The principle of ultrasound: Difference between revisions

In clinical imaging, the ultrasound beam is electronically focused as well as it is steered.  This became possible after phased array technology was invented.  By applying electrical current in a differential manner and adjusting the timing of individual PZT excitation, the beam can travel in an arch producing a two-dimensional image.  If one applies electricity in a differential manner from outside inward to the center of the transducer, differential focusing can be produced resulting in a dynamic transmit focusing process.   

Briefly, I would like to touch upon '''real time 3D imaging'''.  In order to accomplish this, the PZT elements need to be arranged in a 2D matrix.  Each PZT element represents a scan line, by combining all the data, a 3D set is reconstructed.  For example, if we have a matrix of 128 by 128 PZT elements, one can generate over 16 thousand scan lines.  With careful timing for individual excitation, a pyramidal volumetric data set is created.  When imaged several times per minute (>20), a real time image is achieved.