electric oscillation into acoustic vibration
 Conversion of acoustic vibrations into ac oscillations of the
same frequency.
 These two functions are the transmitter and receiver
transducers.

12. Mohamed M.Elsaied
2017/2018

13. Mohamed M.Elsaied
2017/2018

14. Mohamed M.Elsaied
2017/2018

15. Mohamed M.Elsaied
2017/2018

16. Mohamed M.Elsaied
2017/2018

17.  DISPLAY TECHNIQUES
Mohamed M.Elsaied
2017/2018
 A- mode
 B- mode
 M- mode

18. Mohamed M.Elsaied
2017/2018
 A-Mode Scan
 Records the amplitude of returning echoes from the tissue
boundaries with respect to time. In this mode of imaging
the ultrasound pulses are sent in the imaging medium with
aperpendicular incident angle.

19. Mohamed M.Elsaied
2017/2018
 M-Mode Scan
 Provides information about the variations in signal amplitude
due to object motion.
 A fixed position of the transducer, in a sweep cycle, provides a
line of data that is acquired through A-mode.
 The data is displayed as a series of dots or pixels with brightness
level representing the intensity of the echoes.

20. Mohamed M.Elsaied
2017/2018
M-Mode display of mitral valve leaflet of a beating heart

21. Mohamed M.Elsaied
2017/2018
 B-Mode Scan
 Provides two-dimensional images representing the changes
in acoustic impedance of the tissue
The “B-Mode” image of a beating heart with mitral stenosis.

22.  Troubleshooting
Mohamed M.Elsaied
2017/2018

23. Mohamed M.Elsaied
2017/2018
 Troubleshooting

24. Mohamed M.Elsaied
2017/2018
 Troubleshooting

25. Mohamed M.Elsaied
2017/2018
 Troubleshooting