# Shared Flashcard Set

## Details

Ultrasound Physics--Chapter 10
Axial and Lateral Resolution
9
Physics
Professional
02/08/2021

Term
 Define:         Resolution
Definition
 The ability to create accurate images.
Term
 Define:    Axial Resolution   Units?   Changed by sonographer?   Typical values?   Equation
Definition
 The ability to distinguish two structures that are close to each other front to back, parallel to, or along the beam's main axis.   mm, cm--all units of distance   No, a pulse is a pulse is a pulse   0.05 - 0.5 mm   LARRD resolution (mm) = SPL (mm)/2   remember SPL = λ x #cycles per pulse
Term
 What are some synonyms for axial resolution?
Definition
 LARRD resolution   Longitudinal   Axial   Range   Radial   Depth
Term
 What element in the transducer helps with axial resolution?
Definition
 The backing material is designed to dampen the pulse ring to shorten the pulse duration in order to achieve a better axial resolution.
Term
 What two factors help improve LARRD resolution?
Definition
 Less ringing, fewer cycles in pulse   Higher frequency sound, shorter wavelength   note: As frequency increases, the numerical value of the LARRD resolution decreases. This means that we have improved LARRD resolution and more accurate images with high frequency.
Term
 Define:         Lateral Resolution   Units?
Definition
 The ability to distinctly indentify two structures that are very close together when they are side by side or perpendicular to the sound beam's main axis.   mm, all units of length. A smaller number creates a more accurate image
Term
 What are some synonyms for lateral resolution?
Definition
 LATA resolution       Lateral   Angular   Transverse   Azimuthal
Term
 What determines lateral resolution?
Definition
 Lateral resolution is determined by the beam diameter; narrower beams have better resolution. Beam diameter varies with depth; lateral resolution changes with depth.
Term
 Define:         Focusing   What are the three methods of focusing?
Definition
 Focusing concentrates the sound energy into a narrower beam and thus improves lateral resolution.   external focusing (lens)   internal focusing (curved active element)   phased array focusing (electronic)
Supporting users have an ad free experience!