Diagnostic Imaging 4 – Ultrasound with
correct answers 100% 2026
What type of waves does ultrasound use? - Correct Answers High frequency sound waves
(2-18MHz)
List some characteristics of soundwaves? - Correct Answers -Need material to travel through
-Velocity depends on material (slowest to fastest = air>soft tissue>bone)
-Have properties of a wave (incl reflection, refraction, interference)
How is an ultrasound produced? - Correct Answers -Piezoelectric (crystal) effect (conversion of
electrical energy to kinetic energy which produces sound wave) to generate sound wave
-Electrical voltage applied to a disc (piezoelectric properties) within transducer
-Disc expands or contracts, due to electric voltage applied to it
-Movement proportional to voltage
-Movement gives rise to sound wave
How is the 'pulse' of a ultrasound produced? - Correct Answers -Transducer sends out 'pulse' of
sound
-Typically 3 wavelengths (1.5mm in length, lasts 1us)
-'Waits' for echoes to return from tissues
-Production of ultrasound 1% of the time
-Receiving ultrasound 99% of the time
How is signal received in ultrasounds? - Correct Answers -Sounds returns from tissues to
transducer
-Pressure of sound wave distorts disc
-Generates voltage proportional to pressure
, -Voltage 'processed' by machine & displayed
How does ultrasound travel within the patient? - Correct Answers -Ultrasound beam travels
through tissue
-Tissues vary in acoustic impedance
-When sound crosses a boundary between tissues of different acoustic impedance, some is
reflected back
-Proportion reflected depends on difference in acoustic impedance (little reflectance at soft
tissue boundaries, larger & reflected at soft tissue/bone interfaces)
What factors affect acoustic impedance? - Correct Answers Acoustic impedance = density of
tissue x speed of sound in tissue
(speed constant, so impedance predominantly affected by tissue density)
What is a specular reflection? - Correct Answers Reflection from a smooth surface
What is a non-specular reflection? - Correct Answers -Beam hits small structures (eg inside liver)
-Re-radiated in all directions (weak echoes)
-Gives 'texture' to organs
What are the 3 display modes of ultrasound? - Correct Answers A mode - amplitude
B mode - brightness
M mode - motion
How does B mode work? - Correct Answers -Images a slice through the patient
-Need to scan organs in >1 plane
-'Pencil' beam of ultrasound scans back & forth
correct answers 100% 2026
What type of waves does ultrasound use? - Correct Answers High frequency sound waves
(2-18MHz)
List some characteristics of soundwaves? - Correct Answers -Need material to travel through
-Velocity depends on material (slowest to fastest = air>soft tissue>bone)
-Have properties of a wave (incl reflection, refraction, interference)
How is an ultrasound produced? - Correct Answers -Piezoelectric (crystal) effect (conversion of
electrical energy to kinetic energy which produces sound wave) to generate sound wave
-Electrical voltage applied to a disc (piezoelectric properties) within transducer
-Disc expands or contracts, due to electric voltage applied to it
-Movement proportional to voltage
-Movement gives rise to sound wave
How is the 'pulse' of a ultrasound produced? - Correct Answers -Transducer sends out 'pulse' of
sound
-Typically 3 wavelengths (1.5mm in length, lasts 1us)
-'Waits' for echoes to return from tissues
-Production of ultrasound 1% of the time
-Receiving ultrasound 99% of the time
How is signal received in ultrasounds? - Correct Answers -Sounds returns from tissues to
transducer
-Pressure of sound wave distorts disc
-Generates voltage proportional to pressure
, -Voltage 'processed' by machine & displayed
How does ultrasound travel within the patient? - Correct Answers -Ultrasound beam travels
through tissue
-Tissues vary in acoustic impedance
-When sound crosses a boundary between tissues of different acoustic impedance, some is
reflected back
-Proportion reflected depends on difference in acoustic impedance (little reflectance at soft
tissue boundaries, larger & reflected at soft tissue/bone interfaces)
What factors affect acoustic impedance? - Correct Answers Acoustic impedance = density of
tissue x speed of sound in tissue
(speed constant, so impedance predominantly affected by tissue density)
What is a specular reflection? - Correct Answers Reflection from a smooth surface
What is a non-specular reflection? - Correct Answers -Beam hits small structures (eg inside liver)
-Re-radiated in all directions (weak echoes)
-Gives 'texture' to organs
What are the 3 display modes of ultrasound? - Correct Answers A mode - amplitude
B mode - brightness
M mode - motion
How does B mode work? - Correct Answers -Images a slice through the patient
-Need to scan organs in >1 plane
-'Pencil' beam of ultrasound scans back & forth
