MEDBIO 4475/BIOPHYSICS 9515/BIOMED 9513 Ultrasound Homework
Assigned September 14, 2018
Due September 24, 2018, 3:30 pm
You image the phantom (test object) diagrammed (not to scale) below using a linear-array
ultrasound system with an aperture length of 20 mm, a transmitted pulse duration of
3.0 cycles, and two transmit foci at depths of 25 and 55 mm. Assume both materials are
homogeneous (i.e., there is no scattering from the interior of either material) and assume
a perfectly matched interface between the transducer and Material 1 (i.e., R = 0 and T = 1
at this interface).
probe
c r a
20 mm [m/s]
Medium [kg m3] (dB cm1 MHz 1)
40 mm Material 1 1480 905 0.50
(white)
40 mm Material 2 1600 1030 0.75
(gray)
1.5 mm 0.5 mm 1.5 mm
1.5 mm 1.5 mm
1. Choose the frequency that will provide the finest possible spatial resolution while still
maintaining the echo intensity received from the bottom of Material 2 at –50 dB with
respect to the initial intensity of the transmitted pulse. [10 marks]
2. Compute the actual worst-case axial and lateral resolution at each focus position.
[10 marks]
3. Set the axial dimension of the field of view equal to 80 mm. What is the largest lateral
field of view that can be used while still maintaining a real-time (i.e., 30 Hz) frame
rate? (Note that the size of the phantom does not constrain the field of view and the
system designer would not know the exact acoustic properties of the phantom.)
[15 marks]
4. Sketch the B-mode image displayed by the system and briefly (e.g., in 2-3 sentences)
explain the appearance of the image. (Hint: For simplicity, assume the worst-case
axial and lateral resolution apply throughout the field of view.) [10 marks]
5. Compute the displayed depths of the top and bottom surfaces of Material 2 in the
B-mode image. [10 marks]
This study source was downloaded by 100000899606396 from CourseHero.com on 07-08-2025 22:54:02 GMT -05:00
https://www.coursehero.com/file/139255663/1-Ultrasound-Homework-2018pdf/
Assigned September 14, 2018
Due September 24, 2018, 3:30 pm
You image the phantom (test object) diagrammed (not to scale) below using a linear-array
ultrasound system with an aperture length of 20 mm, a transmitted pulse duration of
3.0 cycles, and two transmit foci at depths of 25 and 55 mm. Assume both materials are
homogeneous (i.e., there is no scattering from the interior of either material) and assume
a perfectly matched interface between the transducer and Material 1 (i.e., R = 0 and T = 1
at this interface).
probe
c r a
20 mm [m/s]
Medium [kg m3] (dB cm1 MHz 1)
40 mm Material 1 1480 905 0.50
(white)
40 mm Material 2 1600 1030 0.75
(gray)
1.5 mm 0.5 mm 1.5 mm
1.5 mm 1.5 mm
1. Choose the frequency that will provide the finest possible spatial resolution while still
maintaining the echo intensity received from the bottom of Material 2 at –50 dB with
respect to the initial intensity of the transmitted pulse. [10 marks]
2. Compute the actual worst-case axial and lateral resolution at each focus position.
[10 marks]
3. Set the axial dimension of the field of view equal to 80 mm. What is the largest lateral
field of view that can be used while still maintaining a real-time (i.e., 30 Hz) frame
rate? (Note that the size of the phantom does not constrain the field of view and the
system designer would not know the exact acoustic properties of the phantom.)
[15 marks]
4. Sketch the B-mode image displayed by the system and briefly (e.g., in 2-3 sentences)
explain the appearance of the image. (Hint: For simplicity, assume the worst-case
axial and lateral resolution apply throughout the field of view.) [10 marks]
5. Compute the displayed depths of the top and bottom surfaces of Material 2 in the
B-mode image. [10 marks]
This study source was downloaded by 100000899606396 from CourseHero.com on 07-08-2025 22:54:02 GMT -05:00
https://www.coursehero.com/file/139255663/1-Ultrasound-Homework-2018pdf/
