[Predavanja] Predavanje na K5

[Tina Ručigaj]

Spoštovani 

Spoštovani!

 

Vabimo vas na predavanje, ki ga organizira Odsek za elektronsko keramiko K-5, v torek, 13. septembra 2005 ob 14. uri.

 

Predaval bo

 

prof. dr. Marc Lethiecq

 

Ultrasound Group, François-Rabelais University; Tours, Francija

 

 

Naslov predavanja

 

Ultrasonic Transducers for High Resolution Imaging : from

Piezoelectric Structures to Medical Diagnostics

 

 

 

Predavanje bo v Kolarjevi predavalnici.

         

Vljudno vabljeni!

 

 

Povzetek predavanja:

 

The fields of medical diagnostics, namely for examination of skin, eye and blood vessels, of medical research on small animals, of cosmetics and also of non destructive testing of small parts all require very high resolution imaging techniques. Ultrasonic waves, at frequencies between 20 and 100 MHz, allow the observation of structures of several mm size with resolutions in the micrometers range. For this, specific systems including ultrasonic transducers, transmit/receive electronics and image processing and display need to be developed, since classical ultrasonic systems operate only in the 1-15 MHz range. The electroacoustic performance of transducers is one (if not the) key element of such systems. Parameters such as the centre frequency, the relative bandwidth and the loop sensitivity need to be optimised and adjusted for each application. They define both the axial resolution of the images produced and the depth of penetration, and also influence the contrast. To obtain high lateral resolution, the transducers must be focused, which implies either using a focusing lens or shaping the transducer surface.

 

The talk will describe current work on piezoelectric materials and structures, namely thick films, developed specifically for these applications. Material properties measured on different samples (including thin plates, thick films on several substrates, machined bulk ceramics) will be presented and compared. The design of transducers using those materials identified as potentially most efficient will be discussed, in particular through optimisation procedures. Transducer fabrication will be shortly described, and measured performance will be highlighted.

 

Images obtained using specifically designed systems will be shown for several of the application fields of high resolution ultrasonic imaging. Emerging fields such as high resolution 3D imaging, elasticity imaging and tissue analysis will be presented through results of current technological and clinical research projects.

 

 

 
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