Revised 8/2008
NOVA COLLEGE-WIDE COURSE CONTENT SUMMARY
DMS 208 - ULTRASOUND PHYSICS AND INSTRUMENTATION I (2 CR.)
Course Description
Discusses and solves mathematical problems associated with human tissue, basic instrumentation and
scanning technology. Lecture 2 hours per week.
General Course Purpose
The purpose of this course is to introduce students to the fundamental principles of acoustical physics.
Course Prerequisites/Co-requisites
The student must satisfactorily complete all previous sonography courses with a grade of "C" or better.
Course Objectives
At the completion of this course the student will be able to:
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Convert numbers from one unit to another in the metric system.
Describe characteristics of a sound wave.
Label waveform anatomy on diagrams of a continuous sound wave (CW) and pulsed sound wave
(PW).
Identify how the different types of wave interference are produced.
Compare and contrast continuous wave (CW) and pulsed wave (PW) characteristics (i.e. duty
factor).
Describe the relationship between speed of sound, frequency and wavelength.
Compare and contrast acoustic variables (density, pressure) and describe their effect on
propagation velocity.
Compare and contrast beam intensity, beam amplitude, beam power and beam area.
Compare the relative propagating velocities and acoustic impedances (Z values) for soft tissue,
bone, air, fat, etc.
Compare the relationship between the media properties (density, compressibility) and their effect
on sound propagation.
Discuss specular reflection with regard to reflected energy level, normal incidence, oblique
incidence.
Discuss scattering with regard to scattered energy level and frequency of the sound beam.
Identify structures within the body causing reflection and scattering.
Discuss the contributions of scattering and specular reflection to a diagnostic ultrasound image.
Identify the effect of acoustic impedance on the sound beam.
Apply Snell’s law to varying degrees of angle of incidence.
Diagram the angle of refraction in the presence of varying Z values and medium velocities.
List and describe the components of sound attenuation.
Discuss the relationship of attenuation to frequency, penetration, and attenuation coefficient.
Compare the relative values for attenuation in soft tissue, bone, air, and fat.
Compare and contrast conventional waves to harmonic waves in relationship to shape,
frequency, generation of beam, returning signal strength.
Identify clinical applications of harmonics and describe appropriate use.
Differentiate between contrast and tissue harmonics.
Describe the process of creating a piezoelectric crystal.
Differentiate between the characteristics of man-made and natural piezoelectric material.
List the functions of each component within a transducer.
Relate damping to axial resolution, transmitted frequency and the Q-factor.
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Explain the physical principles that support the use of a quarter wavelength thickness.
matching layers for transducers.
Describe the basic principles of pulsed ultrasound generation.
Describe the basis for transducer crystals/elements being one half wavelength in thickness and
the relationship to frequency and propagation velocity.
Compare the relationship of the transducer bandwidth (narrow versus broad) to pulse length,
resolution, and system sensitivity.
Compare the best characteristics of low versus high Q-factor transducers.
Identify techniques that will improve the overall sensitivity of an ultrasound machine.
Discuss the relationships of transducer frequency, transducer diameter, near field boundary,
angle of divergence, and wavelength.
Compare the transducer diameter to beam directionality and transducer diameter.
Compare the intensity variation and the beam diameter variation in the near and far fields.
Discuss the effect of transducer focusing on sound beam parameters.
Discuss the advantages and disadvantages of weak, medium, and strong focused transducers.
Identify techniques that improve axial and lateral resolution.
Describe how 1 ½ D arrays improve the image elevational resolution.
Describe the basic construction, operation and characteristics of mechanical contact, mechanical.
liquid-path, electronic sequential array, electronic phased array, and hybrid annular array
transducers.
Differentiate between internal and external focused transducers.
Compare the differences in steering and focusing between the array transducers.
Recognize steered, focused, or combined wave front.
Compare the transducer focusing and steering capabilities for mechanical and electric
transducers.
Identify the functions of the system controls and relate how each affects the image display.
Describe the main clinical applications and characteristics of each scanning mode.
Identify the axis for each scanning mode.
Apply the range equation to image production.
Describe the factors that affect frame rate.
Relate the minimal frames per second needed to achieve acceptable temporal resolution.
Describe physiologic and anatomic factors that influence blood flow.
Describe the effect of energy/pressure on viscosity, friction, and inertia of flow.
Correlate the relationship between the components of Poiseuille’s law.
Apply Poiseuille’s law to a change in vessel radius.
Major Topics to be Included
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Patient identification / documentation
Patient interaction
Verification of requested examination
Emergency situations
Universal precautions
Physics principles
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Properties of ultrasound waves
Interactions of sound with tissue
Power, intensity, and amplitude
Units of measurement
Ultrasound transducers
Transducer construction and characteristics
Transducer types (sector, linear, phased arrays, etc.)
Spatial resolution
Transducer selection
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