Module 3 Physics Flashcards
What is the DR that the human eye can detect
typically less than 64 shades of grey
What parts of the beam does harmonics affect?
only the most intense part (middle)
What does harmonics allow you to do in regards to BW and frequency?
it allows you to transmit at a lower frequency and receive at a higher harmonic frequency
What creates the harmonic frequency?
Created in the body - not by the tx. Spectrum of harmonics is made by the tissue
How is a harmonic beam different than a regular sound beam?
It is much narrower (to increase lateral resolution) and intensity is weaker in the near field (to decrease reverb artifact)
What is reverb artifact
sound hits skin and bounces back to tx repeatedly until it is detected appearing farther on U/S than it is
Harmonic generation occurs where?
mostly farther into mid field
What types of resolution does harmonics improve?
lateral, elevational, contrast
What are the two types of harmonics?
Bandwidth filtering THI and pulse inversion THI
How does SC improve image quality?
reduces the noise (smoothing effect) - better contrast res
What artifact can SC lead to?
motion blur (it affects Fr and temporal res)which becomes worse when tissue or tx is moving
What creates a more triangular posterior shadow compared to the usual rectangle shadow?
Spatial compounding
XRES is a ___ processing only
post
What does RTAF do?
enahnces borders and specular regflectors, while also smoothing
What are the 2 phases of RTAF
- Analysis phase and 2. enhancement phase
