Diagnostic Ultrasound: Principles, Instruments, and Exercises |
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Page 220
... ( SPTA ) for continuous - wave exposures and for pulsed - mode exposures with pulses repeated at a frequency greater than 100 Hz . b Quarter - power ( -6dB ) beam width smaller than four wavelengths or 4 mm , whichever is less at the ...
... ( SPTA ) for continuous - wave exposures and for pulsed - mode exposures with pulses repeated at a frequency greater than 100 Hz . b Quarter - power ( -6dB ) beam width smaller than four wavelengths or 4 mm , whichever is less at the ...
Page 221
... SPTA as measured in a free field in water . Time is total time of exposure to ultrasound ( includes time between pulses in the case of pulsed ultrasound ) . = energy area ( J / cm2 ) ( Table C.4 , Appendix C ) This is the energy passed ...
... SPTA as measured in a free field in water . Time is total time of exposure to ultrasound ( includes time between pulses in the case of pulsed ultrasound ) . = energy area ( J / cm2 ) ( Table C.4 , Appendix C ) This is the energy passed ...
Page 222
... SPTA intensity is used , assuming that temporal average is relevant . Time is total time of exposure to ultrasound ( includes time between pulses in the case of pulsed ultrasound ) . the SPTA intensity ( see Section 2.4 ) of the pulsed ...
... SPTA intensity is used , assuming that temporal average is relevant . Time is total time of exposure to ultrasound ( includes time between pulses in the case of pulsed ultrasound ) . the SPTA intensity ( see Section 2.4 ) of the pulsed ...
Common terms and phrases
acoustic amplitude angle applied array Artifacts attenuation average axial resolution beam diameter boundary brightness called caused cent Chapter compensation continuous convert cycles decreases density depth determined diagnostic ultrasound direction display distance divided doppler shift duty factor dynamic echoes effect electric energy equal equation Example Exercises face Figure flow focusing frame gain given higher imaging impedance incidence increases intensity lateral resolution linear lines material maximum measure medium memory mode motion moving mW/cm² normal occurs operating path period perpendicular present produced propagation speed pulse duration pulse repetition frequency range ratio real-time receiver reflection reflection coefficient reflector refraction region represents scan scattering separation side soft tissue sound spatial pulse length Table tion transducer transmission True or false ultrasound ultrasound imaging ultrasound pulse units variable voltage wave wavelength zone