3 MHz
BNR (Beam Non-uniformity Ratio)
Side radiation
0.8 cm² Applicator
Ultrasound frequency:
1 MHz
3 MHz
ERA (Effective Radiation Area):
IEC 60601-2-5: 2000
21 CFR 1050.10
Beam type:
1 MHz
3 MHz
BNR (Beam Non-uniformity Ratio)
Side radiation
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: 2000
•
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
Duty
modulatie
cycle
Pulsduur
16Hz
5%
16Hz
10%
16Hz
20%
16Hz
33%
16Hz
50%
16Hz
80%
16Hz
100%*
48Hz
5%
48Hz
10%
48Hz
20%
48Hz
33%
48Hz
50%
48Hz
80%
48Hz
100%*
100Hz
5%
100Hz
10%
100Hz
20%
100Hz
33%
100Hz
50%
100Hz
80%
100Hz
100%*
* = continuous mode
: Collimating
: 6:1 maximum
: 10 mW/cm² maximum
: 0.98 MHz ± 5 %
: 3.1 MHz ± 5 %
: 0,6 cm²
: 0,8 cm²
: Collimating
: Diverging
: 6:1 maximum
: 10 mW/cm² maximum
RTPA
3.1ms
20
6.3ms
10
12.5ms
5
20.6ms
3
31.3ms
2
50ms
1.25
62.5ms
1
1ms
20
2.1ms
10
4.2ms
5
6.9ms
3.33
10.4ms
2
16.7ms
1.25
20.8ms
1
0.5ms
20
1ms
10
2ms
5
3.3ms
3.33
5ms
2
8ms
1.25
10ms
1
55