Instrumentation (SPI) Practice
Examination Newest 2025- 2026
Updated Practice Exam | 200 Actual
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1. Which parameter primarily controls the depth of penetration of the ultrasound
beam?
A. Frequency
B. Gain
C. Pulse repetition frequency
D. Dynamic range
✔ Answer: A. Frequency
Higher frequency waves have less penetration due to increased attenuation, while
lower frequencies penetrate deeper.
2. What is the primary purpose of acoustic coupling gel?
A. Reduce attenuation
B. Eliminate air between transducer and skin
C. Increase frequency
D. Enhance reflection
,✔ Answer: B. Eliminate air between transducer and skin
Gel removes air interfaces, which would otherwise reflect nearly all sound due to
impedance mismatch.
3. A sonographer increases overall gain. What is the expected effect?
A. Only near field brightness increases
B. Only far field brightness increases
C. All echoes are amplified equally
D. Resolution improves
✔ Answer: C. All echoes are amplified equally
Increasing overall gain amplifies returning echoes uniformly without affecting
resolution.
4. What is the unit of acoustic impedance?
A. Watts
B. Decibels
C. Rayls
D. Hertz
✔ Answer: C. Rayls
Acoustic impedance is measured in Rayls and determines reflection at tissue
boundaries.
5. Which imaging artifact results from sound traveling at different speeds in
tissue?
A. Reverberation
B. Refraction
C. Mirror image
D. Speed error
✔ Answer: D. Speed error
,Assuming a constant speed of sound (1540 m/s) leads to misplaced structures
when actual speeds differ.
6. What determines axial resolution?
A. Beam width
B. Pulse length
C. Frequency only
D. Frame rate
✔ Answer: B. Pulse length
Shorter spatial pulse length (SPL) improves axial resolution.
7. Which control adjusts amplification at specific depths?
A. Output power
B. TGC
C. PRF
D. Focus
✔ Answer: B. TGC
Time Gain Compensation (TGC) corrects for attenuation with depth.
8. What is the typical assumed speed of sound in soft tissue?
A. 1400 m/s
B. 1480 m/s
C. 1540 m/s
D. 1600 m/s
✔ Answer: C. 1540 m/s
Ultrasound systems assume a constant speed of sound of 1540 m/s in soft tissue.
9. Increasing frequency improves:
A. Penetration
, B. Axial resolution
C. Frame rate
D. Depth
✔ Answer: B. Axial resolution
Higher frequency reduces wavelength, improving axial resolution but reducing
penetration.
10. Which artifact appears as equally spaced echoes?
A. Shadowing
B. Enhancement
C. Reverberation
D. Refraction
✔ Answer: C. Reverberation
Repeated reflections create multiple equally spaced echoes known as
reverberation.
11. What is the main cause of acoustic shadowing?
A. Increased gain
B. Strong attenuation or reflection
C. Low impedance
D. High PRF
✔ Answer: B. Strong attenuation or reflection
Structures like bone cause attenuation, producing shadowing distal to them.
12. What does PRF stand for?
A. Pulse reflection frequency
B. Pulse repetition frequency
C. Phase return factor
D. Pulse range factor