Beam Characteristics, Power, And Intensity Measurement - Accelerated Care Plus OMNISOUND 3000C PRO User Manual

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OMNISOUND 3000C PRO USER MANUAL
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The Omnisound 3000C Pro offers duty factors in pulsed mode of 50, 33, 25, 20, 10 and 5 percent. Decreasing duty
factor will decrease the average ultrasonic power which will lower the thermal effect of the beam on the tissue. The
pulse duration is preset at 2 milliseconds. The system produces square wave output in pulsed mode. Average power
or intensity may be calculated by taking the digital power meter reading and multiplying it by the duty factor.

Beam Characteristics, Power, and Intensity Measurement

Intensity is a quantity used to establish exposure level to the ultrasound beam. It is measured in watts per square
centimeter of effective radiating surface. Ultrasound applicators do not generally produce beams of perfectly
uniform intensity over the surface of the transducer. Thus the measurement represents an average for the effective
radiating surface area.
Beam Divergence
The beam divergence of an ultrasonic therapy applicator is related to the frequency of the ultrasound and the size of
the source (applicator). The lower the ultrasound frequency the greater the beam divergence. Conversely the
smaller the source diameter the greater the beam divergence.
Low Frequency
THE RELATION OF BEAM DIVERGENCE TO FREQUENCY
THE RELATION OF BEAM DIVERGENCE TO SOURCE DIAMETER
In general, the output of a piston radiator (typical ultrasonic therapy applicator) is more complex than the above
since the source does not produce a uniform field over its surface. As the ultrasound leaves the transducer the beam
size remains relatively constant (although there is non-uniformity). This is followed by a region with a more uniform
field. These areas are known as the near and far fields.
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High Frequency
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