# Ultrasound Physics and Instrumentation I

DMS 105W## Course Description

Prerequisite: Must be accepted into the DMS program or have consent of instructor. Concurrent enrollment in DMS 100, DMS 107, DMS 107L, DMS 108W. Introduces the basic acoustic physics including a history of instrumentation, ultrasonic propagation principles, transducer parameters, and basic equipment types. (30-0)

## Outcomes and Objectives

### Understand ultrasonic propagation and how they relate to ultrasonic imaging.

#### Objectives:

- Know the definition of sound and understand the relation of sound waves to ultrasound imaging.
- Know the definition and units of a period along with the typical values of ultrasound period in clinical diagnostic imaging.
- Know the definitions, units, and formula for frequency and the typical value of ultrasound frequency in clinical imaging.
- Identify the three parameters that relate to the size of a sound wave.
- Know the definition and units of amplitude.
- Describe how power relates to the strength of the sound wave and know the units for power.
- Differentiate how power is related to amplitude.
- Know the definition and units of intensity and the typical values of ultrasound intensity in clinical imaging.
- Identify the formula and units for wavelength.
- Differentiate how propagation speed relates to the medium through which sound travels.
- State the average speed of sound in biologic "soft tissue".
- Define a pulse of ultrasound and the 5 descriptors of pulsed ultrasound.
- Know the definition and units of pulse duration along with typical ranges in clinical imaging.
- Describe pulse repetition period and how it relates to imaging depth.
- Know the definition and units of pulse repetition frequency and the range in clinical imaging.
- Identify the formula for Duty factor and the range for clinical imaging.
- Correlate spatial pulse length to wavelength, frequency, cycles, and pulse.

### Demonstrate an understanding of ultrasound intensities and how they relate to attenuation of traveling sound.

#### Objectives:

- Understand the definition of intensity and know the units it is expressed in.
- Describe the four ways to measure intensity.
- Identify the formula for Beam Uniformity Coefficient and how it relates to intensity.
- Demonstrate how to convert from one intensity to another.
- Explain what the unit Decibel is used to describe and know the difference between negative and positive decibels.
- Know the definition of attenuation and how it relates to the sound wave.
- In the clinical setting, determine what frequency transducer to use in relation to the amount of attenuation.
- Identify the three processes that attenuation results from.
- Explain Rayleigh scattering.
- Calculate the Attenuation Coefficient for a given set of parameters.
- State the formula for Half-value Layer thickness.
- Know the definition and units of impedance.

### Demonstrate an understanding of ultrasonic beam transmission.

#### Objectives:

- Know the relationship between intensity and transmission in clinical imaging.
- State the definition of Intensity Reflection Coefficient and Intensity Transmission Coefficient.
- Explain normal incidence and its relation to reflection and transmission.
- Determine how refraction is associated with transmission.
- Define Snell's law.
- Discuss the Range equation and how an ultrasound imaging system determines the depth of a reflecting surface.
- Understand what a transducer is, and what a transducer does in the process of clinical imaging.
- Name the components of a transducer.
- Identify the formula for the operating frequency of a transducer.
- Explain how bandwidth related to the frequency of a transducer.

### Demonstrate an understanding of sound beams and their effect on resolution.

#### Objectives:

- Diagram the anatomy of a sound beam.
- Understand Huygen's principle.
- Explain beam characteristics in relation to crystal attributes.
- Describe the four methods of focusing.
- List factors that affect resolution.
- Compare longitudinal and lateral resolution.