16
W
150 KHz～80 MHz
d=1.2
80 MHz～800 MHz
d=1.2
800 MHz～2.5 GHz
d=2.3
0.01
0.12
0.12
0.23
0.1
0.38
0.38
0.73
1
1.2
1.2
2.3
10
3.8
3.8
7.3
100
12
12
23
For transmitters maximum ratings not listed above, the recommended separation distance, d, in meters
(m), can be determined using the formula in the corresponding transmitter frequency column, where P is
the transmitter provided by the transmitter manufacturer The maximum rated output power in Watts (W).
Note 1: At the 80 MHz and 800 MHz frequency points, the formula for the higher frequency band should
be used.
Note 2: These guidelines may not be appropriate for all situations. Electromagnetic transmission by the
buildings, objects and the body's absorption and reflection.
1.10
ALARA Principle (As Low As Reasonably
Achievable)
Ultrasound should obey the ALARA principle, use the lowest level of energy that does
not lead to biological effects, provided that satisfactory diagnostic information is available.
Ultrasonic energy depends on the size of the output intensity and exposure time. Different
patients and clinical cases require different intensity of ultrasound. Not all inspections can
be done by outputting very low energy ultrasound. Very low energy ultrasound will only
produce low-quality images or weak Doppler signals, thus affecting the reliability of
diagnosis. However, the use of more than actual needs of the acoustic power does not
help to improve the quality of information used for the diagnosis, but will increase the risk of
biological effects.
When obtaining clinical information, the user should perform the ultrasonic inspection
procedure with the lowest output level and irradiation time according to the principle of
small size (ALARA) when a satisfactory clinical diagnostic map is available.
Содержание C-Scan
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