Ultrasonography is the second most commonly used imaging format
Important part of specialty areas in clinical medicine , gynaecology and obstetrics , surgery, cardiology, gastro,
enterology,orthopaedics and ophthalmology Insights into basic anatomy and
physiological processes Almost all organs and tissues are now accessible
Minimally invasive imaging method Least hazards
IS ULTRASOUND? : WHAT IS ULTRASOUND? Ultrasound or ultrasonography is a medical
imaging technique that uses high frequency sound waves and their echoes.
Ultrasound : Ultrasound Ultrasound is defined as sound waves of frequencies
greater than 20,000 Hz. Frequency range of 1-10MHz (max.20MHz) used in diagnostics , sound wave travels in a pulse and when it is reflected back it
becomes and echo. It is the pulse echo principle, which is used for ultrasound
imaging. No propagation in vacuum and poor transmission in gases Generated by
Principle of operation :
Principle A pulse is generated by one or
more piezoelectric crystals in an ultrasound transducer. When these crystals
are stimulated electrically it changes its shape and produces sound waves of
particular frequencies. The frequency of a transducer is determined by the
times the crystals expands and contracts per second. In an ultrasound scanner
the crystal is shocked by a short pulse of electricity to vibrate.
Ultrasound Machine Components
* Central Processing Unit (CPU
* Transducer probe
* Transducer Pulse Controls
* Disk Storage
As the transducer is placed in close
contact with the body surface through a coupling medium, it undergoes
continuous modification that occurs through three processes Absorption,
Reflection And scattering.
Absorption: It occurs when the energy in the
sound beam is absorbed by the tissues thereby converting it into heat.
Absorption process forms the basis of therapeutic ultrasound
Reflection : It is the redirection of a portion
of the ultrasound beam back towards the source. The reflection gives rise to
echo and forms the basis of diagnostic ultrasound. These echoes are converted
by piezoelectric effect into electric signals that are displayed onto on
Scattering : It occurs when the beam
encounters an interface that is irregular and smaller than the sound beam. The
portion of the beam that interacts with this interface is scattered in all the
directions. Two closely related phenomenons occur, refraction and diffraction
of which refraction is a common cause of artifacts.
Echo quantification : Echo quantification For displaying this echo amplitude
information, different modes are used.
Display Modes :
mode (amplitude) : Display Modes : A-mode (amplitude) Reflective
surfaces are displayed as vertical spikes with different amplitudes along
baseline Application: Echo-encephalography Echo-ophthalmography Pregnancy diagnosis
B*mode (brightness) : B-mode (brightness) Returning echoes are displayed as
dots with varying brightness on the monitor Brightness or grey scale.
2*D Brightness mode: * Assembles numerous 1*D scan in to 2*D US image *
Echoes traced along vertical line.
Interfaces that are stationary; are seen in straight line Interfaces that re in
motion ;are seen as wiggly line.
Real Time Mode : Real Time Mode Static organs: Slow frame rate & high scan
line density Cardiological scans: Higher frame rate.
3*D ultrasound ; ultrasound waves are directed from multiple angles ; waves are
reflected back and captured, providing very detailed 3*dimensional images of
the baby 4*D ultrasound ; the process of streaming 3*D images into live,
real;time video of the baby. This allows viewers to see real;time motion.
Triangular or pie shaped (Sector) Use: Echocardiography,Sonography of intra
pelvic & intra thoracic organs, brain, eyes, testes & joints.
Rectangular linear (Linear) Use: Sonography of abdominal organs (extra
thoracic) Sonography of superficial structure (skin, mammary gland, joints and
Trapezoid convex (Curved array) Use: Abdominal ultrasonography Pregnancy
Endorectal Transducer :
Endorectal Transducer Transducer with attached
biopsy guide system and inserted needle Provide advantage of US beam offset by
Ultrasonography involves considerable
cooperation between the patient and the sonologist. The transducer must be in
close contact with the patients skin to have minimum attenuation of the sound
beam. In Vety. Patients it requires clipping of hair and cleaning of skin.
There should not be any air between the transducer and skin, as it will
completely block the beam. So good contact is provided by application of
mineral oil or an aqueous gel between the transducer and contact surface. Any
coupling medium should be applied liberally. Both gas and bone acts as a
barrier to ultrasound beam as these reflect the beam. Therefore, a proper
acoustic window should be formed to visualize the organ.
Some applications for ultrasonic
1. congenital heart diseases.
2. kidney abnormalities.
3. pregnancy check and follow up
4. skin care.
5. gynaecology and obstetrics diagnosis
7. enterology diagnosis.
We are in Technotronics (medical Dept) repair many models of many
ultrasonic devices including:
1. monitor repair
2. power supply repair
3. transducer repair
4. CPU repair
5. INPUT – OUTPUT boards repair
And so many other boards inside
Call us on hotline 01001562186 for more details.