Medical Lesson 2
OUTCOME
By the end of the lesson you will be able to define acoustic impedance and calculate intensity reflection coefficient
Ultrasound is a particular frequency of sound. How the ultrasound travels through tissue is important to produce a scan of the body
LEARNING TASKS
Explain
1. At what frequency is ultrasound?
2. Define acoustic impedance
3. Define attenuation
4. What is meant by resolution in this context?
5. What is the trade off between higher and lower frequency ultrasound?
Explore
Use the wave equation to determine the wavelengths used in ultrasound. How does this compare to the wavelength of audible sound in air?
Why would sound travel faster through bone than muscle?
Why is acoustic impedance important in ultrasound?
Practice calculating acoustic impedance using the example on page 399 and then trying the sample problems
Why is reflection so important for ultrasound?
Practise calculating intensity reflection coefficient using the example of page 400.
Evaluate
Attempt the questions 3 - 9
Do the reading and summary for the next class