Biomedical Engineering Reference
In-Depth Information
1
0.9
0.8
0.7
0.6
f = 5 MHz
0.5
0.4
0.3
0.2
0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Penetration depth
f = 50 MHz
Figure 1.15: Ultrasound beam intensity versus the penetration depth for several
frequencies (5-50 MHz).
Figure 1.16:
A rotatory transducer emits a radially focused beam. Angu-
lar positions
θ
1
and
θ
2
define a segment of arc S, which can be calculated
from the speed of rotation and the speed of propagation of the ultrasound
beam.