RIU 320 Lecture Notes - Lecture 14: Fresnel Zone, Focus 3, Focal Length
3 Jan 2020
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Additional slides transducers level 2: objectives, axial resolution (calculate and know factors that affect it, frequency, q-value, damping, pulse duration (spl, lateral resolution (beam width"s influence, not constant throughout the image, beam width and properties. Large diameter (aperture) = deeper focus i. ii: high frequency = deeper focus, uniformity in near and far fields v. vi. vii. = spl/2: spatial pulse length is affected by . frequency, parameters affecting spl damping a, the matching layer enhances the transmission of energy into the patient and shortens the pulse duration. Reduction of pulse duration introduces additional frequency components into the transmitted pulse wave and increases. Focal depth for a non-focused transducer: determined by, transducer diameter and frequency of the ultrasound ii. 11. sound beam divergence ultrasound: determined by: transducer diameter and frequency of the b. Small pieces of pzt crystal will generate v-shaped waves called. A large, disc shaped element will create many individual wavelets, which interfere to create an hourglass-shaped beam.
