Wednesday, 6 September 2017

ULTRASOUND TRANSDUCER CHARACTERISTICS FOR IMAGING


1. ACOUSTIC WINDOW
  •  Standard acoustic window provides an unobstructed view of organ or region.
  • Typical windows are located in or on the head, chest, abdomen, pelvis, vessels and various orifices of the body.
  • Transducer can associated with certain regions through latin prefixes like:

Trans :- through or across  
Intra : - Into or inside
Endo :- within. 
  • For example Transthoracic means Image through chest.
  • For each type of acoustic window; a particular type transducer is used to get the required sonographic data.
  • Eg:- phased arrays are used for transthoracic window and convex arrays are used for abdominal window.
An acoustic window showing artery and vain


2. PENETRATION 
  • Penetration is the minimum scan depth at which electronic noise is visible; despite optimization of available control.
  • It can be primarily determined by the center of the frequency of the transducer.
  • That is the transducer having high frequency will have low penetration.
Relationship between frequency and penetration

3. SPACIAL RESOLUTION
  • It is the ability to discern the smallest possible dimension in both axial and lateral directions.
  • Axial resolution refers to the ability to distinguish two structures that lie along the axis (i.e. parallel) of the ultrasound beam as separate and distinct.
  • Axial resolution is determined by the pulse length.
  • Lateral resolution refers to resolution of objects lying side by side (i.e., perpendicular to the beam axis).
  • Lateral resolution is directly related to the transducer beam width, which in turn is inversely related to the ultrasound frequency.


4. TRANSDUCER PARAMETERS
  • It includes:
  1. Efficiency
  2. Signal to Noise Ratio,
  3. Absorbtion of the tissues
  4. Band width 
  5. Number of elements in transducer etc. 

No comments:

Post a comment

WHEN WE NEED TO REPAIR THE PROBE ???? Many of the probe damages are repairable at initial state. But in many cases the Practitio...