UTC Ultrasound Technologist Equipment Operation 2 — Questions and Answers
Question 1: Which transducer type is best suited for imaging superficial structures such as the thyroid gland?
- Phased array transducer
- Linear array transducer (Correct answer)
- Curved array transducer
- Mechanical sector transducer
Correct answer: Linear array transducer
Linear array transducers operate at higher frequencies and provide excellent near-field resolution, making them ideal for superficial structures like the thyroid.
Question 2: What does the term 'acoustic impedance mismatch' primarily determine in diagnostic ultrasound?
- The depth of penetration of the ultrasound beam
- The amount of sound reflected at tissue interfaces (Correct answer)
- The frequency of the transducer crystal
- The gain settings required for imaging
Correct answer: The amount of sound reflected at tissue interfaces
Acoustic impedance mismatch between two tissues determines the proportion of sound energy that is reflected versus transmitted at their interface.
Question 3: During a real-time ultrasound exam, 'frame rate' refers to:
- The number of pulses emitted per second
- The number of complete images displayed per second (Correct answer)
- The pulse repetition frequency of the transducer
- The number of scan lines per image
Correct answer: The number of complete images displayed per second
Frame rate is the number of complete B-mode images refreshed per second, and it is inversely related to depth and the number of focal zones.
Question 4: A sonographer increases the number of focal zones from 1 to 4. What is the most likely trade-off?
- Improved penetration depth
- Decreased frame rate (Correct answer)
- Increased acoustic output
- Wider field of view
Correct answer: Decreased frame rate
Adding focal zones improves lateral resolution at multiple depths but requires more time per frame, reducing frame rate.
Question 5: Which artifact appears as a bright echogenic line with posterior reverberation echoes equally spaced behind a reflective surface?
- Shadowing artifact
- Ring-down artifact
- Comet-tail artifact
- Reverberation (A-line) artifact (Correct answer)
Correct answer: Reverberation (A-line) artifact
Reverberation artifacts occur when sound bounces repeatedly between two highly reflective surfaces, producing equally spaced lines behind the interface.
Question 6: What is the primary purpose of applying acoustic coupling gel during an ultrasound examination?
- To sterilize the transducer surface
- To eliminate air between the transducer and skin (Correct answer)
- To increase transducer frequency
- To reduce patient discomfort
Correct answer: To eliminate air between the transducer and skin
Coupling gel eliminates the air gap between the transducer and skin because air causes near-total reflection of the ultrasound beam.
Question 7: In pulsed-wave Doppler, aliasing occurs when the sampled Doppler frequency exceeds:
- The Nyquist limit (one-half the PRF) (Correct answer)
- The transducer center frequency
- The pulse repetition period
- The maximum depth setting
Correct answer: The Nyquist limit (one-half the PRF)
Aliasing occurs when the Doppler shift frequency exceeds the Nyquist limit, which is half the pulse repetition frequency (PRF).
UTC Ultrasound Technologist Equipment Operation 2
Which transducer type is best suited for imaging superficial structures such as the thyroid gland?