Ultrasound uses sound waves with frequencies higher than what humans can hear to produce images of internal organs and structures. It is commonly used in medicine to visualize muscles, tendons and detect abnormalities. Ultrasound is relatively inexpensive compared to other imaging techniques like MRI and CT. Doppler ultrasonography employs the Doppler effect to determine the speed and direction of moving tissues and fluids like blood flow, which is presented using color scales to produce duplex images showing anatomy and velocity.

1. By
Dr.S.Selvaraj
Dept.of zoology
Vivekananda college

2. Ultra Sound Scan
 Ultrasound is sound waves with frequencies higher than
the upper audible limit of human hearing.
 Ultrasound is not different from "normal" (audible) sound
in its physical properties, except that humans cannot hear
it.
 This limit varies from person to person and is
approximately 20 kilohertz (20,000 hertz) in healthy young
adults. Ultrasound devices operate with frequencies from
20 kHz up to several gigahertz.

3. Ultrasound is used in many different fields. Ultrasonic
devices are used to detect objects and measure
distances.
Ultrasound imaging or sonography is often used
in medicine. In the nondestructive testing of products
and structures, ultrasound is used to detect invisible
flaws.
Industrially, ultrasound is used for cleaning, mixing,
and accelerating chemical processes. Animals such
as bats and porpoises use ultrasound for
locating prey and obstacles.

4. Biomedical applications
 Ultrasound also has therapeutic applications, which can be
highly beneficial when used with dosage precautions.
 Relatively high power ultrasound can break up stony
deposits or tissue, accelerate the effect of drugs in a
targeted area, assist in the measurement of the elastic
properties of tissue, and can be used to sort cells or small
particles for research.
Fig.1.Ultra Sound Scan

5.  Medical ultrasound is an ultrasound-based
diagnostic medical imaging technique used to visualize
muscles, tendons, and many internal organs to capture
their size, structure and any pathological lesions with real
time tomographic images.
 Ultrasound has been used by
radiologists and sonographers to image the human body
for at least 50 years and has become a widely used
diagnostic tool.
 The technology is relatively inexpensive and portable,
especially when compared with other techniques, such
as magnetic resonance imaging (MRI) and computed
tomography (CT).
Human medicine

6. Doppler Scan
 Doppler ultrasonography is medical ultrasonography that
employs the Doppler effect to generate imaging of the
movement of tissues and body fluids (usually blood), and their
relative velocity to the probe.
 By calculating the frequency shift of a particular sample
volume, for example, flow in an artery or a jet of blood flow
over a heart valve, its speed and direction can be determined
and visualized.
 Color Doppler or color flow Doppler is the presentation of
the velocity by color scale.

7.  Color Doppler images are generally combined with grayscale
(B-mode) images to display duplex ultrasonography images,
allowing for simultaneous visualization of the anatomy of the
area.
 This is particularly useful in cardiovascular studies
(sonography of the vascular system and heart) and essential in
many areas such as determining reverse blood flow in the liver
vasculature in portal hypertension.
Fig.2.Doppler Scan