Notes in 18 Ultrasound physics

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Status	Last Update	Fields
Published	05/01/2023	Imaging Physics: UltrasoundThe {{c1::decibel::unit}} is a measure of relative {{c2::intensity}} between two sounds
Published	05/01/2023	Imaging Physics: UltrasoundCalculate dB given the intensities of two soundsdB = {{c1::10 log(I/Iref)}}
Published	05/01/2023	Imaging Physics: Ultrasound{{c1::Thermal index (TI)}} {{c2::Maximum temperature rise}} in tissue caused by ultrasound energy absorption
Published	05/01/2023	Imaging Physics: UltrasoundIf the {{c2::thermal::mechanical/thermal}} index exceeds {{c1::1}}, risk benefit analysis should be performed
Published	05/01/2023	Imaging Physics: Ultrasound{{c1::Mechanical index (MI)}} Likelihood of {{c2::cavitation}} based on {{c3::peak rarefactional pressure}} and {{c3::frequ…
Published	05/01/2023	Imaging Physics: UltrasoundIf the {{c2::mechanical::mechanical/thermal}} index exceeds {{c1::0.5}}, risk benefit analysis should be performed
Published	05/01/2023	Imaging Physics: UltrasoundFrame rate {{c1::affects::affects/does not affect}} acoustic output indices
Published	05/01/2023	Imaging Physics: UltrasoundTransmit power {{c1::affects::affects/does not affect}} acoustic output indices
Published	05/01/2023	Imaging Physics: UltrasoundFrequency {{c1::affects::affects/does not affect}} acoustic output indices
Published	05/01/2023	Imaging Physics: UltrasoundTime-gain compensation {{c1::does not affect::affects/does not affect}} acoustic output indices
Published	05/01/2023	Imaging Physics: UltrasoundGrayscale mapping {{c1::does not affect::affects/does not affect}} acoustic output indices
Published	05/01/2023	Imaging Physics: Ultrasound {{c2::Cavitation}} is the formation of {{c1::bodies of gas and/or vapor}} by ultrasound energy
Published	05/01/2023	Imaging Physics: Ultrasound Cavitation is more likely to occur at {{c1::high}}{{c2::pressures::frequencies/pressures}}
Published	05/01/2023	Imaging Physics: Ultrasound Cavitation is more likely to occur at {{c1::low}} {{c2::frequencies::frequencies/pressures}}
Published	05/01/2023	Imaging Physics: Ultrasound {{c1::Stable}} cavitation Regular pulsation of persistent microbubbles
Published	05/01/2023	Imaging Physics: Ultrasound {{c1::Transient}} cavitation Large size changes in microbubbles before collapse
Published	05/01/2023	Imaging Physics: Ultrasound No biologic effects have been observed with spatial peak temporal average intensities below {{c1::1}} W/cm2
Published	05/01/2023	Imaging Physics: Ultrasound Tissue attenuation is approximately {{c1::0.5}} dB per cm per MHz
Published	05/01/2023	Imaging Physics: Ultrasound {{c1::Refraction}} is the  Apparent bending of the ultrasound wave due to different {{c2::velocities of sound}…
Published	05/01/2023	Imaging Physics: UltrasoundUltrasound wave refraction can be calculated using {{c1::Snell's}} law
Published	05/01/2023	Imaging Physics: UltrasoundCalculate the speed of a wave given frequency and wavelength Velocity = {{c1::frequency * wavelength}}
Published	05/01/2023	Imaging Physics: UltrasoundFor a given transducer vibrating at its natural frequency, the {{c2::wavelength}} of the soundwave produced is equal to {{c…
Published	05/01/2023	Imaging Physics: Ultrasound To {{c1::in}}crease {{c2::wavelength::frequency/wavelength}} of a sound wave, the transducer must be made {{c3::thicker::t…
Published	05/01/2023	Imaging Physics: Ultrasound To {{c1::de}}crease {{c2::frequency::frequency/wavelength}} of a sound wave, the transducer must be made {{c3::thicker::th…
Published	05/01/2023	Imaging Physics: Ultrasound The {{c1::near}} field determines the maximum {{c2::depth}} that can be imaged.
Published	05/01/2023	Imaging Physics: Ultrasound Calculate the near field given transducer radius and ultrasound wavelength Near field = {{c1::r2 / λ}}
Published	05/01/2023	Imaging Physics: Ultrasound The {{c1::near}} field is called the {{c2::Fresnel}} zone
Published	05/01/2023	Imaging Physics: Ultrasound The {{c1::far}} field is called the {{c2::Frauenhofer}} zone
Published	05/01/2023	Imaging Physics: Ultrasound {{c1::Axial}} resolution Ability to separate objects lying {{c2::in the direction of the beam::where}}
Published	05/01/2023	Imaging Physics: Ultrasound Axial resolution = {{c1::spatial pulse length / 2}}
Published	05/01/2023	Imaging Physics: Ultrasound Axial resolution {{c1::does not change::improves/worsens/does not change}} with depth
Published	05/01/2023	Imaging Physics: Ultrasound {{c1::Lateral}} resolution Ability to separate objects lying {{c2::adjacent to each other::where}}
Published	05/01/2023	Imaging Physics: Ultrasound Lateral resolution improves with {{c1::in}}creased beam {{c2::focusing}}
Published	05/01/2023	Imaging Physics: Ultrasound Lateral resolution improves with {{c1::in}}creased number of {{c2::scan lines}} per frame
Published	05/01/2023	Imaging Physics: Ultrasound {{c2::Lateral::Axial/lateral}} resolution is approximately {{c1::4}}x {{c1::worse::better/worse}} than {{c2::axial::axial…
Published	05/01/2023	Imaging Physics: Ultrasound Lateral resolution {{c1::worsens::improves/worsens/does not change}} with {{c2::in}}creasing depth
Published	05/01/2023	Imaging Physics: Ultrasound {{c1::Elevational}} resolution Ability to separate objects lying {{c2::in planes perpendicular to the plane of imaging::w…
Published	05/01/2023	Imaging Physics: Ultrasound {{c2::Elevational}} resolution is approximately equivalent to {{c1::lateral}} resolution
Published	05/01/2023	Imaging Physics: Ultrasound Elevational resolution {{c1::changes::changes/does not change}} with depth
Published	05/01/2023	Imaging Physics: Ultrasound Pulse repetition frequency Number of times the transducer outputs {{c1::a pulse of soundwaves}} per second
Published	05/01/2023	Imaging Physics: Ultrasound Increasing pulse repetition frequency (PRF) {{c2::de}}creases the maximum {{c1::depth}} of tissue that can be imaged
Published	05/01/2023	Imaging Physics: Ultrasound Calculate pulse repetition frequency (PRF) given frame rate and lines per framePRF = {{c1::frame rate x lines per frame…
Status	Last Update	Fields