Review Questions for Ultrasound

A Sonographer's Exam Guide

J.A. Miller

• Editore: Routledge
• Anno: 2018
• ISBN:
  9781351418607
• Edizione: 1
• Argomento: Medicina
• Categoria: Teoria, pratica e riferimenti medici

This is a comprehensive, large-format review text with complete answers for the American national examination of the Registry of Diagnostic Medical Sonographers (RDMS). It contains 600 questions divided evenly between sections on physics, the abdomen and small parts, and obstetrics and gynecology. The authors combine many years of experience teaching diagnostic ultrasound and provide illustrative scans and drawings for added comprehension.

SECTION 1: PHYSICS

Each section contains 200 questions in true/false and multiple-choice formats.

Elementary principles

Use the above diagram to answer question 1.001.

1.001 The oscillation of particles occurs in a transverse direction relative to the beam width. true false

A is correct. Ultrasound waves are considered longitudinal waves. This means that the oscillation of particles is in the direction of the propagation of the ultrasound energy. Therefore, both the direction of ultrasound energy propagation and the oscillation of the particles are perpendicular to the crystal face.

1.002 The effect of ultrasound on the medium results in particle motion which produces electrical, rather than mechanical, energy. true false

B is correct. The piezoelectric principle describes the conversion of energy in the crystal from electric to mechanical (movement) energy. This mechanical energy is now transferred into the body.

1.003 With the velocity being constant, if frequency is doubled, wavelength is_______. increased by a factor of 2 decreased by a factor of 2 doubled none of above

A is correct. The velocity of sound in soft tissue is 1.54 mm/μs. In ultrasound physics, it is considered a constant since wavelength × frequency = velocity. Thus, if one is increased, the other is decreased by the same magnitude; for example, if frequency is halved, then the wavelength is doubled.

1.004 If power (or gain), expressed as 40 dB, is reduced by 50%, the new gain is: 20 dB 60 dB 37 dB 80 dB

C is correct. The decibel system was developed to allow comparison of two quantities. However, the difference between some quantities is so vast that a different scale has to be used. This scale is called the logarithmic scale. In decibel notation, the change in power by 50% is a 3-dB change; thus, the correct answer is 37.

1.005 With a 2-MHz transducer, in soft tissue, the wavelength is approximately: 0.5 mm 0.5 cm 0.77 mm 2.0 mm

C is correct. The propagation speed is equal to the wavelength × frequency; thus, 1.54 mm/μs + 2,000,000 cycles/s = 0.77 mm.

1.006 The energy per unit area of a sound beam is called: power amplitude intensity sensitivity

C is correct. Power is the energy of the ultrasound beam and intensity is power divided by an area.

1.007 The peak pressure or height of a wave is known as: A-mode temporal average intensity amplitude frequency

C is correct. Ultrasound has wave properties that are often displayed by a wave schematic. The wave schematic is also a scale that can demonstrate the change in acoustic variables. These changes in variable magnitude are also called changes in amplitude.

1.008 If density is increased, with everything else remaining the same, propagation velocity will: increase remain the same decrease none of the above

C is correct. The propagation velocity is dependent upon medium density and elasticity. The more elastic the medium, the higher the propagation speed. Also, the greater the medium density, the lower the propagation speed.

1.009 If elasticity is increased, propagation velocity will: increase remain the same decrease none of the above

A is correct. The propagation velocity is dependent upon medium density and elasticity. The more elastic the medium, the higher the propagation speed. Also, the greater the medium dens...