CenSSIS: Acoustics Group at Boston University B-scan images 8 Oct 01

Data information:

Schematic of the set-up

Date: 8 October 2001

Sample - ATS Tissue Phantom 539
Scan Surface 1 left hand side Detailed Description
Temperature 22 C
Front surface 10 mm from transducer face
Z scan: 0 to 60 mm in 1 mm steps
Y Scan: -5 to 5 mm in 0.5 mm steps

Transducer: Panameterics V380
Detailed Description
Centre frequency 3.5 MHz
Diameter 1 in
Focal length 2 in

Pulser: Panameterics 5052UA
Energy Level 4
Damping 50
PRF 200 Hz
Receiver: 0 dB atten; no filter, 20 dB gain Marked RF - interface mode

Scope: Le Croy LP 142
Channel 1; AC coupling
Sampling rate: 25 MS/s
Trig: positive slope from 5052 ext trig
Delay: 20.8 microsecs
Number of sweeps for average: 256

Data file
data:8oct01:phantom.mat 2.8 MB
Description of Matlab file format.

Images

At each z-y location an A line was recorded. The time trace was converted into a distance by multiplying by the sound pseed (1500 m/s) - this distance was then divided by 2 to account for the fact that the travel path is a round trip time. Note that x=0 does not correspond to the transducer. The trasnducer is approximately at x=-8 mm.

The front of the phantom can be seen at x=2 mm as a strong reflection.

The presence of small scatterers that were placed at an angle can be seen from x=5, z=5 mm to x=13, z= 45 mm. They are not well resolved because they are in the near field of the transducer.

A line of objects can be seen at z=45 mm. The focal point should be around x=40 mm and one can see the variation in the point spread function due to the focusing of the beam. The scatterers at x=33 and 43 mm are more compact than those at 22 and 52 mm. The physical separation in the phantom between these scatterers was 10 mm - the image is consistent with this.

The two other scatters at x =52 mm can also be detected.

Raw signal