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EN109-1631750-48 IFU
Description of Ultrasound Field
The spatial distribution of the radiated field is a collimated beam (diverging for the 0.8 cm² applicator
at 3 MHz) of ultrasound energy, with a decreasing amplitude at increasing distance from the
applicator surface. This field distribution applies to the radiation emitted into the equivalent of an
infinite medium of distilled, degassed water at 30 ºC and with line voltage variations in the range of ±
10% of the rated value. The ultrasonic beam is characterized by the Effective Radiation Area (ERA) and
the Beam Non-Uniformity Ratio (BNR).
The Effective Radiation Area is the cross-sectional area of the ultrasound beam. Its value depends on
the ultrasound standard used:
•
International: IEC 60601-2-5
•
USA: 21 CFR 1050.10
The Beam Non-Uniformity Ratio is the ratio of the maximum ultrasound Amplitude to the average
ultrasound Amplitude, measured at the Effective Radiation Area. A low BNR value is indicative for the
absence of high and potentially dangerous energy concentrations.
Amplitude Modulation
Duty cycle
Pulse Duration
RTPA
16Hz
5%
3.1ms
20
16Hz
10%
6.3ms
10
16Hz
20%
12.5ms
5
16Hz
33%
20.6ms
3
16Hz
50%
31.3ms
2
16Hz
80%
50ms
1.25
16Hz
100% *
62.5ms
1
48Hz
5%
1ms
20
48Hz
10%
2.1ms
10
48Hz
20%
4.2ms
5
48Hz
33%
6.9ms
3.33
48Hz
50%
10.4ms
2
48Hz
80%
16.7ms
1.25
48Hz
100% *
20.8ms
1
100Hz
5%
0.5ms
20
100Hz
10%
1ms
10
100Hz
20%
2ms
5
100Hz
33%
3.3ms
3.33
100Hz
50%
5ms
2
100Hz
80%
8ms
1.25
100Hz
100%
10ms
1
* = continuous mode
