Lesson 8 (Part 2) Flashcards
What does delta z mean when it is equal to 0?
Total transmission
- no echoes
Echoes
The reflection and scattering of sound waves
What are 2 types of incidences?
- Perpendicular
2. Oblique
Perpendicular incidence
Denotes a direction of travel of the ultrasound wave perpendicular to the boundary between 2 medias
Does transmitted sound change direction?
No, it continues to the second medium
What does intensities depend on?
Incident intensity at the boundary and the impedance of the media on either side of the boundary
What happens to impedance if density and propagation speed increases?
It increases
What happens to the IRC if the difference of impedances increase?
It increases
What does transmission coefficient depend on?
The reflection coefficient
What happens to the ITC if the IRC increases?
It decreases
What happens when ultrasound encounters a boundary with perpendicular incidence?
The impedances of the tissue must be different to produce a reflection
What 2 things must be known in order to calculate the reflected intensity?
- 2 media impedances
2. Incident intensity
With perpendicular incidence, what does the reflected intensity depend on? (2)
- The impedance difference
2. The impedance sum
